Glass-coated product

Abstract

Provided is a glass-coated product having excellent corrosion resistance while being easy to manufacture.　The glass-coated product that is provided comprises a metal product and a glass layer (GL) bonded to a surface of the metal product with the glass layer being baked onto the metal product. The metal product is provided with a base part (BP) formed from an iron-based metal and a highly corrosion-resistant part (HP) formed from a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal. The surface of the metal product is provided with a base surface (SB) which is a surface of the base part (BP) and a highly corrosion-resistant surface (SH) which is a surface of the highly corrosion-resistant part (HP). When an end edge part of the glass layer (GL) is viewed from the thickness direction of the glass layer (GL), the highly corrosion-resistant surface (SH) is provided so as to extend from an end edge of the metal product, and an end edge (GLe) of the glass layer is positioned on the highly corrosion-resistant surface (SH).

Description

Glass-coated products CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application Nos. 2023-140550 and 2023-140552, the disclosures of which are incorporated herein by reference.

[0002] The present invention relates to a glass-coated product comprising a metal product and a glass layer bonded to a surface of the metal product.

[0003] Glass-coated products, such as enamel products, in which a glass layer is bonded to the surface of a metal product, have been widely used. Among these enamel products, glass-lined products are widely used as components of chemical process equipment. Glass-lined products are required to have excellent corrosion resistance due to their intended use. General-purpose enamel products used in building materials such as bathtubs and wall panels, and cooking utensils such as pots and kettles, are also required to have the same excellent corrosion resistance as glass-lined products, because corrosion of the underlying metal product can cause the glass layer to peel off or rust, resulting in a loss of aesthetic appeal.

[0004] The surface of a metal product in a glass-coated product usually has an exposed surface that is not covered with a glass layer and is exposed to the surface of the glass-coated product, and a glass-coated surface that is covered with a glass layer. That is, in a glass-coated product, the edge of the glass layer defines the boundary between the exposed surface of the metal product and the glass-coated surface.

[0005] In this type of glass-coated product, if the metal product is made of a metal with excellent corrosion resistance, the glass-coated product will likely exhibit excellent corrosion resistance. In this regard, for example, it is known that the corrosion resistance of iron-based metals can be improved by adding a large amount of chromium. Nickel-based alloys and other materials are also known to have superior corrosion resistance compared to general iron-based metals. However, these highly corrosion-resistant metals may be more expensive or less workable than general iron-based metals. Furthermore, in conventional glass-coated products, the edge of the glass layer is usually the most likely site of peeling. Therefore, as shown in Patent Document 1 below, in conventional glass-coated products, only the portion of the metal product where the edge of the glass layer is located is made of a highly corrosion-resistant metal.

[0006] Japanese Patent Application Publication No. 2-125729

[0007] The manufacture of glass-coated products involves a glazing process, in which an unfired product is produced by laminating an unfired glass layer on the surface of a metal product, and a firing process, in which the unfired product is fired in a furnace. The glazing process is carried out by pouring or spraying a slurry containing glass powder onto the metal product. This method of glazing makes it difficult to precisely control the area to which the glass powder is applied. When a metal product is partially constructed of a highly corrosion-resistant metal, making a portion of the surface of the metal product highly corrosion-resistant, it becomes difficult to distinguish between the highly corrosion-resistant and non-corrosion-resistant surfaces, making it difficult to determine the area to which the glass powder is applied during the glazing process. Therefore, conventional glass-coated products have difficulty achieving both excellent corrosion resistance and ease of manufacture. The present invention aims to solve this problem by providing a glass-coated product that is easy to manufacture and has excellent corrosion resistance.

[0008] In order to solve the above problems, the present invention provides a glass-coated product comprising a metal product and a glass layer bonded to the surface of the metal product, wherein the metal product comprises a base portion made of an iron-based metal and a highly corrosion-resistant portion made of a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal, and the surface of the metal product is provided with a base surface which is the surface of the base portion and a highly corrosion-resistant surface which is the surface of the highly corrosion-resistant portion, and when the edge portion of the glass layer is viewed from the thickness direction of the glass layer, the highly corrosion-resistant surface is provided so as to extend from the edge of the metal product, and the edge of the glass layer is located on the highly corrosion-resistant surface.

[0009] FIG. 1 is a schematic diagram showing an example of a reaction vessel made of a glass-lined product. FIG. 2 is a schematic diagram showing a lid body which is a glass-lined product. FIG. 3a is a schematic perspective view showing a metal ring which serves as the base of a protection ring of a first example. FIG. 3b is a schematic diagram showing a manufacturing method of the metal ring which serves as the base of a protection ring of a first example. FIG. 3c is a schematic diagram showing a manufacturing method of the metal ring which serves as the base of a protection ring of a first example. FIG. 3d is a schematic diagram showing a manufacturing method of the metal ring which serves as the base of a protection ring of a first example. FIG. 3e is a schematic diagram showing a manufacturing method of the metal ring which serves as the base of a protection ring of a first example. FIG. 3f is a schematic diagram showing a manufacturing method of the metal ring which serves as the base of a protection ring of a first example. FIG. 4a is a schematic plan view showing the metal ring which serves as the base of a protection ring of a first example. FIG. 4b is a schematic plan view showing the protection ring of a first example. FIG. 5 is a schematic cross-sectional view showing the cross-section of the protection ring of a first example. FIG. 6 is a schematic cross-sectional view showing the cross-section of a protection ring of a second example. FIG. 7 is a schematic cross-sectional view showing the cross-section of a protection ring of a third example. FIG. 8 is a schematic cross-sectional view showing the cross-section of a protection ring of a fourth example. FIG. 9 is a schematic cross-sectional view showing the cross-section of a container nozzle of a first example. FIG. 10 is a schematic cross-sectional view showing the cross-section of a container nozzle of a second example. FIG. 11 is a schematic cross-sectional view showing the cross-section of a container nozzle of a third example. FIG. 12a is a schematic perspective view showing a metal ring that serves as the base of a protection ring of a fifth example. FIG. 12b is a schematic diagram showing a primary member used in manufacturing the metal ring that serves as the base of a protection ring of a fifth example. FIG. 13a is a schematic diagram showing a method for manufacturing the metal ring that serves as the base of a protection ring of a fifth example. FIG. 13b is a schematic diagram showing a method for manufacturing the metal ring that serves as the base of a protection ring of a fifth example. FIG. 13c is a schematic diagram showing a method for manufacturing the metal ring that serves as the base of a protection ring of a fifth example. FIG. 14 is a schematic perspective view showing a metal ring that serves as the base of a protection ring according to a fifth example.FIG. 15a is a schematic plan view showing a metal ring that serves as the base of a protection ring of a fifth example. FIG. 15b is a schematic plan view showing a protection ring of a fifth example. FIG. 16a is a schematic cross-sectional view showing the cross-sectional appearance of the protection ring of the fifth example. FIG. 16b is a schematic cross-sectional view showing a modified example in which the arrangement of the glass layer is changed in the protection ring of the fifth example. FIG. 16c is a schematic cross-sectional view showing a modified example in which the arrangement of the glass layer is changed in the protection ring of the fifth example. FIG. 16d is a schematic view showing a method for determining the flatness of a plate-like region. FIG. 16e is a schematic view showing a method for determining the flatness of a plate-like region having a different cross-sectional shape. FIG. 17a is a schematic cross-sectional view showing the cross-sectional appearance of a protection ring of a sixth example. FIG. 17b is a schematic view showing a method for determining the flatness of a plate-like region in the protection ring of the sixth example shown in FIG. 17a. FIG. 18 is a schematic cross-sectional view showing the cross-sectional appearance of a protection ring of a seventh example. Figure 19 is a schematic cross-sectional view showing the cross-sectional appearance of a container nozzle of a fourth example. Figure 20a is a schematic cross-sectional view showing the cross-sectional appearance of a container nozzle of a fifth example. Figure 20b is a schematic diagram showing a method for determining the flatness of the plate-like region in the container nozzle of the fifth example shown in Figure 20a.

[0010] An embodiment of a glass-coated product of the present invention will be described below. The glass-coated product in this embodiment comprises a metal product and a glass layer bonded to the surface of the metal product. The glass-coated product in this embodiment is produced by layering glass powder on the surface of the metal product and firing the resulting product. In this glass-coated product, the glass layer is baked onto the metal product, and the metal product and the glass layer are directly bonded together without the use of an adhesive or the like. Furthermore, in this glass-coated product, the surface layer of the metal product is melted into the glass during firing, and some of the constituent materials of the metal product are diffused into the glass layer. That is, the glass layer has a diffusion region where the metal diffuses at the interface with the metal product.

[0011] The following describes in more detail the embodiments of the present invention, taking specific glass-lined products as examples, but the glass-coated products of the present invention may be glass-lined products other than those exemplified below, or may be general-purpose enamel products other than glass-lined products. Note that, hereinafter, the term "enamel product" will be used to mean general-purpose enamel products, and will be distinguished from glass-lined products.

[0012] The following describes one embodiment of the present invention, taking a reaction tank as an example. The reaction tank 1 illustrated in the figure is a vertical tank. The reaction tank 1 has a tank body 10 with a storage space 10c for storing a reactant. The tank body 10 has an opening at the top for connecting the storage space 10c with the space outside the tank. The reaction tank 1 of this embodiment further includes a lid 20 that closes the opening of the tank body 10. The tank body 10 and the lid 20 are each glass-lined products. That is, the reaction tank 1 illustrated in FIG. 1 is composed of multiple glass-lined products.

[0013] In this embodiment, as shown in Figures 1 and 2, a metal product (metal tank 100) manufactured into a shape corresponding to the tank 10 serves as the base of the tank 10. The tank 10 is composed of the metal tank 100 and a glass layer GL bonded to the metal tank 100. The lid 20 also has a metal product (metal lid material 200) as the base, and includes the metal lid material 200 and a glass layer GL bonded to the metal lid material 200. The glass layer GL is baked onto the surfaces of the metal tank 100 and the metal lid material 200.

[0014] The metal tank 100 includes a metal tank body 1100 that serves as the base of the main body 110 of the tank body 10 , and a metal nozzle 1200 that forms the base of the container nozzle 120 of the tank body 10 .

[0015] The metal tank body 1100 has a barrel portion 1110 that extends cylindrically in the vertical direction. In this embodiment, the barrel portion 1110 is cylindrical. The metal tank body 1100 is arranged so that the central axis 1110c of the cylindrical barrel portion 1110 extends in the vertical direction. The metal tank body 1100 is arranged so that the central axis 1110c extends in the vertical direction. The metal tank body 1100 includes a bottom portion 1120 that closes the cylindrical barrel portion 1110 from the lower end side, and a ceiling portion 1130 that closes the barrel portion 1110 from the upper end side. In this embodiment, the bottom portion 1120 is disc-shaped with a portion near the central axis 1110c bulging downward, and the ceiling portion 1130 is disc-shaped with a portion near the central axis 1110c bulging upward.

[0016] In the tank body 10, the inner surface of the body 1110, the upper surface of the bottom 1120, and the lower surface of the ceiling 1130 are covered with a glass layer GL so that metal products are not exposed to the storage space 10c.

[0017] The ceiling portion 1130 has one or more openings extending vertically. The metal nozzle 1200 is narrower than the body portion 1110 and includes a cylindrical portion 1210 extending upward from the opening in the ceiling portion 1130 as shown in FIG. 2 , and a flange portion 1220 extending radially outward from the upper end of the cylindrical portion 1210. In this embodiment, the cylindrical portion 1210 is cylindrical, and the flange portion 1220 is annular. In the main body 110 of the tank body 10, the inner circumferential surface of the cylindrical portion 1210 and the upper surface of the flange portion 1220 are covered with a glass layer GL. The glass layer GL in these portions is continuous with the glass layer GL in the ceiling portion 1130.

[0018] In this embodiment, the lower surface of the flange portion 1220 is not covered with the glass layer GL. That is, the metal tank 100 of this embodiment has a plate-like portion having an annular shape, the plate-like portion having a first surface 1220a, a second surface 1220b opposite the first surface 1220a, and a side surface 1220c connecting the edges of the second surface 1220b and the first surface 1220a, and only the first surface 1220a of the plate-like portion is covered with the glass layer GL.

[0019] In this embodiment, the annular plate-shaped plate portion (flange portion 1220) has an axial direction along its central axis, a circumferential direction around the central axis, and a radial direction passing through the central axis and perpendicular to the central axis. The first surface 1220a, which is a surface of the plate portion (flange portion 1220) perpendicular to the axial direction, is a glass-coated surface partially or entirely covered with a glass layer GL. Specifically, the radially outer edge of the first surface 1220a is an exposed surface. The exposed surface of the first surface 1220a is provided in a circular shape along the outer periphery of the first surface 1220a. The glass-coated surface of the first surface 1220a is a portion radially inward of the exposed surface. The side surface 1220c extending from the radially outer edge of the first surface 1220a of the plate portion in a direction intersecting the first surface 1220a (axial direction) is an exposed surface that is not covered with the glass layer GL. The second surface 1220b, which is the surface opposite to the first surface 1220a, is also an exposed surface, similar to the side surface 1220c.

[0020] As described above, the tank body 10, which is a glass-lined product, has a main body portion 110 having a shape corresponding to the metal tank body 1100, and the main body portion 110 has a barrel portion 111 that extends cylindrically in the vertical direction.

[0021] The central axis of the main body 110 coincides with the central axis 1110c of the barrel 1110 of the metal tank 100. That is, the main body 110 is arranged so that its central axis extends vertically. The main body 110 includes a bottom 112 that closes the cylindrical barrel 111 from the lower end, and a ceiling 113 that closes the barrel 111 from the upper end. In this embodiment, the bottom 112 also has a disk shape that bulges downward, and the ceiling 113 also has a disk shape that bulges upward, similar to the ceiling 1130 of the metal tank main body 1100.

[0022] The tank body 10 is equipped with a container nozzle 120 having a shape corresponding to the metal nozzle 1200. The tank body 10 is equipped with an opening that penetrates the ceiling portion 113 in the vertical direction, and the container nozzle 120 extends cylindrically from the opening. The container nozzle 120 is thinner than the body portion 111 and includes a cylindrical portion 121 that extends cylindrically upward from the opening in the ceiling portion 113, and an annular plate-shaped flange portion 122 that extends radially outward from the upper end of the cylindrical portion 121, with the inside of the flange portion 122 forming an upper end opening.

[0023] The lid 20, which constitutes the reaction vessel 1 together with the vessel body 10, is also a glass-lined product as described above. As shown in Figure 2, the lid 20 includes a circular protection ring 210 that overlaps the flange 122 of the vessel nozzle 120, and a lid body 220 that overlaps the protection ring 210 with its periphery aligned.

[0024] The metal lid material 200, which is a metal product constituting the lid body 20, includes a metal ring 2100 having a shape corresponding to the protection ring 210, and a metal lid 2200 having a shape corresponding to the lid body 220. In this embodiment, the metal lid 2200 and the metal ring 2100 are joined at one location on the outer periphery by a hinge.

[0025] The annular plate-shaped metal ring 2100 constituting the protection ring 210 has a plate-shaped portion similar to the flange portion 1220, and is substantially composed of only a plate-shaped portion. The annular plate-shaped metal ring 2100 constituting the protection ring 210 has an upper surface (first surface 2100a) facing the metal cover 2200, and a lower surface (second surface 2100b) opposite the upper surface and facing the flange portion 122 of the tank body 10. The metal ring 2100 has side surfaces (2100c1, 2100c2) connecting the edge of the first surface 2100a to the edge of the second surface 2100b. The metal ring 2100 has an outer peripheral side surface 2100c2 that connects the radially outer edge of the first surface 2100a and the radially outer edge of the second surface 2100b, and an inner peripheral side surface 2100c1 that connects the radially inner edge of the first surface 2100a and the radially inner edge of the second surface 2100b.

[0026] The metal cover 2200 has a dome-shaped base portion 2210 that bulges upward from the outer periphery toward the center. The base portion 2210 is annular with an opening in the center that serves as an observation port. The metal cover 2200 includes a metal cover tubular portion 2220 that extends cylindrically from the opening of the base portion 2210, and a metal cover flange portion 2230 that extends outward from the upper edge of the metal cover tubular portion 2220.

[0027] In the lid body 20, the first surface 2100a, the second surface 2100b, and the inner peripheral side surface 2100c1 of the metal ring 2100 are covered with a glass layer GL. In the lid body 20, the lower surface of the substrate portion 2210 of the metal lid 2200, the inner peripheral surface of the metal lid cylindrical portion 2220, and the upper surface of the gold lid flange portion 2230 are covered with the glass layer GL.

[0028] Like the flange portion 1220, the metal ring 2100 has an axial direction along its central axis, a circumferential direction around the central axis, and a radial direction passing through the central axis and perpendicular to the central axis. The first surface 2100a of the protection ring 210, which is a surface perpendicular to the axial direction of the metal ring 2100, is a glass-coated surface at least partially covered with a glass layer GL, similar to the first surface 1220a of the flange portion 1220. Like the first surface 1220a of the flange portion 1220, the radially outer edge of the first surface 2100a is an exposed surface. The exposed surface of the first surface 2100a is arranged in a circle along the outer periphery of the first surface 2100a. The portion of the first surface 2100a radially inward from the exposed surface is a glass-coated surface. In addition, the side surface (outer peripheral side surface 2100c2) extending from the radially outer edge of the first surface 2100a in a direction (axial direction) intersecting the first surface 2100a is not covered with the glass layer GL, as with the flange portion 1220, and is an exposed surface.

[0029] In the protection ring 210, the second surface 2100b of the metal ring 2100 is a glass-coated surface at least partially covered with a glass layer GL, similar to the first surface 2100a. The exposed surface of the second surface 2100b is provided in a circular shape along the outer circumferential edge, similar to the first surface 2100a. The second surface 2100b has a glass-coated surface radially inward from the exposed surface. Furthermore, the side surface (inner peripheral side surface 2100c1) connecting the radially inner edges of the first surface 2100a and the second surface 2100b is a glass-coated surface covered with the glass layer GL. In other words, the glass layer GL of the protection ring 210 is continuously coated on the first surface 2100a, the inner peripheral side surface 2100c1, and the second surface 2100b.

[0030] The lid body 220, which is based on the metal lid 2200 described above, has a dome-shaped base portion 221 that bulges upward from the outer periphery toward the center. The base portion 221 of the lid body 220 is annular and has an opening in the center that serves as an observation window. The lid body 220 has a cylindrical lid portion 222 that extends cylindrically from the opening of the base portion 221, a lid flange portion 223 that extends outward from the upper edge of the cylindrical lid portion 222, a glass plate 224 that abuts against the lid flange portion 223 to close the upper opening of the cylindrical lid portion 222, and a circular window frame portion 225 for sandwiching the glass plate 224 between the lid flange portion 223 and the glass plate 224. The inside of the window frame portion 225 forms a glass window 220w for observing the state of the storage space 10c from the outside.

[0031] The flange portion 122 of the container nozzle 120 and the protection ring 210 are laminated via a circular plate-shaped gasket S1 that is thinner than the protection ring 210 and the flange portion 122. A thin circular plate-shaped gasket S2 is also interposed between the protection ring 210 and the lid main body 220. A circular plate-shaped gasket S3 is also interposed between the lid flange portion 223 and the glass plate 224, and a circular plate-shaped gasket S4 is also interposed between the glass plate 224 and the window frame portion 225.

[0032] The metal tank 100 and metal lid material 200 of this embodiment include a base portion BP made of an iron-based metal and a highly corrosion-resistant portion HP made of a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal. The highly corrosion-resistant portion HP in this embodiment is made of a highly corrosion-resistant metal filled in a notch BP1 provided in the base portion BP. More specifically, the highly corrosion-resistant portion HP in this embodiment is made of a highly corrosion-resistant metal welded to the base portion BP at the notch BP1.

[0033] The highly corrosion-resistant portion HP is provided so as to be exposed on the surface of the metal tank 100 or the metal lid material 200. Therefore, the surface of the metal tank 100 or the metal lid material 200 includes a base surface SB, which is the surface of the base portion BP, and a highly corrosion-resistant surface SH, which is the surface of the highly corrosion-resistant portion HP. The glass layer GL in the tank body 10 or the lid body 20 is provided so that its edge portion is located on the highly corrosion-resistant surface SH.

[0034] Glass-coated products such as glass-lined products are manufactured so that compressive stress acts on the glass layer GL. This allows the glass layer GL to exhibit high strength in glass-coated products. However, when the interface between the glass layer GL and the metal product corrodes and the bonding strength between the glass layer GL and the metal product weakens, the stress distribution in the glass layer GL changes. This causes excessive stress in the glass layer GL, leading to cracks originating from the stress-generating points. The corrosion that causes such cracks progresses from the edge of the glass layer GL. As the corrosion progresses, the glass layer GL breaks into small pieces and peels off from the metal product. This phenomenon is called chipping. The peeling of the glass layer GL also progresses from the edge of the glass layer GL. Therefore, for metal products, constructing the area where the edge of the glass layer GL is located from a highly corrosion-resistant metal is effective in preventing the progression of chipping.

[0035] Examples of iron-based metals constituting the base portion BP include carbon steel and stainless steel, such as SUS301, SUS301L, SUS301J1, SUS302B, SUS303, SUS304, SUS304Cu, SUS304L, SUS304N1, SUS304N2, SUS304LN, SUS304J1, SUS304J2, SUS305, SUS309S, SUS310S, SUS312L, and SUS315 specified in JIS G4304. J1, SUS315J2, SUS316, SUS316L, SUS316N, SUS316LN, SUS316Ti, SUS316J1, SUS316J1L, SUS31 7, SUS317L, SUS317LN, SUS317J1, SUS317J2, SUS836L, SUS890L, SUS321, SUS347, SUSXM7, SUSX Austenitic stainless steels such as M15J1; austenitic-ferritic stainless steels such as SUS329J1, SUS329J3L, and SUS329J4L; SUS405, SUS410L, SUS429, SUS430, SUS430LX, SUS430J1L, SUS434, SUS436L, SUS436J1L, and SUS443J1; Examples of suitable iron-based metals include ferritic stainless steels such as SUS444, SUS445J1, SUS445J2, SUS447J1, and SUSXM27; martensitic stainless steels such as SUS403, SUS410, SUS410S, SUS420J1, SUS420J2, and SUS440A; and precipitation-hardened stainless steels such as SUS630 and SUS631. The iron-based metal may be a low-carbon grade (e.g., SUS304L or SUS316L) having a carbon content of 0.030% by mass or less.

[0036] The highly corrosion-resistant metal constituting the highly corrosion-resistant portion HP preferably has a higher total content of nickel and chromium than that of an iron-based metal, and more preferably has a higher total content of nickel and chromium than that of an iron-based metal. When SUS304 (18Cr, 8Ni) or SUS304L (18Cr, 9Ni) is used as the iron-based metal, for example, SUS316 (18Cr, 12Ni) or SUS316L (18Cr, 12Ni) may be used as the highly corrosion-resistant metal. The highly corrosion-resistant metal may be, for example, a welding material such as 308N2, 309, 309Si, 309Mo, 309L, 309LD, 309LSi, 309LMo, 309LMoD, 309LNb, 309LNbD, 310, 310S, 310L, 312, 316, 316H, 316Si, 316L, 316LSi, 316LCu, 317, 317L, 318, 318L, 320, 320LR, 329J4L, 330, 383, 385, or 2209 specified in JIS Z3321. The highly corrosion-resistant metal may also be a nickel-based alloy known by trade names such as Inconel or Hastelloy. The highly corrosion-resistant metal may be, for example, a corrosion-resistant and heat-resistant superalloy such as NCF600, NCF601, NCF625, NCF690, NCF718, NCF750, NCF751, NCF80A, NCF800, NCF800H, NCF825, NCF020, or NCF354 specified in JIS G4902; or nickel or nickel-based alloys such as NW2200, NW2201, NW4400, NW4402, NW5500, NW0001, NW0665, NW0276, NW6455, NW6022, NW6210, NW6007, NW6985, or NW6002.Examples of highly corrosion-resistant metals include nickel welding materials such as Ni2061 and Ni2061J specified in JIS Z3334; nickel-copper welding materials such as Ni4060, Ni4061, and Ni5504; nickel-chromium welding materials such as Ni6072, Ni6073, Ni6076, and Ni6082; and nickel-chromium welding materials such as Ni6002, Ni6025, Ni6030, Ni6043, and Ni6045. , nickel-chromium-iron welding materials such as Ni6052, Ni6054, Ni6055, Ni6062, Ni6176, Ni6601, Ni6693, Ni6701, Ni6975, Ni6985, Ni7069, Ni7092, Ni7718, Ni8025, Ni8065, Ni8125; Ni1001, Ni1003, The weld metal may be a nickel-molybdenum weld metal such as Ni1004, Ni1008, Ni1009, Ni1024, Ni1062, Ni1066, Ni1067, or Ni1069; a nickel-chromium-molybdenum weld metal such as Ni6012, Ni6022, Ni6035, Ni6057, Ni6058, Ni6059, Ni6200, Ni6205, Ni6276, Ni6452, Ni6455, Ni6625, Ni6650, Ni6660, Ni6686, or Ni7725; a nickel-chromium-cobalt weld metal such as Ni6160, Ni6617, Ni7090, or Ni7263; or a nickel-chromium-tungsten weld metal such as Ni6231.

[0037] When the highly corrosion-resistant portion HP is formed by welding, a small amount of iron-based metal dissolves in the molten weld material, so the highly corrosion-resistant portion HP after welding may not be made of the above-mentioned materials. Whether the corrosion resistance of the highly corrosion-resistant portion HP is higher than that of the base portion BP can also be determined by measuring the corrosion potential.

[0038] The base portion BP and the highly corrosion-resistant portion HP may be joined by a physical joining force such as threading or shrink fitting, or may be joined by a joining material such as a welding material. The highly corrosion-resistant portion HP may be formed by using the highly corrosion-resistant metal as a welding material and welding the welding material to the base portion BP. In such a case, the welding may be fusion welding such as arc welding, gas welding, or laser welding, pressure welding such as spot welding or seam welding, or may be thermal spraying or brazing.

[0039] From the viewpoint of the robustness of the joint between the base portion BP and the highly corrosion-resistant portion HP, the highly corrosion-resistant portion HP may be formed by build-up welding a highly corrosion-resistant metal to the base portion BP. The highly corrosion-resistant portion HP may be a multi-layer laminate including a first weld layer in contact with the base portion BP and a second weld layer overlapping the first weld layer. The highly corrosion-resistant portion HP may be welded so that three or more layers of build-up weld beads overlap.

[0040] As described above, metal products used to manufacture glass-coated products can be produced by carrying out the following steps: a) a preparation step in which a primary member for forming the base portion BP is formed from an iron-based metal; b) a welding step in which a highly corrosion-resistant metal for forming the highly corrosion-resistant portion HP is welded to the primary member to form a secondary member; and c) a finishing step in which the outer shape of the secondary member is processed to form the shape required for the metal product.

[0041] In the preparation step, a primary member having a shape corresponding to the shape of the base portion BP can be formed, and a primary member 2100' having a cutout portion BP1' can be formed. In the welding step, the surface defining the cutout portion BP1' is used as the weld surface, and welding can be performed so that the cutout portion BP1' is filled with a highly corrosion-resistant metal. Since distortion may occur in the primary member 2100' due to heat in the welding step, the primary member 2100' may be slightly larger in thickness and length than the metal product when the highly corrosion-resistant metal is filled in the cutout portion BP1', and the entire surface of the secondary member 2100'' may be machined in the finishing step.

[0042] In the preparation process, for example, a primary component can be formed by cutting a base component before the notch is formed using a lathe or the like to form the notch BP1'. More specifically, in the preparation process, a metal ring entirely made of an iron-based metal can be prepared, and the corners of the metal ring can be cut off using a lathe or the like to form the notch, thereby producing the primary component. The welding process can be performed by welding a welding material to the welded surface of the primary component. In this case, the notch BP1' can be filled with the welding material in a single welding pass, or the notch BP1' can be filled with the welding material through multiple welding passes. When multiple welding passes are performed, the welding can be performed in a direction away from the welded surface. The notch BP1' has an annular shape when viewed from the direction of the central axis of the metal ring 2100. When the notch BP1' is cut along a plane including the central axis, the cross-sectional shape of the notch BP1' is horizontally elongated when the central axis direction is the vertical direction and the direction perpendicular to the central axis is the horizontal direction. In this case, welding may be performed so that beads of the welding material are arranged in the horizontal direction, or so that multiple beads are piled up in the thickness direction.

[0043] In the welding process, more welding material than necessary to fill the notch portion BP1' may be welded. In the finishing process, distortion caused by welding may be corrected or the distorted surface may be cut to make it flat. In the finishing process, excess welding material can be removed by cutting.

[0044] In the preparation step, taking the protection ring 210 as an example, the protection ring 210 in the first example is manufactured using a primary member 2100' shown in Fig. 3b. In the preparation step for manufacturing the protection ring 210, as shown in Fig. 3a, a primary member 2100' is prepared in which notches BP1' are provided at the corners where the first surface 2100a of the metal ring 2100 intersects with the outer peripheral side surface 2100c2 and at the corners where the second surface 2100b intersects with the outer peripheral side surface 2100c2.

[0045] 3b is provided so as to reach the radially outer edge of the metal ring 2100. On the other hand, this cutout BP1' does not reach the radially inner edge of the metal ring 2100. Therefore, the cutout BP1' is defined by two surfaces: an annular bottom wall surface W1 that defines the bottom surface of the cutout BP1', and a vertical wall surface W2 that rises from the inner peripheral edge of the bottom wall surface W1.

[0046] In this embodiment, the cutout portion BP1' is filled with a highly corrosion-resistant metal by welding. Therefore, in this embodiment, the bottom wall surface W1 and the vertical wall surface W2 are welded surfaces to which the highly corrosion-resistant metal is welded. In other words, the highly corrosion-resistant portion HP formed by filling the cutout portion BP1' with the highly corrosion-resistant metal has a surface that contacts the bottom wall surface W1 and the vertical wall surface W2 and forms a joint surface with the base portion BP.

[0047] If the notch does not reach the edge of the primary member and has a groove shape with vertical wall surfaces on both sides of the notch, when welding is performed so that the beads WB are arranged horizontally on the bottom wall surface, the welding area may become narrow when the beads WB are arranged in order from the corner between the bottom wall surface and the vertical wall surface and reach the opposite vertical wall surface, making the work difficult. However, in this embodiment, the notch reaches the edge. Therefore, in this embodiment, even if the beads WB are welded in order from the vertical wall surface W2 side, it is not necessary to fill the narrow area with weld material until the end. In other words, in this embodiment, the metal ring 2100 and the protection ring 210 made using the metal ring 2100 are easily manufactured.

[0048] The bottom wall surface W1 is preferably formed so as to be parallel to the first surface 2100a. In other words, the notch portion BP1′ is preferably formed so that the depth from the first surface 2100a to the bottom wall surface W1 is uniform overall.

[0049] The vertical wall surface W2 may be perpendicular to the bottom wall surface W1. However, if the corner CN where the vertical wall surface W2 and the bottom wall surface W1 intersect is recessed and pointed, it becomes difficult for the highly corrosion-resistant metal to penetrate during welding. Therefore, the vertical wall surface W2 may be formed to intersect with the bottom wall surface W1 at an obtuse angle. The corner CN where the vertical wall surface W2 and the bottom wall surface W1 intersect may have a chamfered or rounded surface. When the corner CN is a chamfered surface, the width of the chamfered surface may be 0.5 mm or more, or 1.0 mm or more. When the corner CN is a rounded surface, the radius of curvature of the rounded surface may be 0.5 mm or more, or 1.0 mm or more. When the angle between the bottom wall surface W1 and the vertical wall surface W2 is an obtuse angle, the angle may be, for example, 95 degrees or more. The angle formed between the bottom wall surface W1 and the vertical wall surface W2 may be 100 degrees or more, or may be 105 degrees or more. The angle may be, for example, 135 degrees or less.

[0050] The angle between the bottom wall surface W1 and the vertical wall surface W2, the width of the C-surface, and the radius of curvature of the R-surface can be measured based on the cross-sectional shape of the primary member 2100′ when cut along a plane along the chipping propagation direction. The chipping propagation direction is typically perpendicular to the direction in which the edge of the glass layer GL extends, which in the case of the protection ring 210 is radially inward. Therefore, the angle between the bottom wall surface W1 and the vertical wall surface W2, the width of the C-surface, and the radius of curvature of the R-surface can be determined in a cross-section of the protection ring 210 cut along a plane including the central axis of the protection ring 210. Note that the cross-section in the direction perpendicular to the direction in which the edge GLe of the glass layer GL extends (or, in the case of a curved edge, the tangent direction (e.g., the direction of arrow D in FIG. 4b)) is a plane along the thickness direction of the glass layer GL, and hereinafter, this cross-section will also be referred to as the "thickness direction cross-section TX." In the following description, the thickness direction in the thickness direction cross section TX will also be referred to as the vertical direction, and the direction perpendicular to the thickness direction will also be referred to as the horizontal direction.

[0051] The depth of the cutout portion BP1′ observed in the thickness direction cross section TX (the depth from the first surface 2100a to the bottom wall surface W1) may be, for example, 0.05 mm or more, 0.1 mm or more, 0.3 mm or more, or 0.5 mm or more. The depth may be 1.0 mm or more, 1.5 mm or more, 2 mm or more, or 2.5 mm or more. The depth may be, for example, 20 mm or less, 10 mm or less, 8 mm or less, or 5 mm or less. The length from the corner CN where the bottom wall surface W1 and the vertical wall surface W2 intersect along the bottom wall surface W1 to the outer peripheral side surface 2100c2 may be 0.8 times or more the depth of the cutout portion BP1′. When a curved or rounded surface is provided at the intersection of the bottom wall surface W1 and the vertical wall surface W2, it may be difficult to visually identify the corner CN. In this case, the length to the outer peripheral side surface 2100c2 can be calculated by taking the center of the width direction of the curved or rounded surface as the corner CN. This length may be 1.0 times or more, 1.2 times or more, 1.5 times or more, or 2.0 times or more the depth of the cutout portion BP1'. This length may be, for example, 5 mm or more. This length may be 8 mm or more, 10 mm or more, 15 mm or more, or 20 mm or more. This length may be, for example, 30 mm or less, 20 mm or less, or 10 mm or less.

[0052] The highly corrosion-resistant portion HP formed by filling the cutout portion BP1' with the highly corrosion-resistant metal preferably has a cross-sectional shape when cut at the thickness direction cross section TX, which is elongated horizontally from the center of the metal ring toward its edge. That is, the cross-sectional shape of the highly corrosion-resistant portion HP is longer in the radial direction than in the axial direction of the protection ring 210. This makes it possible to conserve the amount of highly corrosion-resistant metal used while ensuring a wide highly corrosion-resistant surface SH.

[0053] The notch BP1' on the first surface 2100a side and the notch BP1' on the second surface 2100b side may have the same or different shapes in the thickness direction cross section TX. In this embodiment, the shape of the space in the notch BP1' is an annular plate on both the first surface 2100a side and the second surface 2100b side. Therefore, the highly corrosion-resistant portion HP formed in this embodiment is also an annular plate.

[0054] For example, an annular plate made of a highly corrosion-resistant metal may be prepared in advance so as to have a shape corresponding to the notch portion BP1′, and the metal ring 2100 may be formed by fitting the annular plate into one or both of the notch portion BP1′ on the first surface 2100a side and the notch portion BP1′ on the second surface 2100b side. The fitted annular plate may be fixed to the primary member 2100′ by spot welding or shrink fitting. In this embodiment, build-up welding is performed to achieve high joint strength between the highly corrosion-resistant portion HP and the base portion BP.

[0055] As shown in Figures 3c to 3e, build-up welding can be performed, for example, so that the beads WB are continuously formed in the circumferential direction. Build-up welding can be performed so that the beads WB are arranged side by side on the bottom wall surface W1. Build-up welding may be performed so that the formed height of the beads WB is equal to or greater than the depth of the cutout portion BP1' and so that the beads WB do not overlap in the vertical direction. Build-up welding may be performed so that the formed height of the beads WB is less than the depth of the cutout portion BP1' and so that the beads WB are stacked in the vertical direction.

[0056] It is preferable to perform build-up welding so as to form a layered structure including a first weld layer BL1 in contact with the bottom wall surface W1 and a second weld layer BL2 in contact with the first weld layer BL1 from the opposite side of the bottom wall surface W1. The first weld layer BL1 and the second weld layer BL2 can be formed by welding so that multiple beads WB are arranged concentrically when the protection ring 210 is viewed in the direction of its central axis. The first weld layer BL1 and the second weld layer BL2 can also be formed by welding so that a single bead WB is spirally shaped when the protection ring 210 is viewed in the direction of its central axis. When welding so that the bead WB is concentrically or spirally shaped, the welding can be performed sequentially from the inside in the radial direction. In this case, multiple cross sections of the bead WB are observed for each of the first weld layer BL1 and the second weld layer BL2 in the thickness direction cross section TX. It is preferable that each of the first welded layer BL1 and the second welded layer BL2 be formed so that the cross sections of the multiple beads WB are aligned in the horizontal direction (radial direction) in this manner.

[0057] 3e, the build-up welding can be performed by overlapping the bead WB so that the bead WB protrudes beyond the first surface 2100a and the second surface 2100b. The build-up welding can be performed so that the bead WB protrudes beyond the outer peripheral side surface 2100c2.

[0058] In build-up welding, even if the bead WB is formed using a welding rod made of a highly corrosion-resistant metal, the iron-based metal dissolves in the bead WB at the portion that directly contacts the primary component 2100′ (the bottom wall surface W1 and the vertical wall surface W2). By forming the above-described layered structure, the second welded layer BL2 can be made to have a higher purity than the first welded layer BL1, and the iron-based metal content in the second welded layer BL2 can be reduced. Furthermore, in the second welded layer BL2, the iron-based metal dissolves in the bead WB that is located at the innermost radial position and in contact with the vertical wall surface W2. However, by forming the bead WB so that multiple cross sections are aligned horizontally in the thickness direction cross section TX, the incorporation of the iron-based metal at the outer radial position can be suppressed.

[0059] After the build-up welding, the excess welding material can be removed by cutting or the like to form a secondary component 2100" as shown in Figure 3f. The secondary component 2100" may be used as a metal ring 2100 as is, and glass powder may be baked to form a glass layer GL. The secondary component 2100" may also be further treated, such as by chemical conversion treatment, to form a metal ring 2100.

[0060] The protection ring 210 is manufactured by a glazing process in which a green product having an unfired glass layer is produced by spraying a slurry containing glass powder onto the metal ring 2100, and a firing process in which the green product is fired in a furnace. Since the highly corrosion-resistant surface SH is formed up to the edge of the metal ring 2100, glazing can be easily performed to position the edge of the glass layer on the highly corrosion-resistant surface SH.

[0061] The metal ring 2100 formed as described above has a base surface SB, which is the surface of the base portion BP, and a highly corrosion-resistant surface SH, which is the surface of the highly corrosion-resistant portion HP. As shown in FIG. 4a, the metal ring 2100 is provided so that the highly corrosion-resistant surface SH reaches the radially outer edge when viewed from the thickness direction of the glass layer GL to be coated. The highly corrosion-resistant surface SH extends beyond this edge onto the side surface of the metal ring 2100. At the corner of the metal ring 2100, each of the two surfaces that intersect at the corner is a highly corrosion-resistant surface SH. The line where these two surfaces intersect corresponds to the edge when the metal ring 2100 is viewed from the thickness direction of the glass layer GL to be coated. In other words, at the corner of the metal ring 2100, a highly corrosion-resistant surface SH is provided on each of the two surfaces that intersect via the edge, and the highly corrosion-resistant surface SH on one of the two surfaces is connected to the highly corrosion-resistant surface SH on the other surface at the respective edges.

[0062] In the metal ring 2100, as described above, although there is a possibility that the highly corrosion-resistant portion HP may contain an iron-based metal, the highly corrosion-resistant surface SH is less likely to contain an iron-based metal in the second or subsequent layers of the bead WB. In this embodiment, the highly corrosion-resistant surface SH is formed by the cutting surfaces of the second or subsequent layers of the bead WB, so the purity of the highly corrosion-resistant metal in the highly corrosion-resistant surface SH can be increased. Furthermore, in the inner, radially inner portion of the highly corrosion-resistant surface SH, iron-based metal may be present that has been mixed in from the vertical wall surface W2, but the probability of iron-based metal being present is significantly reduced in portions outer than the radial center.

[0063] In order to position the edge GLe of the glass layer GL on the highly corrosion-resistant surface SH with fewer impurities, the edge GLe may be located at a position separated in the lateral direction (radial direction of the protection ring 210) from the vertical wall surface W2 (the boundary line between the base surface SB and the highly corrosion-resistant surface SH). The distance from the vertical wall surface W2 (the boundary line between the base surface SB and the highly corrosion-resistant surface SH) to the edge GLe of the glass layer GL may be, for example, at least half the lateral length of the highly corrosion-resistant surface SH (the length from the boundary line between the base surface SB and the highly corrosion-resistant surface SH to the edge of the metal ring 2100). This distance may be at least two-thirds or at least three-quarters of the lateral length of the highly corrosion-resistant surface SH.

[0064] For example, 50% to 100% of the area of ​​the highly corrosion-resistant surface SH may be a glass-coated surface. 60% or more of the area of ​​the highly corrosion-resistant surface SH may be a glass-coated surface, 70% or more of the area of ​​the highly corrosion-resistant surface SH may be a glass-coated surface, or 80% or more of the area of ​​the highly corrosion-resistant surface SH may be a glass-coated surface.

[0065] Even in cases where the highly corrosion-resistant surface SH and the base surface SB have similar appearances and it is difficult to determine the boundary between the two just by looking at them, if the glass layer GL is formed up to a position close to the edge (the radially outer edge) of the metal ring 2100 as shown in Figure 4b, the edge portion of the glass layer GL will be baked onto the highly corrosion-resistant surface SH, which is made of a highly pure corrosion-resistant metal, and chipping can be suppressed.

[0066] In the protection ring 210 of this first example, a first surface 2100a, a second surface 2100b, and an inner peripheral side surface 2100c1 of a metal ring 2100 are coated with a glass layer GL. The protection ring 210 includes a metal ring 2100 having a base portion BP made of an iron-based metal and a highly corrosion-resistant portion HP made of a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal, and the metal ring 2100 is provided on its surface with a base surface SB which is the surface of the base portion BP and a highly corrosion-resistant surface SH which is the surface of the highly corrosion-resistant portion HP, and when the edge portion of the glass layer GL is viewed from the thickness direction of the glass layer GL, the highly corrosion-resistant surface SH is provided so as to extend from the edge of the metal ring 2100, and the edge of the glass layer GL is located on the highly corrosion-resistant surface SH.

[0067] As described above, in the protection ring 210 of this embodiment, the end of the glass layer GL, which is likely to be a chipping starting point, is bonded to the highly corrosion-resistant surface SH. Bonding of the glass layer GL to the highly corrosion-resistant surface SH is performed by baking. The highly corrosion-resistant surface SH extends outward from the glass layer GL beyond the edge GLe of the glass layer GL and reaches the edge of the metal ring 2100. The highly corrosion-resistant surface SH also extends beyond the edge of the metal ring 2100 to the outer peripheral side surface 2100c2. This configuration of the protection ring 210 suppresses chipping. The corner between the first surface 2100a and the outer peripheral side surface 2100c2 may be round-chamfered or C-chamfered. Even in such cases, the area where the glass layer GL is formed can be easily determined using the edge of the metal ring 2100 (the edge on the outer peripheral side surface 2100c2 side of the chamfered portion) as a guide, making it easy to suppress chipping. The glass layer GL may be provided so as to extend beyond the corner and wrap around the outer peripheral side surface 2100c2.

[0068] The protection ring 210 illustrated in the figures has two highly corrosion-resistant portions HP, one on each of the first surface 2100a and the second surface 2100b of the metal ring 2100. In the protection ring 210 illustrated in the figures, the two highly corrosion-resistant portions HP are each laminated on the base portion BP in the thickness direction cross section TX, and the highly corrosion-resistant portions HP have a joint surface CF with the base portion BP that is the opposite side to the highly corrosion-resistant surface SH. It is also possible to form the highly corrosion-resistant portions HP with the same thickness as the metal ring 2100 and form the highly corrosion-resistant surfaces SH on both the first surface 2100a and the second surface 2100b with a single highly corrosion-resistant portion HP, but doing so as described above can reduce the amount of highly corrosion-resistant metal used.

[0069] The glass layer GL provided in the protection ring 210 may be a multilayer structure including an undercoat glass layer GL1 that is in direct contact with the metal ring 2100, and an undercoat glass layer GL2 that is in contact with the undercoat glass layer GL1 from the side opposite the metal ring 2100 and is bonded to the metal ring 2100 via the undercoat glass layer GL1, as shown in Figure 5.

[0070] The undercoat glass layer GL1 and the topcoat glass layer GL2 can be formed of a glass composition containing a glass component as an essential component and additive components as optional components. The glass component in the undercoat glass composition constituting the undercoat glass layer GL (hereinafter referred to as the "undercoat glass component") can be a silicate-based glass. The undercoat glass component can be, for example, 58 mol % to 70 mol % of SiO ２ , 3 mol % to 8 mol % Al ２ O ３ , 13 mol % to 17 mol % of B ２ O ３ , 12 mol% to 18 mol% Na ２ O, 2 mol% to 7 mol% K ２ O, 1 mol% to 7 mol% CaF ２ as an essential component, and further, as optional components, 0 mol% to 3 mol% of CaO, 0 mol% to 0.5 mol% of CoO, and 0 mol% to 0.7 mol% of MnO ２ The glass composition for undercoating may contain, as an additive component, for example, TiO ２ , Al ２O ３ , La ２ O ３ , B ２ O ３ and ZnO.

[0071] The top glass composition constituting the top glass layer GL2 may contain, for example, SiO 2 , in the same manner as the undercoat glass composition constituting the undercoat glass layer GL1 . ２ The silicate-based glass composition may contain 50 mol % or more of B. ２ O ３ The borosilicate glass composition may further include:

[0072] The glass component in the glass composition for top coating (hereinafter referred to as "top coating glass component") contains, for example, 50 mol % to 75 mol % of SiO ２ , 2 mol % to 15 mol % ZrO ２ , 10 mol % to 25 mol % of R ２ O (where "R" represents Na, Li, K, or Cs), and 2 mol % to 12 mol % of R'O (where R' represents Mg, Ca, Sr, or Ba). The glass composition for top coating may contain, as additive components, for example, TiO ２ , Al ２ O ３ , La ２ O ３ , B ２ O ３ and ZnO. More specifically, the glass composition for top coating may contain one or more selected from the group consisting of TiO ２ , Al ２ O ３ , La ２ O ３ , B ２ O ３ When the glass composition for size drawing contains only one selected from the group consisting of TiO, and ZnO, the content can be 0.1 mol % to 4 mol %, and when two or more selected from the group consisting of TiO, the content can be 0.1 mol % to 4 mol %, with the total content being 5 mol % or less. ２ , Al ２ O ３ , La ２ O ３, B ２ O ３ When the composition contains only one selected from the group consisting of Al, and ZnO, the one selected from the group consisting of Al ２ O ３ It can be said that:

[0073] The undercoat glass layer GL1 may contain bubbles. The volume ratio of bubbles in the undercoat glass layer GL1 may be greater than that in the topcoat glass layer GL2. The presence of bubbles in the undercoat glass layer GL1 can function to relieve stress, as described below. The size of the bubbles may be greater than 50 μm or may be greater than 100 μm. The size of the bubbles may be, for example, 300 μm or less. When the shape of the bubbles is not spherical, the size of the bubbles can be determined by measuring the longest dimension in the cross section of the glass layer GL.

[0074] The size and content of bubbles in the glass layer GL can be adjusted by the carbon and hydrogen content in the metal product to which the glass is baked and the content of additives in the glass composition.

[0075] In the protection ring 210 shown in Figure 5, the highly corrosion-resistant portion HP formed by the highly corrosion-resistant metal filled in the cutout portion BP1 of the base portion BP has a horizontally elongated shape in the thickness direction cross section TX, but for example, as shown in Figure 6, the cross-sectional shape of the highly corrosion-resistant portion HP may be vertically elongated or may have some other cross-sectional shape.

[0076] In the second example of the protection ring 210 shown in Figure 6, the radial length of the highly corrosion-resistant portion HP can be shortened, thereby reducing the amount of highly corrosion-resistant metal used and reducing the amount of work required for welding. On the other hand, if the difference in thermal expansion coefficient between the highly corrosion-resistant metal and the iron-based metal is large, residual stress may occur at the boundary between the highly corrosion-resistant portion HP and the base portion BP after the metal ring 2100 is frosted and the glass is baked. Such stress is likely to occur at the boundary between the highly corrosion-resistant surface SH and the base surface SB. Making the highly corrosion-resistant portion horizontally elongated, as in the protection ring 210 shown in Figure 5, makes it easier to distance the edge GLe of the glass layer GL from the boundary between the highly corrosion-resistant surface SH and the base surface SB. This further reduces chipping.

[0077] For the reasons described above, it is preferable that the glass layer GL be formed so that its edge GLe is located at a position that is at least a certain distance T from the boundary line LL between the highly corrosion-resistant surface SH and the base surface SB. The distance L1 from the boundary line LL to the edge GLe of the glass layer GL may be ensured on both sides or only one side of the protection ring 210. Furthermore, if the distance L1 from the boundary line to the edge GLe of the glass layer GL is ensured on only one side, it is not necessary to ensure such distance T around the entire circumference of the protection ring 210.

[0078] Although it is preferable that the edge GLe of the glass layer GL be disposed at a distance L1 greater than or equal to a certain distance from the boundary line LL over the entire length, the distance L1 may be provided over a section of the entire length of the edge, for example, 10% or more, 25% or more, 50% or more, or 75% or more.

[0079] The distance L1 between the edge GLe of the glass layer GL and the boundary line LL can be, for example, 3 mm or more. This distance L1 may be 4 mm or more, 5 mm or more, 6 mm or more, 8 mm or more, or 10 mm or more. The distance L1 between the edge GLe of the glass layer GL and the boundary line LL can be, for example, 20 mm or less. This distance L1 may be 15 mm or less, or 10 mm or less.

[0080] The depth L2 of the highly corrosion-resistant portion HP at the location where the edge GLe of the glass layer GL is located (the distance from the joint surface CF with the base portion BP on the opposite side of the highly corrosion-resistant surface SH to the highly corrosion-resistant surface SH) is also preferably at least a certain level. The edge GLe of the glass layer GL is preferably provided at a location where the highly corrosion-resistant portion HP has a depth L2 at least a certain level over its entire length, but the location where the edge GLe is provided at such a depth L2 may be, for example, 10% or more of the entire length of the edge GLe. The section where the edge GLe is provided at a location where the highly corrosion-resistant portion HP has a depth at least a certain level may be 25% or more, 50% or more, or 75% or more of the entire length of the edge GLe.

[0081] The depth L2 of the highly corrosion-resistant portion HP at the position where the edge GLe of the glass layer GL is provided may be, for example, 0.05 mm or more, 0.1 mm or more, 0.3 mm or more, or 0.5 mm or more. This depth L2 may be 1.0 mm or more, 1.5 mm or more, 2 mm or more, 2.5 mm or more, 3 mm or more, or 4 mm or more. The depth L2 of the highly corrosion-resistant portion HP at the position where the edge GLe of the glass layer GL is provided may be, for example, 20 mm or less. This depth L2 may be 10 mm or less, 8 mm or less, or 5 mm or less.

[0082] The highly corrosion-resistant surface SH may have the depth L2 as described above in an area ratio of, for example, 25% or more. The area ratio of the region having the depth L2 as described above to the highly corrosion-resistant surface SH may be 30% or more, 40% or more, 50% or more, or 60% or more. It is preferable that the depth of the highly corrosion-resistant surface SH does not change suddenly within a narrow range. It is preferable that the highly corrosion-resistant portion HP has a constant thickness, or that even if the thickness varies depending on the location, the change in thickness in the planar direction is constant.

[0083] The highly corrosion-resistant portion HP preferably has a plate-like region HPa having a horizontally elongated band-like shape in a thickness direction cross section TX, or a variable-thickness region HPn in which the thickness observed in the thickness direction cross section TX changes at a constant rate in a direction perpendicular to the thickness direction. The glass layer GL is preferably provided so that its edge is located in the plate-like region HPa or the variable-thickness region HPn.

[0084] As described above, the highly corrosion-resistant portion HP in this embodiment is annular. That is, the plate-shaped region HPa extends in the circumferential direction of the protection ring 210, and the horizontally elongated cross-sectional shape is continuous not only in a single plane but also in the depth direction (circumferential direction) of the cross-section. In this embodiment, the cross-sectional shape in all planes including the central axis of the protection ring 210 is horizontally elongated. The plate-shaped region HPa in this embodiment may be formed so that the same cross-sectional shape continues in the extension direction, or may be formed so that the thickness and width dimensions of the cross-sectional shape change in the depth direction (circumferential direction) while maintaining the horizontally elongated cross-sectional shape. In glass-coated products other than the protection ring 210 illustrated in the figures, the plate-shaped region may be, for example, a polygonal frame plate (square frame plate, hexagonal frame plate).

[0085] In this embodiment, not only the plate-like region HPa but also the variable thickness region HPn extends in the circumferential direction of the protection ring 210. The variable thickness region HPn may be formed so that the exact same cross-sectional shape continues in the extending direction, or may be formed so that the thickness of the cross-sectional shape changes at a constant rate in the radial direction while the thickness dimension, width dimension, degree of change, etc. of the cross-sectional shape change in the depth direction (circumferential direction).

[0086] To prevent chipping, the metal product may be formed so that most of the glass-coated surface is the highly corrosion-resistant surface SH, but the highly corrosion-resistant portion HP does not need to be formed over an excessively large area. For example, the highly corrosion-resistant portion HP or the plate-shaped region HPa may be formed in a circular or polygonal plate shape. However, to reduce the amount of highly corrosion-resistant metal used and reduce the labor required for welding, the highly corrosion-resistant portion HP or the plate-shaped region HPa may be formed in a strip-like shape extending along the edge of the glass layer GL. In this case, a region whose cross-sectional shape in a plane perpendicular to the extension direction of the plate-shaped region HPa is a horizontally elongated strip extending continuously throughout the entire section of the plate-shaped region HPa can prevent chipping from progressing in a direction intersecting the extension direction of the plate-shaped region HPa. Furthermore, the variable thickness region HPn can also prevent chipping from progressing in a direction intersecting the extension direction of the variable thickness region HPn. The plate-like region HPa and the variable-thickness region HPn do not necessarily have to be provided over the entire section of the edge portion of the glass layer GL, but may be provided only in a portion thereof. The plate-like region HPa and the variable-thickness region HPn may be provided so as to occupy 50% or more, 70% or more, or 90% or more of the length of the edge portion of the glass layer GL. It is preferable that the plate-like region HPa and the variable-thickness region HPn be provided over the entire section (100%) of the edge portion of the glass layer GL.

[0087] From the viewpoint of workability, it is preferable that the thickness change rate in the variable thickness region HPn is set so that the angle (θ in FIG. 11 ) between the interface with the base portion BP and the highly corrosion-resistant surface SH is 45 degrees or less. The angle may be 30 degrees or less, or may be 20 degrees or less.

[0088] When the highly corrosion-resistant portion HP is laminated on the base portion BP, the presence of a plate-like region HPa in the highly corrosion-resistant portion HP can be confirmed by the fact that the boundary line between the highly corrosion-resistant portion HP and the base portion BP in the thickness direction cross section TX (the cross-sectional shape of the joining surface CF) is a straight line parallel to the highly corrosion-resistant surface SH. The presence of a variable-thickness region HPn in the highly corrosion-resistant portion HP can be confirmed by the fact that the boundary line between the highly corrosion-resistant portion HP and the base portion BP in the thickness direction cross section TX is not parallel to the highly corrosion-resistant surface SH but is a straight line at an angle.

[0089] Whether the interface is linear can be confirmed by checking that the straightness of the boundary line is within 1 mm. The straightness of the boundary line is preferably within 0.5 mm, more preferably within 0.1 mm, and even more preferably within 0.01 mm. Here, the straightness is set to a value equal to or less than the depth L2 of the highly corrosion-resistant portion. In the protection ring 210 illustrated in FIG. 5 , there are two cross sections of the highly corrosion-resistant portion HP, one on the first surface 210a side and the other on the second surface 210b side. Furthermore, although not shown in FIG. 5 , if the protection ring 210 is cut along a plane including the central axis, there will be a cross section of the protection ring 210 cut at a position 180 degrees away from that shown in FIG. 5 , and the two cross sections will be arranged so as to be line-symmetrical about the central axis. Furthermore, in a cross section other than that shown in FIG. 5 , there are also two cross sections of the highly corrosion-resistant portion HP, one on the first surface 210a side and one on the second surface 210b side. That is, when the protection ring 210 is cut along a plane including the central axis, cross sections of the highly corrosion-resistant portion HP are provided in four locations. The straightness may be the same for each of the four cross sections, or the straightness in one cross section may be different from the straightness in another cross section. That is, just as it is not necessary to strictly maintain the cross-sectional shape in the direction in which the plate-like region HPa and the variable-thickness region HPn extend, as described above, the straightness of the boundary line may also change in the depth direction (circumferential direction) of the cross section.

[0090] The plate-shaped region HPa and the variable thickness region may be formed so that their radial length in the thickness direction cross section TX is 5 mm or more. The length of the plate-shaped region HPa and the variable thickness region in the thickness direction cross section TX may be 7 mm or more, or may be 10 mm or more. It is preferable that the protection ring 210 be provided with a plate-shaped region HPa or a variable thickness region having a certain length or more in the circumferential direction (depth direction from the thickness direction cross section TX). In other words, it is preferable that the high corrosion-resistant portion HP is provided so that the same cross-sectional shape continues in the circumferential direction. The circumferential length of the plate-shaped region HPa or the variable thickness region may be 10% or more, 25% or more, 50% or more, or 75% or more of the entire circumferential length. It is preferable that the plate-shaped region HPa and the variable thickness region HPn are provided around the entire circumference.

[0091] 5 and 6 includes a first surface 210a facing the underside of the lid body 220, a second surface 210b opposite the first surface 210a facing the flange portion 122 of the container nozzle 120, an inner peripheral side surface 210c1 connecting the inner peripheral edge of the first surface 210a to the inner peripheral edge of the second surface 210b, and an outer peripheral side surface 210c2 connecting the outer peripheral edge of the first surface 210a to the outer peripheral edge of the second surface 210b. In the protection ring 210, the metal ring 2100 is exposed on these inner and outer peripheral side surfaces 210c2 and is not covered by the glass layer GL. Furthermore, at both axial ends of the protection ring 210, the outer peripheral side surface 210c2 forms a highly corrosion-resistant surface SH, while the middle portion forms a base surface SB.

[0092] When the lid is opened or closed, liquid adhering to the underside of the lid main body 220 may adhere to the protection ring 210. In such a case, to prevent rust or the like from occurring on the base surface SB, the entire outer peripheral side surface 210c2 may be made into a highly corrosion-resistant surface SH, as shown in Fig. 7. That is, as in the protection ring 210 of the third example shown in Fig. 7, the highly corrosion-resistant surface SH of the metal ring 2100 may be provided so as to extend beyond the corner between the first surface 2100a and the outer peripheral side surface 2100c2 to the outer peripheral side surface 2100c2 and to the corner between the outer peripheral side surface 2100c2 and the second surface 2100b.

[0093] In such a case, the metal ring 2100 constituting the protection ring 210 may be composed of two ring members that are doubled radially, one inside and one outside, as shown in FIG. 8 . The metal ring 2100 in the fourth example of the protection ring 210 shown in FIG. 8 is formed by joining the outer peripheral surface of the inner ring 2110, which is on the radially inner side, to the inner peripheral surface of the outer ring 2120 that surrounds the inner ring 2110, by a method such as welding. By using a highly corrosion-resistant metal for the outer ring 2120 in this manner, the metal ring 2100 whose outer peripheral side surface 2100c2 is entirely the highly corrosion-resistant surface SH may be used as a metal product for forming the glass layer GL. When welding the outer ring 2120 and the inner ring 2110, the weld material does not need to be a highly corrosion-resistant metal and may be an iron-based metal, for example.

[0094] 9, the container nozzle 120 also functions in the same manner as the protection ring 210. The container nozzle 120 in this first example has a highly corrosion-resistant portion HP formed by providing a notch in the flange portion 1220 of the metal nozzle 1200 that serves as the base of the container nozzle 120 and filling the notch with a highly corrosion-resistant metal. In this first example, the container nozzle 120 also has a highly corrosion-resistant surface SH and a base surface SB on the upper surface of the flange portion 1220, and the edge GLe of the glass layer GL is positioned on the highly corrosion-resistant surface SH, thereby suppressing chipping.

[0095] Glass-coated products such as the container nozzle 120 can also employ a fitting structure as shown in FIG. 10 . The second example of the container nozzle 120 shown in FIG. 10 has a fitting structure in which a step is formed on the surface of a metal product and a glass layer GL is fitted into the lower step of the step. In the container nozzle 120 illustrated in FIG. 10 , the highly corrosion-resistant portion HP has a step, and the highly corrosion-resistant surface SH has a low step region SHL on the lower step side of the step, a high step region SHH on the higher step side of the step, and a connection region SHC connecting the low step region SHL and the high step region SHH. The glass layer GL is bonded to the low step region SHL, and the edge of the glass layer GL is bonded to the connection region SHC. These bonding processes can be performed when the glass layer GL is formed by baking the glass. This configuration can further suppress chipping. This fitting structure can also be used for the protection ring 210.

[0096] Furthermore, like the container nozzle 120 in the third example illustrated in FIG. 11, the edge GLe of the glass layer GL may be provided in the variable thickness region HPn, which is the same for both the protection ring 210 and the container nozzle 120.

[0097] Although further detailed explanation will not be repeated here, chipping can also be suppressed by forming notches in the outer peripheral corners of the base plate portion 2210 of the metal lid 2200 and the outer peripheral corners of the metal lid flange portion 2230 to form highly corrosion-resistant portions HP and covering them with a glass layer GL. In this case, an inlay structure or the like may also be employed. In this embodiment, regardless of the metal product to be glazed, the area to be glazed can be determined using the edge of the metal product as a guide, improving workability. As described above, this embodiment provides a glass-lined product that is easy to manufacture and has excellent corrosion resistance.

[0098] Although the above examples show products that have a circular shape in a plan view, such as the protection ring 210 and the metal cover flange portion 2230, the above-mentioned effects can also be achieved with products that are square in a plan view or with polygonal shapes other than square. Also, although the above examples show glass-lined products, the same effects can also be achieved with enamel products and the like.

[0099] As described above, this specification includes the following disclosure regarding a first invention of a glass-coated product.

[0100] (A1) A glass-coated product comprising a metal product and a glass layer bonded to the surface of the metal product, wherein the metal product comprises a base portion made of an iron-based metal and a highly corrosion-resistant portion made of a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal, and the surface of the metal product is provided with a base surface that is the surface of the base portion and a highly corrosion-resistant surface that is the surface of the highly corrosion-resistant portion, and when the edge portion of the glass layer is viewed from the thickness direction of the glass layer, the highly corrosion-resistant surface is provided so as to extend from the edge of the metal product, and the edge of the glass layer is located on the highly corrosion-resistant surface.

[0101] (A2) A glass-coated product according to (A1), wherein when a boundary line is set along the edge of the glass layer when viewed in the thickness direction, an imaginary plane perpendicular to the direction in which the boundary line extends is set, and a cross section on the imaginary plane is taken as a thickness direction cross section, the highly corrosion-resistant portion is laminated on the base portion in the thickness direction cross section, and the highly corrosion-resistant portion has a joint surface with the base portion that is the side opposite to the highly corrosion-resistant surface.

[0102] (A3) The glass-coated product according to (A2), wherein the cross-sectional shape of the highly corrosion-resistant portion in the thickness direction cross section is a horizontally elongated shape that is long in a direction perpendicular to the thickness direction.

[0103] (A4) The glass-coated product according to (A2) or (A3), wherein the shape of the joining surface in the thickness direction cross section is linear.

[0104] (A5) A glass-coated product according to any one of (A2) to (A4), wherein the highly corrosion-resistant portion has a plate-like region having a horizontally elongated band-like shape in the cross section in the thickness direction, and the glass layer has an edge portion joined to the plate-like region.

[0105] (A6) A glass-coated product according to any one of (A2) to (A4), wherein the highly corrosion-resistant portion has a variable thickness region in which the thickness observed in the thickness direction cross section changes at a constant rate in a direction perpendicular to the thickness direction, and the glass layer has an edge portion joined to the variable thickness region.

[0106] (A7) A glass-coated product according to any one of (A1) to (A6), wherein the metal product is provided with a plate-shaped portion, the plate-shaped portion having a first surface, a second surface opposite the first surface, and a side surface connecting edges of the second surface and the first surface, the highly corrosion-resistant surface constituting at least a part of the first surface, extending onto the side surface beyond a corner between the first surface and the side surface, and extending to a corner between the side surface and the second surface, and the edge of the glass layer is located on the highly corrosion-resistant surface.

[0107] (A8) A glass-coated product according to any one of (A1) to (A7), wherein the highly corrosion-resistant portion has a step, and the highly corrosion-resistant surface is provided with a low-step region on the low-step side of the step, a high-step region on the high-step side of the step, and a connection region connecting the low-step region and the high-step region, and the glass layer is bonded to the low-step region, and an edge portion of the glass layer is bonded to the connection region.

[0108] The present invention is not limited to the above examples and various modifications can be made.

[0109] A glass-coated product according to a second aspect of the present invention, which focuses on a different effect from the above, is described below. As disclosed in Japanese Patent Application Laid-Open No. 2-125729, the glass-coated product uses a metal product as its base material, in which a highly corrosion-resistant metal is used as the laminated portion of the edge of the glass layer, which is likely to be the starting point for delamination of the glass layer. Where the interface between the highly corrosion-resistant metal and the iron-based metal is nearly perpendicular to the surface of the metal product, excessive stress may be applied to the glass layer due to the difference in the linear expansion coefficients of the highly corrosion-resistant metal and the iron-based metal, making the glass layer coated near such an interface prone to delamination. In the glass-coated product of the following embodiment, the highly corrosion-resistant portion has a plate-shaped region, which prevents the glass layer from delaminating.

[0110] Specifically, the glass-coated product according to the second invention is a glass-coated product comprising a metal product and a glass layer bonded to the surface of the metal product, wherein the metal product comprises a base portion made of an iron-based metal and a highly corrosion-resistant portion made of a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal, the surface of the metal product is provided with a highly corrosion-resistant surface which is the surface of the highly corrosion-resistant portion, and the highly corrosion-resistant portion is provided with a plate-like region having one side which is the highly corrosion-resistant surface and another side opposite the highly corrosion-resistant surface which is a joining surface with the base portion, and which has a cross section which is a horizontally elongated band when cut along a plane perpendicular to the highly corrosion-resistant surface, and the glass layer is bonded to the metal product so as to cover part or all of the plate-like region.

[0111] The glass-coated product of the second invention comprises a metal product and a glass layer baked onto the surface of the metal product, similar to the glass-coated product of the first invention described with reference to Figures 1 to 11.

[0112] The glass-coated product according to the second invention will be described below with reference to Figures 1, 2, and 12a to 20b. In the following description, parts similar to those of the first invention will be described using the same reference numerals as in the description of the first invention. As in the description of the first invention, the glass-coated product according to the second invention will be described below as an example in which the glass-coated product is a protection ring 210 or a vessel nozzle 120. The description of each part and material of the reaction vessel 1 equipped with the protection ring 210 or the vessel nozzle 120 will not be repeated below.

[0113] The metal product used to manufacture the glass-coated product of the second invention can be produced, similarly to the metal product of the first invention, by carrying out the following steps: a) a preparation step of forming a primary member from an iron-based metal to form the base portion BP; b) a welding step of welding a highly corrosion-resistant metal to the primary member to form a secondary member to form the highly corrosion-resistant portion HP; and c) a finishing step of processing the outer shape of the secondary member to form the shape required for the metal product.

[0114] The preparation step, the welding step, and the finishing step can be carried out in the same manner as in the first invention.

[0115] In the preparation process, for example, taking the protection ring 210 in the fifth example as an example, as shown in Figure 12a, a primary member 2100' is prepared in which a notch portion BP1' recessed from the first surface 2100a or the second surface 2100b of the metal ring 2100 is provided on each of the first surface 2100a and the second surface 2100b.

[0116] 12a and 12b are provided at two locations, one on the first surface 2100a side and the other on the second surface 2100b side, and the radially outer ends of the two notches BP1' reach close to the outer edge of the metal ring 2100. On the other hand, the radially inner ends of the notches BP1' are spaced apart from the inner edge of the metal ring 2100. In other words, the notches BP1' are provided radially outward.

[0117] The cutout portion BP1' is formed so that the cross section (thickness direction cross section TX) of the metal ring 2100 when cut along a plane including the central axis thereof has a horizontally elongated band shape that is long in the radial direction. The cutout portion BP1' is formed so that the cross section is recessed and slightly tapered from the first surface 2100a and the second surface 2100b when cut along the plane, resulting in an isosceles trapezoidal cross section. Therefore, the cutout portion BP1' is defined by three surfaces: a bottom wall surface W1 that defines the bottom surface of the cutout portion BP1', and two vertical wall surfaces W2 that rise from the inner and outer peripheral edges of the bottom wall surface W1.

[0118] The cutout portion BP1' is provided continuously in the circumferential direction of the metal ring 2100. The bottom wall surface W1 may be formed to be parallel to the first surface 2100a or the second surface 2100b, or may not be parallel to them. The depth of the cutout portion BP1' from the first surface 2100a or the second surface 2100b to the bottom wall surface W1 may be uniform or non-uniform. In this embodiment, the depth and radial dimension of the cutout portion BP1' are constant in the circumferential direction of the metal ring 2100, which is the depth direction of the cross section, and the cross-sectional shape is also consistent in the circumferential direction. That is, the shape of the cutout portion BP1' in this embodiment is a circular plate shape in which both the thickness and radial dimension are uniform and the radial dimension is greater than the thickness.

[0119] The highly corrosion-resistant portion HP in the second aspect of the invention is formed by filling the notch portion BP1' with a highly corrosion-resistant metal by welding. Therefore, in this embodiment, the bottom wall surface W1, the inner vertical wall surface W2 rising from the inner peripheral edge of the bottom wall surface W1 (hereinafter also referred to as the "first vertical wall surface W21"), and the outer vertical wall surface W2 rising from the outer peripheral edge of the bottom wall surface W1 (hereinafter also referred to as the "second vertical wall surface W22") are welded surfaces to which the highly corrosion-resistant metal is welded. In other words, the highly corrosion-resistant portion HP formed by filling the notch portion BP1' with a highly corrosion-resistant metal has a surface in contact with the bottom wall surface W1 and the two vertical wall surfaces W2 that forms a joint surface with the base portion BP. Furthermore, the highly corrosion-resistant portion HP in this embodiment formed as described above has a shape corresponding to the notch portion BP1' and is an annular plate-like shape whose radial dimension is greater than its thickness. That is, the highly corrosion-resistant portion HP in the metal ring 2100 illustrated in FIG. 14 and the like has a plate-like region whose cross section is a horizontally elongated band-like shape, and is constituted only by this plate-like region.

[0120] If the cutout extends to the edge of the primary member and has a vertical wall on only one side of the cutout, the welding work would require careful attention to prevent the welding material from spilling when the bead WB is aligned from the corner between the bottom wall and the vertical wall and reaches the side without the vertical wall, which can be difficult to do. However, in this embodiment, the vertical wall W2 is provided at both ends of the cutout, which avoids the need for such careful welding work. Furthermore, for example, if the cutout extends to the edge of the metal ring 2100 and is open on two sides, the first surface 2100a and the outer peripheral side surface 2100c2, the welding material would be welded so that it protrudes from these two sides. On the other hand, if the vertical wall W2 exists at both ends of the cutout and the cutout is open only to the first surface 2100a, the welding material would protrude from only one side. Therefore, using a primary member having a notch BP1' as shown in Figure 12b is advantageous in that it reduces the amount of welding material used to form the highly corrosion-resistant portion HP. Furthermore, the highly corrosion-resistant portion HP formed in this manner is joined at both ends to the vertical wall surface W2 of the base portion BP, and therefore can have excellent joining strength with the base portion BP.

[0121] One or both of the first vertical wall surface W21 and the second vertical wall surface W22 may be perpendicular to the bottom wall surface W1. However, if the corner CN where the vertical wall surface W2 intersects with the bottom wall surface W1 is recessed and pointed, it becomes difficult for the highly corrosion-resistant metal to penetrate during welding. Therefore, the vertical wall surface W2 may be formed to intersect with the bottom wall surface W1 at an obtuse angle. Furthermore, the corner CN where the vertical wall surface W2 intersects with the bottom wall surface W1 may have a chamfered or rounded surface. If the corner CN is a chamfered surface, the width of the chamfered surface may be 0.5 mm or more, or 1.0 mm or more. If the corner CN is a rounded surface, the radius of curvature of the rounded surface may be 0.5 mm or more, or 1.0 mm or more. If the angle between the bottom wall surface W1 and the vertical wall surface W2 is an obtuse angle, the angle may be, for example, 95 degrees or more. The angle between the bottom wall surface W1 and the vertical wall surface W2 may be 100 degrees or more, or may be 105 degrees or more. For example, the angle may be 135 degrees or less. The angle between the first vertical wall surface W21 and the bottom wall surface W1 and the angle between the second vertical wall surface W22 and the bottom wall surface W1 may be the same or different. The shape (C-shaped, R-shaped, etc.) of the corner CN where the first vertical wall surface W21 and the bottom wall surface W1 intersect may be the same or different from the shape of the corner CN where the second vertical wall surface W22 and the bottom wall surface W1 intersect.

[0122] The angle between the bottom wall surface W1 and the vertical wall surface W2, the width of the C-surface, and the radius of curvature of the R-surface can be measured based on the cross-sectional shape of the primary member 2100′ when cut along a plane along the chipping progression direction. The chipping progression direction is typically perpendicular to the direction in which the edge of the glass layer GL extends, which in the case of the protection ring 210 is radially inward. Therefore, the angle between the bottom wall surface W1 and the vertical wall surface W2, the width of the C-surface, and the radius of curvature of the R-surface can be determined in a cross-section of the protection ring 210 cut along a plane including the central axis of the protection ring 210. Note that the cross-section in the direction perpendicular to the direction in which the edge GLe of the glass layer GL extends (or, in the case of a curved edge, the tangent direction (e.g., the direction of arrow D in FIG. 15b)) is a plane along the thickness direction of the glass layer GL (thickness direction cross-section TX).

[0123] The depth of the cutout portion BP1′ observed in the thickness direction cross section TX (the depth from the first surface 2100a to the bottom wall surface W1) may be, for example, 0.05 mm or more, 0.1 mm or more, 0.3 mm or more, or 0.5 mm or more. The depth may be 1.0 mm or more, 1.5 mm or more, 2 mm or more, or 2.5 mm or more. The depth may be, for example, 20 mm or less, 10 mm or less, 8 mm or less, or 5 mm or less. The length of the bottom wall surface W1 in the thickness direction cross section TX may be 0.8 times or more the depth of the cutout portion BP1′. When a curved or rounded surface is provided at the intersection of the bottom wall surface W1 and the vertical wall surface W2, it may be difficult to visually identify the corner CN indicating the boundary between the bottom wall surface W1 and the vertical wall surface W2. In this case, the length of the bottom wall surface W1 can be determined by taking the center of the width direction of the curved or rounded surface as the corner CN. The length may be 1.0 times or more, 1.2 times or more, 1.5 times or more, or 2.0 times or more the depth of the cutout portion BP1'. The length may be, for example, 5 mm or more. The length may be 8 mm or more, 10 mm or more, 15 mm or more, or 20 mm or more. The length may be, for example, 30 mm or less, 20 mm or less, or 10 mm or less.

[0124] The highly corrosion-resistant portion HP formed by filling the notch BP1' with the highly corrosion-resistant metal has a cross-sectional shape when cut in the thickness direction, which is oblong in the direction from the center of the metal ring to the edge, thereby ensuring a wide highly corrosion-resistant surface SH while saving the amount of highly corrosion-resistant metal used.

[0125] The notch BP1' on the first surface 2100a side and the notch BP1' on the second surface 2100b side may have the same or different shapes in the thickness direction cross section TX. In this embodiment, the shape of the space in the notch BP1' is an annular plate on both the first surface 2100a side and the second surface 2100b side. Therefore, the highly corrosion-resistant portion HP formed in this embodiment is also an annular plate.

[0126] For example, an annular plate made of a highly corrosion-resistant metal may be prepared in advance so as to have a shape corresponding to the notch portion BP1′, and the metal ring 2100 may be formed by fitting the annular plate into one or both of the notch portion BP1′ on the first surface 2100a side and the notch portion BP1′ on the second surface 2100b side. The fitted annular plate may be fixed to the primary member 2100′ by spot welding or shrink fitting. In this embodiment, build-up welding is performed to achieve high joint strength between the highly corrosion-resistant portion HP and the base portion BP.

[0127] As shown in Figures 13a to 13c, build-up welding can be performed, for example, so that the beads WB are continuously formed in the circumferential direction. Build-up welding can be performed so that the beads WB are arranged side by side on the bottom wall surface W1. Build-up welding may be performed so that the formed height of the beads WB is equal to or greater than the depth of the cutout portion BP1' and so that the beads WB do not overlap in the vertical direction. Build-up welding may be performed so that the formed height of the beads WB is less than the depth of the cutout portion BP1' and so that the beads WB are stacked in the vertical direction.

[0128] It is preferable to perform build-up welding so as to form a layered structure including a first weld layer BL1 in contact with the bottom wall surface W1 and a second weld layer BL2 in contact with the first weld layer BL1 from the opposite side of the bottom wall surface W1. The first weld layer BL1 and the second weld layer BL2 can be formed by welding so that multiple beads WB are arranged concentrically when the protection ring 210 is viewed in the direction of its central axis. The first weld layer BL1 and the second weld layer BL2 can be formed by welding so that a single bead WB is spirally shaped when the protection ring 210 is viewed in the direction of its central axis. When welding so that the bead WB is concentrically or spirally shaped, the welding can be performed sequentially from the inside in the radial direction. It is preferable that the first weld layer BL1 and the second weld layer BL2 be formed so that the cross sections of the multiple beads WB are aligned in the horizontal direction (radial direction) in the thickness direction cross section TX.

[0129] The build-up welding as described above can be performed by piling up the beads WB so that they are raised higher than the first surface 2100a and the second surface 2100b, as shown in FIG. 13c.

[0130] In build-up welding, even if the bead WB is formed using a welding rod made of a highly corrosion-resistant metal, the iron-based metal dissolves into the bead WB in the area directly contacting the primary component 2100′ (the bottom wall surface W1 and the vertical wall surface W2). By forming the above-described layered structure, the second weld layer BL2 can be made more pure than the first weld layer BL1, and the iron-based metal content in the second weld layer BL2 can be reduced. Furthermore, in this embodiment, since the highly corrosion-resistant portion HP (plate-shaped region) has a horizontally elongated cross section, the iron-based metal dissolves from the vertical wall surface W2 and does not easily reach the intermediate portion of the second weld layer BL2, excluding both radial ends. Therefore, the purity of the highly corrosion-resistant metal can be made high in this intermediate portion.

[0131] After build-up welding, the excess welding material can be removed by cutting or the like to form a secondary member 2100" as shown in Figure 14. The secondary member 2100" may be used as a metal ring 2100 as is, and glass powder may be baked to form a glass layer GL. The secondary member 2100" may also be further treated, such as by chemical conversion treatment, to form a metal ring 2100.

[0132] The protection ring 210 is produced by a frosting process in which a green product having an unfired glass layer is produced by, for example, spraying a slurry containing glass powder onto the metal ring 2100, and a firing process in which the green product is fired in a furnace. In this process, the frosting may be performed to cover only a portion of the highly corrosion-resistant surface SH so that the edge of the glass layer is positioned on the highly corrosion-resistant surface SH, or the frosting may be performed to cover the entire highly corrosion-resistant surface SH so that the edge of the glass layer is positioned on the base surface SB.

[0133] The metal ring 2100 formed as described above has a base surface SB, which is the surface of the base portion BP, and a highly corrosion-resistant surface SH, which is the surface of the highly corrosion-resistant portion HP. As shown in FIG. 15a, when viewed from the thickness direction of the glass layer GL to be coated, the metal ring 2100 has the base surface SB at its radially outer edge, and the highly corrosion-resistant surface SH located inside it. As shown in FIGS. 15b and 16a, the glass layer GL is baked onto the metal ring 2100 so as to cover part or all of the highly corrosion-resistant surface SH. In the metal ring 2100 illustrated in the figures, the highly corrosion-resistant portion HP has a plate-shaped region PA, which, as described above, is composed only of the plate-shaped region PA.

[0134] In the protection ring 210 of this embodiment, a glass layer GL is baked onto the first surface 2100a, the second surface 2100b, and the inner peripheral side surface 2100c1 of the metal ring 2100. The protection ring 210 is a glass-coated product in which a glass layer GL is baked onto the surface of a metal ring 2100, which is a metal product. The metal ring 2100 comprises a base portion BP made of an iron-based metal and a highly corrosion-resistant portion HP made of a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal. The surface of the metal ring 2100 is provided with a highly corrosion-resistant surface SH, which is the surface of the highly corrosion-resistant portion HP. One side of the highly corrosion-resistant portion HP is the highly corrosion-resistant surface SH, and the other side opposite the highly corrosion-resistant surface SH is a bonding surface CF with the base portion BP. A plate-shaped region PA is provided, the cross section of which when cut along a plane perpendicular to the highly corrosion-resistant surface SH is a horizontally elongated band, and the glass layer GL is bonded to the metal ring 2100 so as to cover part or all of the plate-shaped region PA.

[0135] The glass layer GL is formed by baking glass onto the metal ring 2100. Glass has a lower linear expansion coefficient than metal and undergoes less volume change due to heat. In other words, during the cooling process after baking, the metal ring 2100 shrinks more than the glass layer GL. As a result, the glass layer GL is under compressive stress. The vertical wall surface W2 is the bonding surface between the iron-based metal and the highly corrosion-resistant metal and is nearly perpendicular to the bonding surface of the glass layer GL. In this location, excessive stress may be generated due to factors such as the difference in the linear expansion coefficients between the iron-based metal and the highly corrosion-resistant metal. In this embodiment, the plate-shaped region PA is horizontally elongated, ensuring a certain distance between the first vertical wall surface W21 and the second vertical wall surface W22. Therefore, even if chipping occurs at the edge GLe of the glass layer GL, the chipping can be prevented from progressing along the highly corrosion-resistant surface SH formed by the plate-shaped region PA.

[0136] As described above, the highly corrosion-resistant portion HP in this embodiment is annular. That is, the plate-shaped region PA extends in the circumferential direction of the protection ring 210, and the horizontally elongated cross-sectional shape is continuous not only in a single plane but also in the depth direction (circumferential direction) of the cross-section. In this embodiment, the cross-sectional shape in all planes including the central axis of the protection ring 210 is horizontally elongated. The plate-shaped region PA in this embodiment may be formed so that the same cross-sectional shape continues in the extension direction, or may be formed so that the thickness and width dimensions of the cross-sectional shape change in the depth direction (circumferential direction) while maintaining the horizontally elongated cross-sectional shape. In glass-coated products other than the protection ring 210 illustrated in the figures, the plate-shaped region may be, for example, a polygonal frame plate (square frame plate, hexagonal frame plate).

[0137] To prevent chipping, the metal product may be formed so that most of the glass-coated surface is the highly corrosion-resistant surface SH, but the highly corrosion-resistant portion HP does not need to be provided over an excessively large area. For example, the highly corrosion-resistant portion HP and its plate-shaped region PA may be formed in a circular or polygonal plate shape. However, to reduce the amount of highly corrosion-resistant metal used and eliminate the labor required for welding, the highly corrosion-resistant portion HP and its plate-shaped region PA may be formed in a strip-like shape extending along the edge of the glass layer GL. In this case, a region whose cross-sectional shape in a plane perpendicular to the extension direction of the plate-shaped region PA is a horizontally elongated strip extending continuously throughout the entire section of the plate-shaped region PA, thereby preventing chipping from progressing in a direction intersecting the plate-shaped region PA. The plate-shaped region PA does not necessarily have to be formed over the entire length of the edge of the glass layer GL, but may be formed only in a portion of the entire section. The plate-shaped region PA may be formed to cover at least 50%, at least 70%, or at least 90% of the length of the edge of the glass layer GL. The plate-like region PA is preferably provided over the entire length (100%) of the edge portion of the glass layer GL.

[0138] Chipping typically progresses in a direction (radial direction of the protection ring 210) perpendicular to the direction in which the edge GLe of the glass layer GL extends (direction of arrow D in FIG. 15b ). Therefore, the highly corrosion-resistant surface SH, which prevents the chipping from progressing, preferably has a certain radial dimension or greater. The radial dimension of the highly corrosion-resistant surface SH can be determined, for example, by measuring the distance between the boundary line LL between the highly corrosion-resistant surface SH and the base surface SB in the thickness direction cross section TX. The radial dimension of the highly corrosion-resistant surface SH can be, for example, 3 mm or greater. This dimension (distance between boundary lines LL) may be 4 mm or greater, 5 mm or greater, 6 mm or greater, 8 mm or greater, or 10 mm or greater. The dimension (distance between boundary lines LL) may be, for example, 30 mm or less. It may also be 20 mm or less. The dimension (distance between boundary lines LL) may be 15 mm or less, or 10 mm or less.

[0139] For example, as shown in FIG. 16a , the plate-like region PA can be formed such that at least a portion thereof has a thickness of 0.05 mm or greater when a virtual line segment XL perpendicular to the highly corrosion-resistant surface SH (first surface 2100a) is drawn in the thickness direction cross section TX, a first intersection XP1 between the virtual line segment XL and the highly corrosion-resistant surface SH, and a second intersection XP2 between the virtual line segment XL and the joint surface CF (bottom wall surface W1) are determined. The distance between the second intersection XP2 and the first intersection XP1 is defined as the “thickness.” The thickness of at least a portion of the plate-like region PA may be 0.1 mm or greater, 0.3 mm or greater, or 0.5 mm or greater. The thickness of at least a portion of the plate-like region PA may be 1.0 mm or greater, 1.5 mm or greater, 2 mm or greater, or 2.5 mm or greater. The thickness of at least a portion of the plate-like region PA may be 3 mm or greater, or 4 mm or greater. The thickness of the plate-like region PA may be, for example, 20 mm or less, or 10 mm or less. The thickness may be, for example, 8 mm or less, 6 mm or less, or 4 mm or less. The plate-like region PA may be formed so that, for example, 50% or more of the region has the above-described thickness. The proportion of the region of the plate-like region PA having the above-described thickness may be 60% or more, 70% or more, 80% or more, or 90% or more. The plate-like region PA may have the above-described thickness throughout the entire region.

[0140] In this embodiment, the cross-sectional shape of the plate-like region PA in the thickness direction cross section TX is horizontally elongated. It is preferable that the cross-sectional shape has a predetermined flatness. When the cross-sectional shape of the plate-like region PA is a horizontally elongated rectangle, the flatness can be calculated using the following formula: Flatness (%) = Short Side ÷ Long Side × 100%. If the cross-sectional shape of the plate-like region PA in the thickness direction cross section TX is not rectangular and the short side and long side are not uniquely defined, the flatness can be calculated by determining the long side and short side of the rectangle with the largest area among the horizontally elongated rectangles that can be drawn to fit within the plate-like region PA. By ensuring that the region composed of the highly corrosion-resistant metal in the plate-like region PA has such a horizontally elongated shape, it is possible to suppress the application of large stress to the glass layer GL. If the cross-sectional shape of the plate-like region PA is not rectangular, but is, for example, a shape (trapezoid) as shown in Figure 16a, then the rectangle with the largest area can be found among the rectangles of a certain width that can be drawn inside the trapezoid, as illustrated in Figure 16d, and the length of its short side L21 and the length of its long side L22 can be found to calculate the flatness (L21 / L22 x 100%).

[0141] The cross-sectional shape of the plate-like region PA is not limited to a rectangle, but may also be rounded as shown in Figure 16e. In this case, the flatness can be calculated by determining the long and short sides of the rectangle with the largest area among the rectangles inscribed within the contour line defining the plate-like region PA. If there are multiple rectangles with the largest area among the rectangles inscribed within the contour line, the flatness is generally calculated based on the length of the short side and the long side of the rectangle with the longest side. The plate-like region PA may also have a more rounded cross-sectional shape, or may have a shape resembling a horizontally elongated ellipse cut in half along its long side. In this case, the flatness can also be calculated in the same manner as described above.

[0142] The flatness is preferably 50% or less. The flatness may be 45% or less, 40% or less, 35% or less, 30% or less, or 25% or less. The flatness may be, for example, 12.5% ​​or more. The flatness may be 15% or more, or 17.5% or more.

[0143] The shape of the plate-like region PA as described above may be the same or different between the highly corrosion-resistant portion HP on the first surface 2100a side and the highly corrosion-resistant portion HP on the second surface 2100b side.

[0144] 16a, the glass layer GL provided in the protection ring 210 may have a multilayer structure including a subbing glass layer GL1 that is in direct contact with the metal ring 2100, and a top-drawn glass layer GL2 that is in contact with the subbing glass layer GL1 from the side opposite the metal ring 2100 and is bonded to the metal ring 2100 via the subbing glass layer GL1. Both the subbing glass layer GL1 and the top-drawn glass layer GL2 may cover the entire highly corrosion-resistant surface SH, with their edges GLe located on the base surface SB.

[0145] As shown in Fig. 16b, the glass layer GL may be provided such that only the base glass layer GL1 entirely covers the highly corrosion-resistant surface SH, or such that the edges of the top glass layer GL2 are positioned on the highly corrosion-resistant surface SH. As shown in Fig. 16c, the glass layer GL may be provided such that the edges of both the base glass layer GL1 and the top glass layer GL2 are positioned on the highly corrosion-resistant surface SH.

[0146] In the embodiment shown in Fig. 16c, the edge GLe of the glass layer GL is located on the highly corrosion-resistant surface SH, which can prevent chipping from occurring. To facilitate the fulfillment of such a function, a highly corrosion-resistant portion HP as shown in Fig. 17a may be provided on the protection ring 210.

[0147] In the fifth example of the protection ring 210 shown in Figure 17a, the metal ring 2100 comprises a base portion BP made of an iron-based metal and a highly corrosion-resistant portion HP made of a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal, and the surface of the metal ring 2100 is provided with a base surface SB which is the surface of the base portion BP and a highly corrosion-resistant surface SH which is the surface of the highly corrosion-resistant portion HP, and when the edge portion of the glass layer GL is viewed from the thickness direction of the glass layer GL, the highly corrosion-resistant surface SH is arranged to extend from the edge of the metal ring 2100, and the edge of the glass layer GL is located on the highly corrosion-resistant surface SH.

[0148] In the protection ring 210 shown in FIG. 17a, similarly to the protection ring shown in FIG. 16a, it is preferable that the plate-like region PA has a predetermined flatness (L21 / L22×100% in FIG. 17b).

[0149] As described above, in the protection ring 210 illustrated in FIG. 17a, the end of the glass layer GL, which is likely to be a chipping starting point, is bonded to the highly corrosion-resistant surface SH. Bonding of the glass layer GL to the highly corrosion-resistant surface SH is performed by baking. The highly corrosion-resistant surface SH extends outward from the glass layer GL beyond the edge GLe of the glass layer GL and reaches the edge of the metal ring 2100. The corner between the first surface 2100a and the outer peripheral side surface 2100c2 may be rounded or chamfered. Even in such cases, the area where the glass layer GL is formed can be easily determined using the edge of the metal ring 2100 (the edge of the chamfered portion on the outer peripheral side surface 2100c2 side) as a guide, making it easier to suppress chipping. The glass layer GL may also be provided so as to extend beyond the corner and wrap around the outer peripheral side surface 2100c2.

[0150] The protection ring 210 illustrated in the figures has two highly corrosion-resistant portions HP, one on each of the first surface 2100a and the second surface 2100b of the metal ring 2100. In the protection ring 210 illustrated in the figures, the two highly corrosion-resistant portions HP are each laminated on the base portion BP in the thickness direction cross section TX, and the highly corrosion-resistant portions HP have a joint surface CF with the base portion BP that is the opposite side to the highly corrosion-resistant surface SH. It is also possible to form the highly corrosion-resistant portions HP with the same thickness as the metal ring 2100 and form the highly corrosion-resistant surfaces SH on both the first surface 2100a and the second surface 2100b with a single highly corrosion-resistant portion HP, but doing so as described above can reduce the amount of highly corrosion-resistant metal used.

[0151] The protection ring 210 shown in Figure 17a has a first surface 210a facing the underside of the lid body 220, a second surface 210b opposite the first surface 210a facing the flange portion 122 of the container nozzle 120, an inner peripheral side surface 210c1 connecting the inner peripheral edge of the first surface 210a to the inner peripheral edge of the second surface 210b, and an outer peripheral side surface 210c2 connecting the outer peripheral edge of the first surface 210a to the outer peripheral edge of the second surface 210b. In the protection ring 210, the metal ring 2100 is exposed and not covered by the glass layer GL on these inner and outer peripheral sides 210c2. Furthermore, at both axial ends of the protection ring 210, the outer peripheral side surface 210c2 is a highly corrosion-resistant surface SH, while the middle portion is a base surface SB. Thus, the formation of the glass-covered surface and the exposed surface in the second invention can be similar to that of the first invention. In the second invention, the formation conditions of the glass-covered surface and the exposed surface may be different from those in the first invention.

[0152] When the lid is opened or closed, liquid adhering to the underside of the lid main body 220 may adhere to the protection ring 210. In such a case, to prevent rust or the like from occurring on the base surface SB, the entire outer circumferential side surface 210c2 may be made into a highly corrosion-resistant surface SH, as shown in Fig. 18. That is, the highly corrosion-resistant surface SH of the metal ring 2100 may be provided so as to extend beyond the corner between the first surface 2100a and the outer circumferential side surface 2100c2 to the outer circumferential side surface 2100c2 and to the corner between the outer circumferential side surface 2100c2 and the second surface 2100b.

[0153] In the sixth example of the protection ring 210 illustrated in Figure 18, the parts made of highly corrosion-resistant metal include a first plate-shaped region PA (first plate-shaped region PA1) that constitutes the highly corrosion-resistant surface SH on the first surface 2100a, and a second plate-shaped region PA (second plate-shaped region PA2) that constitutes the highly corrosion-resistant surface SH on the second surface 2100b, and a connection portion PAC that connects them in the vertical direction at the radially outer edge portion of the metal ring 2100 to form the highly corrosion-resistant surface SH on the outer side surface 2100c2, and they are joined so as to form a C-shaped cross section.

[0154] In this embodiment, the entire exposed surface of the metal ring 2100 becomes the highly corrosion-resistant surface SH, so that the protection ring 210 can exhibit excellent corrosion resistance.

[0155] The container nozzle 120 can have a configuration similar to that of the protection ring 210, as shown in Figure 19. That is, in the fourth example of the container nozzle 120 shown in Figure 19, a notch is provided in the flange portion 1220 of the metal nozzle 1200 serving as the base, and a highly corrosion-resistant metal is filled in the notch to form a highly corrosion-resistant portion HP having a plate-shaped region PA. A highly corrosion-resistant surface SH and a base surface SB are provided on the upper surface of the flange portion 1220, and glass is baked to cover part or all of the plate-shaped region PA that constitutes the highly corrosion-resistant surface SH, forming a glass layer GL. The container nozzle 120 also has a glass layer GL provided on the plate-shaped region PA, which has a horizontally elongated band-like shape in cross section in the thickness direction, thereby preventing chipping from progressing.

[0156] The container nozzle 120 and the like may also employ a fitted structure as shown in FIG. 20a. The fifth example of the container nozzle 120 shown in FIG. 20a has a fitted structure in which a step is formed on the surface of a metal product and a glass layer GL is fitted into the lower step of the step. In the container nozzle 120 illustrated in FIG. 20a, the highly corrosion-resistant portion HP has a step, and the highly corrosion-resistant surface SH has a low step region SHL on the lower step side of the step, a high step region SHH on the higher step side of the step, and a connection region SHC connecting the low step region SHL and the high step region SHH. The glass layer GL is bonded to the low step region SHL, and the edge of the glass layer GL is bonded to the connection region SHC. These bonding processes can be performed when the glass layer GL is formed by baking the glass. In this embodiment, chipping can be suppressed. Such a fitting structure can be adopted for the protection ring 210 and other glass-coated products.

[0157] In the container nozzle 120 shown in FIG. 20a, similarly to the protection ring, it is preferable that the plate-like region PA has a predetermined flatness (L1 / L2×100% in FIG. 20b).

[0158] While the above examples show products with an annular shape in plan view, such as the protection ring 210 and the metal cover flange portion 2230, the above-described effects can also be achieved with products that are square in plan view or with polygonal shapes other than squares. Also, while the above examples show glass-lined products, the same effects can also be achieved with enamel products other than glass-lined products, such as glass-lined products.

[0159] As described above, the glass-coated product according to the second invention is specifically shown in the following (B1) to (B4).

[0160] (B1) A glass-coated product comprising a metal product and a glass layer bonded to the surface of the metal product, wherein the metal product comprises a base portion made of an iron-based metal and a highly corrosion-resistant portion made of a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal, the surface of the metal product is provided with a highly corrosion-resistant surface which is the surface of the highly corrosion-resistant portion, and the highly corrosion-resistant portion is provided with a plate-like region having one side which is the highly corrosion-resistant surface and another side opposite the highly corrosion-resistant surface which is a bonding surface with the base portion, and which has a cross section which is a horizontally elongated band when cut along a plane perpendicular to the highly corrosion-resistant surface, and the glass layer is bonded to the metal product so as to cover part or all of the plate-like region.

[0161] (B2) The glass-coated product according to (B1), wherein the highly corrosion-resistant portion is joined to the base portion at both ends in at least one direction along the highly corrosion-resistant surface.

[0162] (B3) The glass-coated product according to (B1) or (B2), wherein the flatness of the plate-like region in the cross section is 12.5% ​​or more and 50% or less.

[0163] (B4) A glass-coated product according to any one of (B1) to (B3), which is a glass-lined product.

[0164] Various modifications can also be made to the glass-lined product according to the second invention.

[0165] 1: Reaction tank, 10: Tank body, 10c: Storage space, 100: Metal tank, 110: Main body, 111: Body, 112: Bottom, 113: Ceiling, 120: Container nozzle, 121: Cylindrical portion, 122: Flange, 1100: Metal tank body, 1110: Body, 1110c: Central axis, 1120: Bottom, 1130: Ceiling, 1200: Metal nozzle, 1210: Cylindrical portion, 1220: Flange, 1220a: First surface, 1220b: Second surface, 1220c: Side surface, 20: Lid, 200: Metal lid material, 210: Protection ring, 210c1: Inner peripheral side surface, 210c2: Outer peripheral side surface, 220: lid main body, 220w: glass window, 221: base portion, 222: lid cylindrical portion, 223: lid flange portion, 224: glass plate, 225: window frame portion, 2100: metal ring, 2100': primary member, 2100": secondary member, 2100a: first surface, 2100b: second surface, 2100c1: inner peripheral side surface, 2100c2: outer peripheral side surface, 2110: inner ring, 2120: outer ring, 2200: metal lid, 2210: base portion, 2220: metal lid cylindrical portion, 2230: gold lid flange portion, BP: base portion, BP1: notch portion, BP1': notch portion, CN: corner, CF: joining surface, GL: glass layer, GL1: undercoat glass layer, GL2: topcoat glass layer, GLe: edge, HP: high corrosion resistant part, HPa: plate-like region, HPn: variable thickness region, LL: boundary line, S1: gasket, S2: gasket, S3: gasket, S4: gasket, SB: base surface, SH: high corrosion resistant surface, SHC: connection region, SHH: high step region, SHL: low step region, W1: bottom wall surface, W2: vertical wall surface, WB: bead

Claims

1. A glass-coated product comprising a metal product and a glass layer bonded to a surface of the metal product, wherein the metal product comprises a base portion made of an iron-based metal and a highly corrosion-resistant portion made of a highly corrosion-resistant metal having a higher content of at least one of nickel and chromium than the iron-based metal, the surface of the metal product is provided with a base surface which is the surface of the base portion and a highly corrosion-resistant surface which is the surface of the highly corrosion-resistant portion, and when the edge of the glass layer is viewed from the thickness direction of the glass layer, the highly corrosion-resistant surface is provided so as to extend from the edge of the metal product, and the edge of the glass layer is located on the highly corrosion-resistant surface.

2. A glass-coated product as described in claim 1, wherein when a boundary line is set along the edge of the glass layer when viewed in the thickness direction, and an imaginary plane perpendicular to the extension direction of the boundary line is set and a cross section on the imaginary plane is taken as a thickness direction cross section, the highly corrosion resistant portion is laminated on the base portion in the thickness direction cross section, and the highly corrosion resistant portion has a joint surface with the base portion that is the side opposite to the highly corrosion resistant surface.

3. A glass-coated product according to claim 2, wherein the cross-sectional shape of the highly corrosion-resistant portion in the thickness direction cross section is a horizontally elongated shape that is long in a direction perpendicular to the thickness direction.

4. A glass-coated product according to claim 2, wherein the shape of said joining surface in the cross section in the thickness direction is linear.

5. A glass-coated product as described in claim 2, wherein the highly corrosion-resistant portion has a plate-like region having a horizontally elongated band shape in the thickness direction cross section, and the glass layer has an edge portion joined to the plate-like region.

6. A glass-coated product as described in claim 2, wherein the highly corrosion-resistant portion has a variable thickness region in which the thickness observed in the thickness direction cross section changes at a constant rate in a direction perpendicular to the thickness direction, and the glass layer has an edge portion joined to the variable thickness region.

7. A glass-coated product as claimed in claim 1, wherein the metal product is provided with a plate-like portion having a first surface, a second surface opposite the first surface, and a side surface connecting edges of the second surface and the first surface, the highly corrosion-resistant surface constituting at least a part of the first surface, extending onto the side surface beyond a corner between the first surface and the side surface, and extending to a corner between the side surface and the second surface, and the edge of the glass layer is located on the highly corrosion-resistant surface.

8. A glass-coated product as described in claim 1, wherein the highly corrosion-resistant portion has a step, and the highly corrosion-resistant surface is provided with a low-step region on the low-step side of the step, a high-step region on the high-step side of the step, and a connection region connecting the low-step region and the high-step region, and the glass layer is bonded to the low-step region, and an edge portion of the glass layer is bonded to the connection region.

Images