Method of manufacturing enameled product with metal sheet

Abstract

To provide an enamel product with a metal sheet in which the metal sheet is joined to a glass layer in a good state.SOLUTION: To provide a method for manufacturing an enamel product with a metal sheet by which the enamel product with the metal sheet is manufactured by ultrasonically joining the metal sheet to the surface of a glass layer of the enamel product provided with a metal base material and the glass layer baked on the metal base material.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to enamel products. [Background technology]

[0002] Traditionally, enamel products have been widely used in building materials such as bathtubs and wall panels, and cooking equipment such as pots. In addition to these general-purpose enamel products (hereinafter also referred to as "general-purpose enamel products"), enamel products known as glass-lined products are widely used in the manufacturing processes of pharmaceuticals, chemical products, processed foods, and the like. Glass-lined products and general-purpose enamel products are endowed with surface properties such as corrosion resistance by coating a metal substrate with glass. Among enamel products, glass-lined products are required to meet the quality standards specified in the former JIS R 4201, and meticulous inspections are carried out to check corrosion resistance and other aspects when these glass-lined products are manufactured.

[0003] In enamel products, even if the glass layer covering the metal substrate is damaged in one place, such as by a chip or pinhole, it will be difficult to use the product, even if the other parts are in good condition. For this reason, damaged parts of the glass layer are repaired by screwing in a cover made of a highly corrosion-resistant metal such as tantalum (see Patent Document 1 below, paragraph 0038, etc.). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-071140 Summary of the Invention [Problem to be solved by the invention]

[0005] Covering a portion of a glass layer with a metal sheet can be used for purposes other than repairing defects. For example, a metal sheet may be used to cover the sensor attachment location when a temperature sensor or the like is attached to the surface of the glass layer to prevent the sensor from coming into direct contact with the fluid. However, the screw fastening method disclosed in Patent Document 1 requires a lot of work to attach the metal sheet. Simply attaching a tantalum sheet or the like to the surface of the glass layer could involve using an adhesive, but this would expose the adhesive on the surface of the enamel product, potentially compromising the benefits of the enamel product. Furthermore, sufficient research has not been conducted on methods for bonding a metal sheet to a glass layer in a satisfactory state, and a method for manufacturing an enamel product with a metal sheet in which the metal sheet is bonded to the glass layer in a satisfactory state has not yet been established. Therefore, an objective of the present invention is to provide a method for manufacturing an enamel product with a metal sheet. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides: Provided is a method for producing an enamel product with a metal sheet, which comprises an enamel product having a metal substrate and a glass layer baked onto the metal substrate, and ultrasonically bonding a metal sheet to the surface of the glass layer to produce the enamel product with a metal sheet. [Effects of the Invention]

[0007] According to the present invention, an enamel product with a metal sheet can be provided in which the metal sheet is bonded to the glass layer in a good condition. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view showing an enamel product with a metal sheet. [Figure 2] FIG. 2 is a schematic enlarged view showing the area where the metal sheet is joined in the enamel product with the metal sheet (area surrounded by a dashed line and indicated by the symbol II). [Figure 3a]FIG. 3a is a schematic cross-sectional view showing the state of a cross section taken along the line IIIa-IIIa in FIG. [Figure 3b] FIG. 3b is a schematic cross-sectional view of the location shown in FIG. 3a before the metal sheets are joined. [Figure 4] FIG. 4 is a schematic cross-sectional view of an enamel product with a metal sheet in which a filling has been applied to the broken portion. [Figure 5] FIG. 5 is a schematic diagram showing the configuration of an apparatus used to ultrasonically bond a metal sheet to an enamel product. [Figure 6] Figure 6 is a scanning electron microscope (SEM) image showing the interface between the glass layer and platinum sheet in a sample in which a platinum sheet was ultrasonically bonded to the surface of a glass-lined product. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes an embodiment of the present invention, taking as an example a metal sheet-attached enamel product in which a metal sheet is joined to the glass layer that forms the inner wall surface of a vertical tank, which is a glass-lined product. The metal sheet-attached enamel product shown in Figure 1 is a repaired tank 1 in which a part of the glass layer of an existing tank has been damaged and the damaged area has been repaired by covering the damaged area with a metal sheet. The product comprises a tank 10 and a metal sheet 20 joined to the tank 10.

[0010] As shown in Figure 2, the tank 10 in the repaired tank 1 is a glass-lined product including a metal substrate 11 and a glass layer 12 baked onto the surface of the metal substrate 11. As described above, the glass layer 12 in the tank 10 of this embodiment has a broken area 12c where a portion of the glass constituting the glass layer 12 has fallen off and is recessed from the surface 12a of the glass layer 12. As shown in Figures 3a and 3b, the unrepaired tank 10x before repair has a broken area 12c that is a recess extending through the entire thickness of the glass layer 12, and the broken area 12c is in a state where the metal substrate 11 is exposed when viewed from the surface 12a side of the glass layer 12.

[0011] The repaired tank 1 of this embodiment is manufactured by placing a metal sheet before joining (hereinafter also referred to as "unjoined metal sheet 20x") so as to cover the damaged portion 12c of the unrepaired tank 10x, and ultrasonically joining the unjoined metal sheet 20x to the glass layer 12 of the unrepaired tank 10x. Note that the ultrasonic joining of the unjoined metal sheet 20x can be performed so that the joining area 1a between the glass layer 12 and the metal sheet 20 formed after joining is a ring shape surrounding the damaged portion 12c.

[0012] The target of repair using the metal sheet 20 may be a damaged area such as the broken area 12c shown in the figure, where glass has fallen off the entire thickness of the glass layer 12 in the unrepaired tank 10x. It may also be a damaged area where a portion of the glass has fallen off the surface 12a of the glass layer 12, resulting in a recess extending partway through the thickness of the glass layer 12. The damaged area to be repaired may not only be a recess formed by glass falling off, but also a crack on the surface 12a, where no glass has fallen off. The repair target may also be an area that appears fine on the surface but has a large internal void, which could potentially cause damage to the glass layer 12 even with an impact that would not normally cause a problem. In other words, repair of a glass-lined product may be performed as a preventative measure. While having an uneven surface on the glass layer 12 is expected to facilitate bonding during repair, the surface of the glass layer 12 may also be polished to make it smooth. Smoothing the surface of the glass layer 12 is expected to ensure uniform surface contact between the glass layer and the metal sheet when the glass layer and the metal sheet are brought into contact.

[0013] As shown in Figure 4, repairs may be made by filling the broken area 12c with filler 30. Specifically, repairs may be made by filling the broken area 12c with glass, metal, or resin, and then ultrasonically bonding the unbonded metal sheet 20x. Furthermore, in areas where there is no visible problem on the surface but a large void has occurred internally, repairs may be made by striking or cutting the surface 12a of the glass layer 12 to remove the glass from the void to the surface 12a, forming a recess in the area, and then filling the area with filler 30.

[0014] The glass, metal, and resin used as the filler 30 in the damaged area 12c may be in the form of long fibers or particles. Alternatively, the glass, metal, and resin may be formed into a single mass by, for example, filling a recess formed in the glass layer 12 and then heating and melting it. The filler 30 may be filled so as to be flush with the surface 12a of the glass layer 12, or may be filled so as not to reach the surface 12a, or may be filled into the recess so as to slightly protrude from the surface 12a. Filling the recess with a mass of metal or glass before ultrasonically bonding the unbonded metal sheet 20x, and then ultrasonically bonding the mass so that at least a portion of the mass is flush with or protrudes from the surface 12a of the glass layer 12, can produce a repaired tank 1 in which the metal sheet 20 is ultrasonically bonded not only to the surface 12a of the glass layer 12 but also to the surface of the filler 30. In other words, in such a case, the tank 10 (glass layer 12) and the metal sheet 20 can be bonded with greater strength. In addition, by filling the recess with the filler 30 and reducing the space of the recess, it is expected that the effects of expansion and contraction of the gas present in the space when the tank 10 is pressurized or depressurized or heated or cooled can be reduced.

[0015] Each of the glass, metal, and resin may be a single type alone or a mixture of two or more types to form the filler 30. The filler 30 may be composed of, for example, a mixture of glass particles made of one glass composition and glass particles made of another glass composition, a mixture of glass particles and long glass fibers made of the same glass composition, a mixture of glass particles and resin particles, a mixture of glass particles, metal particles, and resin fibers, etc.

[0016] The glass layer 12 of this embodiment may be made of, for example, a silicate-based glass composition containing 50 mol % or more of SiO2. The glass particles or glass fibers filled in the broken portion 12c may be made of a silicate-based glass composition, similar to the glass layer 12. The glass composition may contain a glass component and an additive component that is not completely dissolved in the glass component.

[0017] The glass components in the above glass composition may include, for example, 50 mol % to 75 mol % of SiO2, 2 mol % to 15 mol % of ZrO2, 10 mol % to 25 mol % of R2O (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). Examples of additive components include one or more selected from the group consisting of TiO2, Al2O3, La2O3, B2O3, and ZnO.

[0018] The metal particles or fibers used as the filler may be made of a metal with excellent corrosion resistance, and the metal constituting the metal particles or fibers may be any metal selected from the group consisting of gold, silver, copper, palladium, platinum, rhodium, iridium, ruthenium, tantalum, zirconium, titanium, nickel, aluminum, zirconium alloys, titanium alloys, nickel alloys, and stainless steel.

[0019] The resin may be a typical thermoplastic resin or a reaction-curable resin such as a thermosetting resin. When filling the damaged area 12c with a reaction-curable resin, it need not be in a fully cured, so-called C-stage state; it may be in an A-stage or B-stage state. That is, the damaged area 12c may be filled with a reaction-curable resin that is not fully cured, and the unbonded metal sheet 20x may be ultrasonically bonded, followed by allowing the curing reaction to proceed. Examples of reaction-curable resins that can be used in this method include epoxy resins and unsaturated polyester resins.

[0020] From the viewpoints of corrosion resistance and bonding strength with the glass layer 12, the metal sheet 20 (unbonded metal sheet 20x) in the repaired tank 1 is preferably made of any metal selected from the group consisting of gold, silver, copper, palladium, platinum, rhodium, iridium, ruthenium, tantalum, zirconium, titanium, nickel, aluminum, zirconium alloys, titanium alloys, nickel alloys, and stainless steel. The unbonded metal sheet 20x to be ultrasonically bonded to the glass layer 12 may be entirely made of one of the above metals, or only the surface layer in contact with the surface 12a of the glass layer 12 may be made of the above metal. That is, the unbonded metal sheet 20x before ultrasonic bonding may be a clad sheet in which a sheet made of a metal other than the above metals is integrated with a sheet made of the above metal, or may be a sheet made of a metal other than the above metals coated with the above metal by plating or spraying.

[0021] To ultrasonically bond the unbonded metal sheet 20x to the glass layer 12 of the unrepaired tank 10x, for example, an ultrasonic bonding device A as shown in Fig. 5 can be used. The ultrasonic bonding device A illustrated in the figure includes an ultrasonic oscillator A1 that generates an ultrasonic signal using electrical energy, a vibrator A2 that ultrasonically vibrates in response to the ultrasonic signal generated by the ultrasonic oscillator A1, a horn A3 that transmits the ultrasonic vibration generated by the vibrator to the unbonded metal sheet 20x, and a back pressure machine A4 for applying a load to the horn A3. The horn A3 has a contact surface A3a that contacts the unbonded metal sheet 20x and a back surface A3b opposite the contact surface A3a, and the back pressure machine A4 is configured to contact the back surface A3b so as to apply a predetermined load to the horn A3.

[0022] In this embodiment, an unrepaired tank 10x is repaired using an ultrasonic joining device A equipped with a horn A3 having a contact surface A3a larger in area than the damaged area 12c to be repaired, and an unjoined metal sheet 20x larger in area than the damaged area 12c to be repaired. As described above, the repaired tank 1 (enameled product with metal sheet) in this embodiment is manufactured by placing an unbonded metal sheet 20x at a predetermined position on the glass layer 12 of an unrepaired tank 10x (enameled product) that has a metal base material 11 and a glass layer 12 baked onto the surface of the metal base material 11, and applying ultrasonic vibrations while pressing the unbonded metal sheet 20x toward the glass layer 12, and the product can be manufactured in a state in which the metal sheet 20 is ultrasonically bonded to the surface of the glass layer 12 with excellent strength.

[0023] When ultrasonically bonding an unbonded metal sheet 20x to the surface 12a of the glass layer 12 of the unrepaired tank 10x, for example, a thinner unbonded metal sheet 20x can improve the vibration properties of the unbonded metal sheet 20x due to ultrasonic vibration, thereby achieving a high bonding strength to the glass layer 12. On the other hand, a thicker unbonded metal sheet 20x can be advantageous in terms of strength after repair and preventing damage to the unbonded metal sheet 20x during ultrasonic bonding. The thickness of the unbonded metal sheet 20x used can be, for example, 100 μm or more. The thickness of the unbonded metal sheet 20x used may be, for example, 150 μm or more. The thickness of the unbonded metal sheet 20x used can be, for example, 1000 μm or less. The thickness of the unbonded metal sheet 20x used may be, for example, 500 μm or less. The unbonded metal sheet 20x used for repairing enamel products can be, for example, a metal sheet having an area of ​​400 mm. 2 The unbonded metal sheet 20x can be sized as follows: 2 It may be less than 100 mm 2 May be less than 40mm 2 The size of the unbonded metal sheet 20x used for repairing the enamel product may be, for example, 4 mm or less. 2 The size of the unbonded metal sheet 20x used for repairing enamel products can be 9 mm or more. 2 It may be more than that.

[0024] When ultrasonically bonding the unbonded metal sheet 20x to the surface 12a of the glass layer 12 of the unrepaired tank 10x, for example, keeping the pressure applied to the unbonded metal sheet 20x by the horn below a certain level improves the vibration properties of the unbonded metal sheet 20x, allowing for a high bonding strength to the glass layer 12. On the other hand, a higher pressure applied to the unbonded metal sheet 20x by the horn makes it easier to reliably transmit vibration energy to the unbonded metal sheet 20x. The pressure applied to the unbonded metal sheet 20x by the horn can be, for example, 2 MPa or more. The pressure applied to the unbonded metal sheet 20x by the horn may be 3 MPa or more. The pressure applied to the unbonded metal sheet 20x by the horn can be, for example, 20 MPa or less. The pressure applied to the unbonded metal sheet 20x by the horn may be 12 MPa or less, or may be 8 MPa or less. The pressure (P: MPa) is determined by multiplying the load (F: N) applied to the unbonded metal sheet 20x by the horn by the area (S: mm 2 ) and divide by (P = F / S). Note that the area of ​​the unbonded metal sheet 20x (S': mm 2 ) is smaller than the area of ​​the horn, the area of ​​the unbonded metal sheet 20x (S': mm 2 ) into the area of ​​the horn in the previous formula (S: mm 2 ) and calculate the pressure (P=F / S').

[0025] The duration of ultrasonic application by the horn in ultrasonically bonding the unbonded metal sheet 20x to the surface 12a of the glass layer 12 of the unrepaired tank 10x can be, for example, 0.01 seconds or more. The duration of ultrasonic application may be, for example, 0.05 seconds or more. The duration of ultrasonic application may be, for example, 8.00 seconds. The duration of ultrasonic application may be, for example, 1.00 seconds or less. The frequency of ultrasonic applied by the horn in ultrasonically bonding the unbonded metal sheet 20x can be, for example, 10 kHz or more. The frequency of ultrasonic application may be, for example, 15 kHz or more, or 20 kHz or more. The frequency of ultrasonic application may be, for example, 120 kHz or less. The frequency of ultrasonic application may be, for example, 100 kHz or less, or 60 kHz or less.

[0026] In ultrasonic bonding, the unbonded metal sheet 20x is rubbed against the glass layer 12 at high speed while ultrasonic vibrations are applied. Depending on the type of metal sheet, the oxide film on the surface may be removed at the initial stage, forming a new surface. Over time, the metal sheet undergoes plastic deformation at the interface between the metal sheet and the glass layer, gradually expanding the contact area until the entire metal sheet bonds to the glass layer, forming a strong joint. When applied to enamel products, it is believed that a diffusion layer of several tens of nanometers to several micrometers is formed at the interface between the glass layer and the metal sheet, resulting in interatomic attraction and enhancing adhesion.

[0027] After ultrasonic bonding, the metal sheet 20 is preferably bonded to the glass layer 12 so that, for example, when the peel load is measured using a tensile tester and the maximum value of the load is divided by the area of ​​the metal sheet 20 to determine the peel stress, a peel stress of 5 MPa or more is observed.

[0028] The metal sheet 20 may be joined to the tank 10 for purposes other than repair. The metal sheet 20 may also be used as a protective sheet when a sensor or the like is attached to the glass surface of an enamel product. The metal sheet 20 may also be used as an electrode (terminal). The joining partner of the metal sheet 20 is not limited to the tank 10, but may be various glass-lined products. Furthermore, the joining partner of the metal sheet 20 may not be a glass-lined product, but may be a general-purpose enamel product such as a cooking utensil or a wall material. In other words, the present invention is not limited to the above examples.

[0029] The present specification discloses the following inventions as described above. (1) A method for manufacturing an enamel product with a metal sheet, comprising ultrasonically bonding a metal sheet to the surface of an enamel product having a metal substrate and a glass layer baked onto the metal substrate, to manufacture the enamel product with a metal sheet.

[0030] (2) The enamel product has a broken portion where a part of the glass layer is broken, The method for manufacturing an enamel product with a metal sheet according to (1), wherein the ultrasonic bonding is carried out so as to cover the damaged area with the metal sheet.

[0031] (3) a recess recessed from the surface of the glass layer is formed at the broken portion, The method for manufacturing an enamel product with a metal sheet according to (2), wherein the ultrasonic bonding is carried out after filling the recess with glass, metal, or resin.

[0032] (4) The metal sheet A method for producing an enamel product with a metal sheet according to any one of (1) to (3), wherein the metal sheet is made of a metal selected from the group consisting of gold, silver, copper, palladium, platinum, rhodium, iridium, ruthenium, tantalum, zirconium, titanium, nickel, aluminum, zirconium alloys, titanium alloys, nickel alloys, and stainless steel. [Example]

[0033] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0034] (Example 1) Ultrasonic welding of aluminum sheets A 25 mm wide rectangular enamel product (glass-lined product, hereinafter referred to as "GL sheet") was prepared, in which a glass layer made of silicate glass was formed on one side of a metal substrate. Next, a 0.2 mm thick sheet made of aluminum alloy number A1050 was prepared as a metal sheet to be bonded to the GL sheet. This aluminum sheet was placed on top of the GL sheet with the glass layer facing upwards, and a horn approximately 5 mm square was placed on the top surface of the aluminum sheet. Ultrasonic bonding (frequency 15 kHz, application time 0.2 seconds) was performed while applying back pressure (load: 100 N) to the aluminum sheet with the horn. As a result, we were able to produce an enamel product with a metal sheet in which the aluminum sheet and GL sheet were firmly bonded. When the aluminum sheet and the GL sheet were peeled away, it was confirmed that the glass layer had undergone cohesive failure with part of the glass constituting the glass layer adhering to the aluminum sheet side.

[0035] (Example 2) Ultrasonic welding with platinum sheet, tantalum sheet, and nickel alloy sheet Platinum sheets, tantalum sheets, and nickel alloy (product name Hastelloy) sheets were prepared, and ultrasonic bonding was attempted in the same manner as in "Example 1," except that the horn load was changed from 100 N to 200 N and the ultrasonic application time was changed from 0.2 seconds to 2.0 seconds. With the platinum sheet, it was confirmed that ultrasonic bonding occurred, causing cohesive failure during peeling, just like with the aluminum sheet. However, with the tantalum sheet and nickel alloy sheet, no bonding was observed, and the interface peeled off even without applying force, indicating the need for further adjustment of the bonding conditions.

[0036] A sample was taken from the area where the platinum sheet and glass layer were bonded, and the sample was cut perpendicular to the interface between the platinum sheet and glass layer. The cross section was observed with a scanning electron microscope (SEM) and an image (SEM image) was taken. The SEM image is shown in Figure 6. As can be seen from this figure, the glass (dark area in Figure 6) and platinum (white area in Figure 6) were in a compatible state at the bonded interface, and it was confirmed that the compatible region was several tens of micrometers thick.

[0037] From the above, it can be seen that the present invention makes it possible to provide an enamel product with a metal sheet in which the metal sheet is bonded to the glass layer in a good condition. [Explanation of symbols]

[0038] 1: Repaired tank (enameled product with metal sheet), 10: Tank, 10x: Unrepaired tank, 11: Metal substrate, 12: Glass layer, 12a: Surface, 12c: Damaged area, 20: Metal sheet, 20x: Unbonded metal sheet, 30: Filling, A: ultrasonic bonding device, A1: ultrasonic oscillator, A2: vibrator, A3: horn, A3a: contact surface, A3b: back surface

Claims

1. A method for manufacturing an enamel product with a metal sheet, comprising ultrasonically bonding a metal sheet to the surface of an enamel product having a metal substrate and a glass layer baked onto the metal substrate, to manufacture the enamel product with a metal sheet.

2. The enamel product has a broken portion where a part of the glass layer is broken, 2. The method for manufacturing an enamel product with a metal sheet according to claim 1, wherein the ultrasonic bonding is carried out so as to cover the damaged portion with the metal sheet.

3. a recess recessed from the surface of the glass layer is formed at the broken portion, 3. The method for manufacturing an enamel product with a metal sheet according to claim 2, wherein the ultrasonic bonding is carried out after filling the recess with glass, metal, or resin.

4. The metal sheet 4. The method for producing an enamel product with a metal sheet according to claim 1, wherein the metal sheet is made of a metal selected from the group consisting of gold, silver, copper, palladium, platinum, rhodium, iridium, ruthenium, tantalum, zirconium, titanium, nickel, aluminum, zirconium alloys, titanium alloys, nickel alloys, and stainless steel.

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