Hearth component, hearth component production method

Abstract

This hearth component is provided with an in-incinerator exposed surface that is exposed to the inside of an incinerator. The in-incinerator exposed surface comprises a front surface and an upper surface, and at least the front surface is provided with a protective layer having grooves formed on the surface thereof.

Description

Hearth component and method for manufacturing the hearth component

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to hearth components and methods of manufacturing hearth components.

[0002] A grate is a hearth component located at the bottom of an incinerator. It moves back and forth to stir and transport waste while incinerating it. Grates are typically made of heat-resistant cast steel SCH2 and are primarily manufactured by casting. Patent No. 6730814 proposes a grate manufactured by welding together plates with a first alloy layer and a second alloy layer. Incinerators contain a mixture of incineration ash and non-combustible materials, and grates undergo thinning primarily due to corrosion from chlorine in the waste and wear from contact with hard non-combustible materials. The lifespan of a grate is generally estimated to be approximately 3 to 6 years. To continue using an incinerator, grates must be replaced periodically, but each grate is quite heavy, making replacement costly. Therefore, there is a demand for extending the lifespan of grates.

[0003] Japanese Patent Application Laid-Open No. 7-4634 proposes that the grate body be made of cast iron or high-Cr cast steel, and that a wear-resistant material made of a Co-based alloy be plasma-clad welded to the surface of at least the hanging part of the grate body that hangs down from one end of the flat part for transporting waste.

[0004] It would be desirable to provide hearth components and methods of manufacturing hearth components that have a longer life.

[0005] A hearth component according to one aspect of the present disclosure is a hearth component having an in-furnace exposed surface that is exposed inside an incinerator, the in-furnace exposed surface having a front surface and a top surface, and at least the front surface is provided with a protective layer having grooves formed on the surface.

[0006] A method for manufacturing a hearth component according to one aspect of the present disclosure is a hearth component having an in-furnace exposed surface that is exposed inside an incinerator, the in-furnace exposed surface having a front surface and a top surface, and at least the front surface is provided with a protective layer having grooves formed on its surface, the method comprising the step of forming the protective layer on a body made of casting or plate material by laser build-up welding.

[0007] FIG. 1A is a schematic diagram showing the configuration of an incineration facility according to one embodiment. FIG. 1B is a diagram showing the schematic configuration of the bottom of an incinerator according to one embodiment. FIG. 2 is a perspective view showing the schematic configuration of a hearth component according to one embodiment. FIG. 3 is a photograph of a hearth component according to one embodiment taken from diagonally above and front. FIG. 4 is a photograph of an enlarged front surface of a hearth component according to one embodiment. FIG. 5 is a diagram showing a cross section of a protective layer of a hearth component according to one embodiment, cut along a plane perpendicular to the extension direction of the grooves. FIG. 6 is a graph showing test results of a corrosion wear resistance test on the protective layer of the hearth component. FIG. 7 is a perspective view showing the schematic configuration of a hearth component according to one modified example of one embodiment. FIG. 8 is an enlarged view of a protector in the hearth component shown in FIG. 7. FIG. 9 is a perspective view showing a modified example of the hearth component shown in FIG. 2. FIG. 10 is a perspective view showing a modified example of the hearth component shown in FIG. 7.

[0008] A hearth component according to a first aspect of the embodiment is a hearth component having an in-furnace exposed surface that is exposed inside an incinerator, the in-furnace exposed surface having a front surface and a top surface, and at least the front surface is provided with a protective layer having grooves formed on the surface.

[0009] According to this embodiment, a protective layer is provided on at least the front surface of the hearth component exposed to the incinerator. This prevents the front surface of the hearth component body from being directly exposed to the corrosive gases and non-combustible materials in the incinerator, thereby preventing thinning due to corrosion, mainly caused by chlorine in the waste, and wear caused by contact with hard non-combustible materials. Furthermore, grooves are formed on the protective layer's surface. Corrosion products peel off due to wear at the ridges between the grooves. However, the peeled fine particles, ash, and small non-combustible materials accumulate on the inner surfaces of the grooves. This prevents the inner surfaces of the grooves from being directly exposed to the corrosive gases and large non-combustible materials that affect wear. This reduces thinning due to corrosion and wear, thereby minimizing the amount of thinning of the protective layer as a whole. This, in turn, extends the life of the hearth component.

[0010] By combining the protective layer with an air-cooling or water-cooling structure for cooling the hearth components, the protective layer will be kept below the metal temperature at which thinning due to corrosion or wear is unlikely to occur, thereby further extending the life of the furnace.

[0011] In addition, it is generally difficult to measure the amount of metal loss in hearth components, and the amount of metal loss is basically evaluated relative to other hearth components. However, hearth components clad with corrosion-resistant and wear-resistant alloys have little metal loss, and relative evaluation makes it difficult to determine the extent of metal loss in the clad layer. In contrast, according to the first aspect, grooves are formed on the surface of the protective layer, which has the advantage that the amount of metal loss can be visually confirmed and the approximate lifespan of the hearth components can be determined. Furthermore, by adjusting the depth of the grooves, it is possible to easily determine the timing of replacement or repair.

[0012] A hearth component according to a second aspect of the embodiment is the hearth component according to the first aspect, wherein the protective layer is also provided on at least the front side portion of the upper surface.

[0013] According to this aspect, since the protective layer is also provided on the upper surface of the hearth component exposed to the furnace interior, the protective layer prevents thinning of the grate body on the upper surface as well. In addition, since the protective layer has grooves formed on its surface, the overall amount of thinning of the protective layer can be suppressed, thereby further extending the life of the hearth component.

[0014] A hearth component according to a third aspect of the embodiment is the hearth component according to the first or second aspect, wherein the width of the groove is 5 mm or less.

[0015] The present inventors analyzed the composition of waste in incinerators and found that the average size of non-combustible materials (e.g., hard non-combustible materials) that affect wear is approximately 5 mm. Therefore, if the groove width is greater than 5 mm, not only will fine particles, ash, and small non-combustible materials be less likely to accumulate in the groove, but they will also be more likely to collide with hard non-combustible materials. In contrast, according to the third aspect, since the groove width is 5 mm or less, hard non-combustible materials are less likely to collide with the inner surface of the groove, and the inner surface of the groove is less likely to be worn. This further extends the life of the hearth components.

[0016] A hearth component according to a fourth aspect of the embodiment is the hearth component according to any one of the first to third aspects, wherein the protective layer has an alloy composition, when the entire protective layer is taken as 100% by mass, containing 10% by mass to 50% by mass of Cr, 0% by mass to 50% by mass of Fe, 0% by mass to 10% by mass of Mo, 0% by mass to 5% by mass of Si, 0.05% by mass to 1% by mass of C, 0% by mass to 5% by mass of Cu, 0% by mass to 1% by mass of Co, 0% by mass to 7% by mass of B, and the remainder being Ni and unavoidable impurities.

[0017] According to this embodiment, the corrosion resistance and wear resistance of the protective layer are improved, so that the life of the hearth components can be further extended.

[0018] A hearth component according to a fifth aspect of the embodiment is the hearth component according to any one of the first to fourth aspects, wherein the protective layer has a thickness of 1.0 to 1.2 mm.

[0019] A hearth component according to a sixth aspect of the embodiment is the hearth component according to any one of the first to fifth aspects, wherein the depth of the groove is 0.2 to 0.4 mm.

[0020] A hearth component according to a seventh aspect of the embodiment is the hearth component according to any one of the first to sixth aspects, wherein the protective layer is formed by laser build-up welding.

[0021] According to this embodiment, for example, when a protective layer is formed directly on the surface of a cast body (base material), the heat input is smaller than with plasma buildup welding or arc buildup welding, thereby suppressing thermal deformation and dilution of the cast body (base material). Furthermore, when the cast body (base material) is made of SCH2, which has poor weldability, plasma buildup welding or arc buildup welding will cause the base material to crack unless preheating is performed in advance, which is problematic because preheating requires time and cost. In contrast, by forming the protective layer by laser buildup welding, cracking of the cast body (base material) and the protective layer (buildup material) can be suppressed while omitting the preheating that would normally be required. Furthermore, grooves can be easily formed on the surface of the protective layer during construction, eliminating the need for machining after construction.

[0022] A hearth component according to an eighth aspect of the embodiment is the hearth component according to any one of the first to seventh aspects, and includes a body made of a casting, or a body made of a plate material having a first alloy layer and a second alloy layer on the front and top surfaces. The material of the body made of a casting may be SCH2. The material of the first alloy layer of the plate material body may be, for example, a 5-6C-28-32Cr-2-3Nb-3-5W alloy, which may have higher heat resistance, corrosion resistance, and / or wear resistance than the second alloy layer. The material of the second alloy layer may be a general structural rolled steel plate or a stainless steel plate with excellent weldability.

[0023] A hearth component according to a ninth aspect of the embodiment is a hearth component according to any one of the first to eighth aspects, having a side surface in contact with the front surface and the top surface, the protective layer also being provided on at least a portion of the side surface facing the front surface, and the thickness of the protective layer on the side surface being thinner than the thickness of the protective layer on the front surface.

[0024] A hearth component according to a tenth aspect of the embodiment is the hearth component according to any one of the first to ninth aspects, wherein the protective layer is formed directly on the surface of a body made of a casting or plate material.

[0025] A hearth component according to an eleventh aspect of the embodiment is a hearth component according to any one of the first to eighth aspects, further comprising a protector that is detachable from the front and top surfaces of a body made of a casting or plate material, and the protective layer is formed on the surface of the protector.

[0026] A hearth component according to a twelfth aspect of the embodiment is the hearth component according to the eleventh aspect, wherein the material of the protector is SUS.

[0027] A fire grate according to a thirteenth aspect of the embodiment is a fire grate made of a hearth component according to any one of the first to twelfth aspects.

[0028] A side grate according to a fourteenth aspect of the embodiment is a side grate made of the hearth component according to any one of the first to twelfth aspects.

[0029] A seal block according to a fifteenth aspect of the embodiment is a seal block made of the hearth component according to any one of the first to twelfth aspects.

[0030] A protector according to a sixteenth aspect of the embodiment is a hearth component having an in-furnace exposed surface that is exposed inside an incinerator, the in-furnace exposed surface having a front and an upper surface, and at least the front surface is provided with a protective layer having grooves formed on the surface, and the protector is detachable from the front and upper surfaces of a main body made of casting or plate material, and the protective layer is formed on the surface of the protector.

[0031] An incineration facility according to a seventeenth aspect of the embodiment includes a hearth component according to any one of the first to twelfth aspects.

[0032] A method for manufacturing a hearth component according to an eighteenth aspect of the embodiment is a hearth component having an in-furnace exposed surface that is exposed in an incinerator, the in-furnace exposed surface having a front surface and a top surface, and at least the front surface is provided with a protective layer having grooves formed on its surface, the method comprising the step of forming the protective layer on a body made of a casting or plate material by laser build-up welding.

[0033] Hereinafter, specific examples of embodiments will be described in detail with reference to the accompanying drawings. In the following description and the drawings used in the following description, the same reference numerals will be used for parts that may be configured identically, and duplicate descriptions will be omitted.

[0034] 1A is a schematic diagram showing the configuration of an incineration facility 10 according to one embodiment. As shown in FIG. 1A, the incineration facility 10 includes a platform 21 on which a transport vehicle (garbage truck) 22 carrying waste stops, a waste pit 3 in which waste introduced from the platform 21 is stored, a crane 5 for agitating and transporting the waste stored in the waste pit 3, a hopper 4 into which the waste transported by the crane 5 is introduced, an incinerator 1 for incinerating the waste introduced from the hopper 4, and a waste heat boiler 2 for recovering waste heat from exhaust gas generated in the incinerator 1. The structure of the waste pit 3 is not limited to the single-tier pit shown in FIG. 1A, but may also include a two-tier pit.

[0035] Waste carried in on a transport vehicle 22 is dumped from a platform 21 into a garbage pit 3 and stored in the garbage pit 3. The waste stored in the garbage pit 3 is stirred by a crane 5 and transported to a hopper 4 by the crane 5, and dumped into the incinerator 1 via the hopper 4, where it is incinerated and disposed of.

[0036] FIG. 1B is a diagram showing the schematic configuration of the bottom of the incinerator 1. In this embodiment, as shown in FIG. 1B, the incinerator 1 is a stoker type incinerator. Inside the incinerator 1, fixed grates 12 and movable grates 14 are arranged alternately and in a stepped pattern along the direction of waste flow, spanning the furnace walls 11. Note that FIG. 1B shows only one of the furnace walls 11. An end grate 16 is disposed at the upstream end of these grates 12 and 14. The fixed grate 12 is fixed to a fixed frame 18, and the movable grate 14 is fixed to a movable frame 26 that reciprocates via wheels 22 and rails 24 in response to the operation of a hydraulic cylinder 20. Furthermore, the fixed grate 12 and the movable grate 14 are fitted with scrapers 28 that slide over the upper surfaces of the fixed grate 12 or movable grate 14 located below.

[0037] A pair of side grates 30 are arranged at positions facing the end faces of the fixed grate 12, the movable grate 14, and the end grate 16 of the furnace wall 11, and a seal block 32 (also called a side seal) is arranged above each side grate 30. In Fig. 1, only one side grate 30 and one seal block 32 arranged above this grate are shown.

[0038] As a result, the waste (garbage) thrown in from the garbage hopper 4 (see FIG. 1A) is agitated and sent downward in sequence as the movable grate 14 reciprocates, and is burned. At this time, the end faces of the fixed grate 12, movable grate 14, and end grate 16 press against the surface of the side grate 30 to seal it, and the seal block 32 seals the gap between the side grate 30 and the furnace wall 11.

[0039] 1B, the grates 12, 14, the side grate 30, and the seal block 32 each have an in-furnace exposed surface that is exposed inside the incinerator 1. The in-furnace exposed surface has a front surface 61a and an upper surface 61b (see FIG. 2 described later). Of these, the front surface of the side grate 30 faces the end surfaces (side surfaces) of the grates 12, 14.

[0040] In the incinerator 1 configured as described above, one or more of the grates 12, 14, the side grate 30, and the seal block 32 may be composed of hearth components 6, which will be described later. The hearth components 6 may be air-cooled or water-cooled. Specifically, the air-cooled or water-cooled structure for cooling the hearth components 6 may be the structure described in Japanese Patent No. 3838639. The following description will be focused on the hearth components 6 that make up the grates 12, 14. However, the technology according to this embodiment can be applied to any hearth components that have an exposed surface within the incinerator 1, and is not limited to the grates 12, 14.

[0041] Fig. 2 is a perspective view showing a schematic configuration of the hearth component 6 according to this embodiment. Fig. 3 is a photograph of the hearth component 6 taken from diagonally above the front, and Fig. 4 is a photograph of the hearth component 6 taken at an enlarged scale.

[0042] As shown in Figures 2 to 4, the hearth component 6 has a main body 61 made of a casting or plate material, and a protective layer 62. When the main body 61 is made of a casting, the main body 61 made of a casting may be made of heat-resistant cast steel such as SCH2. When the main body 61 is made of a plate material, the plate material may have a second alloy layer and a first alloy layer located closer to the surface exposed inside the furnace than the second alloy layer. The first alloy layer of the main body made of a plate material may be made of a 5-6C-28-32Cr-2-3Nb-3-5W alloy. The second alloy layer may be made of a general structural rolled steel plate or stainless steel plate with excellent weldability.

[0043] 2 to 4, the protective layer 62 is provided on at least the front surface 61a of the main body 61 made of cast metal or plate material. By providing the protective layer 62 on the front surface 61a of the main body 61 made of cast metal or plate material, the portion of the front surface 61a of the fire grate main body 61 covered with the protective layer 62 is not directly exposed to the corrosive gases and non-combustible materials inside the incinerator 1, and is prevented from being corroded mainly by chlorine in the waste or from being thinned by abrasion caused by contact with hard non-combustible materials.

[0044] In the examples shown in Figures 2 to 4, the protective layer 62 is provided so as to cover the entire front surface 61a of the main body 61 made of cast iron or plate material. However, this is not limited thereto. For example, as shown in Figure 9, the protective layer 62 may be provided excluding a lower portion of the front surface 61a. In this case, when the entire front surface 61a of the main body 61 made of cast iron or plate material is taken as 100%, the protective layer 62 may be provided over an area of ​​50% or more from the upper side (i.e., excluding less than 50% from the lower side), 80% or more (i.e., excluding less than 20% from the lower side), 90% or more (i.e., excluding less than 10% from the lower side), or 95% or more (i.e., excluding less than 5% from the lower side). If the protective layer 62 is provided over the entire front surface 61a of the hearth component 6, the lower end of the protective layer 6 may come into contact with the upper surface of the lower hearth component, which may result in scraping of the upper surface of the lower hearth component when the hearth component 6 is moved back and forth. In contrast, when the protective layer 62 is provided on the front surface 61a of the hearth component 6 except for the lower portion thereof, the lower end of the protective layer 6 does not come into contact with the upper surface of the hearth component below, thereby preventing the upper surface of the lower hearth component from being thinned.

[0045] 2 and 3, the protective layer 62 may also be provided on at least the portion of the upper surface 61b of the main body 61 made of cast metal or plate material on the front surface 61a side. In this case, the upper surface 61b of the grate main body 61 is also not directly exposed to the corrosive gases and non-combustible materials in the incinerator 1, and is prevented from being thinned due to corrosion or wear. Note that the "portion on the front surface 61a side" may be in the range of 15% or less, 10% or less, or 8% or less from the front surface 61a side, when the entire upper surface 61b is taken as 100%.

[0046] As shown in Figures 3 and 4, grooves 63 are formed on the surface of the protective layer 62. In the examples shown in Figures 3 and 4, multiple linear grooves 63 parallel to the left-right direction are formed adjacent to each other in the vertical direction, but the planar pattern of the grooves 63 is not limited to this as long as they are formed to cover the surface of the protective layer 62. For example, multiple wavy grooves 63 meandering along the left-right direction may be formed adjacent to each other in the vertical direction, multiple rectangular grooves 63 of gradually varying sizes may be formed concentrically, or a single groove 63 may be formed in the shape of a rectangular spiral extending from the center to the outer edge. Figure 5 is a diagram showing a cross section of the protective layer 62 taken along a plane perpendicular to the direction in which the grooves extend (line A-A in Figure 4).

[0047] In this embodiment, grooves 63 are formed on the surface of protective layer 62, and therefore corrosion products peel off due to wear at ridges 64 between grooves 63, but the peeled fine particles, ash, small non-combustible matter, etc. accumulate on the inner surface of groove 63, so that the inner surface of groove 63 is no longer directly exposed to the corrosive gases in incinerator 1 or large non-combustible matter that affects wear, making it less likely that thinning due to corrosion or wear will occur. Therefore, the amount of thinning of protective layer 62 as a whole can be suppressed.

[0048] Generally, it is difficult to measure the amount of metal loss in hearth components, and the amount of metal loss is generally evaluated relative to other hearth components. However, hearth components overlaid with corrosion-resistant and wear-resistant alloys exhibit little metal loss, making it difficult to determine the extent of metal loss in the overlaid layer through relative evaluation. In contrast, according to the present embodiment, the grooves 63 formed on the surface of the protective layer 62 allow for visual confirmation of the amount of metal loss, thereby providing the advantage of being able to roughly determine the lifespan of the hearth component 6. Furthermore, adjusting the depth D2 of the grooves 63 makes it easy to determine the timing for replacement or repair of the grate 6. Specifically, for example, for a hearth component 6 having a protective layer 62 with a thickness of 1.2 mm and a groove 63 with a depth of 0.4 mm, assuming that the grooves 63 disappeared six years ago, the remaining useful life can be determined to be approximately 10 years.

[0049] 5, the thickness D1 of the protective layer 62 may be, for example, 1.0 to 1.2 mm. The depth D2 of the groove 63 may be adjusted as appropriate depending on the timing of replacement or repair, and may be, for example, 0.2 to 0.4 mm.

[0050] The width D3 of the groove 63 may be 5 mm or less. Here, the width D3 of the groove 63 refers to the distance between two adjacent ridges 64. The width D3 of the groove 63 is equal to the center-to-center distance between two adjacent grooves 63. The present inventors analyzed the composition of the waste in the incinerator 1 and found that the average size of non-combustible materials (e.g., hard non-combustible materials) that affect wear is approximately 5 mm. Therefore, if the groove width is wider than 5 mm, not only will fine particles, ash, and small non-combustible materials be less likely to accumulate in the groove, but the groove will also be more likely to collide with hard non-combustible materials. In contrast, when the width D3 of the groove 63 is 5 mm or less, as in the present embodiment, non-combustible materials in the waste are less likely to collide with the inner surface of the groove 63, making the inner surface of the groove 63 less susceptible to wear.

[0051] The grate body 61 has a side surface 61c in contact with the front surface 61a and the top surface 61b, and the protective layer 62 may also be provided on at least a portion of the side surface 61c of the grate body 61 on the front surface 61a side. In this case, the thickness of the protective layer 62 on the side surface 61c may be thinner than the thickness of the protective layer 62 on the front surface 61a.

[0052] The material of the protective layer 62 is not particularly limited as long as it is a material that is corrosion-resistant and wear-resistant. For example, when the entire protective layer is taken as 100 mass%, the protective layer may have an alloy composition (hereinafter sometimes referred to as the first alloy composition) that contains 10 mass% to 50 mass% of Cr, 0 mass% to 50 mass% of Fe, 0 mass% to 10 mass% of Mo, 0 mass% to 5 mass% of Si, 0.05 mass% to 1 mass% of C, 0 mass% to 5 mass% of Cu, 0 mass% to 1 mass% of Co, 0 mass% to 7 mass% of B, and the remainder being Ni and unavoidable impurities.

[0053] The reasons for the composition of each element in the first alloy composition are explained below. [Cr: 10% by mass or more and 50% by mass or less] The Cr content may be 10% by mass or more and 50% by mass or less, preferably 10% by mass or more and 35% by mass or less, and more preferably 15% by mass or more and 25% by mass or less. Cr is an essential element for maintaining corrosion resistance at high temperatures, and if it is less than 10% by mass, sufficient corrosion resistance cannot be exhibited. Cr forms precipitates (Cr borides and Cr carbides) with B and C, thereby increasing the hardness of the protective layer 63 and improving wear resistance. On the other hand, if the Cr content is too high, the melting point increases, resulting in poor workability. Therefore, it is preferable to set the upper limit at 50% by mass.

[0054] [Ni: 0% by mass or more and 70% by mass or less] The Ni content may be 0% by mass or more and 70% by mass or less, preferably 50% by mass or less. Ni is known to have excellent corrosion resistance, particularly excellent high-temperature chloride corrosion properties, and it is generally believed that the higher the Ni content, the better the material properties. On the other hand, since Ni is expensive, it is desirable to reduce the amount added from a cost perspective. The present applicant has found from corrosion test results of Ni-Fe-Cr alloys that when the chlorine partial pressure is low, the inclusion of Ni improves corrosion resistance, and when the Ni content exceeds 70% by mass, corrosion resistance is significantly reduced. Therefore, the upper limit of the Ni content is set to 70% by mass.

[0055] [Mo: 0% by mass or more and 10% by mass or less] The Mo content may be 0% by mass or more and 10% by mass or less, preferably 0% by mass or more and 3% by mass or less, or 3% by mass or more and 5% by mass or less. It is known that Alloy 625 containing 9% by mass of Mo exhibits excellent corrosion resistance in chloride-corrosive environments such as those found in waste incinerators. However, it has been found that corrosion resistance deteriorates when the Mo content exceeds 10% by mass. Furthermore, workability also deteriorates as the Mo content increases. On the other hand, with regard to corrosion and wear resistance, reducing the Mo content resulted in a slight reduction in the amount of wall thinning. When workability and corrosion and wear resistance are emphasized, it is preferable to keep the Mo content low, at 0% by mass or more and 3% by mass or less. When corrosion resistance is emphasized, it is preferable to keep the Mo content low, at 3% by mass or more and 5% by mass or less.

[0056] [C: 0.05% by mass or more and 1% by mass or less] The C content may be 0.05% by mass or more and 1% by mass or less, preferably 0.3% by mass or more and 0.7% by mass or less. C forms hard Cr carbides and is generally used to improve the hardness of protective coatings. Precipitation phases centered on Cr carbides protrude and mitigate the wear of the base material, thereby contributing to improved corrosion and wear resistance. If the C content is less than 0.05% by mass, the precipitation of the Cr carbide phase is insufficient, but if it exceeds 1% by mass, the Cr in the base material is excessively consumed as carbides, which may result in a deterioration of corrosion resistance.

[0057] [Cu: 0% by mass or more and 5% by mass or less] The Cu content may be 0% by mass or more and 5% by mass or less. Adding Cu to the Ni-based self-fluxing alloy can improve corrosion resistance.

[0058] [Co: 0% by mass or more and 1% by mass or less] The Co content may be 0% by mass or more and 1% by mass or less. Adding a small amount of Co to a Ni-based alloy can strengthen the γNi matrix. On the other hand, since Co is expensive, it is desirable to reduce the amount added from the viewpoint of cost, and it is preferable to set the upper limit to 1% by mass.

[0059] [B: 0% by mass or more and 10% by mass or less] The B content may be 0% by mass or more and 10% by mass or less, preferably 2% by mass or more and 7% by mass or less, and more preferably 5% by mass or more and 6% by mass or less. B is an essential element for workability (remeltability), and also forms Cr borides in the base alloy, contributing to the hardening of the alloy. When an alloy in which Cr borides are formed is exposed to a corrosive environment, corrosion products are formed on the metal base material. Here, wear is involved, damaging the corrosion products, increasing the corrosion rate, and as a result, promoting thinning of the base material. As a result, the hard and wear-resistant Cr borides protrude and are preferentially hit by ash and incombustible materials, which is thought to mitigate the wear conditions experienced by the base material and suppress the amount of thinning of the base material. However, if the B content is too high, the amount of Cr consumed as borides increases, reducing the corrosion resistance of the base material and making it too hard and brittle. Therefore, it is preferable to set the upper limit to 10% by mass. Although Cr carbide has a similar function, it is Cr boride that plays the main role in the above alloy composition.

[0060] [Si: 0% by mass or more and 5% by mass or less] The Si content may be 0% by mass or more and 5% by mass or less, preferably more than 0% by mass and 2% by mass or less, and more preferably 0.1% by mass or more and 1.5% by mass or less. Si is known to contribute to improving oxidation resistance. However, it has been found that a high Si content reduces corrosion and wear resistance, and corrosion resistance in a trace chlorine-containing environment. As described above, it is desirable to not include Si from the viewpoint of corrosion and wear resistance and corrosion resistance. Therefore, it is preferable to add Si up to an upper limit of 5%.

[0061] In the example shown in FIG. 2 , the protective layer 62 is formed directly on the surface of the main body 61 made of cast or plate material. The protective layer 62 may be formed on the main body 61 made of cast or plate material by laser buildup welding (also referred to as laser cladding). In this case, the heat input is smaller than in plasma buildup welding or arc buildup welding, so thermal deformation and dilution of the main body 61 (base material) made of cast or plate material can be suppressed. Furthermore, if the main body 61 (base material) made of cast metal is SCH2, which has poor weldability, plasma buildup welding or arc buildup welding will cause the base material to crack unless preheated, which is time-consuming and costly. In contrast, forming the protective layer 62 by laser buildup welding can suppress cracking of the main body 61 (base material) made of cast metal and the protective layer 62 (buildup material) while omitting the preheating that would normally be required. Furthermore, when the protective layer 62 is formed by laser build-up welding, the grooves 63 can be easily formed on the surface of the protective layer 62 during construction, which has the advantage that additional machining is not required to form the grooves 63 after construction.

[0062] As a modified example, as shown in FIGS. 7 and 8 , the hearth component 6 further includes a protector 65 detachably attached to the front surface 61 a and the top surface 61 b ​​of the main body 61 made of a cast or plate material, and the protective layer 62 may be formed on the surface of the protector 65. The material of the protector 65 may be, for example, SUS material. The protective layer 62 may be formed on the surface of the protector 65 by laser cladding. In this case, the heat input is smaller than in plasma cladding or arc cladding, so thermal deformation and dilution of the protector 65 (base material) can be suppressed. Furthermore, when the protective layer 62 is formed by laser cladding, grooves 63 can be easily formed to cover the surface of the protective layer 62 during construction, which has the advantage of eliminating the need for additional machining to form the grooves 63 after construction.

[0063] A manufacturing method of the hearth component 6 according to one modification will be described. First, as shown in Fig. 8, a protective layer 62 is formed on the surface of a protector 65. Next, as shown in Fig. 7, the protector 65 and a main body 61 made of a casting or plate material are connected by welding. In this manner, the hearth component 6 according to one modification is manufactured. The hearth component 6 according to one modification has the advantage that, if the protective layer 62 is thinned, the welded portion can be cut off and replaced with a new protector 65, thereby allowing the protective layer 62 to be replaced without removing the hearth component 6 from the incinerator 1.

[0064] 7 and 8, the protective layer 62 is formed to cover the entire front surface 61a of the protector 65. However, this is not limited thereto. For example, as shown in FIG. 10, the protective layer 62 may be formed excluding a lower portion of the front surface 61a. In this case, when the entire front surface 61a of the protector 65 is taken as 100%, the protective layer 62 may be provided over a range of 50% or more from the top (i.e., excluding less than 50% from the bottom), 80% or more (i.e., excluding less than 20% from the bottom), 90% or more (i.e., excluding less than 10% from the bottom), or 95% or more (i.e., excluding less than 5% from the bottom). If the protective layer 62 is provided over the entire front surface 61a of the protector 65, the lower end of the protective layer 62 may come into contact with the upper surface of the hearth component below, which may result in scraping of the upper surface of the hearth component below when the hearth component 6 to which the protector 65 is attached is moved back and forth. In contrast, when the protective layer 62 is provided on the front surface 61a of the protector 65 except for the lower portion thereof, the lower end of the protective layer 62 does not come into contact with the upper surface of the hearth component below, thereby preventing the upper surface of the hearth component below from being thinned.

[0065] According to the present embodiment, the protective layer 62 is provided on at least the front surface 61a of the hearth component 6, which is exposed to the furnace interior. Therefore, the front surface 61a of the body 61, made of cast or plate material, is not directly exposed to the corrosive gases and non-combustible materials in the incinerator 1, and is therefore prevented from thinning due to corrosion, mainly due to chlorine in the waste, or wear caused by contact with hard non-combustible materials. Furthermore, the protective layer 62 has grooves 63 formed on its surface. Corrosion products peel off due to wear at the ridges 64 between the grooves 63. However, the peeled fine particles, ash, and small non-combustible materials accumulate on the inner surfaces of the grooves 63, preventing the inner surfaces of the grooves 63 from being directly exposed to the corrosive gases and large non-combustible materials that affect wear in the incinerator 1. This reduces thinning due to corrosion and wear, thereby suppressing the overall thinning of the protective layer 62. This contributes to a longer life for the hearth component 6. Furthermore, according to this embodiment, since the grooves 63 are formed on the surface of the protective layer 62, it is possible to visually check the amount of thinning, which has the advantage of enabling one to roughly determine the lifespan of the hearth component 6. Furthermore, by adjusting the depth D2 of the grooves 63, it becomes possible to easily determine the timing for replacement or repair.

[0066] Next, a specific example of the present embodiment will be described.

[0067] The present inventors first used five materials, namely, the Ni-based developed material, SFNi4, Inconel (registered trademark) 625, Stellite (registered trademark) 21, and DHECR-TB2 (registered trademark), as build-up materials (powder) to perform laser build-up welding on a main body 61 made of SCH2, thereby forming a protective layer 62 having grooves 63 formed so as to cover the surface. Here, the Ni-based developed material is an alloy having the composition described in claim 1 of Japanese Patent No. 6745735. The alloy composition of SFNi4 is specified in JIS H8303:2010. DHECR-TB2 is an alloy having the composition described in claim 1 of Japanese Patent No. 7044328. Of these, the Ni-based developed material, SFNi4, and DHECR-TB2 are materials that satisfy the first alloy composition described above.

[0068] Next, the corrosion and wear resistance of the protective layer 62 made of various materials was measured using the following method. Two grates each were made of five types of castings with the above five materials laser-clad as the protective layer 62 on the exposed surface inside the furnace, and two grates made of a new existing material (SCH2) (without a protective layer) were randomly arranged in the combustion zone of an actual incinerator where grate damage is particularly severe. The incinerator was then operated. The test period was six months. After the test, the weight change (i.e., the amount of wall thinning) of each grate was measured before and after the test.

[0069] 6 is a graph showing the measurement results of the amount of metal loss of various grates (average value of the amount of metal loss of each of two grates for each type of grate). As shown in Fig. 6, the amount of metal loss of the grate without a protective layer (conventional product) was about 1.4 kg, while the amount of metal loss of the grate with the protective layer 62 was 0.4 kg or less for all materials. This confirmed that the provision of the protective layer 62 on the surface of the grate exposed to the furnace interior can significantly reduce the amount of metal loss.

[0070] The inventors also operated an actual incinerator with grates made of plates laser-clad with DHECR-TB2 placed in the combustion zone, where grate damage is particularly severe. The test lasted six months. After the test, the weight change (i.e., the amount of thinning) of each grate was measured before and after the test. The results were comparable to those reported above, confirming that thinning was suppressed regardless of the base material.

[0071] Although the embodiments and modifications have been described above by way of example, the scope of the present technology is not limited to these, and modifications and variations can be made according to the purpose within the scope of the claims. Furthermore, the embodiments and modifications can be combined as appropriate within the scope of not causing any contradiction in the processing content.

Claims

1. A hearth component having an inner surface exposed to an incinerator, the furnace-exposed surface has a front surface and a top surface; At least the front surface is provided with a protective layer having grooves formed thereon; The protective layer is formed by laser build-up welding. A hearth component comprising:

2. The protective layer is also provided on at least a portion of the upper surface on the front side. The hearth component of claim 1 .

3. The width of the groove is 5 mm or less. The hearth component of claim 1 .

4. When the entire protective layer is taken as 100 mass%, the protective layer has an alloy composition containing 10 mass% or more and 50 mass% or less of Cr, 0 mass% or more and 50 mass% or less of Fe, 0 mass% or more and 10 mass% or less of Mo, 0 mass% or more and 5 mass% or less of Si, 0.05 mass% or more and 1 mass% or less of C, 0 mass% or more and 5 mass% or less of Cu, 0 mass% or more and 1 mass% or less of Co, 0 mass% or more and 7 mass% or less of B, and the balance being Ni and unavoidable impurities. The hearth component of claim 1 .

5. The thickness of the protective layer is 1.0 to 1.2 mm. The hearth component of claim 1 .

6. The depth of the groove is 0.2 to 0.4 mm. The hearth component of claim 1 .

7. Cooled by air or water, 2. The hearth component according to claim 1 ,

8. A body made of casting, 2. The hearth component according to claim 1, further comprising a body made of a plate material having the first alloy layer and the second alloy layer on the front and top surfaces.

9. The material of the body made of cast iron is SCH2. The material of the first alloy layer of the main body made of a plate material is an alloy having higher heat resistance, corrosion resistance, and / or wear resistance than the second alloy layer, The material of the second alloy layer is a general structural rolled steel plate or a stainless steel plate. The hearth component of claim 8 .

10. a side surface in contact with the front surface and the top surface; The protective layer is also provided on at least the front surface side of the side surface, 2. The hearth component of claim 1, wherein a thickness of the protective layer at the side surfaces is less than a thickness of the protective layer at the front surface.

11. The protective layer is formed directly on the surface of the body made of a casting or plate material. The hearth component of claim 1 .

12. The device further includes a protector that is detachable from a front surface and an upper surface of the main body made of a casting or a plate material, The protective layer is formed on a surface of the protector. The hearth component of claim 1 .

13. The material of the protector is SUS. The hearth component of claim 12 .

14. A fire grate comprising a hearth component according to any one of claims 1 to 13.

15. A side grate comprising a hearth component according to any one of claims 1 to 13.

16. A seal block comprising the hearth component according to any one of claims 1 to 13.

17. A hearth component having an in-furnace exposed surface exposed in an incinerator, the in-furnace exposed surface having a front surface and an upper surface, at least the front surface being provided with a protective layer having grooves formed on the surface, the protective layer being formed by laser build-up welding, the hearth component comprising a protector detachable from the front surface and the upper surface of a body made of a casting or a plate material, The protective layer is formed on a surface of the protector. A protector characterized by the above.

18. An incineration facility comprising a hearth component according to any one of claims 1 to 13.

19. A method for manufacturing a hearth component having an incinerator-exposed surface, the incinerator-exposed surface having a front surface and a top surface, at least the front surface being provided with a protective layer having a groove formed on its surface, forming the protective layer on a body made of a casting or a plate material by laser cladding welding; 2. A method for manufacturing a hearth component comprising: