Preparation process for improving structure integrity of high-temperature-resistant and corrosion-resistant alloy thin-wall casting

Abstract

The invention belongs to the technical field of alloy casting, and particularly relates to a preparation process for improving the structure integrity of a high-temperature-resistant and corrosion-resistant alloy thin-wall casting. The preparation technology for improving the structure integrity of the high-temperature-resistant and corrosion-resistant alloy thin-wall casting comprises the steps that a prefabricated crucible is used for forging a furnace lining, a reinforcing coating is applied to the upper portion of the furnace lining after forging is completed, and then a mother alloy rod is prepared through vacuum induction smelting; the master alloy bar is refined for standby application; and finally, the treated mother alloy bar is subjected to secondary remelting and pouring to prepare the thin-wall casting. According to the method, through comprehensive control over preparation links, the structure integrity of the high-temperature-resistant and corrosion-resistant alloy thin-wall casting can be greatly improved, the qualification rate of the casting is increased, and the service life of the casting is remarkably prolonged.

Description

Technical Field:

[0001] The present invention belongs to the technical field of alloy casting, and particularly relates to a preparation process for improving the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings. Background Art:

[0002] High-temperature and corrosion-resistant alloy thin-walled castings have extensive applications in industries such as aviation, chemical engineering, petrochemical, and glass, and are often used as components serving under extreme conditions such as high temperature, high stress, or corrosive environments. Due to the harsh service conditions and high cost, extremely high requirements are imposed on the mechanical and corrosion-resistant properties of the castings. The performance of the castings is mainly affected by the tissue integrity of the castings. The tissue integrity of the castings refers to the proportion of non-discontinuous tissues in the castings. Slag inclusions, pores, porosity, and inclusions can all be regarded as discontinuous tissues, and their existence destroys the integrity of the casting tissue. When the casting bears external stress or corrosive erosion, stress concentration or vacancies will be generated, resulting in microcracks or corrosion pits at the discontinuous tissues of the casting, reducing the serviceability of the casting. Especially for thin-walled castings, due to the narrow size of the thin-walled part (usually less than 10 mm) and the small bearing area, the damaging effect of discontinuous tissues will be more obvious. Therefore, the control of the content of discontinuous tissues in thin-walled castings is more stringent, and waste products are often produced due to improper control. In actual high-temperature and corrosion-resistant alloy thin-walled castings in service, failures often occur due to the existence of discontinuous tissues at the thin-walled parts. Therefore, how to improve the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings is very important.

[0003] However, in the prior art, almost no efforts have been made to start from the overall concept of tissue integrity to improve the yield and service performance of high-temperature and corrosion-resistant alloy thin-walled castings. Instead, attention is usually paid to how to improve the smelting quality of the master alloy and reduce the impurity content in the master alloy. However, the formation of discontinuous tissues in castings is related not only to the impurity content of the master alloy but also to other links in the preparation process. It is difficult to achieve the improvement of the yield and service performance of high-temperature and corrosion-resistant alloy thin-walled castings only by improving the smelting quality of the master alloy. Summary of the Invention:

[0004] The object of the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide a preparation process for improving the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings. Through comprehensive control of the preparation process, the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings can be greatly improved, the qualification rate of the castings can be increased, and the service life of the castings can be extended.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A preparation process for improving the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings. A preformed crucible is used to make the furnace lining. After the lining is made, a reinforcement coating is applied to the upper part of the furnace lining, and then a master alloy rod is prepared by vacuum induction melting. After the master alloy rod is refined, a thin-walled casting is prepared by secondary remelting and pouring.

[0007] Among them, the method of applying the reinforcement coating is as follows: First, apply the bottom coating. Mix the oxide powders with particle sizes of 200 mesh to 400 mesh and 2000 mesh to 3000 mesh evenly. The weight percentage of the 200 mesh to 400 mesh powder is 60% to 75%. Then add a solution to make a slurry. The addition amounts of the powder and the solution are calculated according to the solid weight and the liquid volume. Powder: Solution = (4 - 5):(15 - 20), unit g:mL. Brush the evenly mixed slurry on the refractory furnace lining with a thickness of 1 to 3 mm and bake it with a graphite core for 2 to 3 hours. Then apply the surface coating. Mix the oxide powder with a particle size of 3000 mesh to 4000 mesh with the solution to make a slurry. The addition amounts of the powder and the solution are calculated according to the solid weight and the liquid volume. Powder: Solution = (2 - 3):(20 - 25), unit g:mL. Brush the evenly mixed slurry on the bottom coating with a thickness less than or equal to 1 mm and bake it with a graphite core for 1 to 2 hours.

[0008] In the preparation process for improving the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings, the refinement process of the master alloy rod is as follows: Cut the master alloy rod according to the required weight of the prepared thin-walled casting. Make a circumferential cut from the four sides of the alloy rod and stop cutting when the cut depth does not exceed 4 / 5 of the radius. Then truncate the master alloy rod by impact. Remove the burrs and chips from the truncated master alloy rod by rolling treatment. After the rod material is cleaned, it is ready for use.

[0009] In the preparation process for improving the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings, the oxide powder is alumina powder or zircon powder, and the solution is water glass or silica sol solution.

[0010] In the preparation process for improving the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings, the reinforcement coating has a thermal cycle cracking resistance of ≥20 times at 1100°C.

[0011] In the preparation process for improving the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings, after the master alloy rod is refined, there are no burrs and flash on the surface, and there are no chips in the shrinkage cavity.

[0012] The technical principle of the present invention is as follows:

[0013] Through the comprehensive control of the preparation process, the present invention reduces the proportion of discontinuous tissues in the casting from multiple aspects and improves the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings. This can not only improve the qualified rate of the castings, reduce production costs, but also significantly increase the service life of the castings.

[0014] The premise of controlling the discontinuous structure of castings is to clarify the causes and the links where they occur. The formation causes of the discontinuous structure of castings can be divided into two categories: endogenous causes and exogenous causes. Inclusions and porosity are mainly endogenous defects caused by the high content of impurity elements in the castings. The characteristics of endogenous defects are small size, relatively uniform distribution, large range, and they affect the stability of the mechanical properties of the alloy, but generally do not cause a significant reduction in the yield rate and service life of the castings. While slag inclusions, surface pores, etc. are generally introduced in the environment of casting preparation and belong to exogenous defects. They are characterized by large size, small quantity, random distribution, etc., but they seriously affect the yield rate and service life of the castings, causing huge damage.

[0015] The sources of exogenous defects are generally introduced in the links such as crucible use and master alloy rod treatment. In vacuum induction melting, refractory lining is generally fabricated around the crucible. When the thermal cycle resistance of the lining is poor, cracks will occur during use, resulting in the refractory falling into the solution in the crucible or into the ingot mold during the pouring process of the alloy liquid. When the content of active elements in the alloy is low, the fallen refractory will remain in the solidified casting, forming large-sized slag inclusions; while when the content of active elements in the alloy is high, the refractory will react with the alloy liquid, eventually forming defects such as pores in the casting. Thin-walled castings of high-temperature and corrosion-resistant alloys are usually prepared by remelting master alloy rods, and exogenous defects are easily introduced during the treatment process of the master alloy rods. Since there are generally secondary shrinkage cavities in the master alloy rods, during the process of cutting the master alloy rods, the particles on the cutting disc and the alloy chips will inevitably enter the secondary shrinkage cavities. Due to the complex shape of the secondary shrinkage cavities, it is difficult to clean out the foreign substances that enter them, and these particles and chips become defects such as slag inclusions in the casting during the remelting and pouring of the master alloy.

[0016] Therefore, in view of different sources of foreign defects, the present invention further applies a reinforcing coating after the crucible is formed. Coarse-grained oxides have good thermal cycle resistance and thermal expansion resistance after sintering, while fine-grained oxides have good densification and melt infiltration resistance after sintering. The present invention selects oxide powders with relatively coarse and fine particle sizes for mixing, and controls the weight percentage of coarse particle powders with a lower mesh number to be 60% - 75% to obtain a coating with good comprehensive properties such as good thermal cycle resistance and densification as the bottom coating. Then, a sintered coating of fine-grained oxides is applied as the top coating on the bottom coating to improve the melt infiltration resistance of the reinforcing coating. The reinforcing coating selects powders and solutions that can generate stable and dense structures such as mullite and zircon after sintering. The powders used are alumina powder or zircon powder, and the solutions used are water glass or silica sol solutions. The prepared reinforcing coating has excellent thermal cycle cracking resistance, will not generate cracks during the service life of the crucible, and has good melt infiltration resistance, and there will be no phenomenon of alloy liquid adhering to the sand during the casting process, thus avoiding the introduction of foreign refractory materials during the preparation of high-temperature and corrosion-resistant alloy thin-walled castings. At the same time, for the treatment of the master alloy rod, by circumferential cutting and controlling an appropriate cutting depth, the saw blade can cut as deeply as possible without cutting into the secondary shrinkage cavity, avoiding the chips from entering the secondary shrinkage cavity of the master alloy rod, so as to prevent them from being introduced into the casting through remelting. And through rolling treatment, the burrs and chips on the cut master alloy rod are fully removed, avoiding the introduction of foreign defects in these links and significantly improving the tissue integrity of the high-temperature and corrosion-resistant alloy thin-walled castings.

[0017] The preparation process of the present invention is highly targeted, can greatly improve the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings, increase the qualified rate of castings, significantly improve the service life of castings, and has a relatively low process cost, with good universality and excellent comprehensive economic benefits.

[0018] The advantages and beneficial effects of the present invention are as follows:

[0019] 1. Through the application of a composite reinforcing coating composed of coatings with different properties, the process of the present invention can prevent the furnace lining from cracking during the service life of the crucible, and has excellent melt infiltration resistance, which can avoid the influence of refractory slag falling on high-temperature and corrosion-resistant alloy thin-walled castings.

[0020] 2. After the refined treatment of the master alloy rod, the surface of the present invention's preparation process has no burrs and flash, and there are no chips in the shrinkage cavity, avoiding the influence of foreign inclusions introduced during the cutting of the master alloy on the tissue integrity of high-temperature and corrosion-resistant alloy thin-walled castings.

[0021] 3. The process of the present invention differentiates the factors affecting the integrity of the structure of high-temperature and corrosion-resistant alloy thin-walled castings and controls them separately in each major influencing link, which can comprehensively reduce the content of discontinuous structures in the castings and improve the service performance of the castings. The nickel-based alloy thin-walled castings prepared by the process of the present invention have a high yield rate and good batch stability, and are suitable for large-scale production.

[0022] 4. The implementation method of the present invention is simple and effective, with a relatively low process cost, and has good engineering application value and excellent comprehensive economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS:

[0023] Figure 1 It is a photograph of the typical metallographic structure of the casting in Example 1.

[0024] Figure 2 It is a photograph of the typical metallographic structure of the casting in Comparative Example 1.

[0025] Figure 3 It is a photograph of the machined surface of the casting in Example 2.

[0026] Figure 4 It is a photograph of the machined surface of the casting in Comparative Example 2.

[0027] Figure 5 It is a photograph of the typical microstructure of the surface of the casting in Example 3.

[0028] Figure 6 It is a photograph of the typical microstructure of the surface of the casting in Comparative Example 3. DETAILED DESCRIPTION OF THE INVENTION:

[0029] The following further describes in detail the specific implementation manners of the present invention in conjunction with the drawings, examples and comparative examples. It should be noted here that the description of these implementation manners is used to help understand the present invention, but does not constitute a limitation to the present invention. In addition, the technical features involved in the various implementation manners of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] Example 1

[0031] In this example, a thin-walled turbine casting is cast using a high-temperature and corrosion-resistant alloy. The chemical composition of the alloy used in Example 1 is shown in Table 1.

[0032] Table 1 Chemical composition of the alloy in Example 1 (wt%)

[0033] Element C Cr Mo W Al Ti Nb B Zr Ni Content 0.12 12.5 4.3 6.0 6 0.8 2.2 0.014 0.1 Remainder

[0034] Use a preformed alumina crucible to form the furnace lining, and apply a reinforcement coating on the upper part of the furnace lining after forming. First, apply the bottom layer coating: Mix zirconium silicate powder with a particle size of 200 mesh and zirconium silicate powder with a particle size of 3000 mesh evenly, where the weight percentage of the 200-mesh powder is 60%; then add colloidal silica to make a slurry: The addition amount of the powder and colloidal silica is calculated by the solid weight and liquid volume, powder:colloidal silica = 4:15, unit g:mL. Brush the evenly mixed slurry on the refractory furnace lining with a thickness of 3 mm and bake it with a graphite core for 3 hours; then apply the surface layer coating: Mix zirconium silicate powder with a particle size of 4000 mesh and colloidal silica to make a slurry. The addition amount of the powder and colloidal silica is calculated by the solid weight and liquid volume, powder:colloidal silica = 2:25, unit g:mL. Brush the evenly mixed slurry on the bottom layer coating with a thickness of 1 mm and bake it with a graphite core for 1 hour. The prepared reinforcement coating has 34 times of thermal cycle cracking resistance at 1100 °C. Then, prepare a master alloy rod with a diameter of Φ50 mm by vacuum induction melting.

[0035] Cut the master alloy rod according to the required weight of the prepared thin-walled turbine casting. Cut inwards from the four sides of the alloy rod and stop cutting when cutting in 20 mm, and truncate the master alloy rod by impact; roll the truncated master alloy rod to remove burrs and chips; take out the rod stock and clean the ash chips. After the master alloy rod is refined, there are no burrs and flash on the surface, and there are no chips in the shrinkage cavity. The processed master alloy rod is prepared into a thin-walled turbine casting by secondary remelting and pouring.

[0036] Comparative Example 1

[0037] In this comparative example, a high-temperature and corrosion-resistant alloy is used to cast the thin-walled turbine casting. The chemical composition of the alloy used in Comparative Example 1 is exactly the same as that in Example 1.

[0038] Use a preformed alumina crucible to form the furnace lining, and prepare a master alloy rod with a diameter of Φ50 mm by vacuum induction melting after forming. The vacuum induction melting process is the same as that in Example 1.

[0039] Cut the master alloy rod directly according to the required weight of the prepared thin-walled turbine casting, and then prepare the thin-walled turbine casting by secondary remelting and pouring.

[0040] As Figure 1 shown, it can be seen from the typical metallographic structure photo of the casting in Example 1 that the structure inside the casting is uniform and there is almost no discontinuous structure.

[0041] As Figure 2 shown, it can be seen from the typical metallographic structure photo of the casting in Comparative Example 1 that there are a large number of discontinuous structures composed of slag inclusions, porosity, etc. in the structure, and the size of the discontinuous structure is large. Since the detection standard for defects in thin-walled turbine castings is relatively strict, the existence of these discontinuous structures will seriously affect the yield rate and service performance of the castings.

[0042] Table 2 is a comparison of the casting scrap rate caused by discontinuous structures in the thin-walled turbine castings prepared in Example 1 and Comparative Example 1. The process of Example 1 can greatly improve the casting yield rate and reduce the impact of discontinuous structures in the casting.

[0043] Table 2 Casting scrap rate of Example 1 and Comparative Example 1

[0044] Total number of castings Scrapped due to slag inclusions Scrapped due to gas holes Porosity and inclusion exceeding the standard Scrap rate Example 1 96 1 3 5 9.4％ Comparative Example 1 92 10 7 13 32.6％

[0045] Table 3 is a comparison of the average content of porosity and inclusions and the durability of qualified thin-walled turbine castings prepared in Example 1 and Comparative Example 1. It can be seen that the alloy prepared by the process of Example 1 has a lower content of discontinuous structures such as porosity and inclusions, and the durability of the alloy is improved, thereby improving the service performance of the casting.

[0046] Table 3 Porosity, average inclusion content and durability of castings of Example 1 and Comparative Example 1

[0047]

[0048] Example 2

[0049] In this embodiment, a high temperature resistant and corrosion resistant alloy is used to cast a thin-walled centrifuge casting. The chemical composition of the alloy used in Example 2 is shown in Table 4.

[0050] Table 4 Chemical composition of alloy of Example 2 (wt%)

[0051] Element C Cr W Nb Al Ti Ni Content 0.5 32 5.0 0.8 1.5 2.4 Remainder

[0052] The furnace lining was made using a magnesium oxide prefabricated crucible, and a reinforcement coating was applied to the upper part of the furnace lining after the lining was made. First, the bottom coating was applied: alumina powder with a particle size of 400 mesh and a particle size of 2500 mesh were mixed evenly, wherein the weight percentage of 400 mesh powder was 75%; then water glass was added to make a slurry: the amount of powder and water glass added was calculated by solid weight and liquid volume, powder: water glass = 5:20, unit g:mL. The mixed slurry was evenly brushed on the refractory furnace lining with a thickness of 2mm, and baked with a graphite core for 2 hours; then the top coating was applied: alumina powder with a particle size of 3000 mesh and water glass were mixed to make a slurry. The amount of powder and water glass added was calculated by solid weight and liquid volume, powder: water glass = 3:20, unit g:mL. The mixed slurry was evenly brushed on the bottom coating with a thickness of 0.5mm, and baked with a graphite core for 2 hours. The number of times the prepared reinforcement coating resisted 1100℃ thermal cycle cracking was 26 times. Then vacuum induction smelting was performed to prepare master alloy rods with a diameter of Φ80 mm.

[0053] Cut the master alloy rod according to the required weight of the prepared thin-walled centrifugal casting. Make a circumferential cut from the periphery of the alloy rod inward, stop cutting when cutting in 30 mm, and truncate the master alloy rod by impact; roll the truncated master alloy rod to remove burrs and chips; take out the rod material and clean the ash chips. After the master alloy rod is refined, there are no burrs and flash on the surface, and there are no chips in the shrinkage cavity. The processed master alloy rod is remelted and cast twice to prepare a thin-walled centrifugal casting.

[0054] Comparative Example 2

[0055] In this comparative example, a high-temperature and corrosion-resistant alloy was used to cast the thin-walled centrifugal casting. The chemical composition of the alloy used in Comparative Example 2 was exactly the same as that in Example 2.

[0056] Use a preformed magnesia crucible to make the furnace lining. After completion, vacuum induction melting is used to prepare a master alloy rod with a diameter of Φ80 mm. The vacuum induction melting process is the same as that in Example 2.

[0057] Cut the master alloy rod directly according to the required weight of the prepared thin-walled centrifugal casting, and then remelt and cast it twice to prepare a thin-walled centrifugal casting.

[0058] As Figure 3 shown, from the surface photo of the casting in Example 2, it can be seen that the surface of the centrifugal casting presents a smooth surface after machining, and there is no presence of discontinuous structure.

[0059] As Figure 4 shown, from the surface photo of the casting in Comparative Example 2, it can be seen that obvious porosity, inclusions and other discontinuous structures still exist on the surface of the casting after machining. The existence of these discontinuous structures renders the casting unusable and reduces the yield of the casting.

[0060] Table 5 shows the comparison of the casting rejection rates caused by discontinuous structures in the thin-walled centrifugal castings prepared in Example 2 and Comparative Example 2. The rejection rates such as inclusions in the centrifugal castings prepared by the process of Example 2 are much lower than those of the process of Comparative Example 2, and the proportion of discontinuous structures appearing in the castings is greatly reduced.

[0061] Table 5 Rejection Rates of Castings in Example 2 and Comparative Example 2

[0062]

[0063]

[0064] Table 6 shows the comparison of the average contents of porosity and inclusions and the creep properties in the qualified thin-walled centrifugal castings prepared in Example 2 and Comparative Example 2. The contents of discontinuous structures such as porosity and inclusions in the alloy prepared by the process of Example 2 are significantly lower than those of the process of Comparative Example 2, the creep life of the alloy is greatly improved, and the service performance of the casting is more excellent.

[0065] Table 6 Porosity, average inclusion content and durability of castings of Example 2 and Comparative Example 2

[0066]

[0067] Example 3

[0068] In this embodiment, a high temperature resistant and corrosion resistant alloy is used to cast a thin-walled pump casing casting. The chemical composition of the alloy used in Example 3 is shown in Table 7.

[0069] Table 7 Chemical composition of alloy of Example 3 (wt%)

[0070] Element Cr Mo W Fe B Zr Ni Content 15.5 16.0 4.0 5.0 0.08 0.3 Remainder

[0071] Use magnesium oxide prefabricated crucibles to make furnace linings, and apply reinforcement coatings on the upper part of the furnace linings after making. First, apply the bottom coating: mix alumina powder with a particle size of 300 mesh and a particle size of 2000 mesh, of which the weight percentage of 300 mesh powder is 70%; then add water glass to make a slurry: the amount of powder and water glass added is calculated by solid weight and liquid volume, powder: water glass = 4:18, unit g:mL. Apply the mixed slurry evenly on the refractory furnace lining, with a thickness of 1mm, and bake it with a graphite core for 2 hours; then apply the top coating: mix zircon powder with a particle size of 4000 mesh and silica sol to make a slurry. The amount of powder and silica sol added is calculated by solid weight and liquid volume, powder: silica sol = 3:25, unit g:mL. Apply the mixed slurry evenly on the bottom coating, with a thickness of 0.5mm, and bake it with a graphite core for 1 hour. The prepared reinforcement coating can resist 1100℃ thermal cycle cracking for 20 times. Then vacuum induction smelting was used to prepare master alloy rods with a diameter of Φ85mm.

[0072] Cut the master alloy rod according to the required weight of the thin-walled pump casing casting to be prepared, cut the alloy rod inward from all sides, stop cutting when the cutting is 32mm, and cut the master alloy rod by impact; roll the cut master alloy rod to remove burrs and chips; take out the rod and clean the ash chips. After fine treatment, the master alloy rod has no burrs or flash on the surface, and there is no chip in the shrinkage cavity. The treated master alloy rod is remelted and cast for the second time to prepare the thin-walled pump casing casting.

[0073] Comparative Example 3

[0074] In this comparative example, a high temperature resistant and corrosion resistant alloy is used to cast a thin-walled pump casing casting. The chemical composition of the alloy used in comparative example 3 is completely consistent with that in embodiment 3.

[0075] The furnace lining was made by using a magnesium oxide prefabricated crucible, and after the making was completed, vacuum induction smelting was performed to prepare a master alloy rod with a diameter of Φ85 mm. The vacuum induction smelting process was the same as that of Example 3.

[0076] Cut the master alloy rod directly according to the required weight of the prepared thin-walled pump housing casting, and then prepare the thin-walled pump housing casting through secondary remelting and pouring.

[0077] As Figure 5 shown, it can be seen from the typical microstructural photos of the casting surface in Example 3 that the structure on the casting surface is uniform and there is basically no discontinuous structure.

[0078] As Figure 6 shown, it can be seen from the typical microstructural photos of the casting surface in Comparative Example 3 that larger-sized slag inclusions and porosity and other discontinuous structures can be seen on its surface. The existence of these discontinuous structures will affect the yield rate and service performance of the thin-walled pump housing casting.

[0079] Table 8 shows the comparison of the casting rejection rate and corrosion-resistant service life caused by discontinuous structures in the thin-walled pump housing castings prepared in Example 3 and Comparative Example 3. The casting rejection rate of the thin-walled pump housing casting prepared by the process of Example 3 is much lower than that of the process of Comparative Example 3, and the pump housing has stronger corrosion resistance and a longer service life.

[0080] Table 8 Conditions of average content of porosity, inclusions and service life of castings in Example 3 and Comparative Example 3

[0081]

[0082] The above are only the embodiments of the present invention, and thus do not limit the protection scope of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. Any equivalent changes or modifications made according to the spirit of the present invention are similarly covered within the protection scope of the present invention.

Claims

1. A preparation process for improving the structural integrity of high temperature and corrosion resistant alloy thin-wall castings, characterized in that: Use prefabricated crucibles to make furnace linings, apply a reinforcement coating on the upper part of the furnace lining after making, and then prepare master alloy rods by vacuum induction smelting; after fine treatment of the master alloy rods, remelt and cast them twice to prepare thin-walled castings; Among them, the method for applying the reinforcement coating is: first apply the bottom coating, mix the oxide powder with a particle size of 200 mesh to 400 mesh and the oxide powder with a particle size of 2000 mesh to 3000 mesh evenly, wherein the weight percentage of the 200 mesh to 400 mesh powder is 60% to 75%; then add the solution to make a slurry, the amount of powder and solution added is calculated by solid weight and liquid volume, powder: solution = (4-5): (15-20), unit g: mL; brush the mixed slurry evenly on the refractory furnace lining, the thickness is 1 to 3 mm, and bake it with a graphite core for 2 to 3 hours; then apply the top coating, mix the oxide powder with a particle size of 3000 mesh to 4000 mesh and the solution to make a slurry; the amount of powder and solution added is calculated by solid weight and liquid volume, powder: solution = (2-3): (20-25), unit g: mL; brush the mixed slurry evenly on the bottom coating, the thickness is less than or equal to 1 mm, and bake it with a graphite core for 1 to 2 hours.

2. A preparation process for improving the structural integrity of high temperature and corrosion resistant alloy thin-wall castings according to claim 1, characterized in that: The fine processing process of the master alloy rod is as follows: the master alloy rod is cut according to the required weight of the prepared thin-walled casting, and the ring cutting is carried out from the four sides of the alloy rod to the inside, and the cutting is stopped when the cutting does not exceed 4 / 5 of the radius, and the master alloy rod is cut off by impact; the cut master alloy rod is rolled to remove burrs and chips, and the rod is cleaned and set aside for use.

3. A preparation process for improving the structural integrity of high temperature and corrosion resistant alloy thin-wall castings according to claim 1, characterized in that: The oxide powder is alumina powder or zircon powder, and the solution is water glass or silica sol solution.

4. A preparation process for improving the structural integrity of high temperature and corrosion resistant alloy thin-wall castings according to claim 1, characterized in that: The reinforcement coating can resist 1100° C. thermal cycle cracking for ≥20 times.

5. A preparation process for improving the structural integrity of high temperature and corrosion resistant alloy thin-wall castings according to claim 1 or 2, characterized in that: After fine treatment, the master alloy rod has no burrs or flash on the surface, and no chips in the shrinkage cavity.

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