JPH0375601B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a surface-coated metal, and more specifically, a method for coating the surface of a metal with a layer having properties such as corrosion resistance, high-temperature corrosion resistance, oxidation resistance, and wear resistance. It is related to. [Prior Art] In recent years, due to industrial progress and technological development, materials have come to be used in increasingly harsh environments. For example, in energy resource development, petroleum and natural gas (so-called sour oil and sour gas) containing large amounts of hydrogen sulfide and carbon dioxide are being developed as production fluids, and the materials used in the development, such as oil country tubular goods and line pipes, are being developed. Hastelloy C-276 and Inconel, as low alloy steels cause corrosion and cracking.
A nickel alloy called 625 (both trade names) is already in use. However, a major disadvantage of these alloys is that they are very expensive. Therefore, it is conceivable to use so-called clad steel, in which these alloys are used as a laminating material only on the surface of the structural material, and the strength is ensured by the underlying metal (for example, low-alloy steel). Various manufacturing methods have been established or proposed for clad steel, such as seamless pipe or welded pipe when the shape is a pipe, and rolled plate when the shape is a plate. However, in addition to the drawbacks of complicated manufacturing processes and low yields, both Hastelloy C-
Clad steel made from nickel alloys such as 276 and Inconel 625, especially clad steel pipes, are extremely difficult to manufacture and have not yet been put to practical use. According to research conducted by the present inventors, the reason for this is that the deformation resistance of these alloys during thermal processing is significantly greater than that of the base metals, such as low-alloy steel and carbon steel.
This is thought to be due to the fact that normal manufacturing processes such as hot rolling cannot process the composite material and base material uniformly, and the two metals deform independently, making it difficult to join them. On the other hand, sliding parts such as valve spindles, pistons and cylinders of reciprocating pumps, and parts such as slurry transport pipes require wear resistance, so for example, Stellite alloy (trade name) etc. It is used by overlaying or thermal spraying. Furthermore, for pressure vessels and steel pipes used at high temperatures, for example, Ni-Cr alloy and Ni-Cr-Al-Y
Oxidation resistant materials such as alloys and Co-Cr-Al-Y alloys may be coated by overlay or thermal spraying. However, all of these materials are overlaid or thermally sprayed onto the final product, making them very costly. In addition, it has the disadvantage that it cannot coat narrow areas such as the inner surface of small diameter pipes. Incidentally, the hot isostatic pressing method is a well-known technique, and clad products using this method have also been proposed. For example, Tokukai Akira
Publication No. 61-223106 discloses a method for efficiently manufacturing a high alloy clad product by heating high alloy powder to a temperature higher than the solidus temperature of the powder and pressurizing the high alloy powder with gas. However, this method and other previously reported or proposed methods for manufacturing clad products using hot isostatic pressing methods all involve coating the final product, resulting in high costs;
Another drawback was that it was not possible to manufacture large products or long products (for example, 12 m long). Also, JP-A-61-190007 and JP-A-61
Publication No. 190008 discloses that powder is filled and sealed in a capsule consisting of a thick-walled malleable metal cylinder and a thin-walled metal cylinder with a different diameter, and then the powder is sealed in a cold isostatic A method of compressing the powder into a billet using hydrostatic pressure, which is then hot extruded; A cylindrical material of a malleable metal is housed in close contact with one container wall, and a powder material is filled between the other container wall and the cylindrical material to seal it, and this is then sealed using cold isostatic pressure. A method is disclosed in which the material taken out from the container is hot extruded as a billet. Even with these methods, if a coating layer of a material with high deformation resistance, such as a nickel alloy such as Hastelloy C-276 or Inconel 625, is formed and hot worked, the adhesion to the base material is weak. The problems of peeling from the base material and cracking of the coating layer remain unresolved. [Problems to be Solved by the Invention] In view of the current situation, the present invention provides an inexpensive material in which the base metal has the properties desired by the surface coating, such as corrosion resistance, high-temperature corrosion resistance, oxidation resistance, and abrasion resistance. The present invention provides a method for manufacturing. [Means for Solving the Problem] As a result of various experiments and studies in order to achieve the above object, the present inventors have found that materials with extremely high hot deformation resistance, such as nickel alloys and cobalt alloys, are used as laminated materials. In order to hot-work materials with relatively low hot deformation resistance, such as low-alloy steel or carbon steel, as a base material, the mating material and the base material must be metallically bonded before hot working, and the bonding interface must be If the bonding strength is sufficient, it is possible to hot-work the laminate material and the base material simultaneously and uniformly, and even after hot working, the laminate material and the base material can be metallically bonded. , and it has been found that sufficient bonding strength can be provided at the bonding interface. Furthermore, as a result of investigating various methods for metallically bonding the laminated material and the base material before hot processing and providing sufficient bonding strength at the bonding interface, the hot isostatic pressing method (hereinafter referred to as the HIP method) was developed. It was found to be superior in terms of cost, bonding strength, etc. That is, we have found that it is possible to form a coating layer on a base material by using the HIP method to form the powder of the laminated metal to be coated on the base material, and at the same time provide sufficient bonding strength. Furthermore, even if the coating metal is a difficult-to-process material such as hastelloy or stellite, if the pores in the coating layer are eliminated during HIP, the coating metal will have sufficient hot workability for subsequent hot processing. We also found that it can be applied to We have found that it is possible to manufacture long clad products based on these materials. Furthermore, the present inventors found that applying soaking treatment after HIP further improves the hot workability of the coating layer, and even when the amount of processing is extremely large, the coating layer can be heated without causing defects such as cracks or flaws. I discovered that it can be processed in between. Here, the purpose of the soaking treatment is to dissolve and eliminate coarse precipitates that have precipitated in the coating layer during cooling after HIP treatment, just before hot working. According to this, when the coating metal is made of a Ni-based alloy or a Co-based alloy, it is effective to hold it at 1050 to 11240℃ for 0.5 to 10 hours as a soaking treatment, and when the coating metal is made of a Ti-based alloy, it is effective to hold it as a soaking treatment for 0.5 to 10 hours. It is effective to hold the temperature at 550-900℃ for 0.5-10 hours. In either case, it is important to perform hot working before precipitates precipitate out again after soaking. Furthermore, the present inventors found that when solution heat treatment is applied after HIP, the hot workability of the coating layer is further improved, and the amount of processing is significantly larger, as in the case of hot working immediately after the soaking treatment described above. We have found that hot processing can be performed without causing defects such as cracks and flaws in the coating layer even when the coating layer is hot-processed. The purpose is to dissolve and eliminate coarse precipitates, and according to the study of the present inventors, when the coating metal layer is made of a Ni-based alloy or a Co-based alloy, solution heat treatment at 1050 to 1240°C is performed. 0.5~10h
After holding, it is effective to rapidly cool at a cooling rate of 5 deg/sec or more, and if the coating metal is made of a Ti-based alloy, it is effective to perform a solution heat treatment at 550 to 900 °C.
After holding for 0.5 to 10 hours, it is effective to rapidly cool at a cooling rate of 5 deg/sec or more. The present invention has been made based on the above findings, and the gist thereof is to apply powder of another metal having a higher hot deformation resistance than the metal material to the surface of the metal material. 300 below phase line temperature
Forming a coating layer by hot isostatic pressing applying a gas pressure of Kg/cm ² or more, applying soaking treatment, and immediately hot working and stretching;
Alternatively, there is a method for producing a surface-coated metal, which comprises forming a coating layer by hot isostatic pressing, followed by rapid flow, solution heat treatment, and then hot working and stretching. . Here, there are no particular restrictions on the types of metal materials that serve as the "base material" and other types of metals that serve as the "laminating material." For example, the metal materials include carbon steel, low alloy steel, stainless steel, nickel, etc. Examples include nickel alloys, cobalt and cobalt alloys, titanium and titanium alloys, and the like. On the other hand, the laminating material may be selected depending on the required functions such as corrosion resistance, high temperature corrosion resistance, oxidation resistance, and wear resistance. For example, hastelloy, stellite,
Examples include Ni-Cr alloys, stainless steel, Fe-based superalloys, nickel and nickel alloys, cobalt and cobalt alloys, titanium and titanium alloys. The present invention will be explained in detail below. [Function] First, in the present invention, a coating layer of other metals is formed on the surface of the metal material by HIP. 1 and the other metal powder 2 are filled and sealed in the capsule 3, and then hot isostatic pressing is performed to form the other metal powder as a coating layer, and at the same time, the coating layer and the raw metal are metallurgically bonded. This allows the bonding interface to have sufficient bonding strength. At this time, in order to perform hot working well in the next process, it is necessary to ensure the hot workability of the coating layer, but for this purpose it is important that no pores remain in the coating layer, and it is important to ensure that the coating layer is not airtight. It is important to create a vacuum inside the container and to perform hot isostatic pressing at a sufficiently high temperature and pressure. Vacuum degree is 1x
Preferably higher than 10 ⁻³ Torr. The HIP temperature differs depending on the types of base metal and composite metal, but in order to maintain good hot workability, the HIP temperature must be lower than the solidus temperature of both metals. This is because if the solidus temperature is exceeded, component elements will segregate during cooling, and hot workability in the next step will be significantly reduced. however,
In order to shorten the HIP time, it is effective to set the temperature as high as possible within the above temperature range. on the other hand,
The higher the HIP pressure, the lower the HIP temperature and time; however, if the pressure is less than 300 kg/ ^cm2 , no matter how you select the HIP temperature and time, the sintering of the other metal powder coating layer will be insufficient and the hot workability will deteriorate. Therefore, in order to maintain good hot workability, it is necessary to set the HIP pressure to 300 Kg/cm ² or more. When the coating metal is made of Ni-based alloy or Co-based alloy, the HIP temperature is 1050 to 1240℃, and the HIP time is
It needs to be between 0.5 and 10h. The reason is HIP
If the temperature is less than 1050°C, the HIP time will be extremely long to several tens of hours, making it impractical; if the temperature exceeds 1240°C, hot workability will decrease for the reasons mentioned above, and if the HIP time is less than 0.5h, This is because it is difficult to obtain a coating layer with good hot workability no matter how high the HIP temperature is within the above temperature range, and even if the HIP time is further increased beyond 10 hours, the effect is saturated. Because there is. In addition, if the coating metal is made of a Ti-based alloy and the base metal is made of an iron-based alloy (low alloy steel, carbon steel, stainless steel, etc.), the HIP temperature should be 600 to 900°C and the HIP time should be 0.5 to 10 hours. It is necessary to do so. The reason is that when the HIP temperature is less than 600℃, HIP
This is not practical because the time taken is extremely long, several tens of hours, and when the temperature exceeds 900°C, Ti and Fe react to form a brittle compound, which reduces hot workability. This is because if it is less than 0.5 hours, it is difficult to obtain a coating layer with good hot workability no matter how high the HIP temperature is within the above temperature range.
This is because even if the HIP time is further increased beyond 10 hours, the effect is saturated. On the other hand, the purpose of soaking treatment in the present invention is mainly
The objective is to dissolve and eliminate coarse precipitates that have formed in the coating layer during cooling after HIP treatment, thereby further improving hot workability in the next step of hot working. According to studies conducted by the present inventors, when the coating metal is made of a Ni-based alloy or a Co-based alloy, it is effective to hold it at 1050 to 1240°C for 0.5 to 10 hours as a soaking treatment, and when the coating metal is made of a Ti-based alloy, In such cases, it is effective to hold the temperature at 550 to 900°C for 0.5 to 10 hours as a soaking treatment. The reason is that the soaking temperature is
Below 1050℃ for Ni-based alloys and Co-based alloys, and Ti
This is because precipitates cannot form a solid solution at temperatures below 550°C for base alloys, and when the soaking temperature exceeds 1240°C for Ni-based alloys and Co-based alloys, and above 900°C for Ti-based alloys, heat is generated in the coating layer or bonding interface. This is because machinability deteriorates. Furthermore, in the above temperature range, if the holding time is less than 0.5 hours, the precipitates cannot be sufficiently dissolved even if the soaking temperature is the upper limit of the temperature range, whereas if the holding time exceeds 10 hours, the effect is no longer saturated. Therefore, the retention time is 0.5~10h.
Should be. In addition, when cooling after being held at the soaking temperature, if the hot working is not carried out quickly, precipitates will precipitate again and hot workability will deteriorate, so transportation after soaking should be done as quickly as possible. It's imminent. Furthermore, the purpose of the solution heat treatment in the present invention is to
Similar to the soaking treatment described above, this process mainly dissolves and eliminates coarse precipitates that precipitate in the coating layer during cooling after HIP treatment, further improving hot workability in the next step of hot working. be. According to studies by the present inventors, when the coating metal is made of a Ni-based alloy or a Co-based alloy, the solution heat treatment
It is effective to hold the temperature at ℃ for 0.5 to 10 hours and then rapidly cool it at a cooling rate of 5 deg/sec or more, so that the coated metal is
In the case of Ti-based alloy, it is used as solution heat treatment.
It is effective to hold the temperature at 550 to 900°C for 0.5 to 10 hours and then rapidly cool it at a cooling rate of 5 deg/sec or more. The reason for this is that precipitates cannot be solidly dissolved when the solution temperature is less than 1050°C for Ni-based alloys and Co-based alloys, and below 550°C for Ti-based alloys;
This is because when the temperature exceeds 1240°C for Ni-based alloys and Co-based alloys, and above 900°C for Ti-based alloys, the hot workability of the coating layer or the bonding interface deteriorates. moreover,
In the above temperature range, if the holding time is less than 0.5 hours, the precipitates cannot be sufficiently dissolved even if the solution heat treatment temperature is the upper limit of the temperature range, while if the holding time exceeds 10 hours, the effect is no longer saturated. Therefore, the holding time should be between 0.5 and 10 h.
In addition, when cooling after holding at the solution heat treatment temperature, if the cooling rate is less than 5deg/sec, precipitates will precipitate again during cooling and impair hot workability, so the cooling rate must be 5deg/sec or more. There is. As a method to obtain such a cooling rate,
For example, water cooling, forced air cooling, etc. can be applied. Next, in the present invention, hot working is performed immediately after applying soaking treatment after forming the coating layer, or hot working is performed after rapid cooling after applying solution treatment after forming the above-mentioned covering layer. When the coating layer is formed under the above conditions, even composite materials can be hot worked in the same manner as usual. The purpose of the hot working in the present invention is to produce a long surface-coated metal by stretching the coated metal material, or to produce a surface-coated metal with a complicated shape. Accordingly, hot processing methods such as hot rolling, hot forging, and hot extrusion can be applied. In the present invention, hot working refers to processing in the temperature range in which the metal material as the base material and the coating metal as the bonding material are normally processed for purposes such as forming. Appropriate temperatures need to be selected for both the temperature and the coating layer. In the present invention, when the shape of the metal material is a plate or a pipe, the coating layer may be formed on one surface, for example, the upper surface of the plate, the inner surface of the pipe, or the outer surface of the pipe.
It is also possible to use both sides, ie, the upper and lower sides of the plate, and the inner and outer sides of the pipe. Depending on the situation in which the product is used, one or both sides may be selected as appropriate. After other hot working, heat treatments such as quenching, tempering, and normalizing are performed for the purpose of refining the strength and toughness of the base metal, and solution treatment is performed for the purpose of further improving the corrosion resistance of the coating layer. Other processing may be added as necessary, such as heat treatment such as heat treatment and annealing, and cold processing for the purpose of adjusting the shape of the product. Both require strength,
It can be selected depending on toughness, corrosion resistance, etc. The present invention can be applied to manufacture products that require resistance to corrosive substances, products that require resistance to high temperature oxidation, and products that require wear resistance, such as pipes, containers, plates, etc. It can be applied to various shapes such as rods and rods. It goes without saying that it is also possible to further perform molding, welding, etc. and use it as a material for manufacturing products. Examples of the present invention will be described below. [Examples] Example 1 A material to be subjected to hot working was manufactured using the materials and manufacturing conditions shown in Table 1. Here, invention examples No. 1 to 2
is an example in which a coating layer is formed on the upper surface of a slab, an example of the present invention
No. 3 is an example in which a coating layer is formed on both sides of the slab, Invention examples No. 4 to 8 are examples in which a coating layer is formed on the inner surface of a hollow billet, and Invention examples No. 9 to 11 are examples in which a coating layer is formed on the inner surface of a hollow billet. This is an example in which a coating layer is formed on the outer surface. In each case, alloy powder was formed as a coating layer on the surface of a metal material by hot isostatic pressing. The respective shapes are shown in FIGS. 2, 3, 4, and 5, respectively. FIG. 2 shows an example in which a coating layer 5 is formed on the upper surface of the slab 4. FIG. 3 shows an example in which a coating layer 5 is formed on the upper and lower surfaces of the slab 4. FIG. 4 shows an example in which a coating layer 5 is formed on the inner surface of a hollow billet 6. FIG. 5 shows an example in which a coating layer 5 is formed on the inner and outer surfaces of a hollow billet 6. On the other hand, all of the comparative examples are examples in which alloy powder was formed as a coating layer on the inner surface of a hollow round billet by the HIP method, but they do not meet the conditions of the present invention in the points marked with *. These materials were then hot worked under the conditions shown in Table 2 to produce surface coated metals. The second result is
Shown in the table. Table 2 also shows the results of various tests for those that could be hot-worked well. In Table 2, the bending test is based on JIS G0601.
The bonding strength test was conducted in accordance with JIS H8664, and the defect length ratio of the bonded portion was calculated using the length of the non-bonded portion measured by optical microscopic observation of the cross section as the total length of the interface. It was calculated by dividing. Comparative examples No. 12, No. 14 and No. 2 in Table 2.
16 is a comparative example because the temperature during soaking treatment was too low.
No. 13, No. 15, No. 17, and No. 18 were not subjected to soaking treatment, so although they were all able to be hot worked, cracks or flaws occurred in the coating layer. On the other hand, Example No. 1 manufactured according to the invention
Each of the materials No. 11 to 11 had excellent properties in both bending tests and bonding strength, and no defects such as non-bonded parts were detected in cross-sectional observation using an optical microscope. In addition, the cross-sectional microscopic observation results after hot working confirmed that there were no pores or cracks in the coating layer, and that a uniform and good bonding interface was obtained. It was confirmed that a metal with an excellent surface coating was obtained.

【table】

【table】

[Table] *1 Since it was hot worked immediately after soaking treatment, it is equal to the soaking temperature.
*2 Target product dimensions: Base material outer diameter 60.4φ (mm), coating thickness 0.2 (mm)
Example 2 A material to be subjected to hot working was manufactured using the materials and manufacturing conditions shown in Table 3. Here, invention examples No. 1 to 2
is an example in which a coating layer is formed on the upper surface of a slab, an example of the present invention
No. 3 is an example in which a coating layer is formed on both sides of the slab, Invention examples No. 4 to 8 are examples in which a coating layer is formed on the inner surface of a hollow billet, and Invention examples No. 9 to 11 are examples in which a coating layer is formed on the inner surface of a hollow billet. This is an example in which a coating layer is formed on the outer surface. In each case, alloy powder was formed as a coating layer on the surface of a metal material by hot isostatic pressing. The respective shapes are shown in FIGS. 2, 3, 4, and 5, respectively. FIG. 2 shows an example in which a coating layer 5 is formed on the upper surface of the slab 4. FIG. 3 shows an example in which a coating layer 5 is formed on the upper and lower surfaces of the slab 4. FIG. 4 shows an example in which a coating layer 5 is formed on the inner surface of a hollow billet 6. FIG. 5 shows an example in which a coating layer 5 is formed on the inner and outer surfaces of a hollow billet 6. On the other hand, all of the comparative examples are examples in which alloy powder was formed as a coating layer on the inner surface of a hollow billet by the HIP method, but they do not satisfy the conditions of the present invention in the points marked with *. These materials were then hot worked under the conditions shown in Table 4 to produce surface coated metals. The result is the fourth
Shown in the table. Table 4 also shows the results of various tests for those that could be successfully hot worked. In Table 4, the bending test is based on JIS G0601.
The joint strength test was conducted according to JIS H 8664, and the defect length ratio of the joint was determined by calculating the length of the unbonded part measured by observing the cross section with an optical microscope. It was calculated by dividing by the total length. Comparative examples No. 12, No. 15 and No. 4 in Table 4.
Comparative Examples No. 14, No. 17 because the temperature during solution heat treatment was too low for Comparative Example No. 18, and because the cooling rate after solution heat treatment was too low for Comparative Examples No. 13, No. 16, and No. 19. ,
No. 20 and No. 21 were not subjected to solution heat treatment, so although both were able to be hot worked, cracks or flaws occurred in the coating layer. On the other hand, the materials of Examples Nos. 1 to 11 manufactured according to the present invention were excellent in both the bending test and bonding strength, and there were no defects such as non-bonded parts when cross-sectionally observed with an optical microscope. It was not detected at all. In addition, microscopic observation of the cross section after hot working confirmed that there were no pores or cracks in the coating layer, and that a uniform and good bonding interface was obtained. It was confirmed that a metal with an excellent surface coating was obtained.

【table】

【table】

[Table] [Effects of the Invention] As described above, according to the present invention, it is possible to produce a surface-coated metal having excellent properties, and it greatly contributes to the development of industry.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a filling procedure in hot isostatic pressing for forming a coating layer of another metal on the surface of a metal material. 2, 3, 4, and 5 are all cross-sectional views showing the procedure for laminating processed materials according to the method of the present invention. 1...metal material, 2...other metal powder, 3...
Capsule, 4... Slab, 5... Covering layer, 6...
Hollow billet.

Claims (1)

[Claims] 1. Powder of another metal having a higher hot deformation resistance than the metal material is applied to the surface of the metal material at a gas pressure of 300 Kg/cm ² or more at a temperature below the solidus temperature of the other metal. 1. A method for producing a surface-coated metal, which is formed as a coating layer using a hot isostatic press under a load of 100% by weight, and immediately subjected to hot working and stretched after soaking. 2. The method according to claim 1, wherein the other metal coating layer is formed on both sides of the metal material. 3 The other metal is made of Ni-based alloy, and is treated by hot isostatic pressing at 1050 to 1240°C for 0.5 to 10 hours, and then soaked for 0.5 hours at 1050 to 1240°C.
3. The method according to claim 1 or 2, wherein the holding time is maintained for ~10 hours. 4 The other metal is made of a Co-based alloy, and is treated by hot isostatic pressing at 1050 to 1240°C for 0.5 to 10 hours, and then soaked for 0.5 hours at 1050 to 1240°C.
3. The method according to claim 1 or 2, wherein the holding time is maintained for ~10 hours. 5 The other metal is made of a Ti-based alloy and is treated by hot isostatic pressing at 600 to 900°C for 0.5 to 10 hours, and then soaked at 550 to 900°C for 0.5 to 10 hours.
3. The method according to claim 1 or 2, wherein: 6. Powder of another metal having a higher hot deformation resistance than that of the metal material is applied to the surface of the metal material by applying a gas pressure of 300 kg/cm ² or more at a temperature below the solidus temperature of the other metal. 1. A method for producing a surface-coated metal, which comprises forming a coating layer using a hydraulic press, subjecting it to solution heat treatment, quenching it, then subjecting it to hot working and stretching. 7. The method for producing a surface-coated metal according to claim 6, wherein the other metal coating layer is formed on both sides of the metal material. 8 The other metal is made of a Ni-based alloy and is treated by hot isostatic pressing at 1050 to 1240°C for 0.5 to 10 hours, and then heated to 1050 to 1240°C as solution heat treatment.
8. The method for producing a surface-coated metal according to claim 6 or 7, wherein the temperature is maintained for 0.5 to 10 hours and then rapidly cooled at a cooling rate of 5 deg/sec or more. 9 The other metal is made of a Co-based alloy and is treated by hot isostatic pressing at 1050 to 1240°C for 0.5 to 10 hours, and then heated to 1050 to 1240°C as solution heat treatment.
8. The method for producing a surface-coated metal according to claim 6 or 7, wherein the temperature is maintained for 0.5 to 10 hours and then rapidly cooled at a cooling rate of 5 deg/sec or more. 10 The other metal is made of a Ti-based alloy and is treated by hot isostatic pressing at 600 to 900°C for 0.5 to 10 hours, and then heated to 550 to 900°C as solution heat treatment.
8. The method for producing a surface-coated metal according to claim 6 or 7, wherein the temperature is maintained for 0.5 to 10 hours and then rapidly cooled at a cooling rate of 5 deg/sec or more.