JPH0730364B2 - Method for producing surface-coated metal - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a surface-coated metal, and more particularly, to a layer having characteristics such as corrosion resistance, high temperature corrosion resistance, oxidation resistance, and wear resistance. The present invention relates to a method of coating a metal surface.

[Prior Art] In recent years, materials have come to be used in increasingly severe environments due to industrial progress and technological development. For example, in energy resource development, petroleum and natural gas (so-called sour oil and sour gas) containing a large amount of hydrogen sulfide and carbon dioxide in the production fluid have been developed, but materials for oil well pipes and line pipes used for the development As low-alloy steel causes corrosion and cracking, Hastelloy C-276 and Inconel 625
Nickel alloys such as (both are trade names) have already been used. However, the major drawback is that these alloys are very expensive. Therefore, it has been considered to use so-called clad steel in which these alloys are used as a laminated material only on the surface of the structural material and the strength is secured by the underlying metal (for example, low alloy steel).

Various manufacturing methods have been established or proposed for the clad steel as a seamless pipe or a welded pipe when the shape thereof is a tube, and as a rolled plate when the shape is a plate. However, in addition to the problems that the manufacturing process is complicated and the yield is poor, clad steel with nickel alloy such as Hastelloy C-276 and Inconel 625, in particular, clad steel pipe is very difficult to manufacture, yet It has not been put to practical use. According to the research conducted by the present inventors, the reason is that the deformation resistance of these alloys during hot working is significantly larger than that of the low alloy steel or carbon steel used as the base material, so that ordinary manufacturing such as hot rolling is performed. It is considered that the joining material and the base material cannot be uniformly processed in the process, and the two metals are independently deformed, so that it is difficult to join them.

On the other hand, the spindle part of valves, sliding parts such as pistons and cylinders of reciprocating pumps, and members such as pipes for slurry transportation require wear resistance, so for example, stellite alloy (trade name), etc. Alternatively, it is sprayed and used. Furthermore, for pressure vessels and steel pipes used at high temperatures, for example, Ni-Cr alloy or Ni-Cr-Al-Y
Oxidation resistant materials such as alloys and Co-Cr-Al-Y alloys may be overlaid or spray coated. However, these are all very expensive because they are built up or sprayed onto the final product. in addition,
It has a drawback that it cannot cover a narrow portion such as the inner surface of a small diameter pipe.

By the way, the hot isostatic pressing method is a well-known technique from the past, and proposals for clad products using this method have been made. For example, Japanese Patent Application Laid-Open No. 61-223106 discloses a method of efficiently producing a high alloy clad product by heating the high alloy powder to a temperature above the solidus temperature of the powder and pressurizing with a gas. However, all of the previously reported or proposed methods for producing clad products using the hot isostatic pressing method, such as this method, cover the final product, resulting in high cost and large or long products. There was a drawback that it was not possible to manufacture a length product (for example, a length of 12 m).

Further, JP-A-61-190007 and JP-A-61-190008 disclose powders in capsules composed of a thick-walled malleable metal cylinder and a thin-walled metal cylinder having a different diameter. And then sealed, cold isotropic hydrostatic pressure is applied to compress the powder into a billet, which is hot extruded, and the concentric cylindrical inner and outer double walls are In a container of rubber or similar substance having, a malleable metal cylindrical material is housed in close contact with one container wall, and a powder material is filled and sealed between the other container wall and the cylindrical material. There is disclosed a method of pressurizing this by cold isostatic pressure and hot extruding a material taken out from this container as a billet. Also by these methods, when a coating layer of a material having a large deformation resistance such as a nickel alloy such as Hastelloy C-276 or Inconel 625 described above is formed and hot-worked, the adhesion with the base material is weak, so that The difficulties of peeling and cracking of the coating layer cannot be eliminated.

On the other hand, the present inventors have proposed Japanese Patent Application No. 62-69127 and Japanese Patent Application No.
In Japanese Patent Application No. 62-74484, Japanese Patent Application No. 62-74485 and Japanese Patent Application No. 63-40644, a powder of another metal is applied to the surface of a metal material at a gas pressure below the solidus temperature of the other metal. After forming as a coating layer by hot isostatic pressing (HIP),
A method of performing hot working and stretching, a method of forming a coating layer and then subjecting to solution treatment and hot working, or a method of performing hot working and then immediately performing hot working and stretching. I am proposing methods.

[Problems to be Solved by the Invention] The present invention makes it possible to easily and inexpensively use a material in which a base material is provided with the characteristics desired for surface coating such as corrosion resistance, high temperature corrosion resistance, oxidation resistance, and wear resistance. A method of manufacturing is provided.

[Means for Solving the Problems] The inventors of the present invention have conducted various experiments and investigations to achieve the above object, and as a result, finally, the particle size of the powder of the other metal used for forming the coating layer is not high. It was found that the hot workability after hot isostatic pressing was significantly affected. Therefore, the present inventors manufactured a coating material that was hot isostatically pressed by changing the particle size of the powder of another kind of metal in various ways, and subsequently performed hot working. According to the results of studies by the present inventors, if the particle size of the powder of the other metal is too large, the coating layer is formed during hot working even if the material is formed as a coating layer by hot isostatic pressing. There is a possibility of cracking, such cracks can be prevented by mostly using powders of other metals with a particle size of 300 μm or less, specifically 95% or more by weight fraction, and those with a particle size of 74 μm or less by weight. It has been found that when the ratio is 65% or more, the coating layer and the base metal can be hot-worked simultaneously and uniformly.

Furthermore, as a result of detailed examination of the properties of the coating layer subjected to hot isostatic pressing by the present inventors, when the porosity in the coating layer after hot isostatic pressing is 0.5% or less,
It has been found that it becomes much easier to hot work the coating layer and the base metal simultaneously and uniformly.

The present invention has been made on the basis of the above findings, and the gist thereof is that a powder of another metal is applied on the surface of a metal material at a gas pressure below the solidus temperature of the other metal. In the method of forming a coating layer by isostatic pressing, and then subjecting it to hot working and stretching, the weight fraction of particles having a particle size of 300 μm or less as a powder of another metal is 95% or more and the particle size is 74 μm. 65% by weight of the following particles
Forming a coating layer using the above powder,
More preferably, the method for producing a surface-coated metal is characterized in that the porosity in the coating layer after the hot isostatic pressing is 0.5% or less.

Here, the types of the metal material as the “base material” and the other metal as the “laminating material” are not particularly limited, and examples of the metal material include carbon steel, low alloy steel, stainless steel, nickel and Examples include nickel alloys, cobalt and cobalt alloys, titanium and titanium alloys. On the other hand, other metals may be selected from the functions such as corrosion resistance, high temperature corrosion resistance, oxidation resistance, and wear resistance according to the required function. For example, hastelloy, stellite, Ni-Cr alloy, stainless steel. , Fe-based superalloys, nickel and nickel alloys, cobalt and cobalt alloys, titanium and titanium alloys, and the like.

[Details of the Invention] The present invention will be described in detail below.

First, in the present invention, a coating layer of another kind of metal is formed on the surface of the metal material by hot isostatic pressing (hereinafter abbreviated as HIP). The other kind of metal is powdered, for example, as shown in FIG. As shown, the metal material 1 and the other-type metal powder 2 are filled and sealed in the capsule 3, and then hot isostatic pressing is performed to form the other-type metal powder as a coating layer, and at the same time, the coating layer and the material metal are separated. Metal bonding can be performed, and sufficient bonding strength can be provided at the bonding interface. At this time, in order to satisfactorily hot work in the next step, it is necessary to secure the hot workability of the coating layer. For that purpose, the weight fraction of particles having a particle size of 300 μm or less as the particle size of the other metal powder is required. A powder having a particle size of 95% or more and a weight fraction of particles having a particle size of 74 μm or less of 65% or more must be used. The particle size referred to here corresponds to the mesh referred to in the standard of the standard sieve, 300 mesh is 50 mesh, 74 μm is 2 mesh.
It refers to 00 mesh.

On the other hand, in order to impart more excellent hot workability to the coating layer, it is necessary to minimize the number of pores present in the coating layer after hot isostatic pressing, and the porosity is 0.5%.
Must be: Here, the porosity is represented by the volume ratio or the area ratio in the cross section.

In HIP, it is important to create a vacuum in the closed container, and the pressure of the vacuum in the container is preferably lower than 1 × 10 ⁻³ Torr. Also, it is important that HIP is performed at a sufficiently high temperature and pressure for a sufficiently long time.

The HIP temperature depends on the types of base metal and laminated 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, segregation of the component elements will occur during cooling, and the 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, HIP
Higher pressure can reduce HIP temperature and time.

Next, in the present invention, hot working is performed after forming the coating layer, or hot working is performed immediately after soaking after the formation of the coating layer, or solution treatment is performed after forming the coating layer. Although hot working is carried out later, when the coating layer is formed under the above conditions, even a composite material can be hot worked as usual. The purpose of hot working in the present invention is to produce a long surface-coated metal by stretching a coated metal material, or to produce a surface-coated metal having a complicated shape, depending on the shape of the product. Hot working methods such as hot rolling, hot forging, and hot extrusion can be applied.

In the present invention, hot working refers to working in a temperature range in which a metal material as a base material and a coated metal as a laminated material are normally processed for the purpose of molding or the like. It is necessary to select an appropriate temperature for both the coating layer 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 one surface, for example, the upper surface of the plate, the inner surface of the pipe, the outer surface of the pipe. It is also possible to have both inside and outside. Depending on the situation in which the product is used, one side or both sides may be selected appropriately.

Others After hot working, heat treatment such as quenching, tempering, normalizing, etc. for the purpose of adjusting the strength, toughness, etc. of the base material, solution treatment for the purpose of further improving the corrosion resistance of the coating layer Other processes such as heat treatment and heat treatment such as annealing, and cold working performed for the purpose of adjusting the shape of the product can be further added if necessary. Any of them can be selected according to the required strength, toughness, corrosion resistance and the like.

INDUSTRIAL APPLICABILITY 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, and plates. It can be applied to various shapes such as a rod and a rod. Alternatively, it goes without saying that it can also be used as a raw material for producing a product by performing molding, welding, or the like.

Examples of the present invention will be described below.

[Examples] Materials used for hot working were manufactured under the materials and manufacturing conditions shown in Table 1. Inventive Examples No. 1 to 3 are examples in which a coating layer is formed on the inner surface of the hollow billet, and Inventive Examples No. 4 to 6 are examples in which a coating layer is formed on the inner and outer surfaces of the hollow billet, Inventive Example No. 7,
8 is an example of forming a coating layer on the upper surface of the slab, the present invention example No. 9,1
0 is an example in which the coating layers are formed on both sides of the slab. In each case, the alloy powder for the coating layer was formed as a coating layer on the surface of the metal material by hot isostatic pressing. Each shape is shown in FIG. 2, FIG. 3, FIG. 4 and FIG. 5, respectively. FIG. 2 shows an example in which the coating layer 5 is formed on the inner surface of the hollow billet 4. FIG. 3 shows an example in which the coating layer 5 is formed on the inner surface and the outer surface of the hollow billet 4. FIG. 4 shows an example in which the coating layer 5 is formed on the upper surface of the slab 6. FIG. 5 shows an example in which the coating layer 5 is formed on the upper surface and the lower surface of the slab 6.

On the other hand, Comparative Examples Nos. 11 to 13 are examples in which alloy powder is formed as a coating layer on the inner surface of the hollow billet by the hot isostatic pressing method, and Comparative Examples Nos. 14 and 15 are pipes or plates as another kind of metal. This is a conventional method in which an assembled billet or an assembled slab is manufactured by using it and then hot working.

As the hot working, the billet was hot extruded and the slab was hot rolled.

Next, these materials were hot worked under the conditions shown in Table 2 to produce a surface-coated metal. The results are also shown in Table 2. Table 2 also shows the results of various tests for those which could be satisfactorily hot worked. In Table 2, the bending test is performed according to JIS G 0601 and JIS Z 3124.
The ultrasonic flaw detection test was performed according to JIS G 0601 and JIS Z 3124.

Comparative Examples No. 11 to 13 in Table 2 all have microcracks in the coating layer. In Comparative Examples Nos. 14 and 15, the metal material (base material) and the other kind of metal (laminating material) were not processed uniformly, let alone joining them.

On the other hand, the materials of Examples No. 1 to 10 produced according to the present invention had excellent bending test characteristics, and defects such as non-bonded portions were not detected at all in the ultrasonic flaw detection test. From the results of microscopic observation of the cross section after hot working, it was confirmed that the coating layer had no pores and a uniform and good bonding interface was obtained.

[Effects of the Invention] As described above, according to the present invention, it is possible to produce a surface-coated metal having excellent properties, which is extremely large in contributing to the development of industry.

[Brief description of drawings]

FIG. 1 is a diagram showing a filling procedure in a hot isostatic press for forming a coating layer of another metal on the surface of a metal material. 2, 3, 4, and 5 are sectional views showing the outline of stacking the processing materials according to the method of the present invention. 1 ... Metal material, 2 ... Other metal powder, 3 ... Capsule, 4 ... Hollow billet, 5 ... Coating layer, 6 ... Slab.

Claims (2)

[Claims] 1. A metal material powder is formed as a coating layer on the surface of a metal material by a hot isostatic pressing in which a gas pressure is applied at a temperature below the solidus temperature of the other metal, and then hot working is performed. In the method of subjecting to stretching, a powder having a particle size of 300 μm or less having a weight fraction of 95% or more and a particle size of 74 μm or less having a weight fraction of 65% or more is used as a powder of another metal. A method for producing a surface-coated metal, comprising forming a coating layer using the same. 2. The method according to claim 1, wherein the porosity in the coating layer after hot isostatic pressing is 0.5% or less.