JPH0790329A - Manufacture of surface coating metal - Google Patents

Abstract

PURPOSE:To manufacture the material with the desired property in an inexpensive, easy and precise manner by executing the drawing through the hot extrusion after executing the hot isostatic pressing of the powder of dissimilar metals onto the surface of the metallic stock below the temperature of the solidus under the prescribed gas pressure. CONSTITUTION:A metallic stock 1 is arranged in a capsule 3, the powder 2 of dissimilar metals is filled around the metallic stock according to the desired property, the space is evacuated to the degree of vacuum of approximately <=1X10<-3>, and sealed thereafter. The hot isostatic pressing of this capsule 3 is executed where the gas pressure of 300-80kg/cm<2> is loaded below the temperature of the solidus of the dissimilar metals. The powder 2 of the dissimilar metals is adhered to the surface of the metallic stock 1 with sufficient joining strength, and the stress relief is realized by generating fine separation in each particle of the powder. The drawing is executed by applying the hot extrusion to the metallic stock 1 to which the powder 2 of the dissimilar metals is adhere, thus obtaining the objective surface coated metal in which the desired property is given to the base material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a surface-coated metal, and more particularly to coating a surface of a metal with a layer having characteristics such as corrosion resistance, high temperature corrosion resistance, oxidation resistance and abrasion resistance. It is about how to do it.

[0002]

2. Description of the Related 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.
Hastelloy C is used as a material for oil well pipes and line pipes used for development, because low alloy steels corrode and crack.
Nickel alloys such as -276 and Inconel 625 are already in use. However, the great disadvantage 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 clad steel as a seamless pipe or a welded pipe when the shape thereof is a tube, and as a rolled plate when it is a plate. However, in addition to the drawback that the manufacturing process is complicated and the yield is poor, Hastelloy C-276 and Inconel 62
Clad steel with nickel alloy such as 5 as a composite material,
Above all, the clad steel pipe is very difficult to manufacture and has not yet been put into practical use. According to the study by the present inventors, the reason is that the deformation resistance of hot working of these alloys is significantly larger than that of the low alloy steel or carbon steel as the base material, and therefore, the usual manufacturing process such as hot rolling is performed. Therefore, it is considered that the joining material and the base material cannot be uniformly processed, and both metals are independently deformed, so that it is difficult to join them.

[0004] On the other hand, the spindle portion of the valve, the sliding portion such as the piston and cylinder of the reciprocating pump, and the member such as the slurry transport pipe require abrasion resistance. Alternatively, it is sprayed and used. Further, for pressure vessels and steel pipes used at high temperatures, for example, Ni-Cr alloy,
An oxidation resistant material such as a Ni-Cr-Al-Y alloy or a Co-Cr-Al-Y alloy is used after being coated by overlaying or thermal spraying. However, the cost of each of these is very high because the final product is overlaid or sprayed. In addition to this, there is a drawback that the narrow space such as the inner surface of the small diameter pipe cannot be covered.

By the way, the hot isostatic pressing method is a well-known technique in the past, and cladding products utilizing this method have been proposed. For example, JP-A-61-2
Japanese Patent No. 23106 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 the gas. However, since the method for producing a clad product using the hot isostatic pressing method, which has been reported or proposed in the past, including this method, is to coat the final product,
High cost and large or long products, eg 12m
It was not possible to manufacture long products.

Further, in Japanese Patent Laid-Open No. 61-190007, powder is filled and sealed in a capsule composed of a thick malleable metal cylinder and a thin metal cylinder having a diameter different from that of the cylinder. Then, a method of pressing by cold isostatic pressure to compress the powder to form a billet and hot extruding the billet is disclosed. Further, JP-A-61-1900
No. 08-Gazette, a malleable metal cylindrical material is housed in close contact with one container wall in a container made of rubber or similar substance having concentric cylindrical inner and outer double walls, and the other container wall. There is disclosed a method in which a powder material is filled and sealed between the cylindrical material and the above cylindrical material, the material is pressurized by cold isostatic pressure, and the material taken out from the container is hot extruded 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 to the base material is weak and the base material is weakly adhered. However, the problems of peeling and cracking of the coating layer cannot be solved.

Further, as a method capable of remarkably reducing the occurrence of defects such as cracks and scratches in the coating layer during hot working, Japanese Patent Application Laid-Open No. 64-2022 discloses a method of forming a different metal on the surface of a metal material. The powder should be kept below the solidus temperature of the dissimilar metal for 3
There has been proposed a method in which a hot isostatic press (HIP) with a gas pressure of 00 kg / cm ² or more is applied to form a coating layer, which is then subjected to hot working and stretching. However, in this method, when the surface-coated metal is produced by hot extrusion, defects such as cracks may occur in the coating layer during hot extrusion depending on the HIP conditions, and the problem of defect occurrence is completely solved. It didn't happen.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a base material having characteristics such as corrosion resistance, high temperature corrosion resistance, oxidation resistance, and wear resistance that a base material has, and is inexpensive and easy to use. The object is to provide a method of manufacturing well.

[0009]

The inventors of the present invention have conducted various experiments and studies in order to solve the above-mentioned object, and as a result, H
The mechanism by which the coating layer, which is a difficult-to-process material formed by IP, is satisfactorily hot extruded is that the tensile stress due to the expansion of the billet outer diameter at the time of hot extruding causes minute grain by grain in the old metal powder grain boundary before HIP. It has been found that the stress is relieved by the occurrence of such peeling, and then the peeled grains are pressed again and extruded from the die by the compressive stress in the vicinity of the die. Then, it was found that the gas pressure at the time of HIP needs to be 800 kg / cm ² or less in order to stably cause minute peeling of each old metal powder grain, which is necessary for stress relaxation. . The present invention has been completed based on these findings.

The gist of the present invention is as follows. After forming a powder of a dissimilar metal on the surface of the metal material as a coating layer by a hot isostatic press applying a gas pressure of 300 kg / cm ² or more at a solidus temperature of the dissimilar metal or less, hot extrusion is performed. In the method for producing a surface-coated metal that is subjected to and stretching,
A method for producing a surface-coated metal, characterized in that the gas pressure during hot isostatic pressing is 800 kg / cm ² or less.

Here, the kinds of the metal material as the "base material" and the dissimilar metals as the "laminating material" are not particularly limited. Examples of the metal material include carbon steel, low alloy steel, stainless steel, nickel and nickel alloys, cobalt and cobalt alloys, titanium and titanium alloys, and the like. In addition, the dissimilar metal may be selected from the functions such as corrosion resistance, high temperature corrosion resistance, oxidation resistance, and abrasion resistance, depending on the required function, for example, Hastelloy, stellite, Ni-Cr alloy, stainless steel. , Fe-based superalloys, nickel and nickel alloys, cobalt and cobalt alloys,
Examples include titanium and titanium alloys.

The present invention will be described in detail below. First, a coating layer of dissimilar metals is formed on the surface of a metal material by HIP. For the dissimilar metal, powder is used. For example, the metal material 1 and the dissimilar metal powder 2 are encapsulated in the capsule as shown in FIG. Are filled and sealed, and then hot isostatic pressing is performed to form a different metal powder as a coating layer, and at the same time, the coating layer and the raw material metal are metal-bonded. As a result, the bonding interface can have sufficient bonding strength. At this time, in order to satisfactorily hot work in the next step, the hot workability of the coating layer must be ensured, but for that purpose it is necessary not to leave pores in the coating layer, and It is important to evacuate the closed container and to perform hot isostatic pressing at a sufficiently high temperature and pressure. Vacuum degree is 1 ×
It is preferably higher than 10 ⁻³ Torr.

The HIP temperature depends on the types of the base metal and the laminated metal, but it must be lower than the solidus temperature of both metals in order to maintain good hot workability. 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. 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 is, the more the HIP temperature and time can be reduced. However, as described above, stable fine peeling of each old metal powder grain, which is necessary for stress relaxation during hot extrusion, is stabilized. 800 kg / cm ² to generate
It was found experimentally that there was a need to:
However, if the pressure is less than 300 kg / cm ² , the metal bonding between the coating layer and the base material will not be sufficient, and peeling of the interface will occur during hot extrusion, so a pressure of 300 kg / cm ² or more is required.

In the present invention, hot extrusion is carried out. However, when the coating layer is formed under the above conditions, the composite material can be hot extruded in the same manner as usual. The hot extrusion in the present invention is for producing a long surface-coated metal by drawing a coated metal material or for producing a surface-coated metal having a complicated shape. In addition,
In the present invention, hot extrusion refers to processing within a temperature range in which a metal material as a base material and a coating metal as a bonding material are normally processed for forming, etc. Appropriate temperatures need to be selected for both layers.

In the present invention, when the shape of the metal material is a pipe, the coating layer may be one surface, for example, the inner surface of the pipe or the outer surface of the pipe, and both surfaces, that is, the inner and outer surfaces of the pipe. It is also possible to do so. Depending on the situation in which the product is used, one side or both sides may be selected appropriately. In addition, after hot extrusion, various heat treatments such as quenching, tempering, and normalizing performed to adjust the strength and toughness of the base material can be performed. Further, it can be applied to manufacture products requiring resistance to corrosive substances, products requiring resistance to high temperature oxidation, and products requiring wear resistance, for example, shapes of pipes and rods. Can be applied to. Further, 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.

[0016]

EXAMPLES The present invention will be further described below based on examples. The materials shown in Table 1 and the materials to be subjected to hot extrusion were manufactured under the HIP conditions. Here, the invention sample No. 1,
Sample No. 2 of the present invention sample No. 2 is an example in which a coating layer is formed on the outer surface of the hollow round billet. Nos. 3 and 4 are examples in which a coating layer is formed on the outer surface of the round billet, and Sample No. of the present invention. Reference numerals 5 and 6 are examples in which a coating layer is formed on the inner surface of a hollow round billet. In each case, the alloy powder for the coating layer is formed as a coating layer on the surface of the metal material by hot isostatic pressing.

[0017]

[Table 1]

FIG. 2 shows an example in which the coating layer 5 is formed on the outer surface of the hollow round billet 4, and FIG. 3 shows the coating layer 5 on the outer surface of the round billet 6.
FIG. 4 shows an example in which the coating layer 5 is formed on the inner surface of the hollow round billet 4. On the other hand, Comparative Sample N
o. Sample Nos. 7 to 12 of the present invention sample No. It corresponds to Nos. 1 to 6 and is a material produced for hot extrusion under the condition that only the HIP pressure is different from the example of the present invention.

Next, 20 pieces of each of these materials were hot extruded under the conditions shown in Table 2. The results are also shown in Table 2.

[0020]

[Table 2]

In Table 2, sample No. which is a comparative example. 7,
Nos. 9, 11, and 12 had minute flaws that could be maintained only once in 20. Sample No. In No. 8, one of them had a minute flaw that could be maintained, and one of them had a crack on the outer surface. No. 10 except one,
A crack was generated from the interface. On the other hand, No. 1 manufactured according to the present invention. Each of the materials Nos. 1 to 8 could be hot-extruded satisfactorily without causing any defects.

[0022]

According to the present invention, it is possible to easily and accurately produce a surface-coated metal having excellent characteristics in a stable manner.

[Brief description of drawings]

FIG. 1 is a diagram showing a filling procedure in a hot isostatic press for forming a coating layer of a different alloy on the surface of a metal material.

FIG. 2 is one of the examples of the present invention in which a coating layer is formed on the outer surface of a hollow round billet.

FIG. 3 is one of the examples of the present invention in which a coating layer on the outer surface of a round billet is formed.

FIG. 4 is one of the examples of the present invention in which a coating layer is formed on the inner surface of a hollow round billet.

[Explanation of symbols]

 1 metal material 2 dissimilar metal powder 3 capsule 4 hollow round billet 5 coating layer 6 round billet

Front Page Continuation (72) Inventor Hiroyuki Ogawa 20-1 Shintomi, Futtsu City, Chiba Nippon Steel Corporation Corporate Technology Development Division

Claims (1)

[Claims] 1. After forming a powder of a dissimilar metal on the surface of a metal material as a coating layer by a hot isostatic press applying a gas pressure of 300 kg / cm ² or more at a solidus temperature of the dissimilar metal or less. In the method for producing a surface-coated metal in which hot extrusion is performed and stretched, the gas pressure during hot isostatic pressing is set to 80
A method for producing a surface-coated metal, which comprises 0 kg / cm ² or less.