JPH0361305A - Manufacture of surface-coated metal - Google Patents

Abstract

PURPOSE:To coat the surface of raw material metal with a metal layer having excellent corrosion resistance, oxidizing resistance, wear resistance, etc., by heating in vacuum at the specific temp. after sticking the specific metal powder on the surface of raw material metal of carbon steel, etc., to form the coating layer and executing hot working in the air to draw this. CONSTITUTION:The metal raw material 1, such as carbon steel, alloy steel, stainless steel, is charged into a vessel 3, and the powder 2, such as Ni base alloy, Fe base alloy, Co base alloy, Ti base alloy, is charged into gap 2 between the vessel 3 and the metal raw material 1 and stuck on the surface of metal raw material 1 with a cold isostatic pressing to form the metal powder stuck layer having <30% void ratio. This is held at or below temp. (1050-1240 deg.C in the case of Ni, Fe, Co base alloy, 600-900 deg.C in the case of Ti base alloy) of solid phase temp. of the raw material metal and the stuck layer metal under reduced pressure atmosphere of <=1X10<-3>Torr for 1-10hr to form the coating layer. This is taken out in the air and the hot rolling is executed and by drawing, the metal raw material having excellent corrosion resistant, wear resistant and oxidizing resistant metal layer on the surface thereof, is manufactured.

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 producing a surface-coated metal, and more specifically, a method for producing a surface-coated metal. The present invention relates to a method of coating metal surfaces.

[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. Since low-alloy steels tend to corrode and crack, nickel alloys such as Hastelloy C-275 and Inconel 625 (both trade names) are already in use. However, a major drawback of these alloys is that they are very expensive. Therefore, it has been considered 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, clad steels made from nickel alloys such as Hastelloy C-276 and Inconel 625, and clad steel pipes in particular, are extremely difficult to manufacture and still remain undeveloped. Not put into practical use. According to the research conducted by the present inventors, the reason for this is that the deformation resistance of these alloys during hot working is significantly greater than that of the base material low alloy steel or carbon steel. This is thought to be due to the fact that the mating material and base metal cannot be processed uniformly in the process, and both metals deform independently, making it difficult to join them.

On the other hand, parts such as valve spindles, moving parts such as the pistons and cylinders of reciprocating pumps, and pipes for transporting slurry require wear resistance, so materials such as Stellite alloy (trade name) are used as overlay materials. Or it is used by thermal spraying. Furthermore, for pressure vessels and steel pipes used at high temperatures, for example, Ni-Cr alloys and Ni
An oxidation-resistant material such as -Cr-A I-Y alloy or Co-Cr-A I-Y alloy 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.

Furthermore, JP-A-61-190006 discloses a metal cylinder, a layer in which the metal cylinder is processed by filling powder into the cylinder concentric with the cylinder and hot extrusion, and a solid layer in which the powder layer is converted. A method for obtaining a laminated clad metal tube is disclosed in Japanese Patent Application Laid-open No. 61-190007 and Japanese Patent Application Laid-open No. 61-1900.
-190008 describes a metal cylinder and a cylinder having a different diameter, which is filled with powder and compressed with isostatic pressure to create a billet, which is then hot extruded to produce a metal cylinder. A method for obtaining a clad metal tube laminated with a layer and a solid layer in which the powder layer is converted is disclosed. However, even with these methods, it is not always easy to obtain a good surface coating of a composite material coated with a superalloy or the like without defects such as cracks or voids in the coating metal.

On the other hand, the present inventors have proposed in Japanese Patent Application Laid-Open No. 64-202 that a powder of another metal is applied to the surface of a metal material by applying a gas pressure at a temperature below the solidus temperature of the other metal. A method in which the material is formed as a coating layer by isostatic pressing (HIP) and then subjected to hot processing and then stretched; a method in which the material is further formed as a coating layer and then subjected to solution treatment and then subjected to hot processing and stretched; We are proposing a method in which the material is soaked and then immediately subjected to hot processing and stretched.

[ilffl to be solved by the invention] The present invention provides a material in which the base material has the properties desired by the surface coating, such as corrosion resistance, high-temperature corrosion resistance, oxidation resistance, and abrasion resistance, at a much lower cost. The present invention provides an easy manufacturing method.

[Means for Solving the Problems] In order to achieve the above object, the present inventors continued various experiments and studies, and finally applied powder of other metals to the surface of the metal material (base material). We have now discovered a method of forming a multi-metal coating layer by cold forming and fixing the material, then heating and holding it in a vacuum at a high temperature below the common phase temperature of the metal material and the other metal. The other metal coating layer formed by this method has sufficient hot workability for hot working, and there is sufficient bonding strength between the coating layer (laminated material) and the metal material (B). The coating layer (laminated material) and the metal material (base material) can be processed uniformly and simultaneously in the subsequent hot processing, and the obtained surface coated metal can be processed into the coating layer (laminated material) and the metal material (base material). It was found that there were no defects and dimensions such as wall thickness were uniform with respect to the (base material).Therefore, surface-coated metals can be manufactured more cheaply, quickly, and easily.

Furthermore, as a result of various studies on the conditions for heating and holding in vacuum, the present inventors found that when the other metal is a nickel-based alloy, iron-based alloy, or cobalt-based alloy,
It was found that it is sufficient to maintain the temperature at 240°C for 1 to lOh, and when the other metal is made of a titanium-based alloy and the metal material is an iron-based alloy, it is sufficient to maintain the temperature at 600°C to 900°C for 1 to toh. .

The present inventors investigated methods for coldly fixing powders of other metals onto the surface of metal materials, and found that cold pressing or cold isostatic pressing is suitable for the above purpose. On the other hand, if the porosity of the other metal powder layer after cold fixing the other metal powder is 30% or less,
The hot workability of other types of metal layers after heating and holding in vacuum is further improved, and when heating and holding in vacuum, the atmospheric pressure is reduced to I
It has been found that the hot workability of the coating layer is further improved when the conditions are as follows.

The present invention was made based on the knowledge described in Section L, and its gist is that powder of other metals is cold-adhered to the surface of a metal material and formed as a powder layer, and then the metal is placed in a vacuum. A surface coating characterized by heating and holding the material to a high temperature below the solidus temperature of the material and other metals to form a coating layer, cooling it, taking it out of the vacuum, subjecting it to hot working, and stretching it. In the method for manufacturing metal, the method further includes reducing the porosity of the other metal powder layer to 30% or less by cold, and applying the other metal powder by cold pressing or cold isostatic pressing. The pressure of the atmosphere is I
- Heating and holding in a vacuum of 3 Torr or less; if the other metal is a nickel-based alloy, iron-based alloy, or cobalt-based alloy, the temperature is 1 to io at 1050°C to 1240°C in a vacuum.
h, and when the other metal is made of a titanium-based alloy and the metal material is made of an iron-based alloy, the temperature is 600°C to 90°C in a vacuum.
There is also a method for producing a surface-coated metal in which holding at 00° C. for 1 to 10 hours is applied in combination as needed.

There are no particular restrictions on the metal material that will be the "base material" and the types of other metals that will be the "laminating material." For example, the metal materials may 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 functionality, such as corrosion resistance, high-temperature corrosion resistance, oxidation resistance, and abrasion resistance, such as Hastelloy and Stellite.

Examples include Ni-Cr alloy, stainless steel, Fe-based superalloy nickel and nickel alloy, cobalt and cobalt alloy, titanium and titanium alloy.

The present invention will be explained in detail below.

[Function] First, in the present invention, the powder of the other metal is fixed to the surface of the metal material in a cold manner. The seed metal powder 2 is filled into a container 3, and then cold compressed from the outside of the container to agglomerate the other metal powders and preform them, so that they are fixed to the surface of the metal material of the other metal powder layer. At this time, the inside of the container does not necessarily need to be in a vacuum, and may be left in the atmosphere. Of course, a vacuum may be used. As a method for cold fixing, for example, cold pressing or cold isostatic pressing can be applied. When cold fixing is performed using a cold isostatic press, the inside of the container must be sealed tightly. In the present invention, cold refers to a temperature below the recrystallization temperature of the metal material and other metals. The container does not necessarily have to be highly rigid, and may be made of a material that is soft enough to handle the filling and cold fixing of other metal powders.

Next, in a vacuum, the metal material and other metals are heated to a high temperature below the solidus temperature and held. As a result, the other metals are densified and bonded to the metal material through subsequent hot processing. It becomes possible to do so. The heating temperature varies depending on the types of base metal and composite metal, but in order to maintain good hot workability, it must be below the solidus temperature of both metals. This is because when heated above the solidus temperature, part or all of the material melts, causing segregation of component elements during cooling, resulting in reduced hot workability. However, the higher the heating temperature, the more effective it is within the range below the solidus temperature of the metal material and other metals. After heating and holding in vacuum is completed, cool it down to a temperature that does not pose a problem in handling, and then take it out of the vacuum.

When the other metal is made of nickel-based alloy, iron-based alloy, or cobalt-based alloy, the heating temperature in vacuum is 1.
The temperature range is 050°C to 1240°C, and the heating time is 1 to 10°C.
It is preferable to set it to h. This is because if the heating temperature is less than 1050°C, a very long treatment time will be required, and if the heating temperature exceeds 1240°C, the hot workability of the other metal powder layer will decrease, so in both cases, the subsequent hot working This is because processing becomes difficult.

On the other hand, if the heating time is within the above range, the heating time is 1 hour.
This is because if the heating temperature is less than toh, the effect is insufficient no matter how high the heating temperature is in the above temperature range, and even if the heating time is further extended beyond toh, the effect is saturated.

When the other metal is a titanium-based alloy and the metal material is an iron-based alloy, it is preferable that the temperature is 600°C to 900°C in vacuum and the heating time is 1 to 1Oh. This is because if the heating temperature is lower than 600°C, a very long processing time is required, and if the heating temperature exceeds 900°C, titanium and iron will react, making subsequent hot processing difficult. On the other hand, the reason why the heating time is set in the above range is that if the heating time is less than 1 hour, no matter how high the heating temperature is in the above temperature range, the effect will be insufficient. However, the effect is saturated.

It is preferable that the degree of vacuum during heating and holding in vacuum is high, that is, the pressure of the atmosphere is low. The pressure of the atmosphere is I
If X 10''' is 3 Torr or less, a coating layer having good hot workability can be formed.

On the other hand, in order to obtain a good coated metal after hot working, the higher the relative density of the other metal powder layer cold-fixed before heating, the better; if the porosity is 30% or less, It is possible to bond the other metal powder layer to the metal material by heating at , and at the same time, it is possible to form a coating layer having good hot workability.

Next, in the present invention, hot working is performed after the coating layer is formed, and when the coating layer is formed under the above conditions, even a composite material can be hot worked in the same manner as usual. The purpose of hot working in the present invention is to produce a long surface-coated metal or a complex-shaped surface-coated metal by stretching the coated metal material. 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, but when selecting the processing temperature, 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 vibrator, the coating layer may be formed on one surface, for example, the upper surface of the plate, the inner surface of the vibrator, or the outer surface of the vibrator. It is also possible to have an inside/outside screen. Depending on the situation in which the product is used, either the - side or both sides may be selected as appropriate.

After the geothermal processing, 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. Any of them can be selected depending on the required strength, 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 can also be used as a material for manufacturing products by further molding, welding, etc.

Examples of the present invention will be described below.

[Example] Example! Materials to be subjected to hot working were manufactured using the materials and manufacturing conditions shown in Table 1. Here, present invention examples &1 to 2 are examples in which a coating layer is formed on the inner surface of a hollow billet, present invention examples h3 to 4 are examples in which a coating layer is formed on the inner and outer surfaces of a hollow billet, and present invention examples &5
- 6 are examples in which a coating layer was formed on the upper surface of the slab, Examples 7 and 8 of the present invention were examples in which a coating layer was formed on both sides of the slab, and Example 9 of the present invention was an example in which a coating layer was formed on the outer surface of a round bar. It is. In each case, the metal powder for the coating layer was fixed in a cold state, and then heated and held at a high temperature in a vacuum to form the coating layer. The respective shapes are shown in FIG. 2, FIG. 3, FIG. 4, FIG. 5, and FIG. 6, respectively. FIG. 2 shows an example in which a coating layer 5 is formed on the inner surface of a hollow billet 4. FIG. 3 shows an example in which a coating layer 5 is formed on the inner and outer surfaces 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 a coating layer 5 is formed on the upper and lower surfaces of the slab 6. Figure 6 shows a coating layer 5 on the outer surface of a round bar (solid billet) 7.
This is an example of forming a .

On the other hand, Comparative Examples Comparative Examples 12 and 12 are conventional methods in which a slab is assembled using plates as other metals and then hot worked. These materials were then hot worked under the conditions shown in Table 2 to produce surface coated metals. The results are also shown in Table 2. In addition, for those that have been successfully hot worked, the results of various tests are also included in the second report.
Shown in the table. In Table 2, the bending test is JIS G 0601.
and JIS Z 3124, ultrasonic flaw detection test LLJIS G 0601 and JIS Z 3
The procedure was carried out in accordance with 124-2. O in the bending test results in Table 2
indicates that neither cracking nor peeling occurred.

In Table 2, Comparative Examples &lO~11 all had microcracks in the coating layer. Further, in Comparative Example No. 12, the metal material (base material) and the other metal (laminated material) were not uniformly processed, much less could not be joined together.

On the other hand, the materials of Examples NCL1 to NCL9 manufactured according to the present invention had excellent bending test characteristics, and no defects such as non-bonded parts were detected even in the ultrasonic flaw detection test. Also,
From the results of microscopic observation of the cross section after hot working, it was confirmed that there were no pores in the coating layer and that a uniform and good bonding interface was obtained.

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

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view illustrating a filling procedure in cold preforming for fixing powder of another metal onto the surface of a metal material. FIG. 2, FIG. 3, FIG. 4, FIG. 5, and FIG. 6 are all cross-sectional views showing the procedure for laminating processed materials according to the method of the present invention. l... Metal material, 2... Other metal powder, 3... Container, 4... Hollow billet, 5... Covering layer, 6...
Slab.

Claims (1)

[Claims] 1. After coldly adhering the powder of another metal to the surface of the metal material and forming a powder layer, the powder is heated in a vacuum to a high temperature below the solidus temperature of the metal material and the other metal. 1. A method for producing a surface-coated metal, which comprises heating and holding the layer to form a coating layer, cooling it, taking it out of a vacuum, subjecting it to hot working, and stretching it. 2. The other metal is made of a nickel-based alloy, and when heated and held in a vacuum, it has a temperature of 1050°C to 1240°C.
2. The method for producing a surface-coated metal according to claim 1, wherein the surface-coated metal is maintained for 10 hours. 3. The other metal is made of an iron-based alloy, and when heated and held in vacuum, the temperature is 1 to 10 at 1050℃ to 1240℃
The method for producing a surface-coated metal according to claim 1, wherein the surface-coated metal is maintained at 4. The other metal is made of a cobalt-based alloy, and when heated and held in vacuum, the temperature of 1050°C to 1240°C
2. The method for producing a surface-coated metal according to claim 1, wherein the surface-coated metal is maintained for 10 hours. 5. Claim 1, wherein the other metal is made of a titanium-based alloy, and the metal material is made of an iron-based alloy, and when heated and held in vacuum, the material is held at 600°C to 900°C for 1 to 10 hours.
A method for manufacturing the surface-coated metal described above. 6. Any one of claims 1 to 5, wherein the means for coldly fixing the powder of another metal to the surface of the metal material is cold pressing.
The method for producing the surface-coated metal described in Section 1. 7. The method for manufacturing a surface-coated metal according to any one of claims 1 to 5, wherein the means for coldly adhering the powder of the other metal to the surface of the metal material is cold isostatic pressing. 8. The surface according to any one of claims 1 to 7, wherein the porosity of the other metal powder layer after cold fixing the other metal powder to the surface of the metal material is 30% or less. Method for producing coated metal. 9. The method for producing a surface-coated metal according to any one of claims 1 to 8, wherein the pressure of the atmosphere is 1 x 10^-^3 Torr or less when heating and holding in vacuum.