JPS60115384A - Production of composite material by brazing and rolling - Google Patents

Abstract

PURPOSE:To produce a composite material having a high rate of joining by subjecting either one or both of the joint surfaces of a base metal such as iron and a cladding metal consisting a metallic material to nickel plating and brazing the joint surfaces by copper, etc. as a brazing material then rolling the joined material at the m.p. of the brazing material or below. CONSTITUTION:Either one or both joint surfaces of a base metal such as a iron or iron alloy and a cladding metal consisting of a metallic material are subjected to nickel plating. A brazing material consisting of copper having the m.p. lower than the m.p. of the cladding metal or a copper alloy such as Cu-Mn alloy or the like is sandwiched between the base metal and the cladding metal in such a way that the above-mentioned plating layer contacts with the brazing material and these metals are heated at the temp. between the m.p. of said brazing material and the base metal and higher than 1,050 deg.C, by which the metals are brazed. The slab obtd. in such a way is rolled at the m.p. of the above-mentioned brazing material or below to prevent intrusion of the copper into the grain boundary and enriching of the iron in the weld zone. The composite member which can prevent the cracking in the stage of executing welding and the decrease in resistance to fatigue during use and has a high joining rate is obtd.

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a composite material by brazing rolling,
In detail, (1) of the base material of iron (hereinafter referred to as Fe) or its alloy and the composite material of the metal material, a brazing filler metal of copper (hereinafter referred to as Cu) or its alloy is sandwiched between the parts and brazed rolling. The present invention relates to a method for manufacturing a composite metal material that can reduce the intrusion of the brazing filler metal into the base material of CU and the formation of Fe enrichment in the molten zone.

As the environment in which materials are used becomes more severe, it is becoming increasingly difficult to satisfy a wide variety of performance requirements with a single material. In order to meet these performance requirements by combining several types of materials, development of composite materials is becoming more active.

As methods for manufacturing composite materials, methods such as assembly, casting, overlay, explosive bonding, and fusion bonding have been proposed, and some of these methods have been put into practical use.

Recently, a new brazing method has been proposed in addition to these clad manufacturing methods. This method is attracting attention because it is effective in joining ceramics, which is considered one of the next-generation promising materials, and commonly used steel materials. The manufacturing method of clad steel using this brazing method was disclosed in Japanese Patent Application Laid-Open No. 55-4
As described in Japanese Patent No. 13468, when two or more types of gold (2) layer materials are joined to form a composite material, a material having a melting point lower than that of the metal materials is placed between the metal materials to be joined. It is manufactured by sandwiching a joining metal, melting the joining metal to join the metal materials, and then rolling the joined slab. However, when manufacturing by this method, there are the following problems.

That is, Figure 1 shows 90Cu-1 using pure copper as the brazing material.
This is a microscopic photograph of the cross-sectional structure of the joint when the ONi alloy composite material and the base material of 5S41 steel plate are brazed. ).

When this is rolled, the intruded portion of CU is extended as it is, and the wedge-shaped intruded Cu can be seen at the grain boundaries of the final product. The presence of such Cu causes cracks to occur during welding and a decrease in fatigue strength during use.

Further, when Ni or Mn is used to control the melting point of the brazing material, and Cu--Ni or Cu--Mn alloy is used as the brazing material, the intrusion of Cu into the grain boundaries of the base metal is reduced.

(3) However, the Fe in the base material is undesirably eluted into the brazing material which melts during soldering, forming an Fe-enriched layer as shown in FIG.

Therefore, the present inventors investigated various ways to reduce the above-mentioned intrusion of Cu into the grain boundaries of the base material and the formation of an Fe-enriched layer in the molten zone. However, it was found that by plating the base metal surface with Ni, the intrusion of Cu can be effectively prevented.

The present invention was established based on the above-mentioned findings, and specifically, it uses a brazing rolling method that can prevent Cu from entering into the base metal grain boundaries and prevent oxidation of the joint surface. We propose a manufacturing method for clad steel.

That is, in the method of the present invention, nickel plating is applied to one or both joint surfaces of the base material of iron or iron alloy and the composite material of metal materials, and the melting point of the composite material is applied between the base material and the base material. A brazing filler metal made of copper or copper alloy having a lower melting point is sandwiched so that the plated layer is in contact with the brazing filler metal (4), and then the melting point of the brazing filler metal and the base metal are The brazing material is heated to a temperature higher than 1050° C. and brazed together to form a slab, and then this slab is rolled at a temperature below the melting point of the brazing material.

The method of the present invention will be explained in detail below.

As described above, the shear strength of any stainless clad steel joint produced by brazing rolling according to the method of the present invention depends on the strength of the brazing metal, and is 22 to 24 kg f/mm2.
Met.

Therefore, the stainless clad steel produced in this manner can be used in applications where the shear strength is 20 kgf/m1 or more.

As described above, in order to prevent the intrusion of O into the grain boundaries and the concentration of Fe at the brazed joints, which are the drawbacks of the conventional brazing rolling method, the method of the present invention has been implemented by It is characterized by applying Ni plating to the surface and performing brazing, rolling, etc. under these conditions. According to the method of the present invention, cracking during welding work and decrease in fatigue strength during use can be prevented (
5) It is extremely useful industrially.

Note that any metal material can be used as the bonding material, such as stainless steel, copper alloy (Cu-Ni,
Cu-Mn, etc.) can also be used.

In addition, any iron or its alloy is sufficient as the base material; for example, carbon steel (welded structural steel plates, etc.), low alloy steel (high tensile strength steel Cr-Mo steel, shipbuilding steel plates, etc.), etc. are used. be able to.

First, a metal material having a melting point To (° C.) is used as a bonding material, and Ni plating is applied to the bonding surface of one or both of the carbon steel bonding material as a base material or the base material. Copper or copper alloy whose melting point Ti (°C) is lower than Tc is sandwiched between this base material and the laminated material, and the whole is made such that Tc>T>Ti, T>1050.
A slab is made by heating to a temperature T (°C) that satisfies the temperature and performing brazing.

Thereafter, this slab is rolled at a temperature below Ti (° C.) to produce a composite material.

In this case, if a stainless steel plate is used as the mating material and Ni plating is applied to the joint surface of the stainless steel plate,
As mentioned above, stainless clad steel (6) with few defects can be easily obtained, and furthermore, if N1 plating is applied to both the stainless steel of the mating material and the steel plate of the base material, the joining rate after rolling is extremely high. Become.

To explain in more detail, for example, 90%Cu-10%N
When manufacturing a clad steel plate using the conventional method using pure copper or 89% Cu-11% contact alloy as a joining brazing material between the i-alloy mating material and the 5M41 steel base material, the
Products brazed at 900°C can also be manufactured by rolling at 900°C. In this case, the base metal 5M41 steel plate has Ni on its joint surface.
It is not plated and at this time it is heated to 1000℃.
It can be joined with When pure copper is used as the brazing material during this manufacturing, O penetrates into the grain boundaries of the base metal. On the other hand, when a Cu--Mn alloy is used as the brazing filler metal, the intrusion of Cu into the grain boundaries is reduced, but Fe concentration (1) occurs in the molten zone.

From this point of view, in the present invention, as is clear from FIG. 3, in order to prevent the formation of Cu intrusion into these grain boundaries and concentration of Fe in the molten zone, Ni is added to the bonding surface of the base material.
Apply plating.

(7) Since Ni plating is applied to the base material, the brazing temperature must be a little higher than 1050°C.

By the way, when the old plating with a thickness of 100μ is applied to the base material, the brazing temperature is less than 1 as in the conventional example, as shown in Figure 4.
If the temperature is 00°C or lower, the base material and the composite material will separate during rolling, but if the brazing temperature is increased to 1050°C or less, they will not separate. Therefore, since the base material is plated with Ni in advance and brazed with a copper alloy, the brazing temperature must be 1050° C. or higher in the present invention.

Further, the reason why the rolling temperature is set lower than the melting point of the brazing material is that if it is higher than the melting point of the brazing material, the brazing material will melt and the base material and the bonding material will separate at some parts of the brazing material. Therefore, it is necessary that the rolling temperature of the brazed slab be lower than the melting point of the brazing material.

In addition, setting the brazing temperature lower than the melting point of the laminated material as mentioned above is because if it is too high, the laminated material will melt, requiring the installation of a frame to prevent leakage, and the economic efficiency of the brazed part will be lost. Because it is put away (8). Therefore, the brazing temperature needs to be below the melting point of the laminated material.

Although the above example shows Ni plating on the bonding surfaces of the base materials, it is also possible to apply Ni plating on both bonding surfaces of the bonding material. When Ni plating is applied to the surface, stainless clad steel has an extremely high bonding rate.Under the conditions described above, the method of the present invention applies Ni to the surface of at least one of the base material or the composite material.
After performing the first step, a brazing filler metal of Cu or its alloy is interposed between the base material and the laminated material, and then heated.
After brazing, this slab is rolled at a temperature below the melting point of the brazing material. According to this method, stainless clad steel with a high bonding rate can be produced as follows.

That is, the hot deformation resistance of stainless steel is higher than that of carbon steel, and therefore the rolling temperature of the slab needs to be set higher. In this sense, the brazing filler metal (9) is preferably Cu or an alloy thereof with a melting point as high as possible. Therefore, as a comparative example, 0.2
12 5M41 steel plates of x150x25011111"
Brazing at 50°C and then rolling at 1150°C. In this way, a stainless clad steel with a thickness of 10 mm is obtained. However, this clad steel has an extremely low bonding rate between the laminated material and the base material.

0.2×150 of the brazing filler metal by the method of the present invention
70% Cu -30% Ni alloy plate of X2501111113, laminated material 4x150x200mm” 8083
16 steel plate, base material 30X150X200111m'5
When using M41 steel plates for brazing and rolling as described above, as a pretreatment of the bonding surfaces of the mating materials and the base metal, after polishing to #/20, some materials may have a thickness 10
This is done by applying 0μ Ni plating. By rolling in this manner, stainless clad steel with a bonding rate of 90% or more can be obtained.

Therefore, torsion specimens in the C direction were taken from the ends of each of the clad materials manufactured by the above comparative example and the method of the present invention at 10 intervals in the rolling direction to examine the peeling condition (10). It was as shown in Figure 5.

In FIG. 5, as a comparative example (indicated by reference numeral A), the bonding rate is extremely low when N1 plating is not applied to the bonding material. On the other hand, in the case of the method of the present invention, when Ni plating is applied only to the bonding surface of the laminated material (indicated by the symbol (b)), Ni plating is applied to both the bonding surfaces of the laminated material and the base material. In either case (indicated by symbol (a)), a high bonding rate can be obtained. Furthermore, if Ni plating is applied to both joint surfaces, a joining rate of 90% or more can be ensured, and an extremely excellent clad steel can be obtained.

[Brief explanation of the drawing]

Figure 1 shows 90Cu-1ON i using Cu as the brazing material.
A micrograph of the cross-sectional structure of a clad steel joint. Figure 2 shows the XMA results of a cupronickel clad steel plate joint using 89Cu and -llMn as the brazing filler metal. Fig. 3 is an explanatory diagram showing the state of penetration of O into the metal; An explanatory diagram showing that Ni plating prevents the concentration of Fe in the brazed joint and the intrusion of Cu into the grain boundaries.
Figure 4 is a graph showing the brazing temperature and bonding rate of the rolled material when Ni plating is applied to the base material by the method of the present invention, and the base material and cupronickel are brazed with 89Qu-llMn and then rolled. Figure 5 shows 5 using old 70Cu-30 brazing filler metal.
It is a graph showing the influence of Ni plating on the joining rate of rolled material when US316 clad steel is brazed and rolled. Code (a)...Comparative example (b), (c)...Two invention method patent applicant Kawasaki Steel Co., Ltd. agent Patent attorney Yoshikatsu Matsushita Attorney Vice Fumiyu Shima (12) − 50 [Fig. 4 Goro Lie 1 Onno L <'C) Fig. 5 (C), Distance between Dain 1 and the other side (mm>

Claims (1)

[Claims] Nickel plating is applied to one or both joint surfaces of the base material of iron or iron alloy and the composite material of metal materials, and a melting point lower than the melting point of the composite material is formed between the composite material and the base material. After holding a brazing filler metal made of copper or copper alloy so that the plated N is in contact with the brazing filler metal, the brazing filler metal is heated between the melting point of the brazing filler metal and the melting point of the base metal at a temperature of 1050°C or higher. 1. A method for manufacturing a composite material by brazing rolling, which comprises heating to a high temperature and brazing them together to form a slab, and then rolling this slab at a temperature below the melting point of the brazing material.