JPS6142498A - Production of aluminum-stainless steel clad plate for forming - Google Patents

Abstract

PURPOSE:To obtain a clad plate having excellent joint strength, formability and surface condition by subjecting a laminated plate of a prescribed aluminum metallic material and soft stainless steel to hot rolling and annealing under prescribed conditions. CONSTITUTION:The aluminum plate consisting of 1:5-20:1 constituting ratio of the sheet thickness of blank material or the aluminum alloy sheet contg. <2wt% Mg prior to rolling and the soft stainless steel sheet are laminated into >=2 layers. Such laminated plate is heated to 300-500 deg.C at >=10 deg.C/min heating rate and is hot rolled at 10-40% draft. The hot rolled material is annealed for 0.5- 6hr at 300-550 deg.C.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention relates to a method for producing an aluminum-stainless steel clad plate for forming process, and more specifically, the present invention relates to a method for producing an aluminum-stainless steel clad plate for forming process, and more specifically, it relates to a method for producing an aluminum-stainless steel clad plate for forming process. - Manufacture of stainless steel clad plate) J method.

[Juniorai Edjutsu 1 Aluminum or aluminum alloys are naturally lightweight, have high thermal conductivity, and have high corrosion resistance.They also have excellent properties such as improved strength and moldability due to the inclusion of various elements. However, its rigidity, heat resistance, magnetic properties, etc. may be inferior to the pond material.

Therefore, in recent years, composite materials that are composited with other dissimilar metals or materials have been attracting attention in order to compensate for these characteristics. Clad plates, which are a type of composite material, are manufactured using four traditional materials, and the manufacturing methods include explosion bonding, welding, rowing, heat welding, and rolling welding. Law or known.

Among these, the pressure welding method by rolling is efficient;
It is also suitable for mass production, and there are two types of rolling welding methods: cold rolling and hot rolling.

Therefore, when using a clad plate for forming processing, it is necessary not only to maintain the shape of the plate material such as flatness, distortion, and warpage, but also to maintain sufficient joint strength to withstand processing and formability of the material. This makes it difficult to rotate the rolling welding conditions.

For example, in order to increase the joint strength with hot rolling welding,
It is necessary to raise the rolling start temperature and the rolling reduction rate as high as possible, but if the temperature and rolling reduction rate are made higher than necessary, not only will the flatness deteriorate, but also wrinkles will occur and the rolling reduction rate will be as high as possible. (Aluminum plate and stainless steel plate)
If the softening annealing temperatures are extremely different, the stainless steel sheet cannot be softened and its formability will be significantly degraded.

In other words, in the production of aluminum-stainless steel clad plates for forming, it is important to find conditions for hot rolling welding of stainless steel without work hardening as much as possible, and to select materials suitable for press workability. I understand.

[Problems to be Solved by the Invention 1] As explained in Section 2, the present invention has been made in view of the various problems encountered when manufacturing a clad plate of an aluminum plate or an aluminum alloy plate and a stainless steel plate by the rolling pressure welding method. As a result of intensive research, the inventor of the present invention discovered material conditions, hot rolling welding conditions, and finishing annealing strips of 1!1, and found that the combination of aluminum plate and stainless steel plate with excellent formability was achieved. We have developed a method for manufacturing clad plates.

Means for Solving Problem 1 The feature of the method for manufacturing an aluminum-stainless steel clad plate for forming processing according to the present invention is that the composition ratio of the thickness of the material before rolling is 1:5 to 20:I. An aluminum plate consisting of an aluminum plate or an aluminum alloy plate containing less than 1% M82w and a soft stainless steel plate are laminated in advance in two or more layers,
This laminated material was heated at a heating rate of 1 (1'C/n)
0(1-5(1(1'C) and immediately 10-1[0
% hot rolling and then heating annealing at a temperature of 300 to 55 Q°C for 0.5 to 6 hours.

The method for manufacturing an aluminum-stainless steel plate for forming and processing according to the present invention (hereinafter sometimes referred to as "Fil" as the manufacturing method according to the present invention) will be described in detail below.

The materials used in the manufacturing method according to the present invention will be explained.

As the aluminum or aluminum alloy, pure aluminum or an aluminum alloy with an hqg content of less than 21% is suitable.If the M8 content increases, the aluminum alloy surface will be severely oxidized unless heated in a vacuum or atmosphere, and rolling Sufficient bonding strength cannot be obtained by pressure welding.

Stainless steels can be roughly divided into three types based on their crystal structure: ferritic, austenitic, and two-phase systems in which these two phases coexist. Any type of stainless steel can be used, and regardless of the type of crystal structure of the stainless steel, sufficient bonding strength can be obtained by selecting hot rolling conditions. Furthermore, since these stainless steels do not soften when subjected to heat annealing (which also serves as diffusion annealing) after pressure welding, it is necessary to use a soft material. If a hard material is used, the aluminum plate cannot follow the deformation of the aluminum side during rolling, which tends to cause uneven deformation, and the stainless steel plate tends to break in a sagging pattern. The material plate thickness composition ratio should be 1:5 to 20:1 because if this ratio exceeds 20:1 and the stainless steel plate thickness becomes extremely thin, the stainless steel plate will easily break during rolling and press forming (drawing) will occur. This may cause buckling of the stainless steel plate during processing (processing), causing body wrinkles, and 1:
If it is less than 5, if the aluminum plate or aluminum alloy plate becomes thin, the aluminum plate or aluminum alloy plate will be selectively rolled down during hot rolling, making it difficult to expose the new surface on the stainless steel plate side, and sufficient bonding strength will not be obtained. .

Aluminum plates or aluminum alloy plates and stainless steel plates are laminated in two or more layers.
In order to manufacture layered cladding plates, for example, aluminum plates (including aluminum alloy plates), stainless steel plates,
It is desirable to use a four-layer laminate such as a stainless steel plate and an aluminum plate, or a three-layer laminate such as a stainless steel plate, an aluminum plate, and a stainless steel plate. By stacking the materials symmetrically in this way, a clad plate with excellent flatness can be produced by eliminating warpage caused by the difference in coefficient of linear expansion of each material. However, it goes without saying that other laminated structures may be used.

Next, heating, rolling and annealing of the manufacturing method according to the present invention will be explained.

In order to ensure sufficient bonding strength of clad plates, conventional methods include heating the bonded surfaces in a vacuum or atmosphere or brushing the pressure bonded surfaces to keep the bonded surfaces clean and prevent surface oxidation as much as possible as a pre-bonding treatment. However, according to the research conducted by the present inventor, it was found that sufficient bonding strength can be obtained by specifying the heating rate and holding time even if the laminated materials are heated in the atmosphere. . That is, by heating to 300 to 500° C. at a relatively fast temperature increase rate of 10° C./min or more and immediately performing hot rolling, there is no need for conventional pretreatment.

If the heating rate is less than 10'C/f++in, the oxidation of the bare key joint surface will be severe, and sufficient joint strength will not be obtained even by diffusion heating annealing after hot rolling, and if the heating temperature is less than 300°C, In order to increase the bonding strength, a high rolling reduction rate is required, which causes deterioration in later formability.On the other hand, at temperatures exceeding 500°C, the difference in deformation resistance between the aluminum plate or aluminum alloy plate and the stainless steel plate becomes large. However, if the shape is good or the rad plate is not obtained.

After this heating, hot rolling is performed, but the reduction rate is
If it is less than 10%, the exposed area of the new surface necessary for bonding will be reduced, resulting in a decrease in bonding strength, and if the rolling reduction exceeds 40%, it will be difficult to perform molding in the subsequent process.

After hot rolling, the hot rolled material remains intact.

The bonding strength of the plate was not sufficient, and there were local variations in bonding strength, so the hot open rolling mill was
Heat annealing is performed at a temperature of 50°C for 0.5 to 6 hours,
The bonding strength is increased by causing atomic diffusion in the metal bonding part, and the bonding strength is increased at temperatures below 300°C and 0.5°C.
If the holding time is less than 5 hours, there is no improvement in bonding strength;
If the temperature exceeds 50°C and is maintained for 6 hours, a weak intermetallic compound will be formed at the joint, resulting in a decrease in the joint strength.

[Example 1] A method for manufacturing an aluminum-stainless steel clad plate for forming according to the present invention will be described.

Example I SUS 3 (14 steel (1, 1 mmL, (1, 2+
++++)l, ('l, 311111+L soft material] (15f'l, 3 f'+ 04.5 (152
The strips shown in Table 1 ('
1 by 2, Ol1lbot's Kula State! A plate was prepared and annealed at a temperature of 40 (piC) for 2 hours.

Table 1 shows the results of tests on bonding strength and external shape.

Example 2 SUS 430 steel 0, 5++uat, 1.0+
++mt, 1.5muaL soft material and 1050 alloy 0. I
+nmL, 0.2+n+nt are stacked in 4 layers in advance,
It was heated to a temperature of 400°C at a temperature increase rate of 20'C/min, and immediately hot rolled.

The results are shown in Table 2.

Example 3 S tJ S 403 steel 0.5 mm 1 soft plate was used as both sides, 1100 alloy plate 2. OmmL was stacked in three layers as a core material, and hot rolled under the conditions shown in Table 3, resulting in a total thickness of 2.
, 4 a+mt clad plate was produced.

Table 3 shows the joint strength and plate shape.

15-Example 4 3004 alloy 1.2 mml and 5US430 soft material 0
, 5 +nmt, stacked in four layers of aluminum plate, stainless steel plate, and stainless steel aluminum plate and heated to 400 °C at a temperature increase rate of 50 °C / min,
Immediately hot rolling was performed to produce a 1.4+n+nt clad plate, and diffusion annealing was performed under the conditions shown in Table 4.

Table 4 shows the annealing conditions and bonding strength.

Table 4 X Clad plate manufactured by the manufacturing method according to the present invention.

[Effects of the Invention 1] As explained above, the method for manufacturing a 1 fl aluminum-stainless steel crush plate according to the present invention has the following configuration, and as explained in the Examples. The clad plate produced by the manufacturing method according to the present invention, which is marked with *, has a well-balanced and excellent bonding strength, formability, clad surface condition, and clay P plate shape, similar to the comparative example. Even if the bonding strength is good, there are wrinkles on the surface, cracks occur, and the formability is poor and there is no peeling.Aluminum has excellent formability.
This makes it possible to manufacture stainless steel clad plates with high productivity.

=171

Claims (1)

[Claims] Two or more layers of an aluminum plate or an aluminum alloy plate containing less than 2 wt% Mg and a soft stainless steel plate are laminated in advance, and the laminated plate is heated at 10°C. 3 at a heating rate of /min or more
The hot rolled material is heated to 00 to 500°C, immediately hot rolled by 10 to 40%, and then the hot rolled material is heated to 300 to 550°C.
1. A method for producing an aluminum-stainless steel clad plate for formability, which comprises performing heat annealing at a temperature of 0.5 to 6 hours.