JPH0716765A - Production of stainless steel aluminum clad material - Google Patents

Abstract

PURPOSE:To increase the relative slip at joint surfaces and to provide the clad material having excellent workability by holding the temp. of an aluminum blank material at the inlet of rolling rolls at ordinary temp. and heating a stainless steel blank material at the inlet of the rolling rolls to maintain its temp. in a specific temp. range. CONSTITUTION:While the temp. of the aluminum blank material 5 at the inlet of the rolling rolls 2, 3 is held at ordinary temp., the stainless steel blank material 7 at the inlet of the rolling rolls 2, 3 is heated to maintain its temp. in the 100 too 400 deg.C range. The apparatus for this process consists of the upper and lower rolls 2, 3 and a control means 11 for overall controlling a heating means 4, an aluminum un-coiler 6, a stainless steel un-coiler 8 and a clad material un-coiler 10. A gas firing heating furnace and electric resistance type heating furnace are adequate for the heating means 4. As a result, the stainless steel blank material 7 is heated to the 100 to 400 deg.C range, by which the relative slip at the joint surfaces is increased and the generation of the fresh surfaces is accelerated. The stainless steel and aluminum clad material having the excellent joinability and workability is thus obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for producing a stainless steel / aluminum clad material by a rolling joining method.

[0002]

2. Description of the Related Art A clad material obtained by laminating two or more kinds of metal plates exhibits properties that cannot be obtained by itself, so that demand is rapidly increasing in the industrial field, daily necessities and other fields. Although there are several methods for producing the clad, the rolling joining method is well known for mass production.

In order to manufacture a stainless steel / aluminum clad material by a rolling joining method, generally, a stainless steel strip and an aluminum strip are superposed and joined by rolling them with a large reduction force. Diffusion bonding is achieved by cleaning the metal surfaces of each other and keeping the interatomic distance on both interfaces within the attractive range. This requires a high degree of pretreatment and extremely high pressure, so that joining is not easy. Furthermore, since materials with different deformation resistance are rolled, it is difficult to perform rolling after rolling and joining, and to adjust the plate thickness in the plate width direction, and it is not easy to stably manufacture a clad material with desired performance at low cost. .

Therefore, as an improved technique, Japanese Patent Laid-Open No. 59-76.
The rolling methods of 686 and JP-A-59-215286 have been proposed. In these rolling methods, a pair of strips are made to pass between a pair of rolling rolls rotating in opposite directions, and one strip is wound around one of the upper and lower rolling rolls, whereby the first strip and the second strip are rolled. Is a method of positively changing the peripheral speed (referred to as "different peripheral speed winding rolling method"). By this method, the friction between the soft material and the rolling roll is opposite to that of the normal constant speed rolling method, the stress in the rolling direction becomes tensile near the entrance of the roll gap and the soft material is easily deformed, and the rolling ratio of the hard material is reduced. By suppressing the relative slippage, the relative slip (speed of hard material / speed of soft material) increases, and excellent bondability and workability can be obtained.

Further, there is also disclosed a technique in which the residual stress caused by the joining can be removed by rolling the clad material produced by the above-mentioned different peripheral speed winding rolling method immediately after the rolling joining.
It has been proposed in -238483.

[0006]

However, when the inventors of the present invention evaluated the stainless steel / aluminum clad material produced by the above-mentioned different peripheral speed winding rolling method, it was found that the bondability was insufficient, and that it was It has been found that it may peel off from the bonding interface. Therefore, an object of the present invention is to find the cause of insufficient joining and to enhance the joining property of the stainless-aluminum clad material based on the result.

[0007]

Means and Actions for Solving the Problems The present inventors have
The cause of insufficient joining is due to lack of relative slip, that is,
Based on the finding that the conventional relative speed wrapping rolling method cannot obtain the expected relative slip, we continued our research to increase this relative slip.

FIG. 1 is a graph showing the relationship between the temperature of the stainless material and the relative slip. The relative slip given by the speed of the hard material divided by the speed of the soft material is 1.2 to 1 when the temperature of the stainless material is room temperature. 0.7 to 2.0-2.
It was found that the range of 7 and the range of 1.9 to 2.9 at 300 ° C. significantly increase the relative slip when the stainless steel material is heated to room temperature.

Therefore, in order to achieve the above object, the present inventors set the aluminum material temperature at the inlet of the rolling roll at room temperature in the method for producing a stainless-aluminum clad material, while It is proposed to heat the stainless material so that the temperature T of the stainless material is in the range of 100 to 400 ° C.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a principle diagram of a rolling apparatus for carrying out the method of the present invention. A rolling apparatus 1 includes a pair of upper rolls 2 and lower rolls 3, a heating means 4 for heating a stainless material to a predetermined temperature, Aluminum uncoiler 6 that sends out aluminum material 5 at a predetermined speed, and stainless uncoiler 8 that sends out stainless material 7 at a predetermined speed.
And a clad material coiler 10 that winds the clad material 9 at a predetermined speed, the upper and lower rolls 2 and 3, heating means 4, aluminum uncoiler 6, and stainless uncoiler 8.
And a control means 11 for comprehensively controlling the clad material coiler 10. The heating means 4 is preferably a gas-fired heating furnace or an electric resistance type heating furnace, but in short, any means capable of uniformly heating the stainless steel material 7 to a predetermined temperature may be used.

First, the control means 11 brings the lower roll 3 into the same or low peripheral speed with respect to the upper roll 2. The aluminum material 5 is wound around the lower roll 3, while the stainless steel material 7 is passed through the heating means 4 and is a rolling roll.
It is guided to the entrance of the lower rolls 2 and 3, where it is put along with the aluminum material 5, and these are pressed by the upper and lower rolls 2 and 3.
Back tension may be applied to the materials 5 and 7 with the aluminum decoiler 6 and the stainless decoiler 8 as needed.

A stainless steel (SUS304) coil having a plate thickness of 0.3 mm and a plate width of 100 mm and a plate thickness of 0.5 mm and a plate width of 1
An aluminum (A1100) coil of 00 mm was prepared, and in the rolling device 1, the lower roll ratio R defined by (lower roll peripheral velocity-upper roll peripheral velocity) / upper roll peripheral velocity x 100 was 0, -20, The clad material was manufactured by changing the rolling load P per unit width of the material to -40, ..., -70. The temperature T of the stainless steel material is 100,
The peeling strength and Erichsen value of the obtained clad material were examined by changing the temperature to 200, 300, ... 500 ° C. and shown in Table 1 (Test Nos. 1-27) and Table 2 (Test No. 28-
54). The peeling test is conducted according to JIS K 6854.
Conducted according to JIS Z 224
The peeling strength was 5 N / mm or more and the Erichsen value was 8 mm or more.

[0013]

[Table 1]

[0014]

[Table 2]

Those marked with a circle in the comprehensive evaluation cannot be peeled (the strength is so great that they do not peel) or the peel strength is 5 N / mm or more, and the bondability is sufficiently high. Further, if the Erichsen value is 8 mm or more, press working with a drawing ratio of 2 or less can be endured, so that workability is also good.

FIG. 3 shows the test results of the embodiment as the lower roll ratio,
It is a graph arranged by temperature of stainless steel material (100 to 200 ° C) and rolling load.
= 100 ° C and T = 200 ° C comprehensive evaluation ○, × data (subscript 1 shows data at 100 ° C, subscript 2 shows data at 200 ° C) are plotted, and a regression equation is calculated from ○ and ×. Is. That is, 100 ° C ≤ temperature T of stainless steel material
<200 ° C, rolling load P (N / m per unit width of material)
m) ≧ 4.28 × 10 ²² (−R) ^−4.39 (T) ^−5.99 , it is possible to manufacture a clad material having excellent ^bondability and workability.

FIG. 4 shows the test results of the embodiment as the lower roll ratio,
It is a graph in which the temperature of the stainless steel material (200 to 400 ° C.) and the rolling load are arranged. Specifically, T = 2 in Table 1 above.
Overall evaluation of 00 ° C, T = 300 ° C and T = 400 ° C ○, × data (subscript 2 is data at 200 ° C, subscript 3 is 3
00 ° C., subscript 4 indicates data at 400 ° C. ) Is plotted and the regression equation is calculated from ○ and ×. That is, at a temperature of 200 ° C. ≦ stainless steel temperature T ≦ 400 ° C., a rolling load P (N / mm) per material unit width ≧ 4.4.
If 6 × 10 ³ × 10 ^{0.0126 R} is satisfied, a clad material having excellent ^bondability and workability can be manufactured.

The reason why the lower roll ratio R and the temperature T of the stainless steel material are limited in the present invention is as follows. When the lower roll ratio R is less than -70%, the above Table 2
This is because the aluminum material breaks, as shown by the test number 54 of. Therefore, it is necessary to keep the lower roll ratio R below 70% from the viewpoint of protecting soft materials. Regarding the temperature T of the stainless steel material, if T is less than 100 ° C, the activation energy required for atomic diffusion at the solid-phase interface cannot be reduced and diffusion bonding becomes insufficient, and T is 400 ° C.
If it exceeds, the harmful oxide film is formed on the joint surface and the joint becomes insufficient. Therefore, the stainless material is heated to keep the temperature T of the stainless material in the range of 100 ° C to 400 ° C.

In the above embodiment, the rolling mill is composed of a pair of upper and lower rolls 2 and 3, but the rolling mill is not limited to this.
The rolling mill may be a multi-stage tandem mill, and the number of rolling rolls is arbitrary. In the above embodiment, the lower roll 3
The side is a low peripheral speed roll, but the upper roll 2 side can be a low peripheral speed roll. In this case, the word of the lower roll in claim 2 may be replaced with the upper roll.

[0020]

As described above, according to the present invention, by heating the stainless steel material in the range of 100 to 400 ° C,
It is intended to provide a stainless steel / aluminum clad material having an increased relative slippage at the joint surface and promoting the generation of a new surface due to the increased relative slippage, and thus having excellent jointability and workability.

Further, the lower roll ratio R is less than -70%, the rolling load P per unit width of the material is 100 ° C ≤ the temperature T of the stainless material T <200 ° C, and P ≥ 4.28 × 10
²² (-R) ^-4.39 (T) ^-5.99 , 200 ° C ≤ stainless material temperature T ≤ 400 ° C, P ≥ 4.46 × 10 3 × 10
^By controlling to ^0.0126R , the clad material manufacturing method can be stabilized, and the operation can be simplified.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the temperature and the relative slip of a stainless steel material.

FIG. 2 is a principle diagram of a rolling apparatus for carrying out the method of the present invention.

FIG. 3 is a graph in which the test results of Examples are arranged by lower roll ratio, temperature of stainless steel material (100 to 200 ° C.), and rolling load.

FIG. 4 is a graph in which the test results of Examples are arranged by lower roll ratio, temperature of stainless steel material (200 to 400 ° C.), and rolling load.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rolling device, 2 ... Rolling roll (upper roll), 3 ... Rolling roll (lower roll), 4 ... Heating means, 5 ... Aluminum material, 6 ... Aluminum uncoiler, 7 ... Stainless steel material, 8 ... Stainless steel uncoiler, 9 ... Clad material,
10 ... Clad material coiler, 11 ... Control means.

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[Procedure amendment]

[Submission date] July 2, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Further, the lower roll ratio R is less than -70%, the rolling load P per unit width of the material is 100 ° C ≤ the temperature T of the stainless material T <200 ° C, and P ≥ 4.28 × 10
²² (−R) ^−4.39 (T) ^−5.99 , 200 ° C. ≦ stainless steel temperature T ≦ 400 ° C., P ≧ 4.46 × 10 ³ × 10
^By controlling to ^0.0126R , the clad material manufacturing method can be stabilized, and the operation can be simplified. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 26, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (2)

[Claims] 1. The peripheral speeds of the upper and lower rolling rolls are made different,
In the method for manufacturing a stainless steel / aluminum clad material in which an aluminum material and a stainless material are roll-bonded with this rolling roll, the temperature of the aluminum material at the entrance of the rolling roll is kept at room temperature, while the temperature of the stainless material at the entrance of the rolling roll is maintained. A method for producing a stainless steel / aluminum clad material, which comprises heating a stainless material so that T is in the range of 100 to 400 ° C. 2. When the lower roll side of the upper and lower rolling rolls is a low peripheral speed roll, the lower roll ratio R defined by the following formula (1) is in the range of less than -70%, and The method for producing a stainless steel / aluminum clad material according to claim 1, wherein the rolling reduction is controlled by a rolling load P per unit width of the material given by the equation (2) or the equation (3). Lower roll ratio R; R = (lower roll peripheral velocity-upper roll peripheral velocity) / upper roll peripheral velocity × 100 (1) Rolling load P (N / mm) per unit width of material; 100 ° C. ≦ temperature of stainless material When T <200 ° C., P ≧ 4.28 × 10 ²² (−R) ^−4.39 (T) ^−5.99 ……… (2) 200 ° C. ≦ stainless steel temperature T ≦ 400 ° C., P ≧ 4.46 × 10 ³ × 10 ^0.0126R ………………………… (3)