JPH03258471A - Manufacture of aluminum clad steel plate - Google Patents

Abstract

PURPOSE:To obtain the aluminum clad steel plate having satisfactory jointability by laminating a cladding material of aluminum or an aluminum alloy on the joining predetermined surface of steel which is base metal, heating these at the limit temperature, then, depressing the cladding material part so as to satisfy the relation of an expression and specifying the rolling finishing temperature. CONSTITUTION:In manufacturing the clad steel plate with the aluminum or aluminum alloy as the cladding material and with the steel as the base metal, a composite formed by laminating the cladding material directly on the joining predetermined surface of the base metal is heated so that the temperature of the joining predetermined surface is regulated to 150-350 deg.C. The reduction is applied so that the total reduction of area R(%) of the cladding material part satisfies the relation of the expression according to the above-mentioned temperature T deg.(C) and rolling is carried out under conditions of rolling finishing temperature of >=150 deg.C. Consequently, the aluminum clad steel plate having satisfactory jointability and high shearing strength can be manufactured at a low cost.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method of manufacturing an aluminum clad steel plate by a hot rolling bonding method. (Prior art and problems to be solved) So-called aluminum-clad steel plates, which are steel plates clad with aluminum plates, are being used in various fields as metal materials with complex functions such as mechanical properties, corrosion resistance, and electrical properties. , conventionally. It is manufactured by an explosive crimping method, which utilizes the explosive energy of explosives to bond, or a rolling bonding method, which crimps and bonds by rolling. However, the explosive crimping method has a high production cost and is not suitable for producing inexpensive rad steel plates. On the other hand, the rolling joining method is suitable for manufacturing low-cost and rad steel plates, and includes cold welding of the mating material and the base material using rolling rolls, followed by diffusion annealing, or hot rolling after heating both metals. method is the mainstream. However, the former cold rolling joining method requires a large reduction in joining, and there are restrictions on rolling capacity. On the other hand, the latter hot rolling bonding method has the advantage of being able to significantly reduce the rolling wheel during rolling compared to cold rolling, but it tends to form an oxide film on the bonding interface, resulting in a decrease in bonding strength. tend to occur. The present invention aims to solve the above-mentioned problems regarding the latter hot rolling joining method, and to provide a method for inexpensively producing aluminum clad steel plates that have good joining properties and can impart high shear strength. It is something. (Means for Solving the Problems) In order to achieve the above object, the present inventors have conducted intensive research to find manufacturing conditions that can provide good bonding characteristics, and as a result, hereby, the manufacturing method of the present invention has been developed. I found it. That is, in manufacturing a clad steel plate in which aluminum or aluminum alloy is used as a laminate material and steel is used as a base material, a composite in which the laminate material is directly laminated on the surface to be joined of the base material is manufactured so that the surface to be joined is 150 mm. After heating to a temperature exceeding 350°C or less, the total rolling reduction ratio R (%) of the laminated material part
of an aluminum clad steel sheet, which is rolled under conditions such that the above-mentioned temperature T (°C) satisfies the relationship R≧-0, 2T+90, and the finishing temperature is 150°C or higher. The gist is the manufacturing method. The present invention will be explained in more detail below. (Function) The most distinctive feature of the present invention is to obtain good bondability and high shear strength through ultrasonic flaw detection. It is necessary to keep the surfaces to be joined clean until immediately before joining, and to apply the necessary rolling reduction to achieve a metallic bond between the cladding material and the base steel, and to increase the strength of the cladding material near the joining interface by rolling. The point is that it has become a reality. (i) To keep the surface to be joined clean, after cleaning the base steel surface by polishing etc., the temperature of the surface to be joined is raised to 350℃ to prevent oxidation of the base steel during heating.
It has been found that it is effective to keep the temperature below ℃. 35
If the temperature exceeds 0°C, the bonding interface will be partially oxidized, which will have a negative effect on the bonding strength, which is not desirable. (ii) In order to increase the strength of the laminate near the joint interface, rolling is performed in a temperature range lower than the softening annealing temperature of aluminum or aluminum alloy, 350 to 400°C, to impart processing strain to the laminate. It is effective to do so. From the viewpoints of both (j) and (il), the temperature reached by heating on the surfaces to be joined is limited to 350° C. or less. However, if the temperature reached at the surfaces to be welded is 150° C. or lower, although oxidation of the base steel can be prevented, it is not possible to obtain sound weldability by rolling, which is not desirable. Therefore, the temperature reached by heating on the surface to be joined is 15
The temperature shall be above 0 and below 350°C. Note that this heating may be performed in the air, under vacuum, or in a reducing or inert atmosphere. In the case of heating in the latter mode, oxidation of the surfaces to be bonded is suppressed compared to that in the air, so bondability is improved and higher shear strength can be obtained. (iii) To make a metallic bond between the cladding material and the base material. It is necessary to rupture the oxides on the surfaces of the respective metals to be joined and eliminate microvoids at the joining interface. In other words, the laminate is laminated directly on the surface of the base steel to be joined, but since the surface to be joined is heated to the above temperature, even if the surface of the base steel to be joined is cleaned by mechanical means before heating. Since the presence of oxides cannot be denied in some cases, it is necessary to break the oxides existing in such conditions and eliminate microvoids at the bonding interface. Here is an example of a basic experiment. First, after polishing with a grinder to No. 80, wire brushing was performed to clean the surface.
Two-layer composites were prepared by laminating A1050P (aluminum laminated material) of one thickness, heated to various temperatures, and rolled for one pass at various rolling reduction rates. The resulting rolled material was evaluated for bondability by ultrasonic testing (JIS GO601) and microstructure observation of the bonding interface, and the relationship between bondability, the temperature reached by heating on the surfaces to be bonded, and the reduction rate in the bonded material was determined. Ta. The results are shown in FIG. From Fig. 1, in order to obtain sound bonding properties, the following relational expression % formula % should be applied to the bonding material part according to the temperature of the surface to be joined in the range shown above (over 150°C and below 350°C). : Total rolling reduction rate of the laminate (%) T: Temperature reached by heating on the surfaces to be joined (°C) It is clear that it is necessary to apply a rolling reduction that satisfies the following. However, in the low temperature and low reduction area where the above relational expression is not satisfied (lower left side of R = -0, 2T + 90 in the figure), microvoids occur even when bonded, and even non-bonded areas This is undesirable because it causes Furthermore, if the temperature reached at the surface to be joined is 150°C or lower, the finished rolling temperature cannot be ensured to be 150°C or higher, and non-bonded parts will occur, so it is also understood that the finished rolling temperature needs to be 150°C or higher. In addition, other manufacturing conditions, such as the material and dimensions of aluminum or aluminum alloy composite material and base steel, and the lamination mode (
There are no particular restrictions on whether it is one-sided or double-sided). Next, examples of the present invention will be shown. (Example) After preparing an aluminum plate and a steel plate with the details shown below, and grinding the surface of the aluminum plate to No. 80,
A composite was prepared by placing it directly on one side of a steel plate that had been cleaned by wire brushing, heated under the conditions shown in Table 1, and rolled. Material of aluminum steel plate: 5S41 Dimensions (wm): 25tX 340wX 2500
Q Aluminum plate: A1050P or Al100P Dimensions (question): 8t x 340w x 2500Q The obtained material was examined for bondability and shear strength of the bonding interface by ultrasonic flaw detection test (JrSGO601). The result is the first
Also listed in the table. In Table 1, Comparative Example Na 3 is an example in which the total reduction ratio R of the mating material part satisfies (-0, 2T + 90) or more, but the temperature reached by the surface to be joined by heating exceeds 350 ° C.
In comparative example NQ4, the temperature reached by the surface to be joined by heating was 3.
Although the temperature is below 50°C, the total rolling reduction ratio R in the laminated material part is (
-0.2T+90), and in both cases, although the bondability by ultrasonic flaw detection is good, the shear strength is low. Comparative Example Nn5 is a case where the finishing temperature of rolling was lower than 150° C., and non-bonded portions occurred. On the other hand, in the examples of the present invention, no non-bonded parts occur and they exhibit higher shear strength than the comparative examples. When the microstructures of the bonding interfaces of the materials of the invention examples were observed, no microvoids were observed in any of them. Further, the plate warpage was also smaller than that of Comparative Example No. 4.

[Left below]

(Effects of the Invention) As detailed above, according to the present invention, it is possible to impart good bondability and high shear strength in the production of aluminum clad steel sheets by hot rolling bonding,
Moreover, it is inexpensive to manufacture.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between bondability, the temperature reached by heating on the surfaces to be bonded, and the rolling reduction rate of the laminate portion.

Claims (2)

[Claims] (1) When manufacturing a clad steel plate with aluminum or aluminum alloy as the laminate and steel as the base material, a composite in which the laminate is laminated directly on the surface to be joined of the base material,
After heating the surface to be joined to a temperature exceeding 150°C and below 350°C, the total reduction rate R (%) of the bonding material part is adjusted to the above temperature T (
A method for producing an aluminum clad steel sheet, which comprises applying rolling to satisfy the relationship R≧-0.2T+90 depending on the temperature (°C) and rolling at a finishing temperature of 150°C or higher. (2) The method according to claim 1, wherein the surface of the composite to be joined is heated in a vacuum, a reducing atmosphere, or an inert atmosphere.