JPS6044102A - Hot rolling method of double-layered clad material - Google Patents

Abstract

PURPOSE:To hot roll a double-layered clad material after preventing the front end of a rolling material from causing camber by hot rolling the double-layered clad material in a state of joining a single metallic piece to the front end of material. CONSTITUTION:A single metallic piece 2 is welded and joined to the front end of a double-layered clad material 1. In case of hot rolling the material 1; the piece 2 after passing the upper and lower rolls 5a, 5b of the 1st stand 4, is bitten the upper and lower rolls 7a, 7b of the 2nd stand 6 without causing any troubles in biting due to the generating of a front-end camber. As a result, when the material 1 is rolled by the rolls 5a, 5b of stand 4 while applying a tension to it between the 1st and 2nd stands 4 and 5, the neutral points are moved. That is, the neutral points a1, b1 are symmetrically positioned in case of the piece 2 at the front end, but the neutral points a2, b2 and a3, b3 are moved to the nonsymmetrical positions in accordance with the constituent materials in case of the clad material 1; then the material is rolled in a stable condition, and the camber is not produced at the front end of material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for rolling a cladding material, and particularly to a method for hot rolling a 2N cladding material.

Generally, when hot-rolling cladding materials made of dissimilar metals, there is a problem of warpage caused by differences in deformation resistance, etc. of the metal materials forming the cladding material. A three-layer sandwich structure is generally used.

However, depending on the application, two layers of clad steel, for example stainless steel on the outside and ordinary steel on the inside, may have to be hot rolled. However, as mentioned above, in such two-layer clad steel, the outer material and the inner material have different hot deformation resistance and hot workability, so when hot tandem rolling is carried out, the first stand Due to the rolling, a difference in elongation occurred and the product warped upward, and the product did not get caught in the rolls of the second stand, making tandem rolling impossible. For this reason, 12-layer clad steel is manufactured by reverse rolling.
or can only be rolled by short plate rolling, and for this reason;
There have been problems in that yield and efficiency are poor and manufacturing costs are high.

The present invention was developed in view of the above-mentioned problems, and when hot rolling a two-layer clad material, a single metal piece is joined to the tip of the two-layer clad material and rolled, thereby causing warpage at the tip of the rolled material. It is an object of the present invention to provide a method for hot rolling a two-layer clad material, which prevents the cladding from occurring.

The invention will now be explained with reference to the drawings.

FIG. 1 shows a state in which a single metal piece 2 is joined to the tip of a two-layer cladding material 1 by welding 3.

The single metal piece 2 welded to the tip in this way is rolled onto the upper and lower rolls 5a of the first stand 4 during hot rolling.

5b, it is caught between the upper and lower rolls 7a and 7b of the next second stand 6 without causing the problem of being unable to be caught due to the occurrence of tip warpage. As a result, tension is applied to the material to be rolled between the first and second stands 4 and 5, and the two-layer clad material 1 is rolled onto the upper and lower rolls 5a of the first stand 4.
, 5b, the neutral point shifts. That is, the neutral point a1 in the case of the single metal piece 2 at the tip.
b□ occurs at a symmetrical position as shown in Fig. 8, but in the case of the two-layer clad material 1, the neutral point is located at the fourth point due to its side slope.
In the figure and Fig. 5, a2', , b2 and aa, b
3, it moves to an asymmetrical position, thereby making it possible to roll in a stable state.

The minimum length L-s of a single metal piece to be welded to the tip of the two-layer clad material 1 is determined by assuming that the thickness of the slab is t1, the thickness of the entrance side of the second stand 6 is 22 mm, and the distance between the stands is S fin. Then, it depends on 2 L-8×- 1. Therefore, if the length of the single metal piece 2 is longer than L, it can be rolled. That is, during rolling, the length of the single metal piece 2 must be greater than the distance between the stands.

According to the invention, the above-mentioned stainless steel,! : It can be applied not only to two-layer cladding steel with ordinary steel, but also to stainless steel and high carbon steel, ordinary steel and high carbon steel, aluminum and copper, and various other two-layer cladding.

Next, examples of the present invention will be described.

40m thick stainless steel (SUS304) and 16mm thick
C1lJl (7) Ordinary m' (5PGO) ,! = (1
:) Length 600 at the tip of a double layer clad steel slab with length ``a 60001'l''! (minimum length 88B-
Arc welding rod D30 coated ordinary steel (SPCC) piece of M)
After butt welding and joining using No. 8 was heated to a predetermined rolling heating temperature, it was rolled. At the rough rolling stage, approximately a
Warping of the oome occurred initially, but the warping was improved due to its own weight during table conveyance, and it was able to fit into the next rough stand and be rolled. There were 6 finishing stands, and the stand spacing was 5,500 flllll, and a single common steel plate at the tip was inserted between the stands and rolled without any problems. The thickness at the entrance of the first finishing stand was 22 fJ, and the thickness at the exit of the sixth finishing stand was 4 mm. The length of the single ordinary steel plate at the tip end after rolling on the first finishing stand is approximately 8609+m, and the distance between the stands is 5500m.
It was considerably longer than mN, so it could be rolled into each stand without any problem.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a two-layer clad material with a single metal piece joined to the tip, Fig. 2 is an explanatory diagram showing the rolling state in a tandem rolling mill according to the present invention, and Figs. It is an explanatory view showing movement. 1...2 layers of rad strips 2...Single metal piece 4...
1st stand 6...2nd stand Figure 1-2

Claims (1)

[Claims] 1. A method for hot rolling a 12-layer clad material, which comprises hot rolling a 12-layer clad material by joining a single metal piece to the tip of the 2-layer clad material.