JPH0562036B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for manufacturing clad steel sheets.

(Prior art and its problems) Clad steel sheets, which are made by forming other alloy steel or nonferrous alloy layers on the surface of steel materials, take advantage of the characteristics of each metal material and have excellent corrosion resistance, heat resistance, wear resistance, and crack resistance. It is a composite metal material that can meet the increasingly sophisticated demands for such things, and is widely used in petrochemical plants, seawater desalination equipment, chemical tankers, etc.

Among these clad steel manufacturing methods, the rolling method is the most suitable method for manufacturing a wide variety of clad steel sheets. This method involves laminating base steel sheets and laminate sheets in a sandwich or semi-sandwich pattern, forcibly evacuating the inside through an exhaust port, and then hot rolling the sealed composite to separate the laminate and base materials. This is a method of joining steel.

However, when clad steel plates are manufactured using the conventional rolling joining method, where the high-temperature deformation resistance of the laminate is higher than that of the base steel, the laminate thickness is 1000 to 2000 mm from the leading and trailing edges of the laminate after rolling. A phenomenon occurred in which the thickness of the material became thicker than the thickness of the laminate at the center. The degree of thickening of the laminate material at the leading and trailing ends depends on the type of laminate material, but
Roughly speaking, the thickness of the laminate at the front and rear ends is the same as the thickness of the laminate at the center.
It is about 1.1 to 6. For this reason, there was a technical drawback in that clad steel having a laminate material with higher high temperature deformation resistance than the base steel could not be manufactured at a high yield. That is, specifically, due to the increased thickness of the laminated material at the leading and trailing ends after rolling, the following technical problems occurred.

After rolling, there was a major problem in that the product could not be collected because the predetermined length of the laminate could not be secured. For this reason, it has been necessary to design the thickness of the laminate original plate or the length of the laminate original plate in the rolling direction to be larger by the amount corresponding to the shortfall in length in advance at the composite design stage.

The base material steel thickness at the leading and trailing ends after rolling is thinner than the center part, contrary to the case of laminated material, so the amount of cut off at the leading and trailing ends is minimized and the base material steel thickness is reduced. In order to satisfy the lower limit tolerance of , it was necessary to increase the finished rolled plate thickness in advance.

In addition to the mating material thickness tolerance and base material steel thickness tolerance,
Furthermore, when the upper limit tolerance of the total thickness is set strictly, it is necessary to increase the amount of cutting off at the leading and trailing ends to cut away the uneven thickness of the laminate at the leading and trailing ends.

As described above, in the prior art, clad steel sheets by rolling could only be manufactured at extremely low yields, which was a major economic problem.

(Problems to be solved by the invention) The present invention solves the above-mentioned drawbacks of the prior art, and makes it possible to manufacture clad steel plates uniformly and at a high yield when a metal material with higher high-temperature deformation resistance than base steel is used as a cladding material. The purpose is to provide a method.

(Means for Solving the Problems) The present invention solves the problem of the conventional method in that the contact angle between the laminate original plate and the base steel original plate at the front and rear ends of the composite is approximately a right angle. Focusing on the fact that the strain concentration at the contact area of the material steel increases, and the base material steel part with low deformation resistance deforms more than the laminate part, resulting in an imbalance in wall thickness, By using a laminate whose edges in the rolling direction are tapered so as to face the base steel original plate, strain concentration at the contact area between the laminate edge and the base steel is reduced and the thickness of the laminate is uniform. The objective is to manufacture clad steel sheets with high yields.

That is, the gist of the present invention is as follows: ``When forming a semi-sanderch type or a sanderch type composite, the edges in the rolling direction of a composite sheet of a metallic material having higher high-temperature deformation resistance than the base steel. A method for manufacturing a clad steel sheet, characterized in that a taper for reducing strain concentration at the contact portion with the base steel is formed so as to face the base steel base plate.

Hereinafter, the present invention will be described in detail based on a composite form shown in the accompanying drawings.

(Example) Fig. 1a is a schematic cross-sectional view parallel to the rolling direction of a sanderch-type composite used to produce a clad steel plate according to the present invention, and Fig. 1b is a cross-sectional view of a tapered two-layer composite material. FIG. 3 is a schematic cross-sectional view parallel to the rolling direction of the original plate. 1 is a base steel original plate, 2 is a laminated original plate that has higher high temperature deformation resistance than the base steel, 3 is a separating material, 4 is an insert metal, 5 is a taper formed at the front and rear ends of the laminated original plate in the rolling direction, 6 is Zr , oxides such as Ti, nitride-forming substances, 7 is a frame material, 8 is an exhaust hole, 9 is an exhaust pipe, 10 is a sealing welded part, 11 is a welded part between laminated original plates, 12 is a base steel original plate This is the formed taper. First, as shown in Figure 1b,
Two tapered blank sheets 2 are placed facing each other with a separating material 3 in between so that each taper faces the base steel blank side, and then shield welding 11 is performed to form the taper. A two-layer laminated material original plate is formed. Next, during rolling, at the front and rear ends of the composite, a tapered two-layer laminated material original plate (first
Figure b) is placed. After that, the frame material 7 is placed around the two-layer laminated material original plate, and the frame material 7 located at the side edge part is
A gas-absorbing substance 6 such as Zr or Ti is inserted into the gap between the frame material 7 and the base steel base plate 2, and after the frame material 7 and the base steel base plate 1 are hermetically welded 10, it is forced through the exhaust hole 8 and the exhaust pipe 9. Vent the air and isolate the inside of the composite from outside air. This composite is heated and then hot rolled,
Then, cut around the periphery to separate the two clad steel plates.

Fig. 2a is a schematic cross-sectional view parallel to the rolling direction of a semi-sandwich arch type composite used in another method of implementing the present invention, and Fig. 2b is a schematic cross-sectional view parallel to the rolling direction of a tapered cladding material original plate. It is a diagram. The same numbers as in FIG. 1 indicate members or parts having the same functions. Here, 25 is the laminating material original board and the dummy board 31
26 is a welded portion between the fixed plate 25 and the laminate original plate, and 27 is a welded portion between the fixed plate 25 and the dummy plate 31. In this composite assembly, a laminate original plate 2 with tapers 5 formed on the upper and lower sides is placed via an insert metal 4 on a base steel original plate 1 with tapers formed at the front and rear ends in the rolling direction, similar to the sandwich type composite. A dummy plate 31 having a tapered front and rear end portion, similar to the base steel original plate 1, is placed on the laminating material original plate 2 with a separation member 3 interposed therebetween. Note that the taper cladding material original plate 2 and the dummy plate 31 are fixed plate 25.
It is fixed by welding parts 26 and 27 using. Next, a frame material 7 is placed around the original laminated material plate 2, and a gas absorbing substance 6 is inserted into the gap between the frame material 7 located at the side end and the original laminated material plate 2, and the frame material and the base material steel original plate 2 are inserted.
And the dummy plate 31 is hermetically welded. The composite is heated, hot rolled and then cut around the perimeter to separate the dummy plates.

Next, the present invention will be further explained using specific examples. However, the following is merely a description of typical examples, and it goes without saying that modifications and implementations within the scope of the scope of the claims are included within the scope of the present invention.

Example 1 First, when manufacturing a clad steel plate with a laminate having higher high-temperature deformation resistance than the base steel by the sandwich rolling joining method, an appropriate method for making the laminate thickness uniform at the leading and trailing ends of the laminate after rolling is carried out.
In order to investigate and research the shape of the layered laminated material original plate (two laminated material original sheets stacked together via a separating material), we made it possible to reproduce the high-temperature deformation resistance ratio of the laminated material original plate and the base steel original plate to 2. Using two types of plasticine adjusted to the following conditions, a model composite was prepared in which two types of two-layer structure laminated original plates were arranged, and these were rolled at a rolling reduction amount that made the rolling shape ratio the same as that of the actual composite.

Figure 3 shows the assembly conditions for three types of plasticine model composites. As shown in Figure 3, the shape of the two-layer laminated material base plate investigated was the conventional shape (No.
1, No. 2) and a tapered shape (No. 3). In addition, in the plasticine two-layer laminated material original plate, a single layer structure was adopted without considering the separation part.

FIG. 4 shows a cross section of the leading end of the plasticine model composite after rolling, and the cross section of the rear end was similar to the cross section of the leading end. In composites No. 1 and No. 2 in which two-layer laminated material base plates (No. 1 and No. 2) of conventional shape are arranged, the thickness of the laminate material at the leading and trailing ends is smaller than that when the conventional actual composite is rolled. phenomenon is being reproduced. That is,
It is clear that it is possible to consider measures to make the thickness of the laminate material uniform at the leading and trailing ends by rolling experiments of model composites using plasticine. On the other hand, in Composite No. 3 in which a tapered two-layer laminated original plate is arranged, as shown in Fig. 4, the thickness of the laminated material at the leading and trailing ends of the composite after rolling is almost uniform, which is similar to the conventional shape. It is clear that this is a great improvement compared to the composite made of two-layer laminated original sheets.

In the above-mentioned plasticine plasticine sandwich type composite, the two-layer laminated material base plate has a single-phase structure without considering the separation part, so the results of rolling experiments using this plasticine model composite can be directly applied to the semi-sandermanche type composite. Needless to say, it can be adapted to any situation. That is, in the semi-sand German tie rolling joining method, it is extremely advantageous to use a tapered laminate in order to make the thickness of the laminate at the leading and trailing ends uniform after rolling.

Based on the above, when producing clad steel plates with a laminate having higher high temperature deformation resistance than the base steel using the rolling joining method, the sandwich rolling joining method is effective in making the thickness of the laminate at the leading and trailing edges uniform after rolling. In the case of
Furthermore, in the case of the semi-sand German arch joining method, it has been found that it is effective to use a tapered cladding material original plate.

Example 2 In order to confirm the effectiveness of adopting the tapered two-layer structural laminate original plate for the sanderch type composite of the present invention and the tapered laminate original plate for the semi-sanderch type composite of the present invention selected as described above, using an actual composite, Composites of the present invention and conventional composites shown in Figs. 5 and 6 were prepared using an Incoloy 825 original plate as a composite material original plate and an SS41 base steel original plate as a base steel original plate, and heated to 1100°C. After heating, hot rolling was performed, and the state of deformation of the laminated material after rolling was investigated. Here, the base steel original plate and the laminated material original plate of the sand German arch type composite are 158 mm and 32 mm,
Base steel base plate for semi-sandwich type composite,
The thickness of each of the dummy steel and laminated material original plate is 158
mm, 158mm and 32mm. Furthermore, the final finished thickness after rolling (base material steel thickness and laminated material thickness) is 16 mm and 3.2 mm for both composites.

The results are shown in FIGS. 5 and 6. The maximum thickness of the laminate material at the leading and trailing edges after rolling of a conventional sand-gerch type composite is 4.3 times thicker than that at the center. 1100mm must be cut off from the front and rear ends of each. On the other hand, in the composite of the present invention, the maximum thickness of the composite material at the front and rear ends is 1.2 of the thickness of the composite material at the center.
The target thickness and base material thickness tolerance were satisfied in the area excluding 200mm of the leading and trailing ends of the rolled plate.

Next, in the semi-sand German arch type composite, as shown in Figure 6, in the case of the conventional type,
Similar to the sandwich type composite, the maximum thickness of the laminate after rolling is 4.1 times thicker than the thickness of the laminate in the center, and the
1130mm must also be cut off. However, in the composite of the present invention, the maximum laminate thickness at the leading and trailing ends is 1.1% higher than that at the center.
The target thickness tolerance between the thickness of the laminate and the base metal was satisfied in the region excluding 190 mm from the leading and trailing edges of the laminate after rolling.

From the above, in the case of the sandwich rolling joining method, it is recommended to use a composite in which two tapered two-layer laminated material original plates are stacked with a separation material interposed between them, or to use a semi-sanderch rolled joining method. In the joining method, it has been found that by using a composite with a tapered laminate original plate, the thickness of the laminate after rolling can be made uniform, and clad products with uniform laminate thickness can be manufactured at a high yield.

Another example of a two-layer structure laminated material original plate having the same effect as the tapered two-layer structure laminated material original plate in the Sanderch-type composite according to the present invention is shown in a cross-sectional view in FIG. 22 is the original laminated material, 23 is the separation material,
24 is an outer taper at the leading and rear end of the original plate, 24'
25 is a fixing plate between the laminate original plates, and 26 is a welded portion between the fixing plate 25 and the laminate original plate 22. Even by using a composite in which these deformed structural laminate original plates are arranged, the laminate thickness after rolling can be made uniform, and products having a uniform laminate thickness can be manufactured at a high yield.

Another example of a semi-sandwich type composite having the same effect as the technique of the present invention is shown in cross-sectional views in FIGS. 8a to 8c, respectively.
Here, 34 indicates a taper on the base steel side, and 34' indicates a taper on the dummy plate side. By forming these deformed tapered shapes at the front and rear ends of the laminate original plate, the thickness of the laminate after rolling can be made uniform, as in the case of the Sanderarch type composite, resulting in a uniform laminate thickness. Products can be manufactured with high yield.

(Effects of the Invention) A manufacturing method using a rolling joining method for clad steel using a metal material having higher high-temperature deformation resistance than the base steel as a laminate, in which two original laminate sheets are By arranging tapered two-layer structure laminated material base plates stacked on top of each other with a separating material between two base steel base plates, or when assembling a semi-sandwich type composite, taper By placing the base steel plate between the base steel base plate and the dummy plate, even if the clad steel is made of a metal material with higher high-temperature deformation resistance than the base steel, the The thickness of the laminated material at the tip and rear ends can be made uniform,
It has become possible to manufacture products with uniform laminate thickness at a high yield.

[Brief explanation of drawings]

Fig. 1a is a schematic cross-sectional view parallel to the rolling direction of a sanderch-type composite used for manufacturing clad steel sheets according to the present invention, and Fig. 1b is a schematic cross-sectional view parallel to the rolling direction of a tapered two-layer laminated material original plate. Parallel schematic sectional view, FIG. 2a is a schematic sectional view parallel to the rolling direction of a semi-sandwich arch type composite used in another method of implementing the present invention, and FIG. Schematic sectional view parallel to the direction, 3rd
The figure shows the assembly conditions of three types of plasticine model composites in Example 1, Figure 4 is a sectional view of the tip of the plasticine model composite after rolling, showing the results of Example 1, and Figures 5 and 6. are diagrams showing the composite conditions and results in Example 2, respectively, and Fig. 7 shows another example of a two-layer structure laminated material original plate having the same effect as the tapered two-layer structure laminated material original plate in the sandwich-archetype composite of the present invention. The cross-sectional views shown in FIGS. 8a to 8c are cross-sectional views showing other examples of semi-sandwich type composites having the same effects as the technique of the present invention. 1: Base steel original plate, 2: Laminated material original plate having higher high temperature deformation resistance than base material steel, 3: Separation material, 4: Insert metal, 5: Taper formed at the front and rear ends of the laminated material original plate in the rolling direction, 6: Oxides such as Zr and Ti, nitride-forming substances, 7: Frame material, 8: Exhaust hole, 9: Exhaust pipe, 10: Sealing welded part, 11: Welded part between laminate original plates, 12: Base steel original plate Taper formed in 2
5: Fixing plate for the original laminated material plate and dummy plate 31, 26:
27: Welded portion between the fixed plate 25 and the dummy plate 31; 27: Welded portion between the fixed plate 25 and the dummy plate 31;

Claims (1)

[Claims] 1. When manufacturing a clad steel plate by rolling and joining a metal material that has higher high-temperature deformation resistance than the base steel as a laminate, the edges of the laminate original plate in the rolling direction are formed during composite assembly. The method is characterized in that a taper that reduces strain concentration at the contact portion with the base steel is formed so as to face the base steel original plate to form a sandwich type or semi-sand Germany type composite, and the composite is rolled and joined. A method for manufacturing clad steel sheets. 2 The above two tapered mating material original plates are stacked one on top of the other with a separating material in between so that the taper faces the base steel original plate side, and placed between the two base steel original plates to form a sandwich-archetype composite. The first
The method described in section. 3. The method according to the above-mentioned item 1, wherein the tapered cladding material original plate is arranged between the cladding material original plate and the dummy steel so that the taper thereof faces toward the base steel original plate to form a semi-sandwich arch-type composite.