JPH032590B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing a clad steel plate, which is formed by firmly bonding copper or copper alloy of any thickness to the surface of a steel material. (Prior art) Clad steel sheets, which are made by forming a copper or copper alloy layer on the surface of steel materials such as carbon steel, low carbon steel, and high alloy steel, are developed into more advanced materials by taking advantage of the characteristics of copper or copper alloys. It is a composite metal material that can meet the strict requirements of corrosion resistance, antifouling properties, etc., and is widely used in oil refineries, seawater desalination equipment, seawater heat exchangers, etc., and in recent years has been used for ship hull skins. Application is also being considered. Until now, methods such as explosion rolling, diffusion rolling, and rolling joining methods (open sand German trench type, sand German trench type, semi-sand German trench type) have been used to manufacture copper or copper alloy clad steel sheets. This technique has the following drawbacks, and cannot be said to be a completely satisfactory method. Oxidized scales are not only formed on the surface of copper or copper alloy clad steel sheets made by manufacturing methods such as explosion rolling, diffusion rolling, and open sandwich rolling joining, but also due to heating. During the rolling process, scale flaws or steel indentation flaws occur, resulting in extremely poor surface quality of the laminated material. In the sandwich-type rolling joining method and the semi-sanding Germany-type rolling joining method, the surface quality of the laminate material deteriorates due to the separation material, that is,
Increased surface roughness due to indentation of the separating material during the rolling process or insufficient lubrication of the separating material during rolling, or the surface of the joining material due to intrusion of the separating material itself or gas released from the separating material into the joining material. Deterioration of material properties and surface cracking of the laminated material caused by these deteriorations occurred. In addition, defective joints between the laminate material and the base material occurred due to gas released from the separation material. Due to this, in conventional manufacturing technology, it is unavoidable to carry out a contact repair process for scale flaws, cracks, or poor joints between the cladding material and the base steel, as well as a polishing process for the surface of the cladding material. At the slab design stage, it was necessary to secure an allowance for cleaning defects and cracks and for polishing to remove scale. For this reason, there was an economic difficulty in that the yield was lowered and the manufacturing cost of copper or copper alloy clad steel sheets could not be reduced. Furthermore, when repairing defects, cracks, or joint defects by welding, material properties equivalent to those of laminated materials,
In particular, since it is necessary to guarantee corrosion resistance, when repairing these welds, it is necessary not only to reduce the welding heat input in order to keep the dilution of components from the base steel as low as possible, but also to use multi-pass welding methods. When adopted, it becomes inevitable to secure a certain number or more of laminated layers. As a result, the lower limit of the thickness of the laminate material that can guarantee the quality of the welded repair portion described above is limited. In addition, in the surface polishing step for removing minor surface cracks, scratches, scales, etc., the amount of polishing cannot be strictly controlled due to initial deformation of the clad steel plate, strain induced during polishing, and the like. Therefore, not only is there a risk that some parts may not satisfy the laminated material thickness tolerance, but also welding repair is not possible in the case of clad steel plates formed with extremely thin laminated materials. In addition, in the production of clad steel sheets, the repair and polishing processes described above are unavoidable with the current technology, so there was an extremely large technical problem in that it was impossible to manufacture clad steel sheets with a thin coating thickness. . In order to solve the above-mentioned difficulties, the inventors of the present invention have proposed, in the patent application No. 58-212148, a clad steel with excellent surface quality after rolling of a laminated material using boron nitride (BN) as a separating material. Sandwich-type and semi-sandwich-type rolling joining methods were proposed. In this method, both surfaces of the original laminate are cleaned, and the surface roughness of one of the two surfaces is adjusted.
After arranging boron nitride on a surface with a thickness of 70 μm or less, a sanderch type composite is made in which the surfaces of the two laminate original plates face each other and the joint surfaces of the base steel and the laminate face each other. Alternatively, use a semi-sandwich-type composite in which the surface of the original plate for the laminate and the surface of the dummy steel face each other, and the joint surfaces of the base steel and the laminate face each other at a rate of 3 to 35% per pass. Hot rolled at a reduction rate of . In this method, the surface of the laminated material after rolling is free from defects and has a metallic luster, and the roughness of the surface is
It can be controlled to 100 μm or less. By the way, when this method is applied to copper or copper alloy clad steel, the melting point of the cladding material (copper or copper alloy) is relatively low, and when the hot rolling temperature approaches the melting point of copper or copper alloy, the surface of the clad steel A problem occurs in which the quality deteriorates. (Object of the Invention) An object of the present invention is to provide a method for manufacturing copper or copper alloy clad steel sheets in which the surface quality of the laminate of the clad steel sheets after rolling is excellent in the rolling joining method. As shown in the examples below, boron nitride was used as a separating material placed in the gap between the cladding material and dummy steel (semi-sandermanti type) or between the cladding material and dummy steel (semi-sandermanti type) to be separated after rolling. and the hot rolling start temperature is 100° below the solidus line of the laminate.
It has been found that limiting the temperature to a temperature range lower than ℃ is effective in producing clad steel sheets with excellent surface quality of the laminated material. As a result, we adopted a sandwich-type or semi-sand-Germany type rolling joining method as a manufacturing method, placed boron nitride in the gap between the laminate and the dummy material, or between the laminate and the dummy material, which were to be separated after rolling. By limiting the rolling start temperature to a temperature range that is 100°C or more lower than the solidus line of the laminate, the technical and economical difficulties of the conventional technology were solved at once. (Structure of the Invention) In the present invention, in the rolling joining method of copper or copper alloy clad steel sheets, both surfaces of the laminate original sheet are cleaned, and the surface roughness of one of the two surfaces is set to 70 μm.
Boron nitride is applied to the surface secured to a thickness of less than m, and a sandwich-arch-type composite is heated, in which the surfaces of the two laminate original plates face each other, and the joint surfaces of the base steel and the laminate face each other. Alternatively, heat a semi-sandwich-type composite in which the one surface of the original laminate plate and the dummy steel surface face each other, and the joint surfaces of the base steel and the laminate face each other, and start hot rolling. Temperature 100 below the solidus line of the laminate
Hot rolling is carried out at a temperature lower than 0.degree. C. and a reduction rate of 3 to 35%/pass. In this method, the surface of the laminated material after rolling is free from defects and has a metallic luster, and the roughness of the surface can be controlled to 100 μm or less. FIG. 1 is a schematic cross-sectional view showing an example of a sandwich-type composite assembly for manufacturing a copper or copper alloy clad steel sheet according to the present invention. In Fig. 1, 1 is a base material steel slab, 2 is a copper or copper alloy original plate as a bonding material, 3 is a separating material, that is, boron nitride,
4 is an insert metal, 5 is an oxide-nitride forming substance such as Zr or Ti, 6 is a frame material, 7 is an exhaust port, 8 is an exhaust pipe, 9 is a shield welded part, and 10 is a welded part between the laminated materials. Each is shown below. Note that 11 is a joint surface, and 12 is a separation surface. First, the surface roughness of one of the clean front and back surfaces of the laminated material 2, which will be the separation surface, is set to 70 μm or less.
As shown in FIG. 1, boron nitride 3 is placed in the gap between the separated surfaces of the laminate 2. Thereafter, one surface of the base steel 1 is cleaned, and the mating material 2 and the base steel 1 are placed so that their respective clean surfaces face each other with the insert metal 4 in between, as shown in FIG. Frame material 6
A gas absorbing substance 5 such as Zr or Ti is charged into the gap between the frame material 6 and the base steel 1 at the shield welding part 9, and then passed through the exhaust port 7 and the exhaust pipe 8.
Force exhaust air to isolate the inside of the composite from outside air. Next, the material is heated, and the hot rolling start temperature is set to a temperature lower than the solidus line of the laminate by 100 DEG C. or more, and hot rolling is performed at a rolling reduction rate of 3 to 35% per pass. After rolling, both ends are cut to separate the two clad steel plates. Here, in order to make the bond stronger,
(1) Inserting the insert metal 4 between the cladding material 2 and the base steel 1. (2) In order to keep the bonding surface between the cladding material 2 and the base steel 1 cleaner, and to remove residual gas inside the composite and gas released during heating, which may cause poor bonding, Gas absorption by the absorbing substance 5 and forced exhaust through the exhaust port 7 are used together. As a result, sound bonding can be achieved during the hot rolling process. FIG. 2 is a schematic cross-sectional view of a semi-sandwich type composite. Among the clean front and back surfaces of the laminate material 2, the surface roughness of one surface 12, which will be the separation surface, is 70μ.
m or less. In assembling this composite, boron nitride 3 is placed in the gap between the mating material 2 and the dummy steel 13. Thereafter, one surface of the base steel 1 is cleaned and placed so as to face the clean surface 11 of the laminate 1. A gas suction substance 5 is charged into the gap between the frame material 6 and the mating material 2, and the frame material 6 and the base steel 1 are shield-welded. 9 is a shield welding portion, and 10 is a welding portion between the laminate original plate 2 and the dummy steel 13. After welding, the composite is forcibly exhausted through the exhaust port 7 and the exhaust pipe 8 to shut off the inside of the composite from outside air. Next, heating is performed, and the hot rolling start temperature is set to a temperature that is 100°C or more lower than the solidus line of the laminated material, and 3 to 30°C per pass is applied.
Hot rolled at a rolling reduction of 35%. In the following, specific examples will mainly be explained about copper or copper alloy clad steel sheets produced by the sand-deutsche type rolling joining method. All modified implementations are included within the scope of the present invention. For example, in the production of clad steel sheets using other types of rolling joining methods, such as the semi-sandwich type, or in the production of copper or copper alloy clad steel sheets with two or more layers, the following method may be followed or partially modified. Needless to say, these are included in the present invention. (Example) Example 1 A 90/10 cupronickel (CN) original plate was used as a composite material, and an SM41B base steel slab was used as the base steel, and the procedure described in the configuration of the present invention was carried out. A large number of composites as shown in Figure 1 were assembled. Boron nitride (BN) is placed in the gap between the laminates to be separated after rolling. Using these composites, the effect of rolling start temperature on the surface roughness of the laminate after rolling was investigated. The survey results are shown in Table 1 and Figure 3.
There are no scratches or cracks on the surfaces of all the clad steel plates, and the surfaces maintain a metallic luster. Also, from Table 1 and Figure 3,
By setting the surface roughness of the laminated material original plate to 70 μm or less, using boron nitride as a separating material, and limiting the rolling start temperature to a temperature 100 ° C lower than the solidus line of the laminated material (1000 ° C.) or less, It is clear that the surface roughness of the laminated material after rolling can be controlled to 100 μm or less. Example 2 A composite for large 90/10 cupronixel (CN) clad steel shown in Table 2 was produced using the same procedure as in Example 1, and the rolling start temperature was adjusted to the hardness of the laminate.

【table】

[Table] Surface condition: No defects, metallic luster

[Table] Surface condition of laminated materials: All were rolled at 1000°C, 100°C lower than the metallic luster phase line, with no defects. The measurement results of the surface roughness in the longitudinal direction (L) and the transverse direction (C) of the laminated material after rolling are shown in Table 2. From the same table, the surface roughness of the original laminated material is 70μm or less,
Boron nitride (BN) is used as a separating material, and the rolling start temperature is set to 100°C lower than the solidus line of the laminated material (1000°C).
℃) or less, the surface roughness of the laminate after rolling can be improved.
It can be seen that it can be controlled to 100 μm or less. Also,
As in the case of Example 1, the surface of the laminated material after rolling was free from defects and maintained a metallic luster. From the above, in the sand-deutsch type rolling joining method, the surface roughness of the separation surface of the laminate original plate is set to 70 μm or less, boron nitride is used as the separation material, and the rolling start temperature is set to 100°C below the solidus line of the laminate. If hot rolling is carried out under hot rolling conditions with a rolling reduction rate of 3 to 35%/pass, the surface of the laminate after rolling will be free of defects and have a metallic luster appearance. It was found that the surface roughness of the laminated material could be controlled to 100 μm or less. (Effects of the Invention) In the present invention, boron nitride is used as a separating material, and the rolling start temperature is limited to 100°C or more lower than the solidus line of the laminate, and the rolling rate is 3 to 35%/pass. Boron nitride functions effectively by performing hot rolling within a range of rolling reduction, and the surface of the manufactured clad steel plate has a metallic luster, and there are no scratches or cracks on the surface. It does not occur at all, and the surface roughness of the laminated material can be reduced to 100 μm or less. As a result, it is possible to omit both the surface polishing process and the surface welding repair process of the laminate in the production of copper or copper alloy clad steel sheets, and it is also possible to omit the surface polishing process and surface welding repair process of the cladding material in the production of copper or copper alloy clad steel sheets. It became possible to manufacture clad steel sheets.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a sanderch type composite. FIG. 2 is a schematic cross-sectional view of a semi-sandwich type composite. FIG. 3 is a graph showing the influence of the hot rolling start temperature on the surface roughness of the laminated material in the prototype material. DESCRIPTION OF SYMBOLS 1... Base material steel, 2... Laminating material, 3... Boron nitride, 11... Joint surface, 12... Separation surface (laminating material surface after rolling), 13... Dummy steel.

Claims (1)

[Claims] 1. In a method for manufacturing a copper or copper alloy clad steel sheet using copper or copper alloy as a laminating material, both surfaces of the laminating material original sheet are cleaned, and one of the two surfaces has a surface roughness of 70 μm. After placing boron nitride on the surfaces secured below, heat a sandwich-arch-type composite in which the surfaces of the two laminate original plates face each other and the bonding surfaces of the base steel and the laminate face each other. ,
Alternatively, heat a semi-sandwich-type composite in which the one surface of the original plate of the laminate and the surface of the dummy steel face each other, and the joint surfaces of the base steel and the laminate face each other, and adjust the rolling start temperature. By hot rolling at a temperature 100°C or more lower than the solidus line of the material, the surface of the laminate after rolling is free of defects and has a metallic luster, and the roughness of the surface is controlled to 100 μm or less. A method for producing a copper or copper alloy clad steel sheet with excellent bondability and omitting surface polishing, characterized by: 2. In the method for producing a clad steel sheet as set forth in claim 1, the reduction rate per pass during hot rolling of the above-mentioned sandwich arch type or semi-sand German arch type composite is set to 3 to 35%. A method for manufacturing featured copper or copper alloy clad steel sheets.