JPS6329635B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a so-called clad metal plate, which is an inexpensive metal plate that has excellent corrosion resistance, wear resistance, heat resistance, etc., by laminating and bonding two or more types of metal plates. In general, clad metal plates are manufactured using the explosion bonding method in which the base material and composite material are overlapped and bonded together, or the base material and composite material are overlapped and the overlapping edges of the two are sealed by submerged arc welding. After that, welding assembly method by hot rolling,
A method of welding a composite material by electroslag welding on one side of a base material has been implemented. However, in the case of the explosive bonding method, the places where it can be carried out are severely restricted, and safety must always be controlled during its implementation.In addition, with the welding assembly method, the work of assembling base materials and composite materials is extremely troublesome, and furthermore, In both cases, the slag welding method has disadvantages such as the work itself being extremely time-consuming and the workability being low and making mass production difficult. For this reason, conventionally, as shown in FIG. 4, a base material 41 whose surface has been cleaned and a composite material 42 are placed one on top of the other, and their peripheral edges are placed in a vacuum from the surface side of the composite material 42 along this. Welding is performed with an electron beam at the bottom, and the base material 41 and composite material 4 are welded at this closed loop welding part WB.
A method has been proposed in which the overlapping surfaces of the two are sealed in a vacuum state and then hot rolled as they are (Japanese Patent Publication No. 51-19819, Japanese Patent Application Laid-open No. 13459/1983, etc.). This method combines the vacuum conditions required to perform electron beam welding and the exhaust conditions required to prevent the generation of oxides between the mating surfaces of the base material and composite material in a single vacuum chamber. At the same time, by utilizing the characteristics of electron beam welding, such as its high speed and large penetration depth, it is possible to weld without any of the dangers and restrictions on work areas as in the above-mentioned explosion bonding method. There is no need for assembly work in the assembly method, and there is no need to create a vacuum between the overlapping surfaces of the base material and composite material after assembly, or to replace the work with inert gas, and in addition, the penetration depth of the electron beam can be increased. Taking advantage of this, it is possible to eliminate the trouble of welding along the overlapping edges of the side surfaces of the overlapping base material and composite material. The results of experiments and research conducted by the present inventor have confirmed that the above method improves workability and facilitates mass production. If only the peripheral edge is welded in a closed loop along this state, shearing force that acts along the base material and the overlapping surface, or tensile force that acts in the direction that causes the base material and composite material to separate from each other. During the hot rolling process, when pressure is applied from the rolls during the hot rolling process, cracks occur in the welds along the periphery of the base material and composite material, causing the base material and composite material to crack. Air may enter between the mating surfaces, forming oxides, etc. on the joint surface, resulting in poor bonding between the base material and composite material, or the weld may break and join with the base material. It was discovered that there were problems such as the material separating from the material. The present invention has been made from this point of view, and its purpose is to perform electron beam welding not only on the periphery but also on the central part of the base material and the composite material. It is an object of the present invention to provide a method for manufacturing a clad metal plate that increases the bonding strength and can accurately prevent poor bonding or separation between a base material and a composite material during a hot rolling process. The method for producing a clad metal plate according to the present invention is to laminate a base material and a composite material whose surfaces have been cleaned, and to apply the laminated base material and composite material under vacuum from the surface side of the base material or composite material. In a manufacturing method for clad metal plates that includes a process of welding with an electron beam, a laminated metal plate in which a base material and a composite material are overlapped, and the peripheral edge is welded between the base material and composite material from the outside. The laminated metal plates are welded in a closed loop for shielding, and the central part surrounded by the closed loop weld is welded in a required line to increase the mutual bonding strength between the base material and composite material. It is characterized by rolling in between. The present invention will be specifically explained below based on the drawings.
FIG. 1 is a schematic diagram showing the steps of the method for manufacturing a clad metal plate according to the present invention (hereinafter referred to as the method of the present invention);
FIG. 2 is a schematic diagram showing the welding process of the base material and composite material in the method of the present invention, and FIG. 3 is a cross-sectional view of the base material and composite material welded together. The base material 1 is made of a carbon steel plate, and the composite material 2 is made of a stainless steel plate. The carbon steel plate CS, which is to be the base material 1, is obtained by cutting a continuous cast material CC′, which has been cast with a continuous casting machine CC with the width and thickness set in advance, into the required length to obtain the slab SL. This slab SL is finished into a base material 1 through a surface finishing process A and a surface polishing process B, and then sent to a welding process C. On the other hand, a large number of stainless steel sheets SS that are to become the composite material 2 are prepared in advance according to the specifications of the base material 1, and are finished as the composite material 2 through the surface polishing process B', which is then used as the base material for the welding process C. It is sent to welding process C in accordance with the transfer of step 1. In the welding process C, the composite material 2 is superimposed on the base metal 1, and the peripheral and central parts are welded by an electron beam welding machine EBW.Then, in the hot rolling process D, the composite metal plate CM is formed into a clad metal plate CM. It will be finished. Each of the above steps will be explained in order below. Base material 1
As shown in Figure 1, the carbon steel sheet CS that is the material for
If you select a bottomless mold for the continuous casting machine CC that can produce a continuous cast material CC' with a width and thickness that match the specifications of the base metal 1, the continuous cast material CC' can be determined according to the plate length. Slab SL that matches the specifications of base material 1 by simply cutting to size
is obtained. If the specifications of the slab SL are different from the specifications of the base material 1, the slab SL may be trimmed to match the specifications of the base material 1, or the slab SL may be rolled to the specifications of the base material 1. Of course, the slab SL may also be manufactured using a blooming mill or the like. The slab SL matched to the specifications of the base material 1 is first sent to the surface finishing process A.
is an extension of the continuous cast material CC′ cast by the continuous casting machine CC along with the shot blasting device SB used in the other surface finishing process B and the vacuum chamber VC used in the welding process C. The slab SL is directly sent to the welding process C through each process A and B. The cold scarf burner CD used in the surface finishing process A is composed of a plurality of gas burners arranged in parallel over the entire width of the slab SL, and as the slab SL moves, the surface is exposed to the flames of the gas burners and the edges are Any burrs formed on the surface of the slab SL, scratches or small irregularities on the surface of the slab SL are repaired by melting, and the surface is finished flat. The surface of the slab SL may be processed using a hot scarf. The slab SL whose surface has been finished flat is then sent to a surface finishing process B. In the surface finishing step B, shot blasting or cutting machining is performed. The shot blasting device SB is configured to spray balls made of appropriate steel, glass, etc. at an appropriate speed onto the surface of the slab SL, and in the surface finishing process A, the shot blasting device SB is treated with a cold scarf or hot scarf. Oxides such as scale formed on the surface of the slab SL are removed, and the surface is sent to the welding process C in a purified state. On the other hand, the stainless steel plate SS is prepared in advance according to the specifications of composite material 2 and sent to the surface polishing process B' at a certain timing. The surface finishing process B' of the stainless steel sheet SS consists of a pickling device (not shown), and the pickling process cleans one side that is to be overlapped with the base material 1 and finishes it into composite material 2. and sent to welding process C. The vacuum chamber VC used in the welding process C has an inlet (not shown) for the base material 1 and composite material 2 on the side wall on the shot blasting device SB side, and an inlet for the base material 1 and composite material 2 on the opposite side wall.
Outlet of laminated metal plate (not shown)
These inlets and outlets are closed,
By operating the vacuum pump VP, the vacuum chamber
It is configured to maintain the required degree of vacuum inside the VC. Inside the vacuum chamber VC, a movable cart MC that can move forward and backward and left and right is installed on the floor, and an electron beam welding machine EBW is installed on the ceiling facing downward. This electron beam welding machine
The EBW is configured to weave the beam EB in a desired direction by controlling the electric field. First, the base material 1 is introduced into the vacuum chamber VC, and then the moving trolley
It is set on the MC, and then the composite material 2 is introduced and superimposed on the base material 1. Activate the vacuum pump VP to create the required degree of vacuum in the vacuum chamber VC, usually 1×
10 ^-1 Torr or less, preferably 1×10 ^-3 to 1×
Maintain the temperature at 10 ^-5 Torr and perform welding work. That is, first, by operating the movable cart MC, spot electron beam welding is performed at each P point as shown by the black circles in FIG. Prevent warpage from occurring in the composite material 2 during welding. Next, the target position of the electron beam EB is set, for example, at one corner O of the composite material 2 overlaid on the base material 1, and the movable trolley MC is moved in the front-back or left-right direction to remove the composite material overlaid on the base material 1. The electron beam EB is irradiated from the surface side of the composite material 2 while weaving perpendicularly to the direction of relative movement with respect to the moving cart, melting the composite material 2 from the surface to a predetermined depth of the base material 1. The three sides of 2 are welded in a U-shape, and then welded multiple times parallel to the remaining side at the required pitches, so that the base material 1 and composite material 2 are welded together in a closed loop around the periphery and in the center. The base material 1 is welded in a lattice shape, and even in the subsequent hot rolling process D in the atmosphere.
A vacuum is maintained between the superposed surfaces of the base material 1 and the composite material 2, and the base material 1 and the composite material 2 are welded with sufficient strength so as not to separate, thereby obtaining a laminated metal plate. The bond strength between base material 1 and composite material 2 is determined by the electron beam welding
It can be set arbitrarily by adjusting the weaving width of the EB and the number of welding points with respect to the center part. Note that the penetration depth of the welded portion can be changed as appropriate by adjusting the output of the electron beam welding machine EBW. Fig. 3 is a schematic diagram showing an example of a cross section of a welded part between base material 1 and composite material 2. The thickness of composite material 2 is 20 mm, and the vacuum chamber VC is 10 ^-3 to 10 ^-5 . Torr, electron beam welding machine EBW output: 100KW, welding speed:
The case is shown in which the weld width W: 5 mm, the penetration depth d: 30 mm, and the pitch between welds p: 20 mm at 2.5 m/min. Note that the welding order for the peripheral and central parts of the base material 1 and the composite material 2, and the welding mode for the central part are not limited to the above-mentioned cases. For example, the welding order may be first welding the central part, then The peripheral portion may be welded, and the welding pattern of the central portion may be zigzag, spiral, or the like. Welding process C
The laminated metal plates that have been integrally welded together through the process are heated as a whole to approximately 1250°C in a heating furnace (not shown) or by electromagnetic induction, and then the lower surface of the base material 1 is heated to approximately 1250°C. Cooling device to prevent warping during rolling
The sheet is cooled to around 1180° C. by WC and then rolled in a hot rolling step D to obtain a clad metal sheet CM of desired specifications in which the abutment surfaces of the base material 1 and composite material 2 are integrally joined. Examples are shown below. Example 1 (1) Base material: Low carbon steel (carbon content: 0.11%) (2) Composite material: SUS 304 (3) Welding conditions between base material and composite material: Degree of vacuum: 5×10 ^-4 Torr Welded area Width: 5mm Electron beam output: 100KW Weld pitch: 20mm Welding speed: 2.5m/min Penetration depth: 30mm (4) Welding pattern (center) Grid pattern (5) Specification plate thickness as clad metal plate: 10.0mm Plate width: 1800mm Plate length: 12000mm Cladding ratio: 10% Example 2 (1) Base material low carbon steel (2) Composite material high carbon steel (3) Welding conditions between base material and composite material Vacuum degree: 1 ×10 ^-5 Torr Weld width: 5mm Electron beam output: 40KW Weld pitch: 15mm Welding speed: 0.5m/min Penetration depth: 20mm (4) Welding pattern (center) Grid (5) As a clad metal plate Specifications Plate thickness: 15mm Plate width: 900mm Plate length: 6000mm Clad ratio: 50% Example 3 (1) Base material low carbon steel (2) Composite material Cu+Ni (Cu: 90% Ni: 10%) (3 ) Welding conditions between base metal and composite material Vacuum level: 5×10 ^-4 Torr Electron beam output: 100KW Welding speed: 2m/min Penetration depth: 35mm (4) Welding pattern Zigzag shape (5) As a clad metal plate Specification Plate Thickness: 10mm Plate Width: 1800mm Plate Length: 9000mm Clad Ratio: 10% Table 1 shows the strength test results conducted on the metal plate in the above example where the base material and composite material were welded together. . For comparison, strength test results are also shown for metal plates obtained by a conventional method in which a base material and a composite material having the same material specifications are welded in a closed loop only at the periphery as shown in FIG.

[Table] As is clear from Table 1, both the shear strength and tensile strength between the base material and the composite material are significantly increased compared to the conventional example. Table 2 shows the clad metal plates manufactured according to the above-mentioned examples and the clad metal plates manufactured by rolling a laminated metal plate in which electron beam welding was performed only on the periphery of the base material and composite material as in the past. This figure shows the rate of occurrence of bonding defects in comparison with

[Table] As is clear from Table 2, when the method of the present invention was used, there were almost no defects and a good bonding state was obtained. As described above, in the method of the present invention, the bonding strength between the base material and the composite material is significantly improved, and the bond strength between the base material and the composite material is significantly improved, and the bonding strength between the base material and the composite material is also improved when hot rolling a laminated metal plate into a clad metal plate in which the base material and composite material are joined. There is no air present between the overlapping surfaces of the material and the composite material, and the base material and composite material do not separate, allowing the base material and composite material to be accurately joined to form a clad metal plate. The method of the present invention has excellent effects such as a significant improvement in quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the implementation steps of the method of the present invention,
Figure 2 is a cross-sectional view of a laminated metal plate obtained by welding the base material and composite material, Figure 3 is a cross-sectional view of the base metal and composite material welded together, and Figure 4 is a cross-sectional view of the laminated metal plate obtained by welding the base material and composite material. FIG. 1...Base material, 2...Mixture material, SL...Slab,
EBW...Electron beam welding machine, MC...Moving trolley,
EB...electron beam, CD...cold scarf, SB...shot blast device.

Claims (1)

[Claims] 1 Clad metal, which involves the process of cleaning the surface, laminating the base material and composite material, and welding the laminated base material and composite material from the surface side of the base material or composite material with an electron beam under vacuum in a vacuum. In the manufacturing method of the plate, a laminated metal plate made by overlapping a base material and a composite material is welded along the peripheral edge in a closed loop shape to shield the gap between the base material and composite material from the outside. The central part surrounded by the welded part is welded in a required line to increase the mutual bonding strength between the base metal and composite metal, and then this laminated metal plate is hot rolled. Method of manufacturing metal plates.