JP2599977B2 - Method of manufacturing clad steel plate structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a clad steel plate structure such as a clad steel plate pipe, a clad steel plate tank, and the like.

2. Description of the Related Art For example, in a conventional SUS clad steel pipe, as shown in FIG. 7, both ends of a uniform SUS clad steel sheet are butted and welded to produce a pipe.

Points to note when welding clad steel are described in (Welding Handbook-
794P), dilution of the weld metal of carbon steel or low alloy steel by cladding alloy components must be minimized. Excessive dilution causes various defects such as porosity, hardening, embrittlement and cracking. In consideration of this point, an appropriate shape of the welding groove processing must be selected according to the plate thickness, the cladding component, the welding method, and the like. Therefore, it is important not only to improve the precision of the welding groove processing but also to perform the groove processing extremely accurately.

Also, the SUS cladding is welded so that the first layer does not deeply penetrate into the base metal. For this reason, the welding current is reduced as much as possible without impairing the workability, weaving is performed, and the arc is directed toward the molten zone. However, in the welding of the first layer, if the welding is too much, there is a possibility that the first layer is cracked into a martensite structure.

Conversely, if one layer of the weld metal is completely austenitic with a large amount of Ni, welding with an 18-8 welding rod tends to cause micro-cracks, which makes welding difficult, and requires excessive labor in welding. I need it.

Problems to be Solved by the Invention However, in this method, since the welded portion is made of ordinary steel and SUS layer, two types of materials, it is difficult and time-consuming to weld the pipe surface to a predetermined SUS layer. I needed it. In addition, it is difficult to secure the target SUS component completely at the welded location, and the corrosion resistance is inferior to that of the material at the non-welded location in terms of corrosion resistance, and the welding location often rusts during use. was there.

For example, FIG. 8 shows an enlarged view of a welded portion of a conventional SUS clad steel pipe. A conventional SUS clad steel pipe has a SUS layer 2 of a clad material on the surface of a base material of ordinary steel. When welding, first, weld with the base material part of ordinary steel, grind the surface, and then use low current and low voltage in order to minimize the dilution of the core material with SUS welding material. Weld. Therefore, the time and labor spent on welding was enormous.

On the other hand, since the quality of the weld is also premised on complete welding, it is impossible to make the dilution of the base material zero, and the components become non-uniform compared to the clad material in the non-welded part, and the microscopic Deflection also occurs, and there is a problem in corrosion resistance. Also SU
When the S layer is thin, there is a problem that welding is technically difficult and a thin SUS clad pipe cannot be manufactured.

Means for Solving the Problems To solve the problems, the present invention is to produce a clad steel plate by casting a molten metal of the clad material on the peripheral surface of the core material and rolling the clad slab to a desired plate pressure, A method for manufacturing a clad steel plate structure, comprising: forming a groove on both ends of the clad steel sheet in a width direction of the clad material;

In the case of manufacturing a three-layer clad steel pipe-shaped structure, both ends in the plate width direction are grooved, the clad steel sheet is bent, and an open can is manufactured. The parts are butt-welded.

The above is a method for manufacturing a structure made of a three-layer clad steel sheet. In the method for manufacturing a structure made of a two-layer clad steel sheet, two core materials are overlapped with a release material interposed therebetween, and a peripheral surface of the core material is formed. A clad material is cast by casting a molten metal of the clad material, and the clad material portions at both ends in the width direction of the clad material are cut off along the overlapping surface of the core material, thereby forming two two-layer clad material. Is manufactured, and the clad slab is rolled to a desired thickness to produce a clad steel plate, and the clad material portions at both ends in the width direction of the clad steel plate are grooved, and the groove portions are butted together. Weld and manufacture.

In the case of manufacturing a two-layer clad steel tube-shaped structure, a clad steel plate having both ends in the plate width direction beveled is bent to produce an open can. The parts are butted and welded.

Action Since the welded portion is composed entirely of clad material, welding with a simple clad material is sufficient.For example, when the clad material is SUS, the welding rod and welding method may be SUS welding, and welding work Very easy on. In addition, SU in terms of quality
S can maintain properties such as corrosion resistance.

Embodiment Next, an embodiment will be described.

FIG. 1 is a sectional view of a SUS clad steel pipe manufactured by the method of the present invention.

(A) is a pipe formed by bending a double-sided SUS clad steel plate with a three-layer clad steel pipe and forming a pipe. The base material 1 is made of ordinary steel and the front and back surfaces of the base material are SUS layers having excellent corrosion resistance.
Both ends are made of SUS single layer.

(B) is a two-layer SUS-clad steel pipe, in which a single-sided SUS-clad alternating steel sheet is bent to form a pipe. The base metal 1 is made of ordinary steel and the inner side of the pipe is a SUS layer.
This is a US single layer welded and assembled into a pipe.

FIG. 2 is an enlarged view of a welded section of the SUS clad steel pipe manufactured by the method of the present invention.

As shown in the figure, since the welded portion is made of SUS alone, the welding method can be performed under the same welding conditions as in the case of SUS steel pipe, the welding efficiency is high, and the quality of the welded portion is stable. SUS at both ends of plate width
The width of the single part is 2 to 30 mm. In ERW, a width of 1-2 mm is sufficient. However, large heat input welding of thick steel pipes may require about 30 mm. This width is 30
Although it may be over mm, it is preferably 30 mm or less because the necessary minimum is preferable.

Third is a SUS clad tank manufactured by the method of the present invention. The tank is manufactured by assembling and welding a two-layer clad steel plate as shown in the figure.
The clad steel plate was assembled and welded to form a single layer, and the product was manufactured. The welding efficiency was greatly improved, and the quality was stabilized.

Next, a method of manufacturing a SUS clad slab that is used as a material of the SUS clad steel plate will be described. FIG. 4 is a schematic diagram. A water-cooled mold 7 is provided with a certain gap of the clad thickness around the outer periphery of the core material set vertically on the gantry 14, and the refractory frame 8 is set thereon. When cladding,
First, the core material is raised, and the lower end of the core material 1 having the start tab 12 is energized to the preheating coil 5 to heat the core material 1 until the surface of the core material 1 becomes red-hot.
The molten stainless steel to be melted is poured into the refractory frame 8 from a melting furnace which has been melted and held in advance.

The molten metal flows into the gap between the core material 1 and the water-cooled mold 7, and solidifies via the graphite ring 9 by removing the heat of the water-cooled mold 7. In order to secure a sound boundary layer free from defects such as defective weld metal, a predetermined current is applied to the preheating coil 5 to heat the core 1 to a predetermined temperature, and the molten metal 10 in the refractory frame is heated by the heating coil 6. Electricity is applied, the molten metal is stirred, and the temperature is raised to smooth the boundary welding, the core material 1 is lowered at a constant speed, and the entire surface of the stainless steel clad cast is continuously produced. If the thus produced clad slab is rolled to a desired thickness, a clad steel sheet can be easily produced.

FIG. 5 shows a method for producing a clad cast piece when producing a single-sided clad steel sheet. Further, by selecting the dimension on the long side of the mold, the plate width, that is, the dimension of the pipe can be determined. 2 with the release material 15 interposed between the core material 1 and the core material 1
The sheets are combined and welded at the mating surface to form an integral core material.
Subsequent cladding methods are the same as for the fully clad steel plate.

After the clad slab is completed, it is peeled off from the mating surface after hot rolling as it is to make a single-sided clad steel plate, or it is separated from the mating surface at the stage of the clad slab,
There are two methods of performing hot rolling in the post-process, and either method may be selected.

Figure 6 shows the shape of the clad slab before and after rolling, (1)
Indicates a clad slab after casting. (3) is a clad steel sheet after hot rolling, and both ends in the sheet width direction are made of SUS.
It is characterized by being wrapped in. This is a clad steel pipe,
It becomes the material of the tank.

 Table 1 shows the construction conditions when the slab was manufactured.

Uses low-carbon steel with a core material of 600mm width, 200mm thickness, and 6000mm length, and a water-cooled mold with slab dimensions of 650mm on the long side and 250mm on the short side after cladding. And then cast. The cladding conditions at that time are as shown in Table-1.

Bottom, To
After cutting and removing about 200 mm of each unwelded portion of p and polishing the surface by about 1 mm, the clad slab was heated to about 1100 ° C. and rolled to a thickness of 10 mm at a finishing temperature of 820 to 870 ° C. The thick plate was cut into a size of 10 t × 650 w × 5000 L.

After that, the SUS single-phase portions at both ends in the width direction of the thick plate were formed into a pipe after performing a difference processing, and then the SUS single-phase portions were butt-seam welded to obtain a clad steel pipe. At this time, the SUS single-phase portion at both ends of the clad steel plate was 200 mm.

Effect of the Invention As described above, the clad steel plate structure manufactured by the method of the present invention is different from the conventional method in that the portion to be welded is a SUS single phase. Since welding can be performed under the same conditions as above, the time required for welding can be greatly reduced.

In addition, as a result of the corrosion test, the corrosion resistance of the welded portion is inferior to that of the unwelded clad steel plate because the welded portion is not diluted by the core material like a clad steel pipe made of conventional clad steel plate. Confirmed that there is no.

[Brief description of the drawings]

FIG. 1 shows a sectional view of a clad steel pipe manufactured by the method of the present invention. (A) is a three-layer clad steel pipe. (B) is a two-layer clad steel pipe. FIG. 2 is an enlarged view of a section of a welded portion of a SUS clad steel pipe manufactured by the method of the present invention. (A) is a groove processing figure before welding. (B) shows a welding situation. (C) shows the situation after the grind of the surface layer. FIG. 3 shows a tank manufactured by the method of the present invention. (A) is a perspective view, (b) is a sectional view of a welded portion along a horizontal line (a), and (c) is a sectional view of a welded portion in a vertical direction (a). FIG. 4 is an elevational sectional view showing an outline of a method of manufacturing a clad slab which is a material of a clad steel pipe used in the present invention. FIG. 5 is an explanatory view of a cross section when a single-sided clad slab is formed. FIG. 6 is an explanatory view when a clad slab is rolled into a clad steel sheet after rolling, (1) is a perspective view of the clad slab,
(2) is a sectional view of (1), (3) is a perspective view of a clad steel plate, and (4) is a sectional view of (1). FIG. 7 shows a sectional view of a conventional clad steel pipe. (A) is a three-layer clad steel pipe. (B) is a two-layer clad steel pipe. FIG. 8 is an enlarged view of a section of a welded portion of a conventional SUS clad steel pipe. (A) is a groove processing figure before welding. (B)
Indicates welding of the core part. (C) shows the situation after the grinder care. (D) shows the welding status of the SUS layer.
(E) shows the situation after the surface grinder care. 1 core material 2 clad material 3 weld metal 4
... Weld metal (SUS part), 5 ... Preheating coil, 6 ... Heating coil, 7 ... Water cooling mold, 8 ... Fireproof frame, 9 ... Graphite ring, 10 ... Molten metal, 11 ... Slag, 12 ... ... Start tab, 13 ... Tailing jig, 14 ... Stand, 15 ... Release agent.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiromichi Saito 46-59 Ohara Nakahara, Tobata-ku, Kitakyushu-shi, Fukuoka Prefecture Nippon Steel Corporation Machinery & Plant Division (56) References JP-A-62-148021 (JP, A) JP-A-52-23557 (JP, A)

Claims (4)

(57) [Claims] A clad cast piece is produced by casting a molten metal of a clad material on a peripheral surface of a core material, and the clad cast piece is rolled to a desired thickness to produce a clad steel sheet. A method of manufacturing a clad steel plate structure, comprising forming a groove on clad material portions at both ends in a width direction, and welding the grooved portions against each other. 2. A clad slab is produced by casting a molten metal of a clad material on a peripheral surface of a core material, and the clad slab is rolled to a desired thickness to produce a clad steel sheet. The clad material at both ends in the width direction is beveled and further bent to produce an open can, and the beveled parts of the open can are butt-welded to produce a tube-shaped structure. A method for manufacturing a clad steel plate structure, comprising: 3. The two core materials are overlapped with a release agent interposed therebetween.
A molten metal of a clad material is cast on the peripheral surface of the core material to produce a clad slab, and the clad material portions at both ends in the width direction of the clad slab are cut off along the overlapping surface of the core material, 2
Produce two two-layer clad slab, roll the clad slab to a desired thickness to produce a clad steel plate, and bevel the cladding material portions at both ends in the width direction of the clad steel plate, A method for producing a clad steel plate structure, characterized in that the groove portions are butted and welded to each other. 4. The two core materials are overlapped with a release agent interposed therebetween.
A molten metal of a clad material is cast on the peripheral surface of the core material to produce a clad slab, and the clad material portions at both ends in the width direction of the clad slab are cut off along the overlapping surface of the core material, 2
Produce two two-layer clad slab, roll the clad slab to a desired thickness to produce a clad steel plate, and bevel the cladding material portions at both ends in the width direction of the clad steel plate, A method of manufacturing a clad steel plate structure, further comprising bending and manufacturing an open can, and welding and welding the groove portions of the open can to each other. .