JPS63130277A - Highly efficient slab assembling method - Google Patents

Abstract

PURPOSE:To assemble a slab with high efficiency of superposing clad material upon carbon steel base metal and bringing square clad steel into close contact with the clad material side to perform the fillet full-circled welding of the base metal, the clad material and the clad steel with welding material with similar component respectively. CONSTITUTION:Low carbon steel sheet metal 4 with an area slightly smaller than the base metal 1 is placed on the base metal 1 (carbon steel or low alloy steel) and the clad material 2 with the same dimensions is placed on the sheet metal 4 and a gap between the base metal 1 and the clad material 2 is formed to an inert gas atmosphere. Then, the clad steel 3 whose cross section is square with the component similar to the clad material 2 is brought into close contact with the clad material 2 side and the plate thickness of the clad steel 3 id made to approximately 1/2 of the plate thickness of the clad material 2. The fillet full-circled arc welding of the clad material 2 and the clad surface 5 is performed by the welding materials with the component similar to the clad material 2 to form a fillet welded zone 6 in this state. Further, the fillet full-circled welding of the clad steel 3 and the metal 1 is performed by the welding material with the similar component. In this way, the fillet full-circled welding is performed surely and nondefectively with the high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an efficient slab assembly method for producing rolled clad steel plates made of titanium or the like.

(Prior art) As shown in Fig. 3, the method for producing clad steel plates involves using carbon steel or low-alloy steel as a base material 1, and placing a laminated material 2 on top of the base material.
JP-A-59-19738 discloses a method of manufacturing a clad steel plate by placing a steel sheet and performing roll rolling or the like. Furthermore, as shown in FIG. 4, Japanese Patent Application Laid-open No. 57-168791 discloses a method of stacking a laminated material 2 on a base material 1 and performing ultra-high power electron beam welding 10 to integrate them, and then rolling them to produce clad steel. is also disclosed. Furthermore, JP-A-57-
Publication No. 115991 discloses that, as shown in Fig. 5, base material 1 - laminated material 2 - release agent - laminated material 2 - base material 1 are stacked vertically symmetrically in this order, and then the four sides of the laminated materials are hermetically welded. 9, a method is also disclosed in which a contact plate 7 is placed around the four circumferences of the base material, the edges are welded to ensure sealing during heating and hot working, and hot rolling is performed. Explosive pressure welding is another well-known method for producing clad steel.

(Problems to be Solved by the Invention) As shown in Fig. 3, the method of manufacturing a clad steel plate by placing the laminated material 2 on the base material 1 and performing roll rolling etc. is simple, but Since the material 2 is not bonded, it cannot be applied to the production of titanium clad steel plates, where there is a large difference in elongation between the base material and the composite material at high temperatures. When welding the base material and the cladding material directly from around or above them,
When welding dissimilar materials and, for example, when the joining material is titanium, brittle intermetallic compounds TiC, TiN, and TiFe are generated in the welded portion, making it impossible to reliably join.

Furthermore, as shown in Figure 4, the method of integrating the base material 1 and the mating material 2 by ultra-high power electron beam welding cannot be applied to the production of titanium clad steel sheets, as mentioned earlier, and is Although it seems like a good method, it is expensive in terms of equipment and has the problem that it cannot be applied to the production of long or wide clad steel plates.

Figure 5 shows a method that does not involve welding dissimilar materials. However, if you simply place the backing plate 7 on the side surface of the base metal 1 and weld the edges, the backing plate will not be in close contact with the side surface, so it will not be able to withstand the pressure during rolling down. This method cannot be applied to the manufacture of clad steel plates, as it is certain that the plate will not be able to withstand the pressure and will peel off.As a result, the plate will get caught on the rolling rolls and the rolls will stop rotating, so rolling will have to be stopped. However, the biggest problem with this method is that it requires a step of applying a release agent to form a sand inch shape, and when the laminated material is titanium, it is difficult to fix the laminated material.

The widely known explosive pressure welding method uses the instantaneous high pressure associated with the explosion of gunpowder, but in practice it requires expensive equipment and safety measures, and is easy to use in terms of noise pollution. There are some drawbacks that make it difficult to adopt.

The present invention was made in order to solve the problems in full circumference welding of the fillet in the rolled slab manufacturing method, and it is possible to make the fillet weld strong and defect-free in a short time using relatively simple equipment and methods. This provides rolled slabs with excellent quality.

(Means for Solving the Problems) The gist of the present invention is to stack a base material made of carbon steel or low alloy steel and a laminate material, and when performing seal welding all around the periphery, the side surface of the laminate material is A clad steel with an angular cross section and a clad surface with the same composition as the laminated material is attached to the
The sides of the laminated material and the cladding surface of the square clad steel are arc welded all around the fillets using a welding material with the same composition as the mating material, and the base material of the square clad steel and the slab base material are welded with the same composition. A highly efficient slab assembly method characterized by arc welding the entire circumference of the fillet using weld metal.

(Function) In the present invention G, the base material refers to the material before assembly, and the slab refers to the state after assembly and before rolling.

An example of the slab assembly order in the present invention will be explained.

First, a thin plate of low carbon steel with a slightly smaller area than the base material is placed on top of the base material. This is to reduce carburization from the base material to the rolled joint. Next, place a piece of lumber of the same size on top of it. At this time, create an inert gas atmosphere in the gap between the base material and the bonding material. After that, as shown in FIG. 1, a rod-shaped clad steel with a square cross section made of the same type of material as the laminating material is assembled so as to be tightly attached to the side surface of the laminated material.

FIG. 1 is a longitudinal sectional view of an example of a slab. This is base material 1
, a cladding steel 3, a low carbon steel 4, and a fillet weld 6. Considering the strength of the fillet weld, the size of the clad steel that is brought into close contact with the side surface of the laminated material should be approximately 1/2 of the plate thickness of the laminated material. If the cladding thickness is too thin, there is a risk of it peeling off after welding, so a thickness of 3*1 or more is desirable.

As for the welding method, when the laminated material is titanium, fillet welding between the laminated material and the cladding surface is performed by gas shielded arc welding. In the case of stainless steel, gas shielded arc welding, submerged arc welding, or manual welding may be used.

Fillet welding between the carbon steel or low alloy steel part of clad steel that is in close contact with the side of the cladding material and the base material made of carbon steel or low alloy steel is gas-shielded arc welding regardless of whether the cladding material is titanium or stainless steel. Alternatively, either submerged arc welding or manual welding may be used. Welding of the mating material and the cladding surface uses the same type of welding material. For example, when the laminating material is titanium, a titanium or titanium alloy welding material is used. In the case of stainless steel, if the mating material is austenitic, an austenitic welding material is used, and if it is ferritic, a ferritic welding material is used.

The same level of weld metal is used in welding the carbon steel or low-alloy steel part of the crat steel to the base metal made of carbon steel or low-alloy steel. As for the welding order, first is the fillet all-around seal welding between the carbon steel or low alloy steel part of the clad steel and the base material of the slab, or the fillet all-around seal welding between the joining material and the cladding surface, or You can do both at the same time.

When the mating material is stainless steel, dissimilar metal welding between stainless steel and carbon steel or low alloy steel is generally considered possible, but in 9 cases it is not used in parts where mechanical performance is important. . This is because cracks occur internally due to a lack of ferrite in the weld metal. If hot rolling is performed while cracks have occurred inside, the cracks may not be able to withstand the rolling pressure and the cracks may open, causing the base material and the mating material to separate. One way to prevent the occurrence of cracks is to compensate for the lack of ferrite by using a high-grade welding material, but this method is not preferred because it ultimately increases the product price.

From the above, by using a welding material of the same type of composition through the square clad steel, no cracking occurs and the product price can be reduced.

After completing the assembly and welding in this manner, hot rolling is performed to obtain clad steel.

The effects of the present invention will be explained in more detail below using Examples.

(Example) Table 1 shows the materials of the clad steel used.

The cladding steel in FIG. 2 had a ratio of length to width of 1:1, the thickness of the laminated material was 172 mm, and the cladding thickness was 31 mm.

Table 2 shows the assembly method used. As comparative examples, there is a method shown in Figure 3 in which a laminated material is simply laid on top of the base material (this is referred to as method A), and a method in which a plate is rolled on the back side of the sandwiched material shown in Figure 5. Two methods were used: applying and rolling (this is referred to as method B). The criteria for judgment was whether or not titanium clad steel could be manufactured.

Table 3 shows the hot rolling results.

Table 1 Slabs constructed by the clad steel adhesion method according to the present invention could be hot rolled without any problems, and good titanium clad steel could be obtained. Method A, which was used as a comparative example and involved rolling with only a laminated material layered on the base material, failed to obtain titanium clad steel because the base material and the laminated material deteriorated after hot rolling. Also, place a plate on the side and roll B
During rolling, hot rolling was halted because the backing plate peeled off and got caught in the rolls.

Although the above is an example of titanium, the present invention can of course be applied to other clad steels other than titanium.

(Effects of the Invention) The high-efficiency slab assembly method according to the present invention is capable of welding the entire circumference of the fillet reliably without defects and efficiently, and can obtain land steel that is in good condition after hot rolling. .

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of an example of a slab, Figure 2 is an enlarged view of clad steel in close contact with laminated material, and Figures 3 to 5 are cross-sectional views of slabs showing conventional methods of manufacturing clad steel plates. It is. ■... Base metal, 2... Composite material, 3... Clad steel, 4... Low carbon steel, 5... Clad surface, 6... Fillet weld, 7... Plate, 8...Plate welding part, 9...
- Sealing welding section, 10...electron beam welding section.

Claims (1)

[Claims] Layering the base material, which is carbon steel or low alloy steel, and the composite material,
When seal welding is performed around the entire circumference, a clad steel with an angular cross section and a cladding surface of the same composition as the laminated material is closely attached to the side of the laminated material, and the side of the laminated material and the cladding of the square clad steel are Arc welding is performed on the entire circumference of the fillet using a welding material with the same composition as the surface joining material, and arc welding is performed on the entire circumference of the fillet between the base material of the square clad steel and the slab base material using a welding material with the same composition. A highly efficient slab assembly method characterized by: