JPH0228429B2 - KURATSUDOKOHANNOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing clad steel sheets using a casting method. Conventionally, manufacturing methods such as explosion bonding, rolling, diffusion welding, overlay welding, and casting and ingot forming have been well known as methods for manufacturing clad steel sheets. In all of the previous four manufacturing methods, a clad slab is manufactured by joining the cladding material to the surface of the base steel, whereas the final method using cast walnut ingots produces a walnut material (to be cast) in the steel ingot. Since a clad steel ingot is produced by enclosing a cladding material (laminated material), a clad steel sheet material with a large unit weight can be obtained, and is suitable for mass production. FIG. 1 shows a method for manufacturing clad steel sheets using this cast walnut ingot. According to this method, first, as shown in a, two cast walnuts 2 are welded together with a release agent 6 sandwiched between them (see FIG. 1b) to form a so-called core 7. Next, as shown in b, this core 7 is suspended in a mold 9, and a molten metal casting material (base steel) 10 is injected from the sprue to cover it. This is the process of casting walnut ingots. After this process is completed, the obtained steel ingot (clad steel ingot) is subjected to blooming rolling as shown in c, and the obtained slab (clad slab) is edge-cut as shown in d. After peeling, it is hot rolled into a clad steel plate as shown in e. As mentioned above, this method produces the clad steel sheet material at the steel ingot manufacturing stage, so it is more productive than the explosion bonding method, which creates the clad steel sheet material at the slab manufacturing stage. Since the melting point is different from that of the walnut material 10, it is easy to cause melting damage or poor fusion at the joint between the two, making it difficult to obtain a clad steel plate of excellent quality. Industrial production is possible only when the walnut wood 10 is made of the same metal. That is, if the melting point of the cast walnut material 10 is higher than the melting point of the walnut material 2 to be cast, the melting loss of the walnut material 2 to be cast will be large, and not only will it be impossible to obtain a clad steel plate of the required dimensions, but also the melting point of the walnut material 2 to be cast will be large. There is a problem in that an alloy layer is formed at the joint between the steel and the base steel 10, causing defects such as cracks. On the other hand, the walnut material to be cast 2
If the melting point of the walnut material 2 is higher than that of the walnut material 10, the walnut material 2 and the walnut material 10 will not blend together, resulting in poor fusion welding, and slag will adhere to the surface of the walnut material 2, causing defects in this area and resulting in poor joining. occurs. The present invention aims to solve these problems and provide a method that can consistently produce clad steel sheets of excellent quality regardless of the melting point difference between the cast walnut material and the cast walnut material. The gist of this paper is a method for producing clad steel sheets by casting walnut ingots. That is, a step of manufacturing a first overlapping member by overlapping a cast walnut material on a steel plate made of the same material as the cast walnut material and welding the periphery of the mating surfaces, and a step of manufacturing the first overlapping member obtained in the step of A process of evacuating the inside of the mating surfaces, and after stacking the two first stacked members with the walnut material to be cast inside and sandwiching a release agent between them, the surrounding side surfaces are surrounded by steel plates made of the same material as the base material. producing a second overlapping member; evacuating the inside of the second overlapping member obtained in the step; and suspending the second overlapping member in a mold to form a molten steel. A process of injecting cast walnut material from a sprue into a cast walnut clad steel ingot, and a process of blooming and rolling the clad steel ingot obtained in the process to form a clad slab. There are seven steps: hot rolling a clad slab into a clad steel plate. Note that the steps and can be performed simultaneously as described later. The most significant feature of the method of the present invention is that the walnut material to be cast is wrapped in a steel plate made of the same material as the walnut material to form a walnut ingot. According to this, the walnut material to be cast is separated from the walnut material by the steel plate during ingot making, not only does the walnut material to be cast not suffer melt damage, but also its alloying is prevented, and furthermore, the walnut material to be cast is It also prevents slag from adhering to the surface. Moreover, since the steel plate is made of the same material as the cast walnut material, the steel plate and the cast walnut material fit well together, and the cast walnut material can be completely integrated with the steel plate. The joining of the mating surfaces of the walnut material to be cast and the surrounding steel plate made of the same material as the base steel is basically the same as the rolling method. That is, the cast walnut material in the steel ingot and the steel plate of the same material as the cast walnut material enclosing the steel ingot are joined by diffusion bonding using blooming rolling. This is the reason why the vacuum step is provided in the method of the present invention. Therefore, according to the method of the present invention, the walnut material to be cast is protected from the adverse effects associated with agglomeration, and at the same time, the steel plate serving as the protective material is integrated with the surrounding walnut material, and furthermore, the steel plate is also Since it is well bonded to the cast walnut material by diffusion bonding during the rolling stage, a clad slab with a high degree of bonding can be obtained, thereby making it possible to manufacture high quality clad steel sheets. Furthermore, when the method of the present invention is compared with the rolling method,
The principle of joining the cast walnut material (laminated material in the case of rolling method) and the base material is the same, but in the rolling method, clad steel plate material (clad slab) is assembled by welding, so when assembling large unit weight materials, It is difficult to obtain strength that can withstand rolling, and the dimensions of the material are limited.In contrast, in the method of the present invention, rolling is performed with the cast walnut material completely surrounded by the cast walnut material. Problems such as slab peeling do not occur, and the advantage is that the material can be made larger. Hereinafter, the method of the present invention will be explained in more detail based on the specific example shown in FIG. According to FIG. 2, first, as shown in a, the cast walnut material 2 is superimposed on the steel plate 1 made of the same material as the cast walnut material, and the periphery of the mating surface is welded by fillet welding to form the first superposition. (Process of) obtaining member 5. The back surface 11 of the steel plate 1 is preferably polished in order to prevent scum from adhering to it during the ingot formation stage. In addition, the area between the mating surfaces of the steel plate 1 and the cast walnut material 2 is cleaned, and if necessary, nickel or chromium is added to prevent the formation of an alloy layer due to diffusion and to improve the peel strength at the interface. ,copper,
Apply molybdenum or the like or insert an insert material 3 (see FIG. 3). After completing the step, the next step is to bring the mating surfaces of the steel plate 1 and the cast material 2 into a state as close to a vacuum as possible. For this purpose, for example, a hole for venting air may be made in the welded portion 4, and air may be removed from the hole using a vacuum pump to close the hole. After the process is completed, next, as shown in b, the two first stacking members 5, 5 are stacked with the walnut material 2 to be cast inside and the release agent 6 is sandwiched between them. After that, the peripheral side surface is surrounded by a steel plate 1' made of the same material as the walnut material to be cast, and fixed by welding to produce a second overlapping material (step) (see Fig. 4). Specifically, the release agent 6 is SiO ₂ powder, Al ₂ O ₃
Powder or a mixture thereof is suitable. It is preferable that the back surface 11' of the steel plate 1' is also polished in the same manner as that of the steel plate 1. After completing the step, the second one obtained in the same step is
The inside 8 of the overlapping member 7 is brought into a state as close to a vacuum as possible. For this, the same means as in the step may be adopted, or in the next step, the second overlapping member 7 is placed in the mold 9.
It is also possible to make air holes in advance in the part that becomes the upper surface when suspended inside, and to perform deaeration simultaneously with the ingot formation (see c). The second overlapping member 7 corresponds to a so-called core shown at 7 in FIG. After the process (if degassing is performed in the process, the process is completed), as shown in c, the second overlapping member 7 is suspended inside the mold 9, and the molten metal is cast into a walnut material. (Step of) injecting (base steel) 10 from the sprue and casting the second overlapping member 7 to produce a clad steel ingot. It is preferable to apply a scum repellent to the back surfaces 11, 11' of the steel plates 1, 1'. Since the steel plates 1 and 1' are made of the same material as the cast walnut material,
In the process, the surface layer of the cast walnut material 10 will be eroded, but this melting loss will not extend to the internal walnut materials 2, 2, but rather the steel plates 1, 2.
Cast walnut material 1 due to melting loss of the surface layer of 1'
0 and the steel plates 1 and 1' fit well together and are effectively integrated. After completing the process, the obtained clad steel ingot is
As shown in the figure, it is bloomed and rolled into a clad slab (process). The walnut materials 2, 2 to be cast are dispersively joined to the two steel plates 1, 1 sandwiching the walnut materials 2, 2 to be cast by this blooming rolling.
1' isolates it from the molten steel and prevents alloying and scum from forming on its surface, resulting in very good bonding. After completing the step, the obtained clad slab is made into a clad steel plate according to the conventional method as shown in e to h. In FIG. 2, e represents peeling, f represents hot rolling, g represents peeling, and h represents each stage of the product. Next, the base material is JIS3101SS41 steel plate (thickness 8mm)
So, the laminating material is JIS G4303SUS304L steel plate (thickness 2
An embodiment of the present invention will be described by taking as an example the manufacture of a clad steel plate having a diameter of 1 mm). Table 1 shows the specific compositions of the cast walnut material and the cast walnut material.

[Table] First, in the process, the SUS304L steel plate (thickness 75mm), which is the walnut material to be cast, is superimposed on the SS41 steel plate (thickness 50mm), which is the steel plate 1 made of the same material as the cast walnut material, and the periphery of the mating surface is After fillet welding, the inside of the joint was degassed using a vacuum pump (see Figure 2a). Note that a nickel foil having a thickness of 0.4 mm was interposed as an insert material 3 between the mating surfaces of the steel plate 1 and the cast walnut material 2. Next, in step , the two first overlapping members 5, 5 obtained in the above step are overlapped with a release agent 6 of SiO ₂ +Al ₂ O ₃ powder sandwiched between them, and then the surrounding side surfaces are The second overlapping member 7 was obtained by surrounding it with a 50 mm thick steel plate having the same composition as the cast walnut material shown in Fig. 2 (see Fig. 2b). The outer dimensions of the second overlapping member 7 are 251mm thick x
It is 1300mm wide x 1800mm long. The surface of the second overlapping member 7 was polished, a scum repellent was applied thereto, and the inside was degassed using a vacuum pump. In the next step, the second overlapping member 7 is suspended inside the mold 9 and is cast with a molten metal casting material (base steel) 10 (see FIG. 2c). The dimensions of mold 9 are 750mm x 1500mm x 2300mm
The dimensions of the obtained clad steel ingot also conform to this. The casting conditions are a casting temperature of 1580
℃, and the temperature after bathing was 200 mm/min. Next, as a step, the above clad steel ingot is
After soaking and heating under the conditions of 1290℃ x 6Hr, the slab is bloomed into a 100mm thick x 1500mm wide x 17250mm long slab.
After cutting into dimensions of thickness x 1500mm width x 3500mm length, 1200
After heating under the conditions of ℃×3Hr, hot rolling
Dimensions are mm thickness x 2000mm width x 13125mm length, and after cutting and peeling, (2+8)mm thickness x 1500mm width x
The product had a length of 12,000 mm (Fig. 2 d to h)
reference). This clad steel plate showed a good bonding quality overall, with only a slight bonding failure observed at the bottom side joint. By the way, when clad steel plates of the same steel type and dimensions were manufactured using the conventional method, a wide range of joint failures were observed over almost the entire periphery of the joint due to melting damage and slag adhesion to the cast walnut material. Many poor joints were also found in the center. The melting point of SS41 steel, which is the cast walnut material (base material), is 1510℃, and the melting point of the cast walnut material (base material) is 1510℃.
The melting point of SUS304L steel is 1460℃, and the difference is 50℃. As is clear from the above explanation, the method of the present invention provides a good bonding degree even when the melting point difference between the cast walnut material and the cast walnut material is large, compared to the conventional method using cast walnut ingots. This method has many advantages, such as making it possible to clad non-ferrous metals and allowing easy insertion of insert materials.Furthermore, compared to conventional rolling methods, it is possible to obtain materials with a large unit weight. It is extremely superior.

[Brief explanation of drawings]

Figures 1 a to e are process example diagrams of the conventional method, and Figures 2 a to
h is a process example diagram of the method of the present invention, and Fig. 3 is A of Fig. 2 a.
4 is a sectional view taken along line B-B in FIG. 2b. In the figure, 1, 1': Steel plate made of the same material as cast walnut material,
2: Walnut material to be cast, 3: Insert material, 5: Overlapping member, 6: Release agent, 7: Second overlapping member, 9: Mold, 10: Casting walnut material (base material steel).

Claims (1)

[Claims] 1. A step of overlapping a steel plate made of the same material as the cast walnut material on the upper surface of the cast walnut material and welding the periphery of the mating surfaces to form a first overlapping member, and a first overlapping member obtained in this step.
a step of evacuating the mating surfaces of the superimposed members;
After the two first mating members are stacked with the walnut material to be cast inside through a release agent, the surrounding side surfaces are surrounded by a steel plate made of the same material as the walnut material to be cast, and a second stacking member is formed. a step of evacuating the inside of the second overlapping member obtained in the step; a step of forming the second overlapping member into a cast clad steel ingot with base steel; and a step of blooming the clad steel ingot. A method for producing a clad steel plate by casting ingots, which includes the steps of rolling into a clad slab and hot rolling the clad slab into a clad steel plate.