JPH11309589A - Manufacture of two-layer titanium clad steel plate by casting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing, by a casting method, a two- layer titanium clad steel plate (thick plate product) having excellent adhesivity between core materials and adhesive strength between the core material and a coating material. SOLUTION: An iron plate 4 the carbon content of which is 0.001-0.003 is welded, by evacuating its boundary part after descaling, to the outer surface of a core material wherein two descaled titanium plates 1, 2 are superposed via a peeling agent 3, the outer surface of the iron plate 4 is descaled and an oxydation preventing agent is applied. Thereafter, molten steel for a coating material is cast at a casting speed of 0.15-0.9 m/min to make a clad ingot and it is cooled in the open air. Thereafter, the clad ingot is further slabbed to make a slab, thick plate rolling is executed to the slab so that a total draft in the rolling process becomes 6-20, and two core materials 1, 2 are peeled to obtain a two-layer titanium clad steel plate after removing non-clad parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a two-layer titanium clad steel sheet (thick product) by a casting method, and more particularly, to a method of peeling a titanium clad steel sheet obtained by a casting method to form a thick product. The present invention relates to a method for producing a two-layer titanium-clad steel plate having excellent peelability and adhesion between a core material and a garment material when forming a two-layer titanium-clad steel plate at a high yield.

[0002]

2. Description of the Related Art First, a conventional method for producing a two-layer clad steel sheet by a general casting method will be described with reference to FIGS. As shown in FIGS. 8 and 9, two core members 102 and 103, which are overlapped with each other via a release agent 101, are supported by a hanging tool 104 at a central portion in a mold 100. The core material 102, 103 is cast with a batter 106, and the clad steel ingot 10 shown in FIG.
Get 7. Next, the clad steel ingot 107 is subjected to bulk rolling to form a slab, and after cutting and removing the non-clad portion of the slab, the cores 102 and 103 are separated and subjected to a hot rolling step. The two-layer clad steel sheet 108 shown in FIG.

[0003]

Although the casting method has the advantage of being suitable for mass production, titanium is an extremely oxidizing metal, so that adhesion is impaired by the formation of oxides and molten steel comes into contact with titanium. Due to the formation and coarsening of titanium carbide, there is a problem of brittleness deterioration, and it has been difficult to produce a two-layer clad steel sheet by a casting method using titanium.

[0004] The present invention has been made in view of such circumstances, and overcomes the strong oxidizing property of titanium, suppresses the precipitation of titanium carbide at high temperatures, and secures a sufficient rolling reduction during rolling to ensure adhesion. It is an object of the present invention to provide a method of manufacturing a two-layer clad steel plate (thick plate product) by a casting method using titanium as a core material by increasing the core material.

[0005]

In order to overcome the strong oxidizing property of titanium, it is not enough to apply an antioxidant such as an epoxy resin, which is generally used conventionally. The present inventors have overcome this problem by coating the periphery of titanium as a core material with an iron plate, and evacuating and welding the boundary.

[0006] Regarding the precipitation of titanium carbide at a high temperature, the carbon content of the iron plate covering the periphery of titanium as the core material is set to 0.001 to 0.003% by weight, so that it can be used during casting or heating. Occasionally, even at a boundary temperature of 1200 ° C. or more, precipitation of titanium carbide due to diffusion at the contact surface between titanium and carbon steel could be suppressed.

Furthermore, the casting speed is set to 0.15 to 0.9 m /
Minutes, the titanium has its α⇔β transformation point 8
It was possible to prevent the titanium carbide from being deposited at a temperature of 82 ° C. or more for a long time to suppress the precipitation of the titanium carbide, and to prevent the coated iron plate from being melted. As shown in FIG. 6, the casting speed is 0.15 m
/ Min does not reach or exceeds 0.9m / min,
It is clear that the boundary shear strength decreases. This decrease in the shear strength at the boundary is considered to be due to the effect of cracking due to precipitation of carbides and thermal strain at the boundary.

On the other hand, in order to suppress the precipitation of titanium carbide,
It is preferable that the steel ingot be cooled in a short time, but if it is cooled too quickly, the steel ingot cracks. As described above, since the iron plate having a carbon content of 0.001 to 0.003% by weight is interposed on the contact surface between titanium and carbon steel, the precipitation of titanium carbide can be suppressed even by natural cooling. did it.

Further, by setting the reduction ratio from the thickness of the steel ingot to the thickness of the product at 6 to 20, a titanium-clad steel sheet having extremely high adhesion could be obtained. As shown in FIG. 7, when the reduction ratio does not reach 6, 40 kgf / m
While the desired shear strength of m ² or more cannot be obtained,
When the rolling reduction is 6 or more, the desired shear strength can be obtained. However, when the rolling reduction exceeds 20, the structure of the slab becomes a rolled structure, and the carbide of titanium carbide becomes laminar, which causes troubles such as cracks at the time of working, but also causes poor shape, which is not preferable.

[0010] The present invention has been made based on the above findings, and the method for producing a two-layer clad steel sheet by the casting method according to the first aspect of the present invention comprises the steps of: Polymerization is carried out via a release agent, and an iron plate having a carbon content of 0.001 to 0.003% by weight is welded on the outer surface thereof by descaling a boundary portion thereof and vacuuming the outer surface of the iron plate. After the application of the antioxidant, the molten steel for the batter is cast at a casting speed of 0.15 to 0.9 m / min to form a clad steel ingot. The slab is subjected to thick plate rolling so that the total reduction ratio in the rolling step including the above-described bulk rolling is 6 to 20. Subsequently, the non-clad portion is removed, and then the two core materials are peeled off to remove 2 cores.
It is characterized by obtaining a multilayer titanium clad steel sheet.

[0011] Further, the casting method according to claim 2
The method for producing a layer-clad steel sheet is such that two titanium plates as descaled core materials are polymerized via a release agent, and the outer surface thereof has a carbon content of 0.001 to 0.003% by weight and a sheet thickness of 1%.
After descaling the boundary of the 0 to 20 mm iron plate, vacuuming and welding it, and then descaling the outer surface of the iron plate and applying an antioxidant, the molten steel made of low carbon steel or medium carbon steel is applied. Casting is performed at a casting speed of 0.15 to 0.9 m / min to form a clad steel ingot, and after natural cooling, the clad steel ingot is subjected to bulk rolling to form a slab. Thick plate rolling is performed so that the total draft ratio becomes 6 to 20, subsequently, the non-clad portion is removed, and then the two core materials are peeled to obtain a two-layer titanium-clad steel sheet.

[0012]

Embodiments of the present invention will be described below. Titanium content of 99.7% as core materials 1 and 2
After using heat treatment and descaling of titanium materials of a certain degree, a release agent 3 is applied to the contact surfaces and superposed, and the boundary is evacuated to weld the entire periphery.

Next, the outer surfaces of the welded core materials 1 and 2 are coated with a carbon content of 0.001 to 0.003% by weight and a thickness of 10 to 2 mm.
It is covered with six 0 mm descaled iron plates 4, the boundary is descaled, vacuum is drawn, and the entire circumference is welded.
Then, after descaling the outer surface of each iron plate 4 and applying an antioxidant such as epoxy resin, as shown in FIG. In addition, the hanging leg 11 welds the fixed leg 11a to the iron plate 4a on the upper surface.

Subsequently, molten steel to be the clothing material 5 is injected from the gate 12 by a casting method at a casting speed of 0.15 to 0.9 m / min, and as shown in FIG. The material 5 is cast to form a clad steel ingot 6, which is naturally cooled. As the molten steel to be the clothing material 5, carbon steel may be used, but low-carbon steel or medium-carbon steel is preferable.

At the time of casting, the iron plate 4 melts from the outer surface in contact with the molten steel, but does not melt up to the portion in contact with the cores 1 and 2, so that the cores 1 and 2 come into direct contact with the molten steel. There is no. For this reason, precipitation of titanium carbide due to diffusion occurring at the contact surface between titanium as core materials 1 and 2 and carbon steel as clothing material 5 can be suppressed.

Subsequently, the clad steel ingot 6 is bulk-rolled by a known method into a slab 7 shown in FIG. 8, and the slab 7 is rolled into a thick plate so that the total reduction ratio in the rolling step is 6 to 20. Was given. Next, after cutting and removing the surrounding non-cladding portion by a known method, the two core materials 1 and 2 are peeled off by the same known method, and the titanium surface is polished to obtain a thick plate shown in FIG. A two-layer titanium clad steel sheet 8 as a product was obtained.

Next, a preferred embodiment will be described. Applications Marine corrosion-resistant board Core material component Ti / 99.7% Clothing material component C / 0.15%, Si / 0.34%, Mn /
1.20%, P / 0.020%, S / 0.020% Core material thickness ratio 10% Mold inner average surface width 1000mm Core material thickness 126mm Core material to mold inner surface interval 510mm Pouring speed 0.35m / min Rolling ratio 8

The two-layer titanium clad steel sheet 8 obtained in this embodiment was prepared by mixing a titanium material having a titanium content of 99.7% with a C / O.
15%, Si / 0.34%, Mn / 1.20%, P /
Using 0.020%, S / 0.020% medium carbon steel,
As compared with the two-layer titanium-clad steel sheet manufactured by the conventional rolling method, as shown in FIG. 5, the two-layer titanium-clad steel sheet 8 of the present invention has more inclusions at the interface than the two-layer titanium-clad steel sheet according to the conventional method. It was confirmed that the adhesiveness was excellent due to the small biting area. In addition, the heat treatment characteristics and mechanical properties were not inferior to those of the conventional two-layer titanium clad steel sheet.

[0019]

As described above, according to the present invention,
A two-layer titanium-clad steel sheet with titanium as the core material can be obtained at a high yield by casting, and the two-layer titanium-clad steel sheet of the manufactured thick plate product has excellent adhesion at the boundary, heat treatment characteristics and mechanical properties. This has the effect that the mechanical properties are also good.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a manufacturing process of a clad steel ingot according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a manufactured clad steel ingot.

FIG. 3 is a schematic sectional view showing a slab obtained by rolling.

FIG. 4 is a schematic cross-sectional view showing a two-layer clad steel sheet obtained by cutting and removing a non-clad and peeling a core material.

FIG. 5 is a diagram showing a comparison of the adhesiveness of a boundary portion between the present invention and a conventional rolling method.

FIG. 6 is a diagram showing the relationship between the casting speed and the shear strength at the boundary according to the present invention.

FIG. 7 is a graph showing the relationship between the rolling ratio and the shear strength at the boundary according to the present invention.

FIG. 8 is a schematic sectional view showing a manufacturing process of a clad steel ingot in a conventional casting method.

FIG. 9 is a plan view of the same.

FIG. 10 is a schematic cross-sectional view showing the manufactured clad steel ingot.

FIG. 11 is a schematic cross-sectional view showing a two-layer clad steel sheet obtained by cutting and removing a non-clad and peeling a core material.

[Explanation of symbols]

 1, 2 core material 3 release agent 4 iron plate 5 clothing material 6 clad steel ingot 7 slab 8 two-layer clad steel plate 10 mold 11 hanging tool 12 gate

Claims (2)

[Claims] 1. A two-piece titanium plate as a descaled core material is polymerized via a release agent, and an iron plate having a carbon content of 0.001 to 0.003% by weight is formed on its outer surface. After descaling and vacuum evacuation and welding, after descaling the outer surface of the iron plate and applying an antioxidant, the molten steel material is cast at a casting speed of 0.15 to 0.9 m / min to form a clad steel ingot. ,
After natural cooling, the clad steel ingot was slab-rolled to form a slab, and the slab was subjected to plate rolling so that the total reduction ratio in the rolling process was 6 to 20, followed by removal of the non-clad portion. A method for producing a two-layer titanium-clad steel sheet by a casting method, wherein two core materials are peeled to obtain a two-layer titanium-clad steel sheet. 2. An iron plate having a carbon content of 0.001 to 0.003% by weight and a plate thickness of 10 to 20 mm, which is obtained by polymerizing two titanium plates as descaled core materials through a release agent. After descaling the boundary portion and vacuum-welding, descaling the outer surface of the iron plate and applying an antioxidant, the molten steel made of low-carbon steel or medium-carbon steel is cast at a casting speed of 0.1 mm. After casting at a rate of 15 to 0.9 m / min to form a clad steel ingot, and naturally cooling, the clad steel ingot is subjected to slab rolling to form a slab.
A thick plate rolling is performed so that a non-clad portion is removed, and then two core materials are peeled off to obtain a two-layer titanium-clad steel plate. Production method.