JP6863332B2 - Clad steel sheet manufacturing method and clad steel sheet manufacturing equipment - Google Patents

Description

The present invention relates to a method for manufacturing a clad steel sheet and a facility for manufacturing a clad steel sheet.

The clad steel sheet is a steel sheet formed by crimping a base material plate such as carbon steel and a laminated material plate such as nickel-based alloy or stainless steel, which is a material different from the base material plate. By combining different materials in this way, the clad steel sheet can exhibit excellent corrosion resistance and wear resistance by taking advantage of the characteristics of the base material plate and the laminated material plate.

As a method for manufacturing such a clad steel sheet, a method of heating an assembly slab for rolling produced by superimposing a base material plate and a laminated material plate and then crimping by hot rolling to obtain a clad steel plate is common. is there.

Patent Document 1 discloses the following techniques as a method for producing a clad steel sheet. That is, first, the thin oxide film on the surface of the laminated material plate made of titanium is removed to activate the surface. Next, a nickel plating layer is formed on the surface. Next, an assembly slab for rolling is produced by superimposing the base material plate and the laminated material plate via the nickel plating layer. Next, the assembly slab for rolling is heated to 600 to 850 ° C. and rolled and crimped to obtain a clad steel sheet.

Japanese Unexamined Patent Publication No. 62-9788

In Patent Document 1, by superimposing the base material plate and the laminated material plate via the nickel plating layer, the laminated material plate is oxidized during hot rolling and the carbon in the base material plate is titanium. The formation of titanium carbide induced by diffusion into the base plate is suppressed, and the bondability between the base material plate and the laminated material plate is improved. However, when the clad steel sheet is manufactured by such a method, although the bondability between the base material plate and the laminated material plate is improved, warpage occurs during hot rolling, which causes a problem that a plate passing defect occurs. There is.

Therefore, in view of the above problems, it is an object of the present invention to provide a method for producing a clad steel sheet capable of producing a clad steel sheet having high bondability while suppressing the occurrence of warpage during hot rolling. .. Another object of the present invention is to provide a clad steel sheet manufacturing facility capable of manufacturing a clad steel sheet having high bondability while suppressing the occurrence of warpage during hot rolling.

As a result of studies to solve the above problems, the present inventors have found that the warp during hot rolling is combined with the deformation resistance in the surface layer of the laminated material plate and the base material plate in the assembly slab for rolling to be subjected to hot rolling. It was found that this is caused by a large difference from the deformation resistance in the vicinity of the joint surface with the material plate. Then, as a result of further studies, when hot rolling is performed in a state where the difference in deformation resistance is reduced by heating the surface layer of the laminated material plate, the occurrence of warpage during hot rolling is suppressed. It was found that it can be done.

The present invention is based on the above findings, and its gist structure is as follows.
(1) In a method for manufacturing a clad steel sheet in which a base material plate made of carbon steel and a laminated material plate made of a material different from the base material plate are crimped together.
The first step of forming a plating layer on the surface by plating the surface of the laminated material plate, and
After the first step, a second step of superimposing the base material plate and the laminated material plate via the plating layer to prepare an assembly slab for rolling, and
After the second step, a third step of heating the rolling assembly slab in a heating furnace and
After the third step, a fourth step of heating the surface layer on the laminated material plate side of the rolling assembly slab carried out from the heating furnace, and
After the fourth step, a fifth step of hot rolling the rolling assembly slab into a clad steel sheet, and
A method for producing a clad steel sheet, which comprises.

(2) In the fourth step, the average value of the deformation resistance of the laminated material plate in the plate thickness direction is 0.9 times or more and 1.1 times or less of the average value of the deformation resistance of the base material plate in the plate thickness direction. The method for producing a clad steel sheet according to (1) above, wherein the surface layer of the laminated material plate is heated so as to be.

(3) After the third step and before the fourth step, the rolling assembly slab is hot-rolled once with a rolling reduction ratio of 5% or less. The method for producing a clad steel sheet according to (2).

(4) The method for producing a clad steel sheet according to any one of (1) to (3) above, wherein the material of the laminated material plate is a nickel-based alloy and the plating layer is a nickel plating layer.

(5) A heating furnace for heating an assembly slab for rolling produced by superimposing a base material plate made of carbon steel and a laminated material plate made of a material different from the base material plate via a plating layer.
A surface heating device arranged downstream of the heating furnace and heating the surface layer on the laminated material plate side of the rolling assembly slab, and a surface heating device.
A hot rolling mill located downstream of the surface heating device and hot rolling the rolling assembly slab into a clad steel sheet.
Clad steel sheet manufacturing equipment characterized by being equipped with.

(6) The clad steel sheet manufacturing equipment according to (5) above, further comprising a hot rolling mill between the heating furnace and the surface heating device.

(7) The equipment for manufacturing a clad steel sheet according to (5) or (6) above, wherein the material of the laminated material plate is a nickel-based alloy and the plating layer is a nickel plating layer.

According to the present invention, a clad steel sheet having high bondability can be manufactured while suppressing the occurrence of warpage during hot rolling.

It is the schematic sectional drawing of the assembly slab 20 for rolling produced by the manufacturing method of the clad steel sheet in one Embodiment of this invention. It is the schematic of the manufacturing equipment of the clad steel sheet in one Embodiment of this invention.

Hereinafter, an embodiment of a method for manufacturing a clad steel sheet and a manufacturing facility thereof according to the present invention will be described with reference to the drawings as appropriate.

With reference to FIG. 1, in the method for manufacturing the clad steel sheet 100 according to the embodiment of the present invention, the base material plate 10 made of carbon steel and the laminated material plate 12 made of a material different from the base material plate 10 are pressure-bonded. The clad steel sheet 100 is manufactured by the following steps. That is, first, the surface of the laminated material plate 12 is subjected to a plating treatment to form a plating layer 14 on the surface of the laminated material plate 12 (first step). Next, the base material plate 10 and the laminated material plate 12 are overlapped with each other via the plating layer 14 to produce a rolling assembly slab 20 (second step). Next, the rolling assembly slab 20 is heated in a heating furnace (third step). Next, hot rolling with a rolling reduction ratio of 5% or less is performed once on the rolling assembly slab 20 carried out from the heating furnace. Next, the surface layer on the laminated material plate 12 side of the assembly slab 20 for rolling is heated (fourth step). Next, the assembly slab 20 for rolling is hot-rolled to obtain a clad steel sheet 100 (fifth step).

Here, the carbon steel used as the base material plate 10 is not particularly limited, and a carbon steel having specifications and mechanical properties according to the application destination of the clad steel plate 100 can be appropriately selected. Further, the laminated material plate 12 made of a material different from the base material plate 10 includes, for example, a nickel-based alloy such as Alloy625 or Alloy825, a single nickel (NW2200, NW2201 or the like), or a single titanium (industrial pure titanium type 1: TP270H). , Industrial pure titanium 2 types: TP35H, etc.), stainless steel such as SUS316L can be used.

The above-mentioned first to fifth steps can be performed, for example, by the clad steel sheet manufacturing equipment shown in FIG. In FIG. 2, the arrow indicates the transport direction of the clad steel plate 100. In the clad steel sheet manufacturing equipment, from the upstream side in the transport direction of the clad steel sheet, a slab assembly device (not shown), a heating furnace 1, a first rolling stand 2, a surface heating device 3, and a second rolling stand 4 , Are arranged in this order. Hereinafter, each step in the present embodiment will be described in detail with reference to FIGS. 1 and 2.

[First step: Plating process]
With reference to FIG. 1, in the first step, the surface of the laminated material plate 12 is subjected to a plating treatment to form a plating layer 14 on the surface of the laminated material plate 12. The type of the plating layer 14 formed in the first step can be appropriately selected according to the material of the laminated material plate 12. When the laminated material plate 12 is a nickel-based alloy, a simple substance of nickel or titanium, or stainless steel, the plating layer 14 is preferably a nickel plating layer so as not to form an intermetallic compound. In this case, the plating layer 14 can be formed by an electric field plating method using a known watt bath, citric acid bath, or the like. When the laminated material plate 12 is made of titanium, the plating layer 14 may be an aluminum plating layer or an iron plating layer so as not to form an intermetallic compound. In this case, the plating layer 14 can be formed by an electric field plating method using a molten aluminum liquid, a chloride bath, or the like. The plating method is not limited to the electroplating method, and a known electroless plating method may be preferably used.

By forming the plating layer 14 on the surface of the laminated material plate 12 in this way, the joint surface between the base material plate 10 and the laminated material plate 12 on which the plating layer 14 is formed at the time of hot rolling or the like. Is suppressed from being oxidized. Further, the formation of metal carbide induced by the diffusion of carbon in the base material plate 10 into the laminated material plate 12 is suppressed. As a result, the bondability between the base material plate 10 and the laminated material plate 12 is improved.

The thickness of the plating layer 14 is preferably 20 μm or more and 100 μm or less. This is because if it is 20 μm or more, oxidation of the joint surface and formation of metal carbides can be further suppressed, and if it is 100 μm or less, there is no possibility that the plating layer is cracked or chipped.

Prior to the first step, it is preferable to polish the surface of the laminated material plate 12 to be subjected to the plating treatment by an arbitrary or known method to remove the thin oxide film formed on the surface. This is because the adhesion of the plating layer 14 to the surface of the laminated material plate 12 is improved.

[Second step: Assembly of rolling slab]
With reference to FIG. 1, in the second step, the base material plate 10 and the laminated material plate 12 are overlapped with each other via the plating layer 14 in the slab assembling apparatus to produce a rolling assembly slab 20. In the second step, for example, using a known open sandwich method, the base material plate 10 and the laminated material plate 12 are superposed on the base material plate 10 via the plating layer 14 in the slab assembling device. This can be done by welding around the joint surface with the laminated material plate 12 on which the plating layer 14 is formed.

Here, if oxygen is present between the base material plate 10 and the plating layer 14, the joint surface may be oxidized. Therefore, as the slab assembling device, it is preferable to use, for example, a device having a vacuum chamber and an electron beam capable of welding the periphery of the joint surface in the vacuum chamber. This is because oxidation of the joint surface can be suppressed by welding around the joint surface while evacuating in the vacuum chamber.

[Third step: Heating of rolling slab]
With reference to FIGS. 1 and 2, in the third step, the rolling assembly slab 20 is heated in the heating furnace 1. Here, the heating temperature (slab heating temperature) is preferably set from the following viewpoints according to the material of the laminated material plate 12. That is, it is preferable to set the lower limit of the heating temperature from the viewpoint of sufficiently dissolving the laminated material plate 12. Further, the upper limit of the heating temperature is preferably set from the viewpoint of suppressing the generation of scales that cause surface defects of the laminated material plate 12 during hot rolling. For example, when the material of the laminated material plate 12 is a nickel-based alloy or nickel, the temperature is preferably 1100 ° C. or higher and 1200 ° C. or lower, and when the material of the laminated material plate 12 is titanium, the temperature is 600 ° C. or higher and 850 ° C. or lower. Preferably, when the material of the laminated material plate 12 is stainless steel, the temperature is preferably 1100 ° C. or higher and 1300 ° C. or lower.

In the third step, the rolling assembly slab 20 is generally heated uniformly. Here, in the present specification, unless otherwise specified, the conditions of the temperature and the cooling rate are defined by the average temperature in the plate thickness direction of the assembly slab for rolling and the clad steel sheet. These average temperatures can be determined by using a simulation that can calculate the temperature distribution in the plate thickness direction using the difference method from the plate thickness, surface temperature, and the like. Then, whether or not the rolling assembly slab 20 is uniformly heated can be determined based on the temperature distribution calculated in this way.

[Hot rolling in the first pass]
With reference to FIGS. 1 and 2, hot rolling with a rolling reduction ratio of 5% or less is performed once on the rolling assembly slab 20 carried out from the heating furnace 1 using the first rolling stand 2. Thereby, the following effects can be obtained.

Since minute voids are generated in the vicinity of the joint surface of the rolling assembly slab 20 carried out from the heating furnace 1, these voids are reduced by hot rolling in the first pass. This is because when the surface layer heating (fourth step) on the laminated material plate side of the assembly slab 20 for rolling is performed with the voids reduced, the joint surface is heated during the surface layer heating and during hot rolling after the surface layer heating. , The diffusion of chromium atoms and nickel atoms in the laminated material plate 12 or iron atoms in the base material plate 10 is further promoted. This is because the bondability between the base material plate 10 and the laminated material plate 12 is further improved. From the viewpoint of obtaining such an effect, the reduction rate in this step is preferably 1% or more. If the rolling reduction is 5% or less, even if hot rolling is performed once before the surface layer heating (fourth step), warpage that leads to poor plate passing does not occur.

The first rolling stand 2 is preferably arranged between the heating furnace 1 and the surface heating device 3 so that L1 is 20 m or more and 30 m or less. This is because if L1 is 20 m or more, interference between the preceding material and the succeeding material can be prevented, and if it is 30 m or less, the temperature drop of the rolling assembly slab 20 during transportation can be suppressed.

[Fourth step: Surface heating]
With reference to FIGS. 1 and 2, in the fourth step, the surface layer heating device 3 is used to heat the surface layer on the laminated material plate 12 side of the rolling assembly slab 20. In the present embodiment, it is important to heat the surface layer of the laminated material plate side 12 of the assembly slab 20 for rolling after the hot rolling of the first pass and before the hot rolling of the second pass. .. The technical significance of this will be described below.

When the rolling assembly slab 20 is carried out from the heating furnace 1, the temperature of the surface layer of the laminated material plate 12 drops rapidly due to contact with the atmosphere. On the other hand, the temperature in the vicinity of the joint surface between the base material plate 10 and the laminated material plate 12 is gently lowered as compared with the temperature of the surface layer of the laminated material plate 12. Therefore, the difference between the deformation resistance in the surface layer of the laminated material plate 12 and the deformation resistance in the vicinity of the joint surface between the base material plate 10 and the laminated material plate 12 becomes large. When hot rolling is performed on the assembly slab 20 for rolling in which the difference in deformation resistance is large in this way, warpage occurs during hot rolling, which may cause a plate passing defect. .. Therefore, in the present embodiment, only the surface layer on the laminated material plate 12 side of the rolling assembly slab 20 is heated after the hot rolling of the first pass and before the hot rolling of the second pass. As a result, in the rolling assembly slab 20 used for hot rolling (fifth step) in the second and subsequent passes, the deformation resistance in the surface layer of the laminated material plate 12 and the vicinity of the joint surface between the base material plate 10 and the laminated material plate 12 The difference from the deformation resistance in is small. As a result, the occurrence of warpage during hot rolling is suppressed, and the occurrence rate of plate passing defects is reduced.

Further, by heating the surface layer on the laminated material plate 12, the chromium atoms and nickel atoms in the laminated material plate 12 or the base material plate 10 at the joint surface during the surface layer heating and the hot rolling after the surface layer heating. The diffusion of iron atoms is promoted. As a result, the bondability between the base material plate 10 and the laminated material plate 12 is further improved.

From the viewpoint of sufficiently suppressing warpage, the absolute value of the difference between the average value of the deformation resistance of the base material plate 10 in the plate thickness direction and the average value of the deformation resistance of the mating material plate 12 in the plate thickness direction is the base material plate. It is preferable to heat the surface layer on the laminated material plate 12 side of the assembly slab for rolling so that it is 10% or less of the average value of the deformation resistance in the plate thickness direction of 10. That is, it is preferable that the average value of the deformation resistance of the laminated material plate 12 in the plate thickness direction is 0.9 times or more and 1.1 times or less of the average value of the deformation resistance of the base material plate 10 in the plate thickness direction. The temperature dependence of the deformation resistance of the base material plate 10 and the deformation resistance of the laminated material plate 12 can be obtained in advance by the following method. That is, the base material plate and the laminated material plate of the same material as the base material plate 10 and the laminated material plate 12 used in the method for manufacturing the clad steel plate in the present embodiment are selected according to the material from the temperature range of, for example, 600 to 1300 ° C. In each case, hot rolling is performed independently in a temperature range selected as appropriate. From the rolling load, rolling temperature, plate thickness, etc. at that time, the temperature dependence of the deformation resistance of the base material plate and the laminated material plate can be obtained.

For example, when a base material plate 10 made of carbon steel and a laminated material plate 12 made of a nickel-based alloy are used and the plating layer 14 is a nickel plating layer, rolling is uniformly heated in a temperature range of 1100 ° C. or higher and 1200 ° C. or lower. When the assembly slab 20 for use is carried out from the heating furnace 1, the temperature of the surface layer on the side of the laminated material plate 12 rapidly drops to about 1000 ° C. Then, the absolute value of the difference between the average value of the deformation resistance of the base material plate 10 in the plate thickness direction and the average value of the deformation resistance of the mating material plate 12 in the plate thickness direction is the deformation resistance of the base material plate 10 in the plate thickness direction. It exceeds 10% of the average value of. Therefore, the surface layer on the laminated material plate 12 side (depth of 15 to 20 mm in the plate thickness direction from the surface) so that the absolute value of this difference is 10% or less of the average value of the deformation resistance in the plate thickness direction of the base material plate 10. It is preferable to raise the temperature (the region up to the position) by about 35 ° C to 75 ° C.

With reference to FIG. 2, it is preferable that the surface heating device 3 is arranged so that L2 is 15 m or more and 20 m or less and L3 is 15 m or more and 20 m or less. This is because if L2 is 15 m or more, interference between the preceding material and the succeeding material can be prevented, and if it is 20 m or less, the temperature drop of the rolling assembly slab 20 during transportation can be suppressed. .. Further, if L3 is 15 m or more, interference between the preceding material and the succeeding material can be prevented, and if it is 20 m or less, the temperature drop of the rolling assembly slab 20 during transportation can be suppressed. Is. Further, the surface layer heating device 3 is arranged so that the distance from the surface of the assembly slab 20 for rolling on the laminated material plate 12 side is 50 cm or more and 150 cm or less from the viewpoint of efficiently heating the surface layer of the laminated material plate 12. Is preferable.

The surface layer heating device 3 is not particularly limited as long as it can heat the surface layer of the laminated material plate 12, and for example, a reduction burner or a ceramic fiber burner can be preferably used. Then, rolling is required to make the average value of the deformation resistance of the laminated material plate 12 in the plate thickness direction 0.9 times or more and 1.1 times or less of the average value of the deformation resistance of the base material plate 10 in the plate thickness direction. The gas capacity to be supplied to the burner, the number of burners, the plate passing speed in the surface layer heating device 3, the number of plate passing times, and the like may be appropriately set according to the rising temperature of the surface layer on the laminated material plate 12 side of the assembly slab.

[Fifth step: hot rolling after the second pass]
With reference to FIGS. 1 and 2, in the fifth step, the rolling assembly slab 20 is hot-rolled to obtain a clad steel sheet 100 by using a second rolling stand 4 or the like. In the fifth step, it is preferable to control the finish rolling temperature and the rolling reduction rate within the following ranges.

The rolling finish temperature is preferably 500 ° C. or higher and 900 ° C. or lower. This is because if the temperature is 500 ° C. or higher, the bondability of the clad steel sheet 100 can be sufficiently ensured, and if the temperature is 900 ° C. or lower, the strength and toughness of the base material plate 10 can be ensured.

The rolling reduction ratio is preferably 70% or more in total of all rolling passes from the viewpoint of improving the bondability of the clad steel sheet 100. The upper limit of the rolling reduction ratio is not particularly limited, but is preferably 95% or less in total of all rolling passes from the viewpoint of manufacturing cost. In the present embodiment, the number of rolling passes is not particularly limited as long as the total rolling ratio is within this range.

The method for producing a clad steel sheet and the equipment for producing a clad steel sheet of the present invention have been described above by taking the present embodiment as an example, but the present invention is not limited thereto.

In the above embodiment, the surface layer on the laminated material side of the assembly slab for rolling is heated after the first pass of hot rolling using the first rolling stand 2, and two passes using the second rolling stand 4. The case of performing before hot rolling of the eyes has been described. However, the hot rolling of the first pass using the first rolling stand 2 may be performed after heating the surface layer on the laminated material plate 12 side of the rolling assembly slab 20 carried out from the heating furnace 1. In this case as well, the effects of the present invention can be obtained.

The present invention can also be applied to a clad steel plate having a structure in which both sides of a base material plate are sandwiched between laminated material plates. In this case, from the viewpoint of suppressing the occurrence of warpage during hot rolling, it is preferable to heat the surface layer on both laminated boards.

For each of the invention examples and comparative examples, the component composition of C: 0.04% by mass, Si: 0.3% by mass, Mn: 1.3% by mass, P: 0.005% by mass, S: 0.0004% by mass. A base material plate having a plate thickness of 220 mm, the balance of which is Fe and unavoidable impurities, was prepared. Further, Ni: 59.2% by mass, C: 0.03% by mass, Cr: 21.8% by mass, Mo: 8.9% by mass, Fe: 5.0% by mass, Nb: 4.0% by mass, A laminated material plate having a component composition of Co: 1.0% by mass and a plate thickness of 30 mm in which the balance is an unavoidable impurity was prepared. Using these base material plates and laminated material plates, clad steel sheets were produced under the production conditions shown in Table 2. In Invention Examples 1 to 5 and Comparative Example 2 in which the plating layer was formed on the surface of the laminated material plate, the plating treatment was performed using a known watt bath. Here, in Invention Examples 2 to 5, using the manufacturing equipment shown in FIG. 2, L1 is 30 m, L2 is 15 m, and L3 is 15 m. The distance from the surface on the laminated material plate side was set to 100 cm. In Invention Example 1, the same manufacturing equipment as in Invention Examples 2 to 5 was used except that the first rolling stand was not provided. On the other hand, in Comparative Examples 1 and 2, the same manufacturing equipment as that shown in FIG. 2 was used except that the first rolling stand and the surface heating device were not provided. In Comparative Example 3, the same manufacturing equipment as that shown in FIG. 2 was used except that the first rolling stand was not provided. The "deformation resistance ratio" in Table 1 refers to the deformation resistance in the plate thickness direction of the base metal plate in the assembly slab for rolling immediately after being carried out from the surface heating device in Invention Examples 1 to 5 and Comparative Example 3. It means the ratio of the average value of the deformation resistance of the laminated material plate in the plate thickness direction to the average value. On the other hand, in Comparative Examples 1 and 2, the "deformation resistance ratio" is the average value of the deformation resistance in the plate thickness direction of the base metal plate in the assembly slab for rolling at the position L3 (= 15 m) from the second rolling stand. It means the ratio of the average value of the deformation resistance in the thickness direction of the laminated material plate to.

(Evaluation method)
For each invention example and comparative example, the bondability and warpage were evaluated by the following methods.

<Joinability>
For each of the invention examples and the comparative examples, the peeling on the joint surface of 500 clad steel sheets obtained by manufacturing the above-mentioned clad steel sheet 210 times was visually investigated, and the occurrence rate of the peeling was determined. The evaluation results are shown in Table 2. If the peeling rate is 1.0% or less, it can be evaluated that the bondability is high. Further, the average value of the maximum shear strength was obtained by performing a shear strength test specified in JIS G0601: 2012 on these clad steel sheets. That is, in each invention example and comparative example, a test piece having a size of 3 mm × 7 mm × 5 mm was collected from the tail end of each clad steel sheet so as to include the joint surface. Then, in this test piece, the laminated material plate was peeled off from the base material plate so as to be parallel to the joint surface, the maximum shear strength required at that time was measured, and the average value was obtained. The evaluation results are shown in Table 2. In Table 2, the average value of the maximum shear strength in each of the invention examples and the comparative example was standardized by the average value of the maximum shear strength in the comparative example 1.

<Warp>
For each of the invention examples and the comparative examples, the above-mentioned clad steel sheet was manufactured 100 times, and the warpage was evaluated by determining the occurrence rate of plate passing defects that occurred during hot rolling. The evaluation results are shown in Table 2. If the incidence of poor boarding is 1.0% or less, the yield will not decrease.

(Explanation of evaluation results)
As shown in Table 1, in Comparative Example 1, since the plating treatment and the surface layer heating were not performed, the occurrence rate of peeling and the occurrence rate of plate failure were high, and the bondability could be improved and the warpage could be suppressed. There wasn't. In Comparative Example 2, since the plating treatment was performed, the average value of the maximum shear strength was higher than that in Comparative Example 1, and although the occurrence rate of peeling could be suppressed, sufficient bondability could not be obtained. It was. In addition, since the surface layer was not heated, the incidence of plate failure could hardly be suppressed as compared with Comparative Example 1. In Comparative Example 3, the surface layer was heated, but the incidence of plate failure could hardly be suppressed as compared with Comparative Example 1.

On the other hand, in Invention Examples 1 to 5, since the surface layer was heated in addition to the plating treatment, the occurrence rate of plate passing defects could be suppressed. Even more surprisingly, in Invention Examples 1 to 5, the average value of the maximum shear strength was also improved as compared with Comparative Example 2 in which only the plating treatment was performed, and the occurrence rate of peeling could be suppressed. That is, it was found that by combining the plating treatment and the surface layer heating, not only the warp can be suppressed but also the bondability can be improved. It is considered that this is because Cr and Ni in the laminated material plate and Fe in the base material plate are diffused at the joint surface by the surface layer heating. Further, in Invention Examples 1, 2 and 4, since the surface layer was heated so that the deformation resistance ratio was 0.9 or more and 1.1 or less, the occurrence rate of plate failure was 0.0%, and the warpage The outbreak could be further suppressed. In addition, the average value of the maximum shear strength was further improved, the occurrence rate of peeling was 0.0%, and the bondability was further improved.

According to the present invention, a clad steel sheet having high bondability can be manufactured while suppressing the occurrence of warpage during hot rolling.

1 Heating furnace 2 1st rolling stand 3 Surface heating device 4 2nd rolling stand 10 Base plate 12 Laminated plate 14 Plating layer 20 Assembly slab for rolling 100 Clad steel plate

Claims (3)

In a method for manufacturing a clad steel sheet in which a base material plate made of carbon steel and a laminated material plate made of a nickel-based alloy are crimped together.
The first step of forming a nickel plating layer on the surface by plating the surface of the laminated material plate, and
After the first step, a second step of superimposing the base material plate and the laminated material plate via the nickel plating layer to prepare an assembly slab for rolling,
After the second step, the third step of heating the rolling assembly slab to a temperature range of 1100 ° C. or higher and 1200 ° C. or lower in a heating furnace, and
After the third step, hot rolling is performed on the rolling assembly slab carried out from the heating furnace without hot rolling or on the rolling assembly slab having a rolling reduction ratio of 5% or less. After performing once, the fourth step of heating the surface layer of the assembly slab for rolling on the laminated material plate side so as to raise the temperature by 35 ° C. to 75 ° C.
After the fourth step, a fifth step of hot rolling the rolling assembly slab into a clad steel sheet, and
A method for producing a clad steel sheet, which comprises. In the fourth step, the average value of the deformation resistance of the laminated material plate in the plate thickness direction is 0.9 times or more and 1.1 times or less of the average value of the deformation resistance of the base material plate in the plate thickness direction. The method for producing a clad steel sheet according to claim 1, wherein the surface layer of the laminated material plate is heated. Heating that heats an assembly slab for rolling produced by superimposing a base material plate made of carbon steel and a laminated material plate made of a nickel-based alloy via a nickel plating layer in a temperature range of 1100 ° C. or higher and 1200 ° C. or lower. Furnace and
A surface layer heating device arranged downstream of the heating furnace and heating the surface layer on the laminated material plate side of the rolling assembly slab so as to raise the temperature by 35 ° C. to 75 ° C.
A hot rolling mill located downstream of the surface heating device and hot rolling the rolling assembly slab into a clad steel sheet.
Equipped with a,
There is no additional hot rolling mill between the heating furnace and the surface heating device, or one heat for hot rolling with a rolling reduction ratio of 5% or less with respect to the rolling assembly slab. manufacturing facility clad plate, wherein Rukoto provided between the rolling mill.

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