JP6127669B2 - Manufacturing method of hot stamping molded product and manufacturing method of blank material - Google Patents

Description

  The present invention relates to a method for manufacturing a hot stamp molded article, and more specifically, a hot stamp molded article for manufacturing a hot stamp molded article by performing hot stamp molding using a blank material in which a plurality of metal plates are laminated. It relates to a manufacturing method.

  As disclosed in International Publication No. 2012/36261 (Patent Document 1), the body of an automobile includes a lightweight and highly rigid monocoque body (unit construction body).

  With reference to FIG. 1, the monocoque body 1 includes a plurality of constituent members 2 to 12. The components include, for example, a front side member 2, a bumper reinforcement 3, a front crash box 4, a front upper rail 5, a side sill 6, a floor cross member 7, a floor panel 8, a center pillar 9, a roof rail side 10, a rear side member 11, And a rear crash box 12 or the like.

  Among these structural members, structural members that require high strength include members in which a plurality of steel plates are stacked. For example, components such as a front side member and a center pillar include a hat-shaped member 13 and a closing plate 14 that is a flat plate, as shown in FIG. The hat-shaped member 13 and the closing plate 14 are joined by welding such as spot welding.

  The hat-shaped member 13 has a transverse shape on the hat side. The hat-shaped member 13 includes a main member 131 and a reinforcing member 132. The reinforcing member 132 is joined to the back surface of the main member 131 so as to cover the convex portion and the ridge line portion of the main member.

  As a method of manufacturing such a member 13, a main member 131 and a reinforcing member 132 are formed by processing each steel plate, and a method of manufacturing them by superimposing them, and a blank material in which steel plates are preliminarily stacked are produced, There is a method of manufacturing a member (main member 131 and reinforcing member 132) having a predetermined shape by integrally forming a blank material with a press.

  In the case of a manufacturing method by integral molding using a blank material, it is preferable to fix the stacked steel plates. As a method of fixing the stacked steel plates, a method of fixing the steel plates by spot welding has been proposed and used. However, when fixation by spot welding is performed, the strength of the constituent members after press molding may be low.

  Other fixing methods for steel plates of blank materials are disclosed in JP 2002-178069 (Patent Document 2), JP 2004-141913 (Patent Document 3), and JP 2011-88484 (Patent Document). 4).

  In Patent Document 2, a brazing material (hard solder) is disposed between stacked steel plates (plate assemblies). The plate assembly sandwiching the brazing material is heated to the molding temperature and hot press molded. After hot pressing, the brazing material is solidified by cooling the plate assembly in the mold. The plate assembly with the brazing material sandwiched is temporarily fixed by welding.

  In Patent Document 3, heating is performed by sandwiching a brazing material having a liquidus temperature of 700 ° C. or higher between blank steel plates made of a plurality of aluminum-plated steel plates. And the hot blank material is hot press-molded at a temperature not higher than the liquidus temperature of the brazing material.

  In patent document 4, after apply | coating a brazing material on the one steel plate for blank materials, a steel plate is heated and a brazing material is fuse | melted. Thereafter, another steel plate is placed on the brazing material to cool the brazing material. A blank material is manufactured by the above process.

International Publication No. 2012/36261 JP 2002-178069 A JP 2004-141913 A JP 2011-88484 A

  The blank material of the said patent documents 2-4 can be utilized also for the hot stamp shaping | molding which implements quenching within a metal mold | die while hot-pressing. However, when hot stamping is performed by the methods of Patent Documents 2 to 4, a gap that is not partially filled with brazing material remains between the stacked steel plates, and the strength and rigidity of the manufactured hot stamping product. May be low.

  The objective of this invention is providing the manufacturing method of the hot stamping molded article from which high intensity | strength is obtained.

  The method for manufacturing a hot stamped molded article according to the present embodiment includes a step of preparing a plate assembly in which a plurality of metal plates are laminated and a brazing material is disposed between adjacent metal plates, and the plate assembly is equal to or higher than the melting point of the brazing material. The process of heating at the above temperature, the process of producing a blank material by pressing the plate assembly in the thickness direction of the metal plate at a temperature equal to or higher than the melting point of the brazing material, and hot stamping the blank material A process.

  The manufacturing method according to the present embodiment can manufacture hot stamped molded articles having high strength.

FIG. 1 is a perspective view of a monocoque body of an automobile. FIG. 2 is a perspective view of an example of the structural member in FIG. FIG. 3 is a cross-sectional view of a plate set used in the method for manufacturing a hot stamped article according to the present embodiment. FIG. 4A is a process diagram in the initial stage of heating in the case where heating is performed while supporting a plate assembly on a support member. FIG. 4B is a process diagram in the latter stage of heating following FIG. 4A. FIG. 5A is a process diagram in the initial stage of heating in the case of heating a plate assembly arranged on a flat surface. FIG. 5B is a process diagram in the latter heating stage following FIG. 5A. FIG. 6A is a schematic diagram for explaining a pressurizing process for the plate assembly. FIG. 6B is a schematic diagram for explaining a heating process of the plate set shown in FIG. 6A. FIG. 7 is a schematic diagram for explaining a three-point bending test method. FIG. 8 is a diagram showing the relationship between the stroke amount (mm) of the impactor obtained by the three-point bending test and the load (kN) applied to the hot stamp molded product of each mark. FIG. 9 is a cross-sectional photograph of the mark 1 in the example after a three-point bending test. FIG. 10 is a cross-sectional photograph of the mark 3 in the example after a three-point bending test.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  The method for manufacturing a hot stamped molded product according to the present embodiment includes a step of preparing a plate assembly in which a plurality of metal plates are laminated and a brazing material is disposed between adjacent metal plates, and the plate assembly is equal to or higher than the melting point of the brazing material. A step of heating at a temperature, a step of pressing a plate assembly in the thickness direction of the metal plate at a temperature equal to or higher than the melting point of the brazing material, and a step of performing hot stamping on the blank material With.

  When a brazing material is applied between steel plates to form a blank material by the methods described in Patent Documents 2 to 4, a gap may be formed between the brazing material and the steel plate. That is, a region where the brazing material is not filled can be formed between the steel plates. Even if such a blank material is hot stamped, it is difficult to produce a hot stamped product having high strength due to the influence of the gap. The reason why such a gap is formed is that when the blank material is heated, the steel plate sandwiching the brazing material is deformed by heating, and a gap is formed between the steel plate and the brazing material.

  Therefore, in the manufacturing method of the present embodiment, a blank is manufactured by pressing the plate assembly during or after heating in the thickness direction of the metal plate at a temperature equal to or higher than the melting point of the brazing material. In this case, the brazing material and the metal plate are easily in close contact with each other, and the gap as described above is unlikely to occur. Therefore, the strength of the hot stamp molded product is increased.

  Preferably, in the step of performing hot stamping, hot stamping is started at a temperature below the freezing point of the brazing material.

  In this case, liquid phase brazing material can be suppressed during hot stamping. Therefore, it can suppress that metal plates shift | deviate by hot stamping. Furthermore, generation | occurrence | production of a liquid metal embrittlement crack can be suppressed.

  Preferably, the pressurizing step is performed during heating of the plate assembly, and in the pressurizing step, the plate assembly being heated is further pressurized.

  The metal plate of the plate set is likely to be deformed during the temperature rise. By pressurizing the plate assembly during the temperature rise, the deformation of the metal plate can be suppressed.

  The blank material by this Embodiment is manufactured according to the said process.

  Hereinafter, the manufacturing method of the hot stamping molded article by this Embodiment is explained in full detail. In the present embodiment, description will be made assuming a case where a structural member (hot stamp molded product) used for a front side member, a center pillar, or the like of an automobile is manufactured using a plate set in which two metal plates are stacked. . However, the manufacturing method according to the present embodiment may use a plate set in which three or more metal plates are laminated, and the shape of the hot stamp molded product is not particularly limited.

[Outline of manufacturing process]
As described above, the method for manufacturing a hot stamped molded product according to the present embodiment includes a step of preparing a plate assembly (preparation step), a step of heating the plate assembly (heating step), and pressurizing the plate assembly to obtain a blank material. And a step of performing hot stamp molding (hot stamp molding step). Hereinafter, each process is explained in full detail.

[Preparation process]
First, the plate set 100 shown in FIG. 3 is prepared. Referring to FIG. 3, plate set 100 includes a plurality of metal plates 101 and a brazing material 102. The plurality of metal plates 101 are stacked on each other, and the brazing material 102 is disposed between the adjacent metal plates 101. In FIG. 3, one of the two metal plates 101 is a metal plate for a main member, and the other is a metal plate for a reinforcing member.

[Metal plate 101]
The material and thickness of the metal plate 101 are not particularly limited. The hot stamp molded product manufactured in this embodiment requires high strength. Therefore, the metal plate 101 is, for example, a high-strength steel plate, and it is preferable that the chemical composition and other designs are made so as to obtain the required high strength after hot stamping. In hot stamping, quenching is performed during molding (inside the mold). Therefore, it is preferable that the hardenability of the metal plate 101 is high. That is, it is preferable that the metal plate 101 contains an element that enhances strength and hardenability.

  The metal plate 101 may be a plated steel plate. The plated steel sheet is, for example, a known zinc-based plated steel sheet or an aluminum-based plated steel sheet.

[Brazing material 102]
The brazing material 102 is a known brazing material. The brazing material 102 is, for example, a Cu—Sn based, Cu—Zn based, Ag—Cu based, Ni—P based, Ni—Cr—P based, Al—Si based brazing material or the like.

  The brazing material 102 is preferably solidified at the time of starting hot stamping. This is because liquid metal embrittlement cracking may occur if the liquid phase brazing material remains during hot stamping. In hot stamping, the metal plate 101 is quenched during forming, and therefore, the forming start temperature of hot stamping is usually equal to or higher than the Ms point of the metal plate 101. Therefore, the preferable freezing point of the brazing filler metal 102 is 700 ° C. or higher, more preferably 750 ° C. or higher.

  On the other hand, the heating temperature in the heating step is usually 800 to 1000 ° C., and is assumed to be 1200 ° C. in the highest case. At such a heating temperature, it is preferable that the brazing filler metal 102 is melted and hardly evaporated.

  The brazing material 102 satisfying the above conditions is, for example, a Cu—Sn based, Cu—Zn based, Ag—Cu based, Ni—P based, and Ni—Cr—P based brazing material.

[Plate assembly manufacturing process]
The plate assembly 100 is manufactured by the following method. A plurality of metal plates 101 are overlapped with the brazing material 102 interposed therebetween. At this time, the liquid brazing material 102 may be applied onto the surface of the metal plate 101 using a spray or the like, or the solid brazing material 102 may be disposed on the surface of the metal plate 101.

  After overlapping the metal plates 101 with the brazing material 102 interposed therebetween, welding may be performed on the metal plates 101. The welding is typically spot welding, and may be laser welding, TIG welding, seam welding, or the like. In this case, the positions of the metal plates 101 are fixed, and the degree of adhesion between the metal plates 101 is increased.

  Each metal plate 101 may have the same chemical composition and thickness, or may have different chemical composition and / or thickness. The shape of each metal plate 101 may not be the same. For example, when the hot stamp molded product is a center pillar, the metal plate 101 serving as the main member may be mild steel, and the metal plate 101 serving as the reinforcing member may be a high strength steel plate having a thickness different from that of the main member. In this case, the metal plate 101 serving as the reinforcing member overlaps a part of the surface of the metal plate 101 serving as the main member. In short, the combination of the plurality of metal plates 101 in the plate set 100 may be selected depending on the required application and performance.

  The thickness of the brazing material 102 in the plate assembly 100 is not particularly limited. A preferable thickness of the brazing material 102 is 0.03 to 0.15 mm.

[Heating process]
The prepared plate assembly 100 is heated to a temperature equal to or higher than the melting point of the brazing material 102. In the heating step, the brazing material 102 is melted, and the plate assembly 100 is heated to a temperature sufficient for hot stamping. A preferred lower limit of the heating temperature is _{A 3} point or 800 ° C. of the metal plate 101, the upper limit of the preferred heating temperature is 1000 ° C..

  The heating method is not particularly limited. The plate assembly 100 may be heated using a heating furnace, or the plate assembly 100 may be heated by energization heating or induction heating. The kind of heating furnace is not particularly limited, and may be an electric furnace or a gas furnace.

[Pressure process]
In the heating step, the metal plate 101 of the plate assembly 100 is partially deformed by heating. For example, when a plate assembly 100 is placed on a support member 160 (for example, a walking beam) and heated using a walking beam type or batch type heating furnace as shown in FIG. 4A, as shown in FIG. 4B. The metal plate 101 portion between the support members 160 is deformed and bent downward. At this time, a gap 140 is formed between the metal plate 101 and the brazing material 102.

  Similarly, referring to FIG. 5A, when the plate assembly 100 is arranged and heated on a flat surface like a conveyor-type heating furnace, as shown in FIG. The edge is deformed and warped. As a result, a gap 140 is formed between the metal plate 101 and the brazing material 102 at the end of the plate assembly 100.

  If the plate assembly 100 with such a gap 140 left is hot stamped, a gap remains in the hot stamped product, and it is difficult to obtain high strength.

  Therefore, in this embodiment, pressure is applied in the direction of the thick plate of the metal plate 101 to the plate assembly during or after heating. By pressurizing, the gap 140 between the metal plate 101 and the brazing material 102 can be suppressed, and the brazing material 102 is filled between the metal plates 101.

  There are various pressurization methods. For example, as shown in FIG. 6A, the support plate 200 is disposed below the plate assembly 100, and the pressing plate 300 is disposed above the plate assembly 100. Then, as shown in FIG. 6B, the plate assembly 100 sandwiched between the pressing plate 300 and the support plate 200 is heated in a heating furnace 400. At this time, the plate assembly 100 is pressurized with the pressure P by the weight of the pressing plate 300. By this pressurization, deformation of the metal plate 101 in the plate assembly 100 is restrained. Therefore, in the plate assembly 100 after heating, the gap 140 is hardly formed between the metal plate 101 and the brazing material 102, and the metal plates 101 are in close contact with the brazing material 102.

  In this example, the assembled plate 100 being heated is pressed by the presser plate 300 and the support plate 200. The metal plate 101 of the assembled plate 100 is easily deformed during the temperature rise. If the assembled plate 100 is heated, the deformation of the metal plate 101 is suppressed, and as a result, the gap 140 is not easily generated.

The support plate 200 and the presser plate 300 are not particularly limited as long as they have sufficient strength and / or thickness to suppress deformation of the metal plate 101 during heating. The preferable average load with respect to the metal plate 101 at the time of pressurization is 1.0 × 10 ^{−3 to} 1.0 MPa. Therefore, it is preferable that the pressing plate 300 has a weight that can apply the average load to the metal plate 101.

  When the plate assembly 100 is heated in the heating furnace 400 using the support plate 200 and the presser plate 300, the support plate 200 and the presser plate 300 shield the heat, and thus the temperature of the plate assembly 100 may be difficult to increase. . Therefore, the support plate 200 and the presser plate 300 may have a thin plate thickness or a lattice-like or net-like structure within a range in which strength sufficient to prevent deformation during heating can be secured.

  The plate assembly 100 sandwiched between the holding plate 300 and the support plate 200 is extracted from the heating furnace. The blank material 150 is manufactured by the above process.

[Hot stamp molding process]
The blank material 150 extracted from the heating furnace is conveyed to a hot stamp forming apparatus. Although the support plate 200 is removed when the blank material 150 is transported, the presser plate 300 may be transported while being covered on the blank material 150. In this case, the further temperature fall of the blank material 150 can be suppressed.

  Preferably, after the temperature of the plate assembly 100 becomes lower than the freezing point of the brazing material 102, the holding plate 300 and the support plate 200 are removed. In this case, since the brazing material 102 becomes a solid phase, the gap 140 is hardly formed between the metal plate 101 and the brazing material 102.

  In consideration of productivity, it is preferable to remove the pressing plate 300 at a time as late as possible after the heating process until the blank material 150 is arranged in the hot stamp forming apparatus. It is further preferable to remove the pressing plate 300 from the blank material 150 immediately before placing 150.

  After conveyance, the pressing plate 300 is removed and the blank material 150 is placed on a mold in the hot stamping apparatus. And hot stamp molding is implemented with respect to the blank material 150, and a hot stamp molded product is manufactured. In this case, a hot stamp molded product having high strength can be manufactured.

  The temperature of the blank 150 at the start of hot stamping (hereinafter referred to as forming start temperature) is equal to or higher than the Ms point of the metal plate 101. In this case, the metal plate 101 is effectively quenched during hot stamping. On the other hand, the preferable upper limit of the molding start temperature is less than the freezing point of the brazing material 102. In this case, the brazing filler metal 102 is a solid phase during hot stamping. Therefore, liquid metal embrittlement cracking is unlikely to occur.

[Other embodiments]
In the above-described embodiment, the pressing step is performed during the heating step using the presser plate 300 and the support plate 200. However, you may implement a pressurization process by another method.

  For example, a press device may be provided in the vicinity of the extraction port in the heating furnace. In this case, the plate assembly 100 is heated without using the pressing plate 300 and the support plate 200. Then, in the vicinity of the extraction port of the heating furnace immediately before the end of the heating process, the plate assembly 100 is pressed in the plate thickness direction by a press device. Although the metal plate 101 may be deformed by heating, the metal plate 101 and the brazing filler metal 102 are brought into close contact with each other and the gap 140 is suppressed by the press processing by the press device.

  Further, a pressing device may be provided separately from the heating furnace. In this case, the plate assembly 100 is heated without using the presser plate 300 and the support plate 200. Then, the blank set 150 is manufactured by pressing the plate set 100 extracted from the heating furnace in the plate thickness direction using a press device. In this case, the temperature of the blank material 150 after press working may be excessively lowered. Therefore, even if hot stamping is performed after the blank material 150 after press working is heated for a short time by energization heating or induction heating to raise the temperature of the blank material 150 to the Ms point or more of the metal plate 101. Good.

  As described above, the pressurizing step may be performed during the heating step, or may be performed after the heating step and before the hot stamping step.

  The blank material 150 manufactured by the above-described manufacturing method can be used for press processing other than hot stamping. Even if the blank material 150 is used for other press processing, the processed metal plates 101 are difficult to peel off. Therefore, the product after processing has high strength.

  A set of marks 1 to 5 shown in Table 1 was prepared.

  For each mark, two cold-rolled steel plates (HS steel plates) of the same steel type were used. It was used. The steel plate for the main member (hereinafter referred to as the main steel plate) was 595 mm long × 225 mm wide × 1.2 mm thick. A steel plate for a reinforcing member (hereinafter referred to as a reinforcing steel plate) was 595 mm long × 170 mm wide × 1.4 mm thick. For both the main steel plate and the auxiliary steel plate, the tensile strength before hot stamping was about 600 to 700 MPa, and the tensile strength after hot stamping was 1500 MPa.

  The brazing material was bronze brazing, the Sn content was 20% by mass, and the balance was Cu and impurities. The liquidus temperature (melting point) of the brazing material was 925 ° C., and the solidification temperature was 770 ° C. The brazing material was in the form of a sheet and the thickness was 30 μm.

[About Mark 1]
The plate set of the mark 1 includes the main steel plate and the reinforcing steel plate, and further includes a brazing material disposed between the main steel plate and the reinforcing steel plate. As shown in Table 1, in the plate set of mark 1, spot welding was performed on the surfaces of the main steel plate and the reinforcing steel plate, and temporarily fixed at two locations.

  As shown in FIG. 6A, the plate assembly of the mark 1 was inserted between the support plate and the holding plate and charged into the heating furnace. Both the chemical composition of the support plate and the pressing plate corresponded to SUS304, the thickness of the supporting plate was 6 mm, and the thickness of the pressing plate was 9 mm.

The furnace atmosphere of the heating furnace was a reducing atmosphere, and the furnace temperature was 1000 ° C. In the mark 1, the in-furnace time was set to 15 minutes because the plate assembly was pressurized using the support plate and the holding plate. The load applied to the plate assembly during heating was 7 × 10 ⁻⁴ MPa. A plate assembly sandwiched between the support plate and the holding plate was extracted from the heating furnace, and cooled (cooled) to less than 770 ° C. to obtain a blank material.

  Subsequently, hot stamp molding was performed on the blank material, and a hot stamp molded product 500 as a hat-shaped component shown in FIG. 7 was manufactured. The molding start temperature during hot stamping was 700 ° C.

[About Mark 2 to Mark 5]
In the plate assembly of mark 2, as shown in Table 1, spot welding was performed at 60 locations on the surface of the plate assembly. Other configurations were the same as those of the mark 1 plate assembly.

  The plate set of the mark 2 was heated and pressed under the same conditions as the mark 1 to perform hot stamping.

  For mark 3, the same plate set as mark 1 was used. However, in the mark 3, the pressurizing process was not performed on the plate assembly. That is, the plate assembly was inserted into a heating furnace and heated without sandwiching the plate assembly between the support plate and the pressing plate. The in-furnace time was 10 minutes. Other heating conditions and hot stamping conditions were the same as those for mark 1.

  In the mark 4, a plate assembly sandwiching the brazing material was prepared, but spot welding was not performed on the plate assembly. Other manufacturing conditions were the same as those for mark 3.

  The plate assembly of the mark 5 did not include brazing material, and spot welding was performed at 60 locations on the plate assembly surface. Other manufacturing conditions were the same as those for mark 3. Further, the spot welding conditions and position were the same as those of the mark 2.

[Three point bending test]
As shown in FIG. 7, a hot stamp molded product 500 of each mark was welded to a closing plate 503 to manufacture a constituent member. The closing plate 503 is a cold-rolled steel plate having a tensile strength of 780 MPa, and has a thickness of 1.8 mm, a length of 595 mm, and a width of 150 mm.

  A three-point bending test shown in FIG. 7 was performed on the constituent members of each mark. Between the impactor 600 and a pair of support members (support points) 601, the constituent members of the respective marks were arranged. At this time, the convex portion 501 of the hot stamp molded product 500 was in contact with the impactor 600, and the closing plate 503 joined to the flange portion 502 was in contact with the pair of support members 601.

  The radius of curvature R1 of the impactor 600 was 150 mm. The distance between the support points (the distance between the central portions of the support member 601) D0 was 500 mm, and the radius of curvature R0 of the support point of the support member 601 was 30 mm. The impactor 600 was lowered at a crushing speed of 0.25 mm / sec, and the load (kN) applied to the hot stamped molded product 500 was measured. The maximum stroke amount of the impactor 600 was 50 mm.

[Cross-section observation test after three-point bending test]
The cross section of the hat-shaped member of each mark after the three-point bending test was visually observed, and it was determined whether or not the main steel plate and the reinforcing steel plate were maintained joined.

[Test results]
FIG. 8 is a diagram showing the relationship between the stroke amount (mm) of the impactor 600 at each mark and the load (kN) applied to the hot stamping molded product 500 obtained by the three-point bending test. 9 is a cross-sectional photograph of the hat-shaped member of the mark 1 after the three-point bending test, and FIG. 10 is a cross-sectional photograph of the hat-shaped member of the mark 3 after the three-point bending test.

  A curve M1 in FIG. 8 shows the test result of the mark 1. Similarly, curves M2 to M5 indicate the test results of marks 2 to 5, respectively. Referring to FIG. 8, mark 1 and mark 2, which are examples of the present invention, had a high maximum load and exceeded 60 kN. On the other hand, in Marks 3 to 5 as comparative examples, the maximum load was less than 60 kN.

  In addition, an increase in load (inclination of curves M1 to M5 in this region) in the range where the stroke amount of the three-point bending test is 0 to 5 mm (that is, during elastic deformation) is an indicator of the bending stiffness of the hot stamped product of each mark To do. The inclination of the mark 1 and the mark 2 in this region in FIG. 8 is larger than the inclination of the other marks 3 to 5, and the hat-shaped members of the mark 1 and the mark 2 showed excellent rigidity.

  Referring to the cross section of mark 1 after the three-point bending test (FIG. 9) and the cross section of mark 3 (FIG. 10), the main steel plate and the reinforcing steel plate are in close contact with each other even after the three-point bending test. The same applies to Mark 2. On the other hand, in the mark 3, the main steel plate and the reinforcing steel plate are separated at the corner, and the same applies to the mark 4 and the mark 5. In marks 3 to 5, it was considered that the steel plates were peeled off after the three-point bending test because gaps remained in the blank.

  While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and can be implemented by appropriately modifying the above-described embodiment without departing from the spirit thereof.

100 plate assembly 101 metal plate 102 brazing material

Claims (4)

A step in which a plurality of hot stamping steel plate are laminated, to prepare a plate sets the brazing material to the steel plates are disposed adjacent,
Heating the plate assembly at a temperature equal to or higher than the melting point of the brazing material;
Wherein at a temperature above the melting point of the brazing material, the plate set in the heated pressurized in the thickness direction of the steel plate by heating, the step of producing a blank,
And a step of performing hot stamp molding on the blank material. The manufacturing method according to claim 1,
In the step of performing the hot stamp molding, the hot stamp molding is started at a temperature lower than the freezing point of the brazing material. The manufacturing method according to claim 1 or 2 ,
The said pressurizing process is implemented while heating the said board assembly, The load applied to the said board assembly at the time of the said pressurization is 1.0 * 10 < ^-3 > -1.0MPa. A step in which a plurality of hot stamping steel plate are laminated, to prepare a plate sets the brazing material to the steel plates are disposed adjacent,
Heating the plate assembly at a temperature equal to or higher than the melting point of the brazing material;
Wherein at a temperature above the melting point of the brazing material, and a step of pressurizing the plate set in the raised in the thickness direction of the steel plate by heating, the production method of the blank for hot stamping.