JP2000153325A - Clad die for hot press and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve high temp. softening resistance and wear resistance of a die by using a powder tool steel made of a specified composition for an engraving face material, using a hot tool steel, which has a specified composition and is made of melting or powder, for a die base material, cladding the engraving face material and a base material with HIP (hot static pressure compression) and using at the state subjected to the HIP treatment. SOLUTION: The powder tool steel, which has, by weight, an essential composition of 0.7-2.5% C, <=2.0% Si, <=1.5% Mn, 3.0-6.0% Cr, a first selection composition of 3.0-10.0% Mo, 1.0-20.0% W, a second selection composition of 0.8-25.0% V, 0.1-5.0% Nb and the balance Fe, is used for an engraving face material of a die, the hot tool steel made of melting or powder, which contains, by weight, 0.1-0.55% C, <=1.2% Si, 0.3-2.0% Mn, 0.3-2.0% Ni, 1.0-4.0% Cr, 0.2-3.0% Mo, 0.4-6.0% W, further, 0.05-0.7% V, 0.01-0.15% and the balance Fe, is used for a metal base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clad mold for hot pressing and a method for manufacturing the same, which improves the life of the mold.

[0002]

2. Description of the Related Art Conventionally, in order to prolong the life of a hot-pressing die, tool improvements such as resistance to high-temperature softening and abrasion resistance of tool steel for a hot-pressing die have been made. With such improvement, the life of the mold is improved by 10 to 20%, and at most about 50%. However, the tool steel used for the hot press mold has a problem that the contact with the non-forged material (a billet) does not occur. As a result, the surface thereof rises to a high temperature of 600 to 650 ° C., causing damage such as abrasion due to heat softening, so that a dramatic improvement in service life cannot be expected.

[0003]

In order to suppress the above-mentioned mold wear, for example, as shown in JP-A-6-23448, a cladding material having excellent resistance to high-temperature softening and wear. However, since overlay welding tends to cause welding defects and multi-layer welding tends to cause welding cracks, the life of the overlay welding mold is not necessarily limited. It cannot be improved. Also,
As shown in JP-A-5-269538,
Nickel-based or cobalt-based alloy on the surface of tool steel
P diffusion bonding is performed, and a nickel-based or cobalt-based alloy is provided to a mold as a die-sculpture surface. Tool steels listed in the examples include JIS-standard SKT4, SKD61,
It is indicated that SKD62 or its improved material is used.

However, in SKD61 and SKD62, Cr is used.
Since the content is high, the hardenability is good, and the hardness becomes 45 HRC or more even in the slow cooling by the HIP treatment, and the workability is poor and the HIP treatment cannot be used as it is.
Actually, in this embodiment, quenching and tempering are performed, and re-heat treatment is required, so that economic efficiency is poor. In addition, the entire mold is made of a nickel-based or cobalt-based alloy. In this case, the abrasion resistance is excellent, but the nickel-based or cobalt-based alloy has low toughness, so the impact resistance is low and the mold is large. There is a problem that there is a risk of cracking. The present invention has been made in order to solve the above-mentioned problems, and by using powder tool steel having excellent resistance to high-temperature softening resistance and abrasion resistance as a mold surface material, high-temperature softening resistance of a mold for hot pressing. It is an object of the present invention to provide a clad mold for hot pressing and a method for manufacturing the same, which can improve the resistance and wear resistance and improve the life of the mold.

[0005]

In order to achieve the above object, a clad mold for hot pressing and a method of manufacturing the same according to the present invention are as follows: (1) C: 0.7 to 2.5% by weight% , Si: 2.0
%, Mn: 1.5% or less, Cr: 3.0 to 6.0
%, An essential component of Mo: 3.0 to 10.0%, and W: 1.0 to 20.0%, or a first selected component of both, and V: 0.8 to 25. 0% and Nb:
Powder tool steel composed of 0.1 to 5.0% of one or both of the second selected components and the balance of Fe and unavoidable impurities is used as a die surface material of a mold.
0.1 to 0.55%, Si: 1.2% or less, Mn: 0.
3 to 2.0%, Ni: 0.3 to 2.0%, Cr: 1.0
To 4.0%, and Mo: 0.2 to 3.0%, W:
One or more of 0.4 to 6.0% (Mo and W are
(1 / 2W + Mo: 0.2-3.0%), V: 0.05-0.7%, Nb: 0.01-0.1
A molten or powdered hot work tool steel containing 5% of one or more kinds and the balance of Fe and unavoidable impurities was used as a mold base material, and these mold surface materials and base materials were HIP (heat A clad mold for hot pressing, characterized in that it is clad by hot isostatic pressing and used as it is after HIP treatment.

(2) C: 0.7 to 2.5% by weight,
Si: 2.0% or less, Mn: 1.5% or less, Cr: 3.
0 to 6.0% of essential components, and Mo: 3.0 to 10.0.
%, And W: any one or both of 1.0 to 20.0% of the first selected component, V: 0.8 to 25.0%, and Nb: any of 0.1 to 5.0%. Powder tool steel consisting of one or both of the second selected components and the balance of Fe and unavoidable impurities is used as a die surface material of the mold, and also in the same weight%, C: 0.1 to 0.55%, Si : 1.2% or less,
Mn: 0.3-2.0%, Ni: 0.3-2.0%, C
r: 1.0 to 4.0% and Mo: 0.2 to 3.0
%, W: 0.4 to 6.0%, or two or more (Mo and W
Contains 1 / 2W + Mo: 0.2-3.0%), V: 0.05-0.7%, Nb: 0.01-0.
One or more of 15% and Co: 0.2 to 3.0
%, With the balance being Fe and unavoidable impurities, a molten or powdered hot work tool steel is used as a mold base material, which is formed by cladding the mold surface material and the base material by hot isostatic pressing (HIP). A clad mold for hot pressing, characterized in that the clad mold is used as it is after being HIPed.

(3) C: 0.7-2.5% by weight,
Si: 2.0% or less, Mn: 1.5% or less, Cr: 3.
0 to 6.0% of essential components, and Mo: 3.0 to 10.0.
%, And W: any one or both of 1.0 to 20.0% of the first selected component, V: 0.8 to 25.0%, and Nb: any of 0.1 to 5.0%. Powder tool steel containing one or both of the second selected components and 4.0 to 12.0% of Co and the balance of Fe and unavoidable impurities is used as a die surface material of a mold, and is similarly weight%. And C: 0.
1 to 0.55%, Si: 1.2% or less, Mn: 0.3 to
2.0%, Ni: 0.3 to 2.0%, Cr: 1.0 to
4.0%, Mo: 0.2-3.0%, W: 0.
4 to 6.0% of one or more kinds (Mo and W are 1 /
2W + Mo: 0.2-3.0%).
V: 0.05-0.7%, Nb: 0.01-0.15%
A molten or powdered hot work tool steel containing one or more of the following, and the balance being Fe and unavoidable impurities, is used as a mold base material. A clad mold for hot pressing, characterized in that it is clad by hydrostatic pressure compression and used as it is after HIP treatment.

(4) C: 0.7-2.5% by weight,
Si: 2.0% or less, Mn: 1.5% or less, Cr: 3.
0 to 6.0% of essential components, and Mo: 3.0 to 10.0.
%, And W: any one or both of 1.0 to 20.0% of the first selected component, V: 0.8 to 25.0%, and Nb: any of 0.1 to 5.0%. Powder tool steel containing one or both of the second selected components and 4.0 to 12.0% of Co and the balance of Fe and unavoidable impurities is used as a die surface material of a mold, and is similarly weight%. And C: 0.
1 to 0.55%, Si: 1.2% or less, Mn: 0.3 to
2.0%, Ni: 0.3 to 2.0%, Cr: 1.0 to
4.0%, Mo: 0.2-3.0%, W: 0.
4 to 6.0% of one or more kinds (Mo and W are 1 /
2W + Mo: 0.2-3.0%).
V: 0.05-0.7%, Nb: 0.01-0.15%
A molten or powdered hot work tool steel containing one or more of the following and Co: 0.2 to 3.0%, the balance being Fe and unavoidable impurities is used as a mold base material, A clad mold for hot pressing, characterized in that a mold surface material and a base material are clad by HIP (Hot Isostatic Pressing) and used as they are after HIP treatment.

(5) When clad the die-sculpture material and the base material described in the above (1) to (4), the die-sculpture material corresponds to a surface portion of the mold, that is, a portion which is severely damaged by wear. The method for manufacturing a clad mold for hot pressing is characterized in that the thickness of the die surface material is designed so as to be a part and the inner part, that is, the concave part of the mold becomes a base material part.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The reasons for limiting the various components of the engraved face material in the present invention will be described below. C: 0.7 to 2.5% C is Cr, V, Mo, W and N which contribute to wear resistance.
b is indispensable for carbide formation, and must be added in an amount of at least 0.7% in order to form a solid solution in the matrix and give sufficient hardness, but if it exceeds 2.5%, the hardness after HIP becomes too high. As a result, the workability is deteriorated, so that it is impossible to use the HIP process as it is. Therefore, the component range of C is set to 0.7 to 2.5%. Si: 2.0% or less Si is mainly added as a deoxidizing agent, but if added in excess of 2.0%, toughness is deteriorated. Therefore, the component range of Si is set to 2.0% or less.

Mn: 1.5% or less Mn is added as a deoxidizing agent similarly to Si.
If added in excess of 5%, the toughness decreases. Therefore, Mn
Is 1.5% or less. Cr: 3.0 to 6.0% Cr needs to be at least 3.0% in order to obtain sufficient wear resistance. However, Cr carbide is liable to agglomerate and coarse.
It is not preferable to add more than 6.0%. Therefore, the component range of Cr is set to 3.0 to 6.0%.

V: 0.8 to 25.0% V forms a stable MC-type carbide which is hard to form a solid solution, serves to refine crystal grains to improve toughness and markedly improves wear resistance. . If it is less than 0.8%, the effect of improving wear resistance is small, and if it exceeds 25%, a giant eutectic carbide is formed and the toughness is deteriorated. Therefore, the component range of V is 0.
8 to 25.0%.

Mo: 3.0 to 10.0%, W: 1.0 to 20.0% Mo and W both form fine carbides and improve wear resistance. Is larger and has about twice the influence of W. Mo has high hardenability as well as wear resistance. To obtain these effects, at least 3.0% is required, but if it exceeds 10.0%, carbides become coarse.
W is at least 1. to improve abrasion resistance.
Although 0% is required, carbide is less likely to be coarser than Mo, so the upper limit was set to twice Mo.

Co: 4.0-12.0% Co is added according to the purpose in order to improve heat resistance. Co forms a solid solution in the matrix, suppresses the coarsening of carbides, and increases the softening resistance during tempering. To obtain this effect, at least 4.0% is required, but 1%
Even if added in excess of 2.0%, the effect does not increase. Therefore, the component range of Co is set to 4.0 to 12.0%. Nb: 0.1 to 5.0% Nb is added to improve toughness. Nb forms stable carbides and prevents coarsening of crystal grains,
If it is less than 0.1%, the effect is not exhibited, and if it exceeds 5.0%, the softening resistance at the time of tempering is lowered and the toughness is deteriorated. Therefore, the component range of Nb is set to 0.1 to 5.0%.

Next, the reasons for limiting various components of the mold base material in the present invention will be described. C: 0.1 to 0.55% C is an element necessary for maintaining hardenability and high-temperature hardness, and combines with Cr, V, Mo, W, Nb and the like to form carbides, It is an element necessary for obtaining a crystal grain refining effect, abrasion resistance and the like. If it is less than 0.1%, a minimum hardness as a mold cannot be obtained, and if it exceeds 0.55%, excessive precipitation of carbides is caused to deteriorate toughness.
Even after high-temperature heating and slow cooling by HIP, the hardness exceeds HRC45 and machining such as cutting becomes difficult.
It is possible to use the HIP processing which is a feature of the present invention as it is. Therefore, the component range of C is set to 0.1 to 0.55%.

Si: 1.2% or less Si has a solid solution in the matrix to increase matrix strength and has an effect of deoxidation. However, if added in excess of 1.2%, toughness deteriorates. Was set to 1.2% or less. Mn: 0.3 to 2.0% Mn is an element necessary for improving the hardenability and obtaining the hardness required for the mold base material. Since the effect is saturated when it is small and exceeds 2.0%, Mn is set to 0.3 to 2.0%.

Cr: 1.0 to 4.0% Cr is an element that improves hardenability and combines with C to form a hard carbide and contributes to wear resistance. 1.0
%, The above effect cannot be obtained. If it exceeds 4.0%, the hardness exceeds HRC45 even after high-temperature heating and slow cooling, making it impossible to use the HIP treatment as it is. Therefore, Cr was set to 1.0 to 4.0%. V: 0.05 to 0.7% V is an element that forms a carbide that hardly forms a solid solution and improves wear resistance and softening resistance. In order to obtain an improvement in wear resistance, at least 0.05% is necessary, and if added over 0.7%, the toughness is reduced.
0.7%.

Ni: 0.3 to 2.0% Ni is an element that enhances the toughness of the matrix itself.
At least 0.3% is necessary, but if added over 2.0%, the effect is saturated, so that Ni should be 0.3 to 0.3%.
2.0%. Co: 0.2 to 3.0% Co is an element that suppresses carbide agglomeration at a high temperature and is particularly effective for softening resistance. To obtain these effects, at least 0.2% is required, and if added over 3.0%, the toughness is reduced.
0%.

Mo: 0.2-3.0%, W: 0.4-
6.0% of one or two types (1/2 W + M in the case of two types)
(o: 0.2 to 3.0%) Mo and W are both elements that form fine carbides and improve wear resistance and softening resistance. The effect is Mo
Is twice as strong as W and W is Mo to achieve the same effect.
Is twice as much as If both elements are added in too large amounts, the toughness and the heat check resistance are deteriorated.
The equivalent (1 / 2W + Mo) was 3%. Further, in order to obtain the above effects, at least Mo equivalent is required to be 0.2%. Therefore, Mo equivalent (1 / 2W + Mo) is 0.2
３3.0%.

Hereinafter, a clad mold for hot pressing and a method of manufacturing the same according to the present invention will be described. FIG. 1 shows diffusion welding of powdered or fused tool steel, which is a base material of a mold of the present invention, and powdered tool steel, which is excellent in high-temperature softening resistance and wear resistance, as a die surface material. FIG. 3 is a view showing a method for HIP, in which 3 is a can for HIP using a mild steel plate. Reference numeral 1 denotes a melted or powdered tool steel constituting a base material of a mold. Two melted or powdered tool steels 1 are installed in a HIP can 3, and a powdered tool steel 2 of powdered tool steel is placed therebetween.
Fill. At this time, when divided in the final step, the width of filling the powder material 2, that is, two pieces of the melted or powdered tool steel, so that the die face material corresponds only to the portion where the damage due to wear becomes severe. 1 gap is installed. After filling, after degassing by vacuum heating from the degassing can 4, the degassing tube 4 is sealed and heated and pressurized by HIP. HIP is pressurized 100
0 to 2000 kgf / cm ² , heating temperature 1000 to 12
It is performed under the condition of 00 ° C., and thereafter, it is gradually cooled. After the HIP treatment, the powder material 2 is sufficiently densified and is diffusion-bonded to the molten or powdered tool steel 1. Thereafter, the HIP can 3 is removed by machining.

FIG. 2 shows a state in which the HIP can 3 has been removed after the HIP processing. By cutting the central part of the powder material in the figure by electric discharge machining, the base material as shown in FIG. 3 is made of molten or powdered tool steel, and the high-temperature softening resistance and abrasion resistance are formed on the mold surface. In this case, two molds for hot pressing in which powder tool steel excellent in cladding are clad are manufactured, and the surface of the powder tool steel 2 is engraved by electric discharge machining or cutting to be forged.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The features of the present invention will be described below with reference to embodiments. Table 1 shows the chemical components of the test mold. Inventive mold A is manufactured by the manufacturing method of the present invention, using powder tool steel for the mold surface and ingot of hot tool steel for the base metal. The comparative mold B is not a clad mold but a quenched and tempered single-piece ingot tool steel SKD61, which is a tool steel conventionally used for a hot press mold. Table 2 shows the hardness of the invention mold A after the HIP treatment. From the same table, the hardness of the mold of the invention is not less than HRC38 enough to be used as a hot press mold. HRC45 that can be easily cut in engraving
I have the following.

[0023]

[Table 1]

[0024]

[Table 2]

Next, FIG. 4 shows the high-temperature softening characteristics of the powder material portion serving as the die-sculpture surface of the inventive mold A in the HIP state and the comparative mold B. For the test, 5m from each part
A test piece of mx 5 mm x 20 mm was sampled, held at 600 ° C for each hour, and then cooled and air-cooled. The hardness was measured and evaluated. Is lower than SKD61 (Comparative mold B), but the degree of softening is small even after holding for a long time, and the hardness becomes higher than Comparative mold B when the holding time exceeds 10 hours. It is clear that even when used in a hot press mold whose surface is heated to 600 ° C. or higher, damage due to settling and abrasion of the mold surface due to high temperature softening is suppressed as compared with the conventional mold. .

FIG. 5 shows the results of a JIS No. 3 Charpy test specimen taken from each part of the base material of the invention mold A and the comparative mold B (SKD61) and subjected to an impact test. The mold is usually preheated prior to use, and at 200 ° C., the approximate internal temperature when preheated, the invention mold A
The toughness of the base material tool steel is superior to that of SKD61, which is a comparative mold, and the mold base material has sufficient toughness.

As described above, in the powder tool steel excellent in resistance to high-temperature softening and abrasion resistance used in the die face material of the present invention, the concave portions of the mold have sufficient concave portions even after high-temperature heating and slow cooling by HIP. Since the thickness of the die face material is designed to be a tough base material portion, it is possible to suppress large cracks from the concave portion of the mold, and a further improvement in life can be expected.
Thus, as compared with the conventional method, the present invention is different in that the component design is made so that a less expensive powdered tool steel can be used as it is in the HIP processing, The life is improved by designing the thickness.

[0028]

As described above, according to the present invention, there is provided a method of manufacturing a die for hot press which is very economical in view of both improvement of die life and reduction of die manufacturing cost. Is possible. Also, as in the invention molds described in the examples, by appropriately selecting the material for both the engraved surface and the base material, the HIP is performed without heat treatment such as quenching and tempering after the HIP treatment.
It is possible to manufacture a hot press die that can be used as it is, and it is possible to further reduce the die manufacturing cost and shorten the delivery time by omitting the heat treatment step.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for diffusion bonding tool steel and powder material according to the present invention.

FIG. 2 is a view showing a state in which a HIP can has been removed after HIP processing.

FIG. 3 is a perspective view of a hot press mold in which tool steel serving as a base material of a mold and powder tool steel serving as a mold surface material are diffusion bonded by HIP.

FIG. 4 is a view showing the high-temperature softening characteristics of a powder material portion serving as a die engraving surface of a mold A of the present invention and a comparative mold B.

FIG. 5 shows a base material of a mold A of the present invention and a comparative mold B (SKD).
FIG. 61 is a diagram showing the Charpy impact characteristics of No. 61).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molten or powder tool steel 2 Powder tool steel 3 HIP can 4 Degassing pipe

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B22F 7/06 B23K 20/00 310L 7/08 C22C 38/00 301H B23K 20/00 302E 310 38/26 C22C 38/00 301 38/30 302 38/48 38/26 38/52 38/30 B22F 3/14 E 38/48 R 38/52 5/00 F (72) Inventor Shigehiro Oi Nakajima, Shima, Himeji City, Hyogo Prefecture No. 3007, Sanyo Special Steel Co., Ltd. EB11 EC03 4K018 AA24 KA18

Claims (5)

[Claims] An essential component of C: 0.7 to 2.5%, Si: 2.0% or less, Mn: 1.5% or less, Cr: 3.0 to 6.0% by weight. And Mo: 3.0
And 10.0%, and W: 1.0 to 20.0%, or both of the first selected components, and V: 0.8 to 2%.
Powder tool steel comprising 5.0% and Nb: any one or both of 0.1 to 5.0% of the second selected component and the balance of Fe and unavoidable impurities is used as a die face material for a mold. C: 0.1-0.55%, Si: 1.2% or less, Mn: 0.3-2.0%, Ni: 0.3-2.0%, Cr: 1 0.0-4.0%, and Mo: 0.2-3.
0%, W: one or more of 0.4 to 6.0% (Mo and W
Contains 1 / 2W + Mo: 0.2 to 3.0%), and further contains one or more of V: 0.05 to 0.7%, and Nb: 0.01 to 0.15%. A molten or powdered hot work tool steel containing the balance of Fe and unavoidable impurities is used as a mold base material, and these mold surface materials and the base material are clad by HIP (Hot Isostatic Pressing). A clad mold for hot press, characterized in that it is used as it is. 2. Essential components of C: 0.7 to 2.5%, Si: 2.0% or less, Mn: 1.5% or less, Cr: 3.0 to 6.0% by weight. And Mo: 3.0
And 10.0%, and W: 1.0 to 20.0%, or both of the first selected components, and V: 0.8 to 2%.
Powder tool steel comprising 5.0% and Nb: any one or both of 0.1 to 5.0% of the second selected component and the balance of Fe and unavoidable impurities is used as a die face material for a mold. C: 0.1-0.55%, Si: 1.2% or less, Mn: 0.3-2.0%, Ni: 0.3-2.0%, Cr: 1 0.0-4.0%, and Mo: 0.2-3.
0%, W: one or more of 0.4 to 6.0% (Mo and W
Contains 1 / 2W + Mo: 0.2 to 3.0%), and further contains one or more of V: 0.05 to 0.7%, Nb: 0.01 to 0.15%. ,
Melt or powder hot tool steel containing Co: 0.2-3.0%, the balance being Fe and unavoidable impurities is used as a mold base material, and this is used as a mold surface material and a base material as HIP. A clad mold for hot press, characterized in that it is clad by (hot isostatic pressing) and used as it is after HIP treatment. 3. Essential components of C: 0.7 to 2.5%, Si: 2.0% or less, Mn: 1.5% or less, Cr: 3.0 to 6.0% by weight. And Mo: 3.0
And 10.0%, and W: 1.0 to 20.0%, or both of the first selected components, and V: 0.8 to 2%.
5.0%, and Nb: 0.1 to 5.0%, or both of the second selected components, and Co: 4.0 to 12.
Powder tool steel containing 0%, the balance being Fe and unavoidable impurities was used as the die surface material of the mold, and the same weight% was used.
C: 0.1 to 0.55%, Si: 1.2% or less, Mn: 0.3 to 2.0%, Ni: 0.3 to 2.0%, Cr: 1.0 to 4 2.0% and Mo: 0.2-3.
0%, W: one or more of 0.4 to 6.0% (Mo and W
Contains 1 / 2W + Mo: 0.2 to 3.0%), and further contains one or more of V: 0.05 to 0.7%, and Nb: 0.01 to 0.15%. A molten or powdered hot work tool steel comprising the remaining Fe and unavoidable impurities is used as a mold base material, and this is formed into a cladding of a mold surface material and a base material by hot isostatic pressing (HIP). A clad mold for hot pressing, wherein the clad mold is used while being subjected to HIP processing. 4. An essential component of C: 0.7 to 2.5%, Si: 2.0% or less, Mn: 1.5% or less, Cr: 3.0 to 6.0% by weight. And Mo: 3.0
And 10.0%, and W: 1.0 to 20.0%, or both of the first selected components, and V: 0.8 to 2%.
5.0%, and Nb: 0.1 to 5.0%, or both of the second selected components, and Co: 4.0 to 12.
Powder tool steel containing 0%, the balance being Fe and unavoidable impurities was used as the die surface material of the mold, and the same weight% was used.
C: 0.1 to 0.55%, Si: 1.2% or less, Mn: 0.3 to 2.0%, Ni: 0.3 to 2.0%, Cr: 1.0 to 4 2.0% and Mo: 0.2-3.
0%, W: one or more of 0.4 to 6.0% (Mo and W
Contains 1 / 2W + Mo: 0.2-3.0%), and further contains one or more of V: 0.05-0.7%, Nb: 0.01-0.15%. ,
Co: 0.2 to 3.0%, and a hot-worked or powdered hot tool steel containing the balance of Fe and unavoidable impurities is used as a mold base material. A clad mold for hot pressing, characterized in that it is clad by (hot isostatic pressing) and used as it is after HIP treatment. 5. The cladding of the die-sculpture material and the base material according to claims 1 to 4, wherein the die-sculpture material is a surface portion of a mold, that is, a portion corresponding to a portion severely damaged by wear. A method for designing a cladding die for hot pressing, characterized in that the thickness of the die surface material is designed so that the inner part, that is, the concave part of the die becomes a base material part.