JP2000160270A - Anvil for forging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anvil for forging applied as the anvil used at forging time and having excellent high temp. strength, wear resistance, high temp. setting resistance, heat cracking resistance, etc., needed to the anvil for forging and also, excellent in profitability. SOLUTION: As the anvil for forging, to a base part formed of a carbon steel for machine structural use (SC), alloy steel for machine structural use (SCM etc.), tool steel for hot-working die (SKD, SKT, etc.), etc., having inexpensive and easily workable blank, a build-up welding is executed with alloy powdery material consisting by wt.% of <=0.05% C, 0.01-1.0% Si, <=0.5% Mn, 10-25% Cr, 1.5-3.0% Al, 1.0-3.5% Ti, 10-13% Co, <=1.5% Fe, 5.5-6.5% Mo, 0.5-2.0% W and the balance substantially chemical component range of Ni and 5.0% Al-Ti and excellent in the heat resistance, wear resistance and high temp. setting resistance in 10-30 mm thickness to the contacting surface with the forged material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied as an anvil used for forging, and is excellent in high-temperature strength, abrasion resistance, high-temperature set resistance, heat crack resistance, etc. required for forging anvil. At the same time, it relates to an economical forging anvil.

[0002]

2. Description of the Related Art Forging, which is one of the hot working of steel, includes forging, upsetting, tap forming, spine cutting, perforation, etc. In these forgings, a forging tool called an anvil is used. Forging dies are used. The anvil is required to have excellent properties such as high-temperature strength, abrasion resistance, high-temperature resistance, and heat crack resistance. Conventionally, the materials for this anvil include carbon steel for machine structure (SC) and alloy steel for machine structure (SCM).
Etc.), hot die tool steel (SKD, SKT, etc.), Ni-base heat-resistant superalloy (Nimonic 80A, etc.)
No. 11 discloses an alloy or the like.

[0003]

Among the conventional anvil materials as described above, carbon steel for machine structure (SC), alloy steel for machine structure (SCM, etc.), tool steel for hot mold (SKD, S
KT, etc.) are inexpensive, easy to process as anvil from the material, and inexpensive in processing cost, but have insufficient high temperature strength, abrasion resistance, high temperature resistance, etc. Alloys (Nimonic 80A etc.) have high temperature strength,
Although it fully satisfies the characteristics required for anvil such as wear resistance, high temperature resistance, heat crack resistance, etc., the material is expensive, processing from material to anvil is difficult and processing cost is expensive. is there.

[0004] In the case of Ni-base heat-resistant superalloys, the production of large-sized anvils having an anvil weight of more than 3 tons is not common because of difficulty in producing the material. Furthermore, when stellite is overlaid, heat cracks are easily generated on the surface of the anvil, so that the heat cracks are transferred to the forged product, and there is a problem that harmful irregularities are formed on the product surface. Further, the forging anvil made of an alloy disclosed in the above-mentioned Japanese Patent Publication No. 5-47611 is expensive and difficult to work with, as is the case with Ni-based heat-resistant superalloys (Nimonic 80A, etc.) because the entire anvil is made of the alloy. However, there was a problem that the cost of making the anvil was high.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended to provide high-temperature strength, abrasion resistance, high-temperature set resistance, and heat crack resistance required for anvils. It is an object of the present invention to provide an anvil that is excellent in various characteristics such as the above and at the same time is particularly excellent in economic efficiency. The gist of the present invention is that forging anvils, carbon steel for machine structure (SC), alloy steel for machine structure (SCM, etc.), tool steel for hot mold (SKD), which is inexpensive and easy to process, are used as forgings. , SK
T), etc., on the contact surface with the forging material in weight%, C: 0.05% or less, Si: 0.01 to 1.0
%, Mn: 0.5% or less, Cr: 10 to 25%, Al:
1.5-3.0%, Ti: 1.0-3.5%, Co: 1
0 to 13%, Fe: 1.5% or less, Mo: 5.5% or more
6.5%, W: 0.5% to 2.0%, balance substantially Ni
Alloy powder with a chemical composition range of 5% and Al-Ti: 5.0%, which is excellent in heat resistance, abrasion resistance, and high-temperature resistance, is subjected to overlay welding with a thickness of 10 to 30 mm. It is in the anvil. The alloy according to the present invention is as described in the above-mentioned Japanese Patent Publication No. 5-4761.
With respect to the alloy disclosed in Japanese Unexamined Patent Publication (Kokai) No. 1 (Kokai), the content of Mo was increased in order to improve the high-temperature strength and wear resistance, and the Al-Ti content was the welding limit in order to improve the aging effect. It is characterized by being limited to 0%.

FIG. 1 is a schematic diagram thereof. The base 1 is made of carbon steel for machine structure (SC), alloy steel for machine structure (SCM
Etc.), tool steel for hot molds (SKD, SKT, etc.), etc., and the overlay portion 2 is in weight%, C: 0.05% or less, S
i: 0.01 to 1.0%, Mn: 0.5% or less, Cr:
10 to 25%, A: 1.5 to 3.0%, Ti: 1.0
To 3.5%, Co: 10 to 13%, Fe: 1.5% or less, Mo: 5.5% to 6.5%, W: 0.5% to 2.0
%, The balance substantially having a chemical composition range of Ni, and Al
-Ti: 5.0%, made of an alloy powder having excellent heat resistance, wear resistance, and high temperature resistance, and the thickness t of the built-up portion is 10 to 30 mm. Also, if a forging anvil is made by this method, a large forging anvil, which is difficult to make by the conventional method, for example, a flat anvil of 1,000 mm in width, 1600 mm in length and 500 mm in thickness can be easily and inexpensively made. It is.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The forging anvil according to the present invention can be applied to any of the upper anvil and the lower anvil, and also a flat anvil, a tap anvil,
It can be applied to any of V-shaped anvils and the like. Here, the reason for limiting the overlay welding thickness of the forging anvil overlay according to the present invention will be described. In order to satisfy the heat resistance, abrasion resistance, and high temperature resistance required for forging anvils, 10 mm
It is necessary to build up with the above thickness. However, if the thickness is too large, the cost of the overlay material and the processing cost of the overlay will increase, so that
mm or less.

[0008] Next, the reasons for limiting the component range (% by weight) of the forging anvil overlay according to the present invention will be described. C: 0.05% or less C is an element effective for forming carbides and increasing high-temperature strength and high-temperature hardness. However, if the content is too large, the toughness and ductility are reduced, and the fracture resistance is deteriorated. Si: 0.01 to 1.0% Since Si acts as a deoxidizing material during melting and is an element effective for improving oxidation resistance, it is necessary to use 0.01% It is necessary to contain the above. However, if the content is too large, the toughness decreases, so the upper limit is set to 1.0%.

Mn: not more than 0.5% Mn acts as a deoxidizing agent during melting, and forms S
It is an element effective for fixing as nS and reducing harm caused by S. However, if contained in a large amount, the oxidation resistance deteriorates, so the content was made 0.5% or less. Cr: 10 to 25% Cr is an element effective for improving M oxidation resistance.
Particularly, in order to prevent grain boundary oxidation, it is necessary to contain 10% or more. However, if the content is too large, the strength and the ductility are deteriorated.

Al: 1.5-3.0% Al is an effective element for improving the high-temperature strength by forming a γ 'phase by combining with Ni and Ti. It is necessary to contain 1.5% or more. However, if the content is too large, the ductility is deteriorated. Ti: 1.0 to 3.5% Ti is an element effective for increasing the high-temperature strength together with Al, and is contained in an amount of 1.0% or more in balance with Al.
However, if the content is too large, the ductility decreases, so that the content is set to 3.5% or less. However, since the welding limit value of Al-Ti for improving age hardening is 5.0%, Al: 2.0%, Ti:
3.0% is optimal.

Co: 10 to 13% Co is an element effective in securing high-temperature strength and improving oxidation resistance.
% Or more. However, since it is expensive, the content is set to 13% or less in consideration of substitution with Ni. Fe: 1.5% or less Fe is contained as an impurity, but if it is too much, the oxidation resistance deteriorates.

Mo: 5.5% to 6.5% Mo is an element effective for improving high-temperature strength and abrasion resistance by combining with C to form a carbide. In order to obtain the effect, the content is made 5.5% or more. However, if it is too much, the toughness and the oxidation resistance deteriorate, so the content is made 6.5% or less. W: 0.5% to 2.0% W combines with C to form a carbide, and is an element effective for improving high-temperature strength and wear resistance. To achieve this effect, the content is made 0.5% or more. However, if it is too much, the toughness and oxidation resistance deteriorate, so the content is made 2.0% or less. Ni: balance Ni is an important element together with Co as an anvil material for forging. In particular, γ ′ phase Ni ₃ (A, T
i) was precipitated and increased in strength at high temperatures, so the balance was left.

[0013]

EXAMPLES Alloys and steels having the chemical components shown in Table 1 were prepared to form an anvil for forging, installed on a press having a capacity of 3000 Ton, and chromium molybdenum steel of JIS G 4105 was used as a forged material at a temperature of 800 to 1250 ° C. Was forged. Here, the service life (hour) of the used anvil was the result shown in Table 2. In addition, those for which the cost of making the anvil are inexpensive are indicated by ○, those which are slightly expensive are indicated by Δ, those which are expensive are indicated by X, those whose surface skin used is good are indicated by ○, and those which are defective are indicated by ×. See Table 2

[0014]

[Table 1]

[0015]

[Table 2]

As shown in the table, the forged anvil having the alloy composition and structure of the present invention has a relatively long service life, requires less frequent replacement of the anvil, and is relatively inexpensive in production cost. The result was very excellent. In addition, No. 1 to No. 5 of the invention example are hot die steel (equivalent to SKD61), No. 6 and No. 7 are carbon steel for machine structure (S45C), and No. 8 and 9 are alloy steel for machine structure (SCM440) at the metal base. ) Was used, but the service life was different due to the difference in the hot strength of the anvil base.
In addition, due to differences in anvil base material price and workability, invention examples No. 1 to 5 and invention example N
o8, 9 and Invention Examples No. 6 and 7.

On the other hand, both the structural carbon steel and the alloy tool steel of the comparative example can be produced at low cost, but have an unfavorable result in that the service life is extremely short and the surface texture after use is not good. Furthermore, in the case of the Ni-base heat-resistant superalloy and the example of Japanese Patent Publication No. 5-47611, although the service life was longer than that of the present invention, the production cost was extremely high, and the result was totally unfavorable.

[0018]

As described above, the forged anvil according to the present invention is excellent in various properties required for the forged anvil, such as high-temperature strength, high-temperature set resistance, splitting resistance, and heat crack resistance. In particular, since the cost of making the anvil is low, it is possible to reduce the number of times of repairing the anvil, increase the life of the anvil, reduce the frequency of replacing the anvil, reduce the downtime of the forging press, and improve the dimensional accuracy of the forged product. This leads to a very excellent effect that not only can the forging be improved, but also the forging cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a view showing the structure of a forged metal anvil according to the present invention.

[Explanation of symbols]

 1 Anvil base 2 Overlay

Claims (1)

[Claims] 1. The material is made of carbon steel for machine structure (SC), alloy steel for machine structure (SCM, etc.), tool steel for hot die (SKD, SKT, etc.), etc., which are inexpensive and easy to process. C: 0.05% or less, Si: 0.01 to 1.0%, Mn: 0.5% or less, Cr: 10 to 25%, Al: 1.5-3.0%, Ti: 1.0-3.5%, Co: 10-13%, Fe: 1.5% or less, Mo: 5.5% -6.5%, W: 0 0.5% to 2.0%, the balance substantially having a chemical composition range of Ni, and Al-T
i: An anvil for forging obtained by overlay-welding an alloy powder having excellent heat resistance, abrasion resistance and high-temperature set resistance of 5.0% to a thickness of 10 to 30 mm.