JP2000263177A - Hot-die forging method and heat insulating lubricator for hot-die forging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the development of crack on the surface of a forged product even in the case of using a die at a room temp. by hot-die forging after spreading heat-insulating lubricator for hot-die forging composed of the mixture of vegetation powder, releasing agent and one or more kinds of lubricants on a lower die. SOLUTION: The heat insulating lubricant for hot-die forging in the mixture of the vegetation powder, releasing agent and one or two kinds of lubricants. The vegetation powder is the one pulverizing the vegetation of wooden powder of sawdust etc., coffee distilled residue, chaff powder, grain powder, etc., and therein, it is desirable to use the wooden powder of the sawdust because of easily getting and easy treatment, etc. Further, the releasing agent is used to boron nitride powder, alumina, etc., and therein, the boron nitride is desirable. The lubricant is used to graphite powder, molibdenum disulfide, amorphous graphite powder, etc., of which the graphite powder is desirable. After spreading the heat-insulating lubricant for hot-die forging on the lower die, the heated forging material is laid and forged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot die forging method and a heat insulating lubricant for hot die forging using a heat insulating lubricant for hot die forging.

[0002]

2. Description of the Related Art Hot die forging has been used in the production of many mechanical parts and the like because it has good reproducibility and can be forged into a desired shape. The forged product manufactured by the hot die forging is provided to the product in the same shape or used after being slightly cut, so that the allowable standard for surface cracking is strict. On the other hand, metals generally have the property of easily cracking when the temperature decreases, so the temperature of the surface in contact with the lower mold in hot die forging sharply decreases, and superalloys with low hot workability In some cases, cracks may occur.

Conventionally, in hot die forging, if the mold is kept at room temperature, cracks will occur on the surface in contact with the lower mold, so that the mold is heated and forged so that cracks do not occur. A method has been implemented. As one example of the constant temperature forging method, a constant temperature stamping and forging method in which a graphite-based lubricant or a boron nitride-based release agent is applied to a heated mold and forged is disclosed in Japanese Patent Application Laid-Open No. Hei 6-25468. ing. However, in this constant temperature die forging method, the die must be heated to a high temperature of 1000 ° C. or higher for a relatively long time, and the material that can be used for the die has high thermal brittleness, so that the strength is low. However, there are problems such as lowering the temperature, use of the material in a non-oxidizing atmosphere, and occurrence of seizure with the forged material.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hot die forging method and a heat insulating lubricant for hot die forging in which a crack does not occur on the surface of a forged product even when a mold at room temperature is used. And

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, in the hot die forging method of the present invention, a plant powder is mixed on a lower mold with one or two of a release agent and a lubricant. This is to perform hot die forging after spraying a heat insulating lubricant for hot die forging comprising a mixture. In order to solve the above-mentioned problems, in the heat-insulating lubricant for hot die forging of the present invention, one or two kinds of a lubricant such as a plant powder such as wood powder, a release agent such as boron nitride powder and a graphite powder are used. It must consist of a mixture with seeds.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail.
First, the heat insulating lubricant for hot die forging will be described. The heat insulating lubricant for hot die forging of the present invention is a mixture of vegetable powder and one or two of a release agent and a lubricant. The vegetable powder is wood powder such as sawdust, coffee extraction residue, It is obtained by crushing plants such as rice husk powder and cereal powder. Sawdust wood powder is preferable because it is easily available and easy to handle.

The release agent has been conventionally used as an anti-seizure agent or a release agent such as boron nitride-based powder and alumina, but boron nitride powder is preferred. The lubricant may be a known high-temperature lubricant such as graphite powder, dihydrated molybdenum, or amorphous graphite powder, but graphite powder is preferred.

The mixing ratio of the heat insulating lubricant for hot die forging of the present invention is 30 to 70 vol% of vegetable powder, and 70 to 30 vol% of one or two of release agent and lubricant. As an example, 45 to 55 vol% of sawdust and 55 to 45 vol% of boron nitride-based powder are used. These powders need to be uniformly mixed, but any mixing method may be used as long as they can be uniformly mixed.

Next, the hot die forging method of the present invention will be described. In the hot die forging method of the present invention, the above-mentioned heat-lubricating lubricant for hot die forging is sprayed on the forging surface of the lower die in an amount of 1 to 3 g / cm ² , and then the heated forged material is placed thereon and forged. Can be forged. The method of spraying may be by an apparatus as long as it can be sprayed uniformly, or by human power.

[0010]

When the insulated lubricant for hot die forging of the present invention comes into contact with a heated forged material, the plant powder burns and generates heat, and generates carbon powder and combustion gas. Therefore, since a gas such as a combustion gas exists between one or two of the release agent and the lubricant between the forged material and the lower mold and the carbon powder, the heat insulating property is excellent, and the plant powder is excellent. Since the surface of the lower mold is heated by the heat generated by the combustion of the material, the surface of the forged material that contacts the lower mold is not rapidly cooled. In addition, since one or two of the release agent and the lubricant and the carbon powder serving as the lubricant are present, the lower die and the forged product do not seize, and the molding can be performed efficiently.

[0011]

Example: Cr: 19.5%, Co: 13.5%, M
o: 4.3%, Al: 1.3%, Ti: 3.0%, diameter 450 mm of precipitation hardening type Ni-base superalloy consisting of the balance Ni
In the hot die forging of the disk for a gas turbine having the shape shown in FIG. 1, a heat-insulating lubricant for hot die forging having the composition and amount shown in Table 1 below is applied to the entire forging surface (?) Of the lower die shown in FIG. Was sprayed, and the forged material heated to 1150 ° C. having the shape shown in FIG. 2 was die-forged by the number shown in the following table, and the results shown in Table 2 below were obtained.

[0012]

[Table 1]

[0013]

[Table 2]

From the above results, the embodiment of the present invention has
In each case, no cracks occurred. Also, the forged product did not seize on the lower mold. On the other hand, Comparative Example 1
No cracking occurred, but seizure occurred. In the case of Comparative Examples 2 to 4, seizure did not occur, but cracks occurred on the surface in contact with the lower mold in all of them.

[0015]

The hot die forging method and the heat insulating lubricant for hot die forging of the present invention have the following excellent effects by having the above-mentioned constitution. (1) Hot die forging of a Ni-based superalloy that could only be forged by constant temperature die forging can be performed without heating the die. (2) The heat-insulating lubricant for hot die forging of the present invention simply mixes waste plant powder or inexpensive cereal flour with a conventional mold release agent or lubricant, and thus does not increase the cost. An insulating lubricant for die forging can be obtained. (3) The hot die forging method of the present invention can be carried out in the same manner as a conventional method, since only the heat insulating lubricant for hot die forging is replaced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a gas turbine disk manufactured in one embodiment of the present invention.

FIG. 2 is a conceptual sectional view for explaining hot die forging of the gas turbine disk.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Gas turbine disk 2 Lower die 3 Upper die 4 Forged material 5 Heat insulating lubricant for hot die forging

Claims (4)

[Claims] 1. A hot die forging after spraying a heat insulating lubricant for hot die forging in which a vegetable powder and one or two kinds of a lubricant and a lubricant are mixed on a lower die. Hot die forging method. 2. An insulating lubricant for hot die forging, comprising a mixture of a vegetable powder and one or two of a release agent and a lubricant. 3. The heat insulating lubricant for hot forging according to claim 1, wherein the plant powder is wood powder. 4. The heat insulating lubricant for hot die forging according to claim 2, wherein the release agent is boron nitride powder.