Cold-work die steel and die

Inactive Publication Date: 2010-06-03
KOBE STEEL LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0011]The invention has been made in view of these circumstances, and objects thereof are to provide a cold-work die steel which exhibits excellent basic properties (including hardness and toughness), and besides, which is adaptable satisfactorily to a variety of hard coating treatments, and to provide a die.

Problems solved by technology

With the increase in demand for such high-tensile steel plates, there has arisen a problem of damaging the surface coating films of dies at an early stage and thereby causing “galling” (a seizing-up phenomenon occurring under press forming) to result in extreme loss of die life.

Method used

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  • Cold-work die steel and die
  • Cold-work die steel and die

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examples

[0081]Now, the invention will be illustrated in more detail by reference to the following examples, but the invention should not be construed as being restricted by these examples. In carrying out the invention, it is possible as a matter of course to make changes and modifications as appropriate so long as they conform to the foregoing and following imports, and any of modes undergoing such changes and modifications are included in the technical scope of the invention.

[0082]A variety of steel species listed in Table 1 were used and, from each of these steel species, 150 kg of ingot was produced by melting in a vacuum induction melting furnace. Then, each ingot was heated to a temperature in a range of about 900° C. to about 1,150° C., and forged into two plates each having a size of 40 mmT×75 mmW×about 2,000 mmL. Thereafter, each plate obtained was slowly cooled at an average cooling rate of about 60° C. / hour. After cooling to a temperature of 100° C. or less, the resultant was re-...

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Abstract

The present invention relates to a cold-work die steel, comprising by mass %: 0.5 to 0.7% of C; 0.5 to 2.0% of Si; 0.1 to 2.0% of Mn; 5 to 7% of Cr; 0.01 to 1.0% of Al; 0.003 to 0.025% of N; 0.25 to 1% of Cu; 0.25 to 1% of Ni; 0.5 to 3% of Mo; 2% or less (including 0%) of W; and 0.1% or less (excluding 0%) of S, with a remainder being iron and an unavoidable impurity; wherein the following requirements (1) to (3) are satisfied: (1) [Cr]×[C]≦4; (2) [Al] / [N]: 1 to 30; and (3) [Mo]+0.5×[W]: 0.5 to 3.00%, wherein the bracket means a content (%) of an element written therein.

Description

TECHNICAL FIELD[0001]The present invention relates to a cold-work die steel and a die, and more specifically to a die steel useful as a material of dies used in carrying out cold / worm press forming (stamping, bending, drawing, trimming, etc.) of steel plates for cars, steel sheets for home electric appliances and so on.BACKGROUND ART[0002]With increases in strength of steel plates and sheets, dies used in carrying out forming of steel plates for cars, steel sheets for home electric appliances and the like are required to undergo further improvement in their life. As to the steel plates for car in particular, in consideration of environmental issues and with the intention of enhancing fuel economy of cars, demand for high-tensile steel plates having tensile strengths of about 590 MPa or more has grown sharply. With the increase in demand for such high-tensile steel plates, there has arisen a problem of damaging the surface coating films of dies at an early stage and thereby causing “...

Claims

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Application Information

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IPC IPC(8): C22C38/42C22C38/60B21D37/00
CPCC21D6/002C21D9/00C22C38/00C22C38/002C22C38/46C22C38/04C22C38/06C22C38/42C22C38/44C22C38/02
Inventor MURAKAMI, SHOGONAMBA, SHIGENOBUYAMAMOTO, KENJITONOMURA, TSUYOSHI
Owner KOBE STEEL LTD
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