Title:
STEEL FOR COLD FORGING AND PRODUCTION METHOD THEREOF
Document Type and Number:
WIPO Patent Application WO/2018/061191
Kind Code:
A1
Abstract:
This steel for cold forging has a predetermined chemical composition and satisfies d + 3σ ≤ 10. 0 and SA/SB < 0. 30. The steel includes sulfides having a circle equivalent diameter of 1. 0-10. 0 μm at 1200 particles/mm2 or more in the metal structure. The average distance between the sulfides is less than 30. 0 μm. Here, d is the average value of circle equivalent diameters of sulfides having a circle equivalent diameter of 1. 0 μm or more, σ is the standard deviation of the circle equivalent diameters of sulfides having a circle equivalent diameter of 1. 0 μm or more, SA is the number of sulfides having a circle equivalent diameter of 1. 0 μm or more and less than 3. 0 μm, and SB is the number of the sulfides having the circle equivalent diameter of 1. 0 μm or more.
Inventors:
SHIGA AKIRA (JP)
KUBOTA MANABU (JP)
HASEGAWA HAJIME (JP)
KUBOTA MANABU (JP)
HASEGAWA HAJIME (JP)
Application Number:
PCT/JP2016/079080
Publication Date:
April 05, 2018
Filing Date:
September 30, 2016
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
C22C38/00; B22D27/04; C21D8/00
Foreign References:
| JP2015007278A | 2015-01-15 | |||
| JP2012035286A | 2012-02-23 | |||
| JP2001234279A | 2001-08-28 | |||
| JP2000282171A | 2000-10-10 | |||
| CN104120371A | 2014-10-29 | |||
| JPS5114689B1 | 1976-05-11 | |||
| JPS5114753B1 | 1976-05-12 | |||
| JP2000282171A | 2000-10-10 | |||
| JPS4924422B1 | 1974-06-22 |
Other References:
KOICHI ISOBE ET AL.: "Analysis about behavior of formation of MnS during solidification of resulphurized free cutting steel", JOURNAL OF THE IRON & STEEL INSTITUTE OF JAPAN, vol. 72, no. 12, September 1986 (1986-09-01), pages 273, XP009509728, DOI: doi:10.2355/tetsutohagane1955.72.12_S1043
W. KURZ; D. J. FISHER: "Fundamentals of Solidification", 1998, TRANS TECH PUBLICATIONS LTD., pages: 256
See also references of EP 3521470A4
W. KURZ; D. J. FISHER: "Fundamentals of Solidification", 1998, TRANS TECH PUBLICATIONS LTD., pages: 256
See also references of EP 3521470A4
Attorney, Agent or Firm:
SHIGA Masatake et al. (JP)
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