Title:
STEEL FOR CASE HARDENING WHICH HAS EXCELLENT COLD WORKABILITY AND MACHINABILITY AND WHICH EXHIBITS EXCELLENT FATIGUE CHARACTERISTICS AFTER CARBURIZING AND QUENCHING, AND PROCESS FOR PRODUCTION OF SAME
Document Type and Number:
WIPO Patent Application WO/2010/116555
Kind Code:
A1
Abstract:
Provided is a steel for case hardening, which is to be subjected to cold working, machining, and carburizing and quenching, and in which the occurrence of coarse particles is prevented. The steel for case hardening has excellent cold workability and machinability and further exhibits excellent fatigue characteristics after carburizing and quenching. The steel for case hardening is characterized by: containing, by mass, 0.001 to 0.15% of S, 0.05 to 0.2% of Ti, at most 0.04% of Al, at most 0.0050% of N, and specific amounts of other specific components, and further containing at most 0.003% of Mg, and/or at most 0.01% of Zr, and/or at most 0.005% of Ca; having a content of precipitated AlN of 0.01% or less; and satisfying the relationship: d ≤ 1700[S]+20 [wherein d is the density (particles/mm2) of sulfides which have equivalent circle diameters exceeding 20μm and aspect ratios exceeding 3; and [S] is the content (mass%) of S].
Inventors:
HASHIMURA MASAYUKI (JP)
MIYANISHI KEI (JP)
KOZAWA SHUJI (JP)
KUBOTA MANABU (JP)
OCHI TATSURO (JP)
MIYANISHI KEI (JP)
KOZAWA SHUJI (JP)
KUBOTA MANABU (JP)
OCHI TATSURO (JP)
Application Number:
PCT/JP2009/068083
Publication Date:
October 14, 2010
Filing Date:
October 14, 2009
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
HASHIMURA MASAYUKI (JP)
MIYANISHI KEI (JP)
KOZAWA SHUJI (JP)
KUBOTA MANABU (JP)
OCHI TATSURO (JP)
HASHIMURA MASAYUKI (JP)
MIYANISHI KEI (JP)
KOZAWA SHUJI (JP)
KUBOTA MANABU (JP)
OCHI TATSURO (JP)
International Classes:
C22C38/00; C21D8/06; C22C38/60; C21D1/06
Foreign References:
| JP2005240175A | 2005-09-08 | |||
| JP2004183064A | 2004-07-02 | |||
| JP2005220423A | 2005-08-18 | |||
| JP2007031787A | 2007-02-08 | |||
| JP2008106308A | 2008-05-08 | |||
| JPH11335777A | 1999-12-07 | |||
| JP2001303174A | 2001-10-31 | |||
| JP2004183064A | 2004-07-02 | |||
| JP2004204263A | 2004-07-22 | |||
| JP2005240175A | 2005-09-08 |
Other References:
YUKITAKA MURAKAMI: "Metal Fatigue - Effects of Small Defects and Nonmetallic Inclusions", YOKENDO, 1993, pages 233 - 239
See also references of EP 2418296A4
See also references of EP 2418296A4
Attorney, Agent or Firm:
AOKI, Atsushi et al. (JP)
Atsushi Aoki (JP)
Atsushi Aoki (JP)
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