Title:
CASE-HARDENED STEEL, CARBURIZED COMPONENT, AND PROCESS FOR PRODUCING CASE-HARDENED STEEL
Document Type and Number:
WIPO Patent Application WO/2017/115842
Kind Code:
A1
Abstract:
This case-hardened steel has a chemical composition which contains, in terms of mass%, 0.10-0.30% C, 0.02-1.50% Si, 0.30-1.80% Mn, 0.003-0.020% S, 0.40-2.00% Cr, 0.005-0.050% Al, 0.06-0.20% Ti, 0.0001-0.0050% Bi, 0-1.50% Mo, 0-3.50% Ni, 0-0.50% V, 0-0.0050% B, and 0-0.040%, excluding 0.040%, Nb and has contents of P, N, and O reduced to 0.050%, 0.0060%, and 0.0025%, respectively, with the remainder comprising iron and impurities, and which satisfies Ti/S≧6.0. When a lengthwise-direction section of the steel is examined under such conditions that the examination area is 100 mm2, the number of fields of view to be examined is 16, and the area for which prediction is made is 30,000 mm2, then the maximum diameter of Ti-based precipitates which is predicted by analysis by extreme value statistics is 40 µm or smaller.
Inventors:
MIYANISHI KEI (JP)
SHIGA AKIRA (JP)
NEISHI YUTAKA (JP)
MIZUKAMI HIDEO (JP)
SHIGA AKIRA (JP)
NEISHI YUTAKA (JP)
MIZUKAMI HIDEO (JP)
Application Number:
PCT/JP2016/089086
Publication Date:
July 06, 2017
Filing Date:
December 28, 2016
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
C22C38/00; C21D8/06; C22C38/58; C21D1/06
Foreign References:
| JP2010248630A | 2010-11-04 | |||
| JP2011219854A | 2011-11-04 | |||
| JP2012062536A | 2012-03-29 | |||
| JP2007031787A | 2007-02-08 | |||
| JP2005240175A | 2005-09-08 |
Other References:
See also references of EP 3399063A4
Attorney, Agent or Firm:
SHIGA Masatake et al. (JP)
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