Title:
STEEL WIRE ROD FOR HIGH-STRENGTH SPRING HAVING EXCELLENT DRAWABILITY INTO WIRE AND EXCELLENT POST-DRAWING BENDABILITY, PROCESS FOR MANUFACTURING SAME, HIGH-STRENGTH SPRING, AND PRODUCTION PROCESS THEREFOR
Document Type and Number:
WIPO Patent Application WO/2014/157142
Kind Code:
A1
Abstract:
To provide a steel wire rod which exhibits excellent wire drawability and excellent post-drawing bendability. This steel wire rod for a high-strength spring contains 0.5 to 0.8% of C, 1.5 to 2.5% of Si, 0.5 to 1.5% of Mn, 0.05 to 0.5% of Ni, 0.05 to 2.5% of Cr, 0.05 to 0.5% of V with the balance being iron and unavoidable impurities, wherein: the area fraction of pearlite is 95% or more relative to the whole structure; the tensile strength (TS) and the reduction of area (RA) satisfy the relationship (1) [TS ≤ 1250MPa and RA ≥ 35%]; the standard deviation (TSσ) of tensile strength and the standard deviation (RAσ) of reduction of area satisfy the relationship (2) [TSσ ≤ 55.0 and RAσ ≤ 6.0]; and the area fraction of perlite having an interlamellar spacing of 0.9μm or more is 20% or less as observed at a position of d × 1/4, d being the diameter of the steel wire rod.
Inventors:
OURA HIROSHI
YOSHIHARA NAO
NAITO TAKAYUKI
YOSHIHARA NAO
NAITO TAKAYUKI
Application Number:
PCT/JP2014/058191
Publication Date:
October 02, 2014
Filing Date:
March 25, 2014
Export Citation:
Assignee:
KOBE STEEL LTD (JP)
International Classes:
C22C38/00; C21D9/52; C22C38/46; C22C38/54; F16F1/06
Foreign References:
| JP2010222604A | 2010-10-07 | |||
| JP2012072492A | 2012-04-12 | |||
| JP2004137597A | 2004-05-13 | |||
| JP2008261028A | 2008-10-30 | |||
| JP2009046763A | 2009-03-05 | |||
| US20120227872A1 | 2012-09-13 |
Attorney, Agent or Firm:
UEKI, Kyuichi et al. (JP)
Hisakazu Ueki (JP)
Hisakazu Ueki (JP)
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