The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Nov. 11, 2025

Filed:

Aug. 30, 2023
Applicant:

Posco Co., Ltd, Pohang-si, KR;

Inventor:

Kwan-Ho Kim, Pohang-si, KR;

Assignee:

POSCO CO., LTD, Pohang-si, KR;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D 9/52 (2006.01); C21D 6/00 (2006.01); C21D 8/06 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/34 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C22C 38/18 (2006.01);
U.S. Cl.
CPC ...
C21D 9/525 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/065 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/34 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C21D 2211/001 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/18 (2013.01);
Abstract

A wire rod and a steel wire which are for springs and have excellent corrosion fatigue resistance properties, and a method for producing same. The wire rod and steel wire containing, in wt %, 0.40-0.70% of C, 1.20-2.30% of Si, 0.20-0.80% of Mn, 0.20-0.80% of Cr, 0.015% or less of P, 0.015% or less of S, and 0.010% or less of N, with the remainder including Fe and other unavoidable impurities, along with at least one among 0.01-0.20% of V and 0.01-0.10% of Nb, wherein the V and Nb satisfy relational expression 1 below, the average grain size of prior austenite is no greater than 20 μm, and the surface decarburization depth is no greater than 0.1 mm. [Relational expression 1] [V]+ [Nb]≥0.08 (where the V and Nb contents are in wt %).


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