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.
Patent No.:
Date of Patent:
May. 14, 2019
Filed:
Oct. 20, 2015
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
Abstract
A steel wire rod includes, in terms of mass %, 0.95-1.10% C, 0.10-0.70% Si, 0.20-1.20% Mn, 0.90-1.60% Cr, 0-0.25% Mo, 0-25 ppm B, 0-0.020% P, 0-0.020% S, 0-0.0010% O, 0-0.030% N, and 0.010-0.100% Al. In a surface area of the steel wire rod, the Vickers hardness is HV 300 to HV 420, the area ratio of pearlite is 80% or more, and the area ratio of pro-eutectoid cementite is 2.0% or less. In an inner area of the steel wire rod, the area ratio of pearlite is 90% or more, and the area ratio of pro-eutectoid cementite is 5.0% or less. In the steel wire rod, the area ratio of pearlite blocks having an equivalent circle diameter of more than 40 μm is 0.62% or less, and the difference in Vickers hardness between the surface area and a center portion is HV 20.0 or less.