Patent ID: 6551419
Filing Date: 2003-04-22
Classification: C21D

Abstract:
A hot rolled steel wire rod or bar for machine structural use, characterized in that: the wire rod or bar is made from a steel consisting essentially of, in weight,0.1 to 0.5% of C, 0.01 to 0.5% of Si, 0.3 to 1.5% of Mn, and the balance consisting of Fe and unavoidable impurities; its microstructure consists of ferrite and pearlite; its ferrite crystal grain size number defined under Japanese Industrial Standard (JIS) G 0552 is 11 or higher; and a granular carbide 2 &mgr;m or less in circle-equivalent diameter and having an aspect ratio of 3 or less accounts for a percentage area of 3 to 15%.