It is low production mannered null 0.01 - 0.20

摘要

PROBLEM TO BE SOLVED: To provide a method for efficiently manufacturing a steel material having a low yield ratio, without complicated hot rolling and heat treatment steps leading to low productivily.;SOLUTION: The method for manufacturing the steel material having a low yield ratio comprises rolling a steel material which has a predetermined composition and contains 20% or more of ferrite structure by a fraction, with a low rolling reduction of 0.1 to 0.5% at such a temperature as not to cause aging. Here, the temperature, which does not cause aging, is preferably the temperature satisfying the following expressions: T≤250-26,000*[(N%)-(Ti%)/3.4-(Al%)/29](°C); and T=0 in the case of [(N%)-(Ti%)/3.4-(Al%)/29]0.;COPYRIGHT: (C)2006,JPO&NCIPI