Production manner null of bar wire rod for cold working

摘要

PURPOSE:To produce a soft steel wire rod for cold working capable of attaining superior softening level by means of ordinary spheroidizing annealing. CONSTITUTION:A steel having a composition containing 0.1-1.5% C and 0.25-2.0% Mn is heated up to 900-1250 deg.C to undergo hot rolling. The steel is rolled at =30% total reduction of area at a temp. in the range between Ar3 and (Ar3+200 deg.C) or between Arcm and (Arcm+200 deg.C), and, after the ferrite.pearlite transformation or the pro-eutectoid cementite.pearlite transformation is completed, rolling is done at 10-70% total reduction of area at a temp. in the range between (Ac1-400 deg.C) and Ac1, or further, after final finish rolling, cooling is done through the temp. region down to 300 deg.C at =1 deg.C/sec average cooling rate. By subjecting the wire rod produced according to this invention to spheroidizing annealing, a superior spheroidized structure can be obtained.