METHOD OF PRODUCING HIGH-STRENGTH STAINLESS STEEL STRIP HAVING DUPLEX STRUCTURE AND EXCELLENT SPRING CHARACTERISTICS.

摘要

A high-strength stainless steel strip having a duplex structure is produced by the following processes; i) a cold rolled stainless steel strip contg. Cr (10.0-20.0 wt.%), C (0.01-0.15 wt.%), Ni, Mn and/or Cu (0.1-4.0 wt.%) is obtd. by hot rolling and cold rolling. ii) the cold rolled stainlees steel strip is heated at the ferrite/austenite duplex temp. iii) a ferrite/maltensite duplex structure stainless strip is obtd. by quenching the heated strip iv) the obtd. strip is continuously aged at 300-650 deg.C in a continuous heat treating furnace for 10 mins. or less. After continuous ageing the stainless steel strip has a HV (hardness factor) of 400 or less, a Kb (spring value) of 60 kg f/mm2 or more in the direction of rolling and the direction at right angles to the direction of rolling. Between steps (iii) and (iv) a rolling step (rolling coeff. = 10% or less) for improving the quality can be inserted.