The Effect of Strain Rate on the Sheet Tensile Properties and Formability of Ferritic Stainless Steels

High strain rate sheet tensile tests (up to 300s^-1) and Ohio State University (OSU) formability tests (up to an estimated strain rate of 10s^-1) were performed to examine the effect of strain rate on the mechanical properties and formability of five ferritic stainless steels: HIGH PERFORMANCE-10™ 409 (HP-10 409), ULTRA FORM^® 409 (UF 409), HIGH PERFORMANCE-10™ 439 (HP-10 439), two thicknesses of 18 Cr-Cb™ stainless steel, all supplied by AK Steel, and Duracorr^®, a ferrite-tempered martensite dual-phase stainless steel supplied by Bethlehem Steel Corporation. Tensile results show that increasing strain rate resulted in increases in yield stress, flow stress, and stress at instability for all alloys tested. In addition, increases in uniform and total elongation were also found for each of the five alloys. Formability was generally found to decrease with increasing strain rate or decreasing temperature in the OSU formability test, but was found to be more a function of changing frictional conditions than of mechanical properties.