Effect of Strain Rates on Strength of Sheet Steels

Abstract

Stain rate sensitivity of deformation behavior in various sheet steels were investigated in order to find out the suitable steel for automotive anti-crash parts. Dual phase steels consisted of ferrite and martensite phases absorbed higher energy at strain rate of 2 × 10³/s with lower yield strength at strain rate of 2 × 10^-2/s, compared with other steels. Higher energy absorption of dual phase steels was due to high strain rate sensitivity of yield strength and n-value. Increase of volume fraction or large surface area of martensite phase in dual phase steel led higher strain rate sensitivity in work hardenability as well as yield strength.