차체용 TRIP강과 DP강의 동적 인장 특성

Abstract

An important challenging issue in the automotive industry is the light-weight, safe design and enhancement of crash response of an auto-body structures. These objectives lead to increasing adoption of TRIP-type and DP-type steel sheets for an inner part of auto-body members. This study evaluates the dynamic tensile characteristics of TRIP60, TRIP80, DP60 and DP80 at the range of strain rate from 0.003/sec to 200/sec. The tensile tests acquire stress-strain relation and fracture elongation of each material. The experimental results show that the flow stress is increased as strain rate increases and elongation is not decreased even when the strain rate increases. In order to investigate the pre-strain effect at high strain rate, TRIP60 and DP60 were deformed with 5, 10% pre-strain at 0.003/sec strain rate. Then dynamic tensile test was carried out at the strain rate of 0.003, 1, 10, 100/sec. The results demonstrate that the material properties are noticeably influenced by the pre-strain at the high strain rate. The ultimate tensile strength as well as the yield stress is increased due to the pre-strain.