Effect of Two Steps Overaging on Mechanical Properties of Tailor Rolled Blank of Dual Phase Steel

Herein, a new kind of overaging strategy: two steps for tailor rolled blank dual phase steel (DP-TRB) was investigated. The results indicate that the process is useful way to control mechanical properties DP-TRB. In premise satisfying requirement strength DP590 grade, total elongation can be significantly increased (3~7% in most cases). Due different degrees ferrite recrystallization (differences densities dislocation) among thicknesses, obvious changes thicknesses are found. zones 1.0~1.4 mm show lower strength, while 1.6~1.8 present higher strength. Otherwise, high density dislocations samples provide more locations Cottrell atmospheres, yield plateau occur easier. with one DP-TRB kinds behaviors (continuous and non-continuous yield) simultaneously. subtle C diffusion by step leads quite pinning effect atmospheres. Thus, occurs gradual way, transition state behavior, which combines characteristic smooth curve continuous yield,