EFFECT OF GRAIN SIZE AND MARTENSITE FRACTION ON THE DYNAMIC FACTOR OF DUAL PHASE STEEL MICROSTRUCTURES

摘要

Dual phase microstructures with various ferrite grain sizes and martensite fractions were obtained by a variety of heat treatment conditions on the as-received cold rolled sheet steels. The static (0.01 mm/s) and dynamic (25 m/s) mechanical properties of various microstructures were measured by means of shear punch testing. It was found that both static and dynamic strengths decreased with increasing ferrite grain size. It was also observed that the variation of the dynamic factor with static strength was independent of grain size, but a higher alloying level gave higher dynamic factor values.