Effects of Microstructures on the Mechanical Properties of Multi-phase Sheet Steels

抄録

Several microalloyed steels were intercritically annealed and then aircooled to room temperature or water-quenched to obtain different microstructures. The effects of the amount and the nature of low-temperature transformation products on the deformation behavior, stretch-flangeability and fracture-toughness after cup deep-drawing of multi-phase sheet steels were examined. Bainite has a slight deleterious effect on strength-uniform elongation relationship but has a favorable effect on stretch-flangeability and on fracture toughness after cup deep-drawing as compared with martensite. It is also suggested that ferritic-bainitic (-martensitic) steel may be preferred to “dual phase” steel in some complex pressings.