Abstract: The lamellar-type dual phase steel were obtained by prequenching at 1150℃ interstitially quenching with slow heating rate (2℃/min). It was shown that the tensile strength and uniform elongation to necking of the lamella- type deal phase steel were higher than that of the island-type dunk phase steel in the range of Vu<50％. The work hardening exponents m1 and m2 of the lamellar-type dual phase steel were lower than that of the island-type dual phase steel were lower than that of the island-type dual phase steel, which indicated the work harden ting rates and wok hardening capacity of the former were higher than that of the latter. It was the accommodation dislocations formed in both ferrite and marten site of fine lamellar-type dual phase steel during tensile deformation due to the inhomogeneous distribution of strain that caused significantly the hardening effect and gave rise to the increase of work hardening rates.

Key words: C-J分析, 层片状, 岛状, 加工硬化指数, 双相钢