Abstract: Wear-resistance steel plates may be scrapped when they are worn to a certain degree， so it is not necessary for the steel plates to have full hardening layer in thickness direction. However， the steel plates are all treated with full size quenching now. So， a flash processing technique was used to obtain the steel plate with differential properties in thickness direction. 40Cr steel plate with thickness of 30mm was used for the experiment. The results show that after flash processing， the plates’ surface layers are acicular martensite and lath martensite， and the microstructure of transition layers changes from lath martensite and bainite to pearlite and ferrite. The hardness of surface layers is 710HV. The depth of hardening layer is 9mm， while the depth of transition layer is 5mm. The 40Cr steel plate with differential properties prepared in the experiment exhibits good impact toughness and wear-resistance. The proposed method provides a new choice for mechanical industry which needs “hard surface and tough inside” steel plates.

Key words: differential property, flash processing, microstructure, mechanical property, wear-resistance