40Cr厚向性能差异化钢板的组织与性能

Microstructure and Mechanical Properties of 40Cr Steel Plate with Differential Properties in Thickness Direction

通常情况下耐磨钢板磨损到一定程度即报废,因此耐磨钢板厚度方向上不必全为淬硬层,而现有耐磨钢板热处理都是以全尺寸淬透为目标.针对此问题,提出采用瞬时淬火工艺制备厚向性能差异化钢板.实验选用厚度为30 mm的40Cr钢板,处理后其表层为针状马氏体和板条马氏体混合组织,过渡层由板条马氏体和贝氏体混合组织逐渐过渡为珠光体和铁素体混合组织,表面硬度710 HV,淬硬层深度9 mm,过渡层深度5 mm.试制的40Cr厚向性能差异化钢板具有良好的冲击韧性和耐磨性,为机械工程行业需要的"表硬里韧"钢板提供了一种新的选择.

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 30 mm 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 710 HV. The depth of hardening layer is 9 mm, while the depth of transition layer is 5 mm. 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.