Effect of laser hardening on microstructure and hardness of CrMo cast iron surface

doi:10.13251/j.issn.0254-6051.2022.11.029

Abstract

Abstract: TH-3DC3000 laser processing system was used to laser hardening treatment on CrMo cast iron. The effects of different laser power and scanning speed on microstructure, surface hardness and hardened layer depth of CrMo cast iron were studied. The results show that after laser hardening, the microstructure of CrMo cast iron consists of three regions, which are hardened zone, transition zone and matrix. The microstructure of hardened zone is cryptocrystalline martensite, retained austenite and spherical graphite. The microstructure of transition zone is cryptocrystalline martensite, pearlite and spherical graphite. The microstructure of matrix is ferrite, pearlite and spherical graphite. When laser surface hardening does not have overheating effect on the test piece, the increase of laser power and the decrease of scanning speed will improve the surface hardness and hardened layer depth of the CrMo cast iron. Under the rectangular laser spot of 5 mm×20 mm, the optimal parameter combination is determined as laser power of 2300 W and scanning speed of 0.003 m/s. When this parameter combination is used for laser hardening of the CrMo cast iron, the surface hardness is 760 HV0.3, the average hardness of the hardened layer is 724 HV0.3, and the depth of hardened layer is more than 1.4 mm.

Key words: CrMo cast iron, laser surface hardening, laser parameters, microstructure, hardness analysis

CLC Number:

TG115
TG143

Zhang Yonghui, Zhang Shuangjie, Wang Wei, Ma Shibo, Yan Huajun. Effect of laser hardening on microstructure and hardness of CrMo cast iron surface[J]. Heat Treatment of Metals, 2022, 47(11): 160-164.

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