A comparative study of laser surface hardening of AISI 410 and 420 martensitic stainless steels by using diode laser

•High Power Diode laser used for comparing Surface Hardening of AISI 410 and 420.•Geometry of the hardened area, micro hardness and microstructure are investigated.•In the same parameters depth & width of hardness of AISI 410 is more than AISI 420.•Effects of material properties and laser absorption on the laser hardening process. Laser surface hardening process is one of the new technologies for improving the surface of metals, especially steels, which in recent decades has received a lot of attention. This paper surveys the capability of laser surface hardening of AISI 410 and AISI 420 martensitic stainless steel by using continues wave diode laser with a maximum power of 1600 W, experimentally. Microstructure of the laser treated area by using optical microscope (OM), Field emission Scanning Electron Microscope (FESEM), and XRD were investigated and compared. Geometrical dimension, micro-hardness deviation (MHD) from the micro-hardness of the base metal, ferrite percentage, and the grain size of the hardened zone are the other considered responses. The results indicate that in the same input parameters the AISI 420 has higher surface hardness and less penetration depth and width than the AISI 410 stainless steel. Observations showed that a laser surface hardened layer of AISI 410 is about 620 HV with 1.8 mm depth and while for AISI 410 is about 720 HV with 1.2 mm depth is obtained. Comparing the results with the furnace hardening heat treatment show that the laser hardening process is more effective and precise than conventional processes.