The steel 9Cr2-0.80~0.95C

0.40Si

0.40Mn

1.30~1.70Cr was laser quenched surface heat treatment by a 3 kW continuous CO₂ cross current laser with laser power 1.8~2.4 kW and laser beam scan velocity 500~1000 mm/min

and the surface structure and the case hardening depth were analyzed and tested. The test results showed that with higher laser power and lower beam scan velocity the case structure consisted of melting zone

phase transformation zone

heat influence zone and matrix and the case hardening depth was 0.4~0.8 mm;and with lower laser power and higher beam velocity the case structure consisted of phase transformation zone

heat influence zone and matrix and the case hardening depth was 0.2~0.6mm