The invention relates to the technical field of
laser quenching, in particular to a
laser quenching heat treatment method which comprises the following steps: S1, normal-temperature phosphating; s2,
dehydrogenation tempering is conducted, oil stains and
rust on the
tooth part and the inner hole of the gear subjected to normal-temperature phosphating are removed, and
dehydrogenation treatment is conducted on the gear; s3,
laser quenching is conducted, specifically, the target
tooth surface of the gear teeth serves as a quenching surface, the opposite
tooth surface serves as a cooling surface, and when
laser quenching is conducted on the quenching surface, a
cooling medium flows through the cooling surface to conduct auxiliary cooling; s4, low-temperature
tempering is carried out, normal-temperature phosphating treatment is carried out on the surface of the gear to replace brushing of a light absorption material, auxiliary cooling is carried out while
laser quenching is carried out, the requirement for the quenching critical
cooling speed is met through the heat dissipation capacity of a
cooling medium, and the problem that the heat dissipation efficiency of the gear is insufficient due to self heat dissipation is solved; and auxiliary cooling is performed on the opposite surface while
laser quenching is performed on the quenching surface, so that the surface
hardness of the part can be improved, and the
hardness requirement of the gear is met.