The invention discloses a
laser quenching method and device. According to the method, single heating in the conventional
laser quenching technology is changed into multi-
irradiation heating, or even high-frequency multi-
irradiation heating by combining multi-
irradiation heating with a quick scanning function of a rotating mirror; the heat conduction process caused by input of
laser energy is injected into the surface of a workpiece within short
heating time in a multi-stacking mode, so that the accumulation of the laser energy absorbed by a
metal base body is increased, and the accumulation of the heat conduction depth is also increased. The device comprises a laser device, a
control system, a
light guide system, a mechanical motion device and a
laser processing head. Even if technical parameters adopt high laser power, and when the scanning speed is high, and an irradiation interval exists, the surface temperature of the
metal is always controlled to be below a
melting point, and heat can be effectively and continuously expanded from the surface of the workpiece into the workpiece; and therefore, on the premise that the surface of the
metal is prevented from being melted, the depth of an austenitizing region on the surface of the workpiece is increased, and the
laser quenching efficiency is obviously improved.