Laser heat treatment of die steel uses high energy of laser beam to heat the surface of the upper part quickly, and then relies on the thermal conductivity cooling of the part itself to make it quenched. Now we're using CO2 lasers. Compared with induction hardening, the hardened layer obtained by laser hardening is very fine martensite structure, so it has higher hardness, wear resistance and fatigue strength than high frequency induction hardening. After laser quenching, the deformation of the upper part is very small, which is only 1 / 3-1 / 10o of that of the high frequency induction heating quenching.

激光热处理首要外为两种工艺：激光相变硬化、激光熔凝硬化。

Laser heat treatment mainly includes two processes: laser transformation hardening and laser melting hardening.

(1)激光相交硬化是以高能量的激光束快速扫描工件，使被照射的金属或合金表面温度以极快速度升到高丁相变点rb低于熔化温度。当激光束脱离被照射部位时，由于热传导的作用，处十冷态的基体使其敏捷冷却而进行9冷淬火，从而完结工件的表面相变硬化。

(1) Laser cross hardening is to scan the workpiece rapidly with high-energy laser beam, so that the surface temperature of the irradiated metal or alloy rises rapidly to the high-temperature transformation point Rb, which is lower than the melting temperature. When the laser beam breaks away from the irradiated part, due to the effect of heat conduction, the matrix in the ten cold state cools rapidly and then carries out nine cold quenching, thus completing the surface transformation hardening of the workpiece.

这一进程是在快速加热和快速冷却下完结的，所以得到的硬化层组织较细，硬度进步30％—50％，t无表面热变形。

This process is completed under rapid heating and rapid cooling, so the microstructure of the hardened layer is fine, the hardness is improved by 30% - 50%, and there is no surface thermal deformation.

(2)激光熔凝硬化是以很高的激光功率密度．在极短的时间内4金属交互作用，使金属表面部分区域在瞬间被加热到恰当高的温度使之熔化．随后借助于冷态的金局基体吸热和传导作用．使已熔化的极薄表层金属快速凝结。激光熔化凝结硬化得到的是铸态组织，其硬度较高，耐磨性也较好.

(2) Laser melting hardening is a process in which four metals interact with each other in a very short period of time at a very high laser power density. Part of the surface of the metal is heated to an appropriate high temperature to melt. Then, with the help of the heat absorption and conduction of the cold local metal matrix, the melted very thin surface metal is rapidly condensed. As cast structure is obtained by laser melting and condensation hardening, which has higher hardness and better wear resistance

激光熔覆是经过在基材表面添加熔覆材料，并使用高能密度的激光束使之与基材表面薄层一同焙凝，使基材表面构成与基体冶金结合的添料熔覆层。

Laser cladding is to add cladding material on the surface of the substrate, and use high-energy density laser beam to make it and the substrate surface thin layer bake together, so that the substrate surface and the substrate metallurgical combination of the cladding layer.

粉末容量由送粉体系进行控制，熔覆层的厚度可调，并可多层重熔。上件熔覆后再经过机械加工，从而到达修正部分损害工件的意图。

The powder capacity is controlled by powder feeding system, the thickness of cladding layer is adjustable, and multi-layer remelting can be realized. After cladding, the upper part is machined to correct the damage of the part.