Laser surface treatment technology

Refers to a certain power density of laser surface treatment technology of laser beam irradiation at a certain scanning speed to the workpiece, in a short time, and make the processed surface rose sharply due to the absorption of laser energy, when the laser beam away, are processed by the base material surface conduction and rapid cooling, physical and chemical changes, thus forming has certain properties of surface layer, improve the material surface hardness, strength, wear resistance, corrosion resistance and high temperature performance, etc. , can significantly improve the quality of the products, and improve the mold ( Or artifacts) Life, to achieve good economic benefit. Used for surface treatment has its unique advantages, laser metal on the laser absorption coefficient is as high as 105 ~ l06cm - 0 1, the absorption process in the surface. 01 ~ 0. 1 microns thick thin layer. The depth of the laser surface treatment depends on the distance from the surface to the internal thermal diffusion, its value is very small, and easy to control. The power density of laser spot, can be accurately directed to different parts of the mold surface, or in a certain area. To make local processing, surface power density can be controlled accurately, the energy input mould small, mold deformation of small, after the processing surface can be machined or is no longer just a small amount of machining. In addition, the laser has no chemical pollution, easy to transport, switching and automatic control. At present, the domestic laser heat treatment has been used in production practice. GCrl5 steel punching die after laser hardening treatment, its service life is increased 2 times, silicon steel sheet mold after processing, the service life of the improved 10 times. Laser surface treatment technology including phase-change hardening, fused, coating, alloying, amorphous and microcrystalline and impact reinforcement, etc. Laser phase transformation hardening of laser phase transformation hardening is also known as laser quenching, it is a high energy laser beam, rapid scanning artifacts, quickly heating the surface layers of components to the austenitizing temperature, internal material is kept cold, then through the conduction heat deep into matrix, make the heating surface at the speed of fast cooling, get very fine martensite structure, its hardness is mainly depends on the base material, carbon content and grain size of austenite, achieve the goal of self hardening. Is the main purpose of the laser transformation hardening in the surface of the selective local produce sclerosis band to reduce wear and tear, and produce a compressional stress on the surface to improve the fatigue strength. The main advantage of the laser phase transformation hardening is as follows. 1) Can get high quality hardening, refine its organization, compared to the conventional quenching hardness increased by 15% ~ 20%. 2) Heating speed, short process period, high efficiency, without the quenching medium, the process is easy to control. 3) For the hole shape and tube of cavity wall and other special parts, as long as the laser beam irradiation to all can be processed. Such as deep hole wall, such as deep groove and lateral parts. 4) For large parts of the local surface hardening treatment and complex shape parts. 5) Hardening layer depth can be precisely controlled. 6) The heat treatment deformation. Laser heating speed of metal, austenitic phase transformation is large in heat within a very short time, high temperature, deformation and critical radius of nucleus is small, makes austenite fit nuclear number increase. At the same time, the instantaneous heat quenching after the super fine austenite grain size grew up too late, the residual austenite volume increases, the carbon to spread the carbon content in retained austenite increases, as the austenite to martensite