激光淬火技术在模具表面处理中的应用与展望

Application and Prospect of Laser Quenching Technology in Mould Surface Treatment

简述了通过模具生产零件的优点及其在工业生产中的地位,而且对模具使用寿命的影响因素进行了分析,并对模具失效的主要形式做了简要说明。总结了以往人们对金属进行表面改性几种主要的工艺方法,将激光淬火技术与传统的热处理工艺进行了对比,并指出了激光淬火的优点。总体概括介绍了激光淬火技术的发展历史、激光淬火硬化机理,指出了影响激光淬火工艺的参数和确定三种主要影响因素大小的试验方法,并分析了激光淬火处理后工件不同深度的组织形成过程和相应的各项性能,尤其是对第一层的相变硬化层形成过程中的原子扩散机理作了详细说明。针对提高材料表面吸收激光率而预处理的有效方法及优点进行了论述。简述了激光淬火过程中常用激光器有CO2激光和YAG激光及相应的用途。列举了热作模具、冷作模具、塑料模具各种不同钢经不同的激光淬火参数淬火后,其硬化层的组织和相应的显微硬度,指出了这三种模具钢利用激光淬火的主要目的。最后对激光淬火技术的优缺点作了总结,并对模具表面激光改性的未来进行了展望。

The work aims to analyze factors affecting the service life of mould and summerize main forms of mould failure based on illustrating advantages of producing parts by utilizing a mould and its status in industrial production. Major techniques used to modify metallic surface previously were summarized. The advantages of laser quenching were pointed out by comparing laser quenching technology with traditional heat treatment process. The development history of laser quenching technology and the mechanism of laser quench hardening were introduced generally. Parameters influencing the laser quenching process and test methods for determing sizes of three major factors were put forward. In addition, formation and various properties of structure at different depths of workpieces subject to the laser quenching process were also anlyzed with detailed instruction on atomic diffusion organism during the formation of the first layer of phase-change hardening layer. Moreover, effective methods and advantages of pretreatment were discussed to improve laser absorptivity of material surface. It was indicated that CO2 laser and YAG laser were commonly used in the laser quenching, their corresponding purposes were briefly discussed. Microstructure and corresponding micro hardness of hardened layers in hot working dies, cold working dies and plastic moulds steel subject to quenching under different laser quenching parameters were listed. The main purpose of applying laser quenching to the three kinds of die steel was pointed out. Finally, the advantages and disadvantages of the laser quenching technology as well as prospect of laser modification on mold surface were summarized.