304不锈钢激光抛光的参数优化及抛光层性能分析  

Optimization of Laser Polishing Parameters of 304 Stainless Steel and Performance Analysis of Polishing Layer

作　　者：李道齐 王涛[1] 杨紫璠 李宇彬 王书文 Li Daoqi;Wang Tao;Yang Zifan;Li Yubin;Wang Shuwen(College of Mechanical Engineering,Hebei University of Technology,Tianjin 300401,China)

机构地区：[1]河北工业大学机械工程学院,天津300401

出　　处：《中国激光》2023年第4期213-222,共10页Chinese Journal of Lasers

基　　金：国家自然科学基金(51775166)。

摘　　要：将光纤脉冲激光器的激光功率、重复频率、离焦量和扫描速度作为影响因素,以AISI304不锈钢的表面粗糙度作为评价指标,设计了激光抛光的正交试验,通过极差分析得到最佳工艺参数组合,在此参数组合下快速将表面粗糙度降低约67%。使用扫描电子显微镜、X射线衍射仪、电化学工作站等研究了激光抛光前、后的表面性能变化及机理。结果表明:激光抛光后,试样表面硬度降低了约15%,自腐蚀电流密度提高了10.978μA/cm^(2)。抛光层内C、Cr元素含量(质量分数)分别降低了约2.4%和3.2%,平均晶粒尺寸减小了约0.37μm,抛光表面的残余应力约为139.6 MPa。分析得出,随着C元素含量的减少,试样表面浅层金属发生软化,从而表面显微硬度降低;Cr元素含量的减少弱化了不锈钢的钝化能力,同时晶粒细化与残余拉应力的存在为腐蚀性Cl-提供了快速扩散路径,使得试样自腐蚀电流密度明显提高。Objective As a new technology for laser surface treatment,laser polishing has the advantages of being a no-contact and non-polluting approach with high controllability.Laser polishing is accompanied by rapid heating and cooling of the shallow metal layer in the area being polished.Changes in polishing layer performance and their causes must be multifaceted.Few studies have been conducted on the performance changes and mechanisms associated with the pulse laser polishing process.Moreover,the variation trend of element content has not been considered while analyzing the mechanism of polishing layer performance in previous studies.In this study,an orthogonal experiment of laser polishing of AISI304 stainless steel is conducted;the correlation among various process parameters is analyzed,and the optimal combination of process parameters for achieving high polishing performance is determined.In addition,the properties of the surface before and after laser polishing are evaluated,and the mechanism of the properties of the polishing layer is analyzed based on grain size,residual stress,and variations in the element content.We expect that our findings will serve as a reference for improving metal surface quality using laser-polishing technology in future.Methods In this study,the laser power,repetition frequency,defocus distance,and scanning speed of the pulse laser are considered as the influencing factors,and surface roughness is used as the evaluation index to design an orthogonal laser polishing experiment.The polishing route has a“bow”shape[Fig.3(b)],with a 0.03 mm gap between the filling lines.The three-dimensional(3D)morphology of the surface is observed using an optical microscope,and the surface roughness is measured using a probe roughness instrument.The surface microhardness values of the samples are measured using a Vickers hardness tester.In addition,electrochemical polarization tests are conducted in an electrochemical workstation to detect the corrosion resistance before and after laser polishing.The p

关 键 词：激光技术 激光抛光 304不锈钢 正交试验 参数优化 性能分析 

分 类 号：TN249[电子电信—物理电子学]