预热对激光熔覆陶瓷涂层温度场和应力场影响  

Numerical simulation of preheating on temperature and stress fields by laser cladding Ni-based ceramic coating

作　　者：李美艳[1] 蔡春波[1] 韩彬[1] 王勇[1] 

机构地区：[1]中国石油大学(华东)机电工程学院,山东青岛266580

出　　处：《材料热处理学报》2015年第12期197-203,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51179202);山东省自然科学基金(ZR2014EEQ037);863计划项目(2012AA09A203);山东省自主创新计划(2012CX80101);中国石油科技创新基金(2013D-5006-0309);中央高校基本科研业务费专项资金(15CX05020A)

摘　　要：采用SYSWELD软件建立激光熔覆Ni-WC-Cr3C2涂层的热应力分析的有限元模型,通过熔池形貌对比验证模型的可靠性。利用建立的模型,进一步分析陶瓷涂层冷却阶段温度梯度和应力场的变化规律及基板预热对温度梯度和应力分布的影响。结果表明,激光熔覆处理是经历了快速加热、快速冷却的过程,陶瓷涂层内呈拉应力状态,极易沿垂直扫描方向发生脆性开裂。基板预热可以显著降低陶瓷涂层的冷却速度,且预热温度越高,冷却速度降低越明显,涂层内应力也随之降低。预热350℃及以上可以有效抑制裂纹产生。A finite element model for single track laser cladding Ni-WC-Cr3C2 ceramic coating was established using SYSWELD software.By observing the molten pool＇s morphology,the simulation shows a good agreement with the experiment,which indicates the model is reliable. The variation of temperature and stress distribution during the cooling stage and the effect of preheating on temperature gradient and stress distribution were both analyzed. The results show that the melt undergoes rapid heating and cooling during laser cladding process,and the residual tensile stress is generated in the ceramic coating,which brings out brittle fracture perpendicular to the scanning direction. Furthermore,the cooling velocity of the ceramic coating decreases with preheating temperature increasing as well as the residual stress in the ceramic coating. The higher the preheating temperature is,the lower the cooling velocity and residual stress are. It is possible to restrain the formation of cracks by preheating substrate above 350 ℃.

关 键 词：激光熔覆 镍基陶瓷涂层 预热 数值模拟 温度场 应力场 

分 类 号：TG174.453[金属学及工艺—金属表面处理]