摘要
目的揭示激光熔覆过程基材变形演变机理,同时研究不同扫描方式对中空环形激光熔覆层残余应力分布及基材变形的影响规律,以期减小熔覆层残余应力,控制基材形变量。方法利用有限元分析软件ANSYS APDL编程语言,首先建立单道模型,探究了熔覆过程基板变形演变机理;其次建立单层多道有限元模型,模拟了6种不同扫描方式对激光熔覆层残余应力分布及基材翘曲变形的影响。基于“光束中空、光内送粉”熔覆工艺,开展了基板翘曲变形量实验研究。结果数值模拟结果表明,基板在激光熔覆起始阶段产生了背向光源的弯曲变形,随着冷却的进行,开始转变为面向光源的翘曲变形。以减小熔覆层残余应力为评价指标,获得不同扫描方式的优越性排序为:沿长边往复扫描方式>沿短边往复扫描,外螺旋式扫描>分块式扫描>内螺旋式扫描>往复扫描。从降低基板翘曲变形程度来看,不同扫描方式的优越性排列为:沿长边往复扫描方式>沿短边往复扫描,分块式扫描>内螺旋式扫描>外螺旋式扫描>往复扫描。实验测量结果表明,基板变形程度的趋势与数值模拟结果一致,验证了数值模拟的正确性。不同扫描方式下,熔覆层残余应力水平与基材翘曲变形程度基本呈正相关趋势。结论采用分块扫描方式可以显著降低熔覆层残余应力分布,改善基材翘曲变形程度,为提高中空环形激光熔覆成形质量路径规划选择提供参考。
In order to reduce the residual stress of the cladding layer and control the substrate deformation,the influence of different scanning patterns on the residual stress distribution of the cladding layer and the substrate deformation produced by hollow-ring laser is investigated.The mechanism of the substrate deformation evolution process is revealed as well.This paper firstly establishes a single-track model by the finite element analysis software ANSYS APDL programming language to study the substrate deformation mechanism during the cladding process,secondly builds a multi-track finite element model to simulate the influence of six different scanning patterns on the residual stress of cladding layer and the substrate deformation,and experimentally studies the substrate deformation amounts based on“hollow-beam,inside-beam powder feeding”process.The results show that the substrate deformation direction is opposite of the light source at the initial stage of laser cladding,and then faces the light source after cooling.From the perspective of reducing the residual stress of the cladding layer,the superiority of different scanning patterns is:reciprocating scanning along the long path>reciprocating scanning along the short path,outer spiral scanning>partition scanning>internal spiral scanning>reciprocating scanning,while from the perspective of reducing the substrate deformation,that is:reciprocating scanning along the long path>reciprocating scanning along the short path,partition scanning>internal spiral scanning>outer spiral scanning>reciprocating scanning.The experimental measurement results show that the trend of substrate deformation degree is consistent with the numerical simulation results,which verifies the correctness of the numerical simulation.The residual stress level is basically positively related to the substrate deformation degree under different scanning patterns.Finally,combining the analysis indicators of equivalent residual stress and substrate warpage deformation,it can be concluded that the
作者
李广琪
王丽芳
朱刚贤
赵亮
石世宏
LI Guang-qi;WANG Li-fang;ZHU Gang-xian;ZHAO Liang;SHI Shi-hong(College of Mechanical and Electrical Engineering,Soochow University,Suzhou 215021,China;Engineering Training Center,Soochow University,Suzhou 215021,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2021年第3期158-170,共13页
Surface Technology
基金
国家重点研发计划(2016YFB1100300)。
关键词
中空环形激光
扫描方式
熔覆层
等效残余应力
翘曲变形
hollow-ring laser
scanning patterns
cladding layer
equivalent residual stress
warpage deformation
