超声冲击处理对316LN不锈钢残余应力影响的数值模拟

Simulation of Residual Stress in 316LN Steel Induced by Ultrasonic Impact Treatment

采用超声冲击处理技术对316LN奥氏体不锈钢试样进行残余应力模拟分析,得出不同影响因素对残余应力的影响。采用有限元分析软件ABAQUS模拟了超声冲击处理对316LN奥氏体不锈钢的冲击过程,分析了不同的冲击针形状和尺寸、冲击功率以及冲击次数等参数的影响。结果表明,平头针超声冲击产生的应力场较圆头针均匀,而圆头针产生的残余应力数值较大,φ5mm平头针产生的残余应力范围略>φ4mm平头针;提高冲击次数,应力场数值和范围均有显著增加,冲击3次后产生的残余压应力值为0.5MPa,约为单次冲击后的2倍,但继续将冲击次数增加到6次时产生的残余应力较冲击3次后产生的残余应力变化并不大;随着冲击功率的增加,残余应力场的数值和范围也逐渐增加,但增加的幅度并不明显。通过对不同冲击因素进行研究,发现了超声冲击对于提高材料表面残余应力的有效性,可为今后工艺优化提供一定的依据支持。

By measure of the residual stress of ultrasonic impact treatment （UIT）, the influences of different influencing factors of the residual stress are found out. An ABAQUS Finite element model is employed to analyze the distribution of re- sidual stress field in 316LN austenite steel induced by UIT. In the model, the UIT pin size and shape, impact power and time are considered. The result shows that the flathead pin can produce residual stress more uniformly compared with bulle- thead pin, but the bullethead pin has bigger value. The residual stress range produced by 5mm flathead pin is more than 4mm flathead pin. In addition, increasing the impact time has significant effect on residual stress value and range, and the value of impact three times is 0.5 MPa. It is double effect of impact once, but the effect is not obviously when continuously increasing the impact times to the six. Along with the increasing of the impact power, the value and range of residual stress increases slightly. By study of the different influencing factor, the validity of the residual stress is found. It can provide some basis support for process optimization.