Dong Wenbin, Zhang Yajing, Bao Le, Shin Kyoosik
Department of Mechanical Engineering, Anhui Science and Technology University, Chuzhou 233100, China.
Department of Mechatronics Engineering, Hanyang University, Ansan 15588, Gyeonggi-do, Republic of Korea.
Materials (Basel). 2024 May 17;17(10):2415. doi: 10.3390/ma17102415.
Laser bending is a kind of cumulative forming technology and bending efficiency is one of its most important indexes. This study investigates the bending behavior and the microstructure of DP980 steel plates under different laser scanning strategies, using an IPG laser system. Two sets of experiments varied the accumulated line energy density (AED) by altering the laser scanning velocity and number of scans. The results show that, for the single laser scanning process, the bending angle of the plate increases with AED, due to a larger temperature gradient through the thickness direction; however, this relationship is nonlinear. A higher AED led to a sharper initial increase in bending angle, which then plateaued. Under the same AED conditions, the bending angle of the plate undergoing multiple laser scans increases by at least 26% compared to the single one, due to the microstructure changes. It is revealed that the bending efficiency is affected by both the AED and the resultant microstructure evolution in the DP980 steel. Higher AED values and appropriate peak temperatures facilitate better bending behavior due to the formation of uniform martensite and grain refinement. Conversely, excessive peak temperatures can hinder bending due to grain growth.
激光弯曲是一种累积成形技术，弯曲效率是其最重要的指标之一。本研究使用IPG激光系统，研究了不同激光扫描策略下DP980钢板的弯曲行为和微观结构。两组实验通过改变激光扫描速度和扫描次数来改变累积线能量密度（AED）。结果表明，对于单次激光扫描过程，由于沿厚度方向的温度梯度较大，板材的弯曲角度随AED的增加而增大；然而，这种关系是非线性的。较高的AED导致弯曲角度最初急剧增加，然后趋于平稳。在相同的AED条件下，由于微观结构的变化，经过多次激光扫描的板材的弯曲角度比单次扫描的至少增加26%。结果表明，DP980钢的弯曲效率受AED和由此产生的微观结构演变的影响。较高的AED值和适当的峰值温度有利于形成均匀的马氏体和细化晶粒，从而获得更好的弯曲性能。相反，过高的峰值温度会由于晶粒长大而阻碍弯曲。
