CAJ | 학술논문

采用CO2激光对高热裂倾向的ZK60高强镁合金挤压板材进行焊接，研究焊接工艺参数对焊缝成形特征及裂纹倾向的影响规律。结果表明：激光焦点位置设定在板材上表面时，焊缝可以获得最大的熔深和深宽比；焊接速度过高或过低均会导致焊缝深宽比的减小和热裂纹的产生，采用优化的焊接速度可得到成形形状良好且无裂纹的焊缝；激光深熔焊匙孔形成所需的功率密度阈值在0.99×105~1.23×105W/cm2之间，为了保证深熔匙孔的稳定，激光功率选择的下限应不低于750 W；而功率增大到一定值以后，焊缝的熔深不再增大，功率选择的上限应不高于750 W。高速焊接条件下，随着焊接速度的增大，焊缝热裂倾向增大，且开裂形式逐渐由横向裂纹向纵向裂纹转变。
채용CO2격광대고열렬경향적ZK60고강미합금제압판재진행한접，연구한접공예삼수대한봉성형특정급렬문경향적영향규률。결과표명：격광초점위치설정재판재상표면시，한봉가이획득최대적용심화심관비；한접속도과고혹과저균회도치한봉심관비적감소화열렬문적산생，채용우화적한접속도가득도성형형상량호차무렬문적한봉；격광심용한시공형성소수적공솔밀도역치재0.99×105~1.23×105W/cm2지간，위료보증심용시공적은정，격광공솔선택적하한응불저우750 W；이공솔증대도일정치이후，한봉적용심불재증대，공솔선택적상한응불고우750 W。고속한접조건하，수착한접속도적증대，한봉열렬경향증대，차개렬형식축점유횡향렬문향종향렬문전변。
The high cracking susceptible ZK60 magnesium alloy plates were welded by CO2 laser beam. The effects of welding parameters on the appearance and cracking tendency of the welds were studied. The results show that weld with maximum penetration and aspect ratio can be obtained when the position of focal point is adjusted on the top surface of the plate. Too higher or too lower welding speed deteriorates aspect ratio and leads to the occurrence of hot cracking. Under optimum welding speed range, the weld with high aspect ratio and free of cracking can be manufactured successfully. The threshold power density for deep penetration mode welding of ZK60 alloy is approximately between 0.99×105 and 1.23×105 W/cm2, thus the minimum laser power to sustain is about 750W, and the upper limit of recommend laser power for welding should be lower than that results in maximum penetration deep. Under the condition of higher welding speed, ZK60 alloy presents stronger cracking tendency and morphologies of cracks evolve from transverse to longitudinal with the welding speed increasing further.