DP780镀锌钢激光焊接性能与工艺

Laser welding performance and process of DP780 galvanized steel

针对0.8 mm的车用DP780镀锌双相钢,采用4 k W的连续光纤激光器对材料进行激光搭接试验,通过调节两板间的预留间隙、激光功率、焊接速度、离焦量,研究了工艺参数对焊接接头焊缝的成形影响规律,同时分析各工艺参数对焊缝下塌量、抗拉强度、气孔状况的影响规律;最后基于焊缝抗拉强度、焊缝下塌量以及焊接过程中气孔状况评价焊接质量.结果表明,功率在3 800 W、焊接速度在95~100 mm/s,离焦量在–2~2 mm,预留间隙在0.2~0.25 mm区间的工艺参数条件下,焊接成形较好,此时的抗拉强度保持在180 MPa以上,下塌量总量在0.35~0.45 mm,以及飞溅和外部气孔较少.建立抗拉强度—焊缝下塌量—气孔状况方法评价焊接质量,采用此方法,能够改善气孔缺陷,提升焊接效率.

DP780 galvanized dual phase steel used for vehicles with thickness of 0.8 mm was laser welded in lap joint by 4 kW continuous fiber laser.By adjusting the reserved gap between the two plates,laser power,welding speed and defocusing amount,the influence of process parameters on the shaping of welds was studied.Then,the effect of various process parameters on the amount of subsidence,tensile strength,and porosity of welds was analyzed.Finally,the welding quality was evaluated based on the tensile strength,the amount of welds subsidence and the condition of porosity.The results showed that when the power of 3800 W,the welding speed of 95-100 mm/s,the amount of defocusing distance in the-2 mm-+2 mm,leave the reserved gap in the process parameters of the 0.2-0.25 mm conditions,the good welding shaping was achieved.By the above welding parameters,the tensile strength was maintained more than 180 MPa,the total amount of welds subsidence was between 0.35-0.45 mm,and the porosity condition which had splashes and the external porosity was less.The tensile strength-the amount of welds subsidence-the condition of porosity method is proposed to evaluate welding quality,it can improve the porosity defects and the welding efficiency.