超高强钢焊点的S-N对数正态分布

为了研究超高强钢焊点的疲劳性能,以22Mn B5点焊结构为研究对象,采用中频伺服点焊设备对2 mm厚试件进行了焊接.利用高频疲劳试验机、激光补焊设备和光学显微镜,研究了不同焊接工艺参数下试件的S-N曲线.结果表明,焊接时间与电流参数会对高应力等级焊点的疲劳寿命产生明显影响,而其对低应力区焊点的疲劳寿命影响较小.合理的工艺参数可以有效提高焊点的疲劳寿命.利用激光工艺对焊点的微小圆周薄弱区进行补焊后,可以有效增强焊点的结构强度.

S-N lognormal distribution of ultra-high strength steel welding spot

In order to research the fatigue properties of ultra-high strength steel welding spot, the 22MnB5 spot-welding structure was taken as the research object. An intermediate frequency servo spot-welding device was used to weld the specimens with a thickness of 2 mm. With the high-frequency fatigue testing machine, laser repair welding device and optical microscope, the S-N curves of specimens under different welding process parameters were studied. The results show that the welding time and current parameters have obvious influence on the fatigue life of welding spot in the high stress area, while have small influence on the fatigue life of welding spot in the low stress area. In addition, the reasonable process parameters can effectively improve the fatigue life of welding spot. After the repair welding for the tiny circumferential vulnerable zone of welding spot with the laser process, the structural strength of welding spot can be effectively enhanced.