激光焊接工艺对BIM钢结构焊接接头组织与性能的影响

Influence of Laser Welding Process on Microstructure and Properties of Welded Joint of BIM Steel Structure

研究了激光功率和焊接速度对DX51D/JFE-HITEN780S不等厚钢结构钢板激光焊接接头成形质量、显微组织和硬度的影响。结果表明,激光功率在1.0 k W及以上时,焊接接头可焊透,且随着激光功率的增加,焊缝正面熔宽和背宽都呈现为逐渐增加的趋势;不同激光功率下的焊接接头焊缝区组织都为板条马氏体＋铁素体,且随着激光功率的增加,板条马氏体愈发粗大,焊接接头焊缝硬度平均值呈现逐渐增加的趋势。焊接速度在1600～2400 mm/min时,焊接接头具有较好的焊接成形质量,随着焊接速度的增加,焊接接头焊缝处的正面熔宽和背面熔宽都呈现逐渐降低的特征,焊缝区板条马氏体含量逐渐减少,而铁素体含量逐渐增多,同时焊缝中心的晶粒有所细化;DX51D/JFE-HITEN780S异质钢板适宜的焊接激光功率为1.2 k W、焊接速度为2400 mm/min,此时焊接接头具有良好的焊接成形质量,焊缝区硬度较大且在热影响区中不存在软化点。

The effects of laser power and welding speed on the forming quality, microstructure and hardness of the laser welded joint of DX51 D/JFE-HITEN780 S steel plates with unequal thickness were studied. The results show that when the laser power is above 1.0 k W, the welded joint can be penetrated, and with the increase of laser power, the weld width and back width increase. The microstructure of welded joints with different welding powers is lath martensite and ferrite, and with the increase of laser power, the lath martensite is thicker, the average hardness of welded joints shows a trend of gradual increase.When the welding speed is 1600-2400 mm/min, the welding joints have good forming quality, and with the increase of welding speed, the weld width and back width decrease gradually, the lath martensite content decreases gradually in the weld zone, while the ferrite content increases gradually, and the grains in weld center are refined. The suitable welding power of DX51 D/JFE-HITEN780 S heterogeneous steel plates is 1.2 k W and the welding speed is 2400 mm/min, while the welded joint has good welding quality, the hardness of the weld is big and there is no softening point in the heat affected zone.