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使用YAG型光纤激光器对DP590钢进行激光焊接试验,研究了焊接接头的微观组织和显微硬度。结果表明:激光输出功率为3 k W,焊接速度为3、4、5 m/min时,焊接接头外观形貌较好,没有出现裂纹、气孔。随着焊接速度的增大,焊接接头的焊缝区和热影响区的宽度逐渐减小。焊缝中心的组织为板条状的马氏体,靠近焊缝热影响区的组织为马氏体和少量的铁素体,靠近母材热影响区的组织为马氏体和大量的铁素体。接头焊缝区的显微硬度明显高于母材,焊缝中心的最高硬度为380 HV。焊接接头的硬度从焊缝到母材呈逐渐减小的趋势。
The laser welding experiment of DP590 steel with YAG fiber laser was carried out to study the microstructure and microhardness of the welded joints. The results show that when the laser output power is 3 kW and the welding speed is 3, 4 and 5 m / min, the appearance of welding joint is good and no cracks and pores are found. With the increase of welding speed, the width of weld zone and HAZ of welded joints gradually decreases. The microstructure of the weld center is lath-shaped martensite. The microstructure of the HAZ close to the weld is martensite and a small amount of ferrite. The microstructure of the HAZ near the base material is martensite and a large amount of ferrite body. The micro-hardness of the joint weld zone is obviously higher than the base metal, and the maximum hardness of the weld center is 380 HV. The hardness of welded joints from the weld to the parent metal showed a decreasing trend.