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针对12mm厚超低碳贝氏体(ULCB)钢,采用中小功率CO2激光与气体金属电弧(GMA)复合进行了多层焊接试验。试验结果表明,采用3层焊接,且每层热输入均匀变化时即可获得良好的焊缝成形。焊接过程中,打底焊时激光焦点要严格控制在焊缝坡口钝边金属之内,填充层对激光焦点位置的要求并不严格;为了充分发挥激光的作用,应采用较高的送丝速度。此外,焊缝的拉伸力学性能测试结果表明,超低碳贝氏体钢激光-GMA电弧复合焊接接头的抗拉强度可达到母材的95%以上,甚至部分焊缝超过母材,其平均抗拉强度达到829.5MPa。当试样断于焊缝时,焊接缺陷是造成焊缝强度下降的主要原因。
For 12mm thick ultra-low carbon bainitic (ULCB) steel, multi-layer welding tests were performed using a combination of small and medium power CO2 laser and gas metal arc (GMA). The test results show that good weld seam formation can be achieved with 3 layers of welding with uniform heat input changes for each layer. During the welding process, the laser focus should be strictly controlled within the bevel edge of the weld groove, the requirements of the filler layer on the laser focus position are not strict; in order to give full play to the role of the laser, a higher wire feed should be adopted speed. In addition, the tensile mechanical properties of the weld test results show that ultra-low carbon bainitic steel laser-GMA arc hybrid welded joints can reach more than 95% of the base metal tensile strength, and even part of the weld over the base metal, the average Tensile strength reached 829.5MPa. When the sample is broken in the weld, the welding defect is the main reason for the decrease of weld strength.