厚板碳钢激光-MAG复合焊接工艺研究及接头组织性能分析

发布时间：2018-06-06 15:11

本文选题：碳钢 + 激光-MAG复合焊接　；参考：《华中科技大学》2015年硕士论文

【摘要】：碳钢在各种工程结构、零件加工及模具制造中占有相当大的比重,尤其是20mm左右大厚度碳钢在各行各业的发展中均发挥着不可替代的作用。激光-MAG复合焊接技术综合了激光焊接热量集中且焊缝深宽比大、传统MAG焊工艺适应性强应用广泛的优点,在难熔金属、大厚构件的焊接中具有显著优势,且工艺适应性较高,在焊接加工领域逐渐展现出了广阔的应用前景。本文以碳钢为基材,研究激光-MAG复合焊接工艺在厚板碳钢上的应用,并分析了焊接接头的组织性能。本文通过大量实验,研究了激光-MAG复合焊接的主要工艺参数,比如激光功率、电弧电流、焊接速度、光丝间距等对接头形貌的影响,确定了高品质焊缝对应的工艺窗口。并且,重点分析了激光-MAG复合焊接时接头熔透状态不稳定导致的背面成形不连续问题,提出了先稳定电弧后开启激光、设置间隙量等相应的解决方案。在此基础上,本文进一步研究了20mm厚碳钢的激光-MAG复合焊接工艺。通过双面无坡口焊接、双面开坡口焊接、单面开坡口焊接三种形式均实现了完全焊合,并对比各焊接形式在接头形貌、加工效率等方面的优劣,优化了工艺参数。最后,通过分析接头的显微组织特征,总结了工艺参数与接头性能之间的规律。并且,针对整个实验过程中出现的常见焊接缺陷,如气孔、裂纹、未熔合及热源耦合不当等问题进行了分析,寻找其形成的原因,总结了施焊过程中应该重视的问题,规范工艺以避免焊接缺陷的产生。
[Abstract]:Carbon steel occupies a large proportion in various engineering structures, parts processing and die manufacturing, especially carbon steel with large thickness about 20mm plays an irreplaceable role in the development of various industries. The laser-MAG composite welding technology combines the advantages of laser welding heat concentration and weld depth to width ratio, and traditional MAG welding technology has strong adaptability and wide application. It has significant advantages in the welding of refractory metal and large thick components, and the process adaptability is high. In the field of welding processing has gradually shown a broad application prospects. In this paper, the application of laser-MAG composite welding technology to thick plate carbon steel is studied, and the microstructure and properties of welded joints are analyzed. In this paper, the effects of laser power, arc current, welding speed and optical wire spacing on the morphology of laser MAG composite welding are studied, and the process window corresponding to high quality weld is determined. In addition, the discontinuity of backside forming caused by the unstable penetration state of the joint during laser-MAG composite welding is analyzed, and the corresponding solutions such as stabilizing the arc first and then opening the laser and setting the gap are put forward. On this basis, the laser-MAG composite welding process of 20mm thick carbon steel is further studied in this paper. The welding process parameters are optimized by welding without groove on both sides, welding with double groove and welding with single groove, and comparing the advantages and disadvantages of each welding form in terms of joint appearance and processing efficiency. Finally, by analyzing the microstructure of the joint, the relationship between the process parameters and the properties of the joint is summarized. In addition, the common welding defects, such as porosity, crack, non-fusion and improper coupling of heat source, which appear in the whole experiment process, are analyzed, the reasons for their formation are found, and the problems that should be paid attention to in the process of welding are summarized. Standardize the process to avoid welding defects.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG457.11

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