超薄不锈钢激光焊接工艺及接头性能研究

发布时间：2018-06-17 14:43

本文选题：光纤激光焊 + 超薄不锈钢　；参考：《应用激光》2017年03期

【摘要】：超薄不锈钢在航天、医疗器械、日用品中的应用日趋广泛,对其激光焊接质量也提出了更加苛刻的要求。由于材料很薄,易于汽化穿孔,要想得到连续、无烧穿的焊缝,关键是对参数的精确控制。采用光纤激光实现了0.2mm厚1Cr18Ni9Ti不锈钢片的对接及搭接焊。研究了激光功率、焊接速度、离焦量、脉冲频率、占空比等工艺参数对焊缝表面成形的影响规律,并对焊缝显微组织及接头力学性能进行了考察。结果表明,在连续焊模式下,即使采用非常小的热输入,也无法避免焊缝起始及收尾处出现的烧穿;脉冲焊模式下,热输入一定时,采用低的脉冲频率、占空比及焊接速度相比高的脉冲频率、占空比及焊接速度可以有效减少单脉冲能量,从而避免焊缝在起始及收尾处的烧穿。在优化的工艺参数下可得到表面成形良好、无烧穿的对接及搭接焊缝。焊缝中心区由柱状晶与等轴晶组成,几乎不存在热影响区,对接接头抗拉强度可高于母材,搭接接头经拉剪测试断于母材。
[Abstract]:Ultra-thin stainless steel has been widely used in aerospace, medical instruments and daily necessities. Because the material is very thin and easy to be vaporized and perforated, the key to obtain continuous, non-burn-through welds is to control the parameters accurately. The butt joint and lap welding of 1Cr18Ni9Ti stainless steel sheet with 0.2mm thickness have been realized by fiber laser. The effects of laser power, welding speed, defocus, pulse frequency and duty cycle on the weld surface forming were studied. The microstructure and mechanical properties of the joint were also investigated. The results show that even if very small heat input is used in the continuous welding mode, the burn-out at the beginning and the end of the weld can not be avoided, while in the pulse welding mode, the low pulse frequency is used when the heat input is fixed. The pulse frequency, duty cycle and welding speed with higher duty cycle and welding speed can effectively reduce the single pulse energy, thus avoiding the weld penetration at the beginning and the end. The butt and lap welds with good surface forming and no burn-through can be obtained under the optimized process parameters. The center of weld is composed of columnar crystal and equiaxed crystal, there is almost no heat affected zone, the tensile strength of butt joint can be higher than that of base metal, and the lap joint is broken by tensile and shear test.
【作者单位】：上海航天设备制造总厂特种焊接中心;
【分类号】：TG456.7

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