高氮钢复合焊接接头组织与力学性能研究

发布时间：2018-01-01 10:07

本文关键词：高氮钢复合焊接接头组织与力学性能研究　出处：《中国机械工程》2016年24期 　论文类型：期刊论文

【摘要】：热输入对焊接接头组织与力学性能有重要影响。采用激光-电弧复合焊接方法,研究了不同电弧能量和激光能量下的接头组织、焊缝氮含量、拉伸与冲击性能及接头显微硬度。研究表明:焊缝组织为奥氏体+少量δ铁素体,焊缝中析出的δ铁素体随热输入加大而增多;当电流达到200A后,熔池液态金属中氮的溶解近于饱和,即使焊接电流增大,焊缝氮含量依然趋于恒定;而当激光功率增至2.0kW后,焊接过程中的匙孔维持在稳定状态,焊缝氮含量也近于恒定;拉伸断裂位置均在焊缝区,当焊接电流为200A时,平均拉伸强度最高,达到967.58MPa,当激光功率为1.6kW时,平均拉伸强度可达962.88MPa;焊缝冲击功随激光功率的增大呈先降低后升高的变化趋势,但随电流的增大其变化趋势相反;熔合线的冲击功随着焊接参数的变化呈现出相同的变化趋势,焊缝和熔合线的最大平均冲击功分别为47.60J和62.85J;拉伸和冲击的断裂形式均为韧性断裂;焊缝区显微硬度最低,导致拉伸测试时均断裂于焊缝区。
[Abstract]:Heat input has an important effect on the microstructure and mechanical properties of welded joints. By using the method of laser arc hybrid welding, the joint research organization of different arc energy and laser energy, nitrogen content of the welds, tensile and impact properties and microhardness of the welded joints. The study shows that the weld microstructure is austenite and a little ferrite, delta iron weld precipitates in ferrite with the heat input increasing and increased; when the current reaches 200A, close to the liquid metal in the molten pool of dissolved nitrogen saturation, even if the welding current is increased, the nitrogen content of the weld still tend to be constant; and when the laser power increases to 2.0kW, the keyhole welding process in the stable state, the weld nitrogen content nearly constant; the tensile fracture in the weld zone when the welding current is 200A, the average highest tensile strength reached 967.58MPa, when the laser power is 1.6kW, the average tensile strength of 962.88MPa impact energy of the weld seam; The change trend with the increase of laser power was first decreased and then increased with the increase of electric current, but the opposite trend; the impact of the fusion line with the change of welding parameters showed the same trend, the maximum average impact of weld and welding line power were 47.60J and 62.85J; the tensile and impact fracture forms are fracture toughness; weld microhardness tensile test were the lowest, leading to fracture in the weld region.

【作者单位】：长春理工大学;长春奥普光电技术股份有限公司;长城汽车股份有限公司;
【基金】：国家自然科学基金资助项目(51305044)
【分类号】：TG407
【正文快照】： 0引言高氮钢具有优异的力学性能及耐腐蚀、耐氧化、耐磨损等性能。这些优异的性能使其迅速成为造船、航空及兵器等领域装备制造中的重要材料,而焊接技术是决定其推广应用的重要因素[1-4]。由于高氮钢自身具有氮含量高的特点,焊接过程中常因母材氮析出而导致焊接气孔问题,热影

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