【作者】 韩峰；

【导师】 韩端锋；

【作者基本信息】 哈尔滨工程大学 ， 船舶与海洋结构物设计制造， 2017， 硕士

【摘要】 不锈钢材料由于具有优良的耐腐蚀性能、令人满意的机械强度及良好的韧性,在现代船舶制造中得到越来越广泛的应用。等离子弧焊是利用等离子弧作为热源的一种焊接方法,具有能量密度大、焊接速度快、不需要焊丝且焊缝质量好等优点。若将等离子弧应用到船用不锈钢的焊接中,会提高焊接速度,降低造船成本,进而增加船厂利润。本文以304不锈钢为试验材料开展工艺试验,研究不锈钢穿孔型等离子弧焊接的工艺特性。通过多次试验发现焊缝成形主要受焊接速度影响;焊缝熔透度主要受焊接电流、钨极内缩度以及焊枪离焊件距离影响。为此,设计了五因素三水平的正交试验,研究焊接速度、焊接电流、等离子流量、钨极内缩度、焊枪距工件距离五个因素对焊接质量的影响规律。在此基础上,分析船用不锈钢穿孔型等离子弧焊的成形机理,分析立焊时的熔池受力状态。通过等离子弧立焊试验,探究焊缝成形的最佳工艺参数范围。将试验得到成型较好的焊件做线切割,进行拉伸试验和金相试验,观察接头的形状和微观组织形貌,分析焊缝的力学性能。结果表明,立焊焊缝的力学性能与平焊焊缝相差不多,达到母材力学性能的90%以上,均为一级焊缝。更多还原

【Abstract】 Stainless steel materials have been widely used in modern shipbuilding industry owing to their excellent corrosion resistance,satisfactory mechanical strength and good toughness.The PAW(Plasma-Arc Welding)uses plasma arc as a heat source which has the advantages of high energy density,fast welding speed,no need of welding wire and good weld quality.If the plasma arc welding could be applied to the welding of marine stainless steel,it will increase the welding speed,reduce the costs,and increase profits of the shipyard.In this paper,we use 304 stainless steel to carry out the experiment to study the characteristics of the stainless steel perforated plasma arc welding process.Through several tests,it is found that the weld forming is mainly affected by the welding speed.The weld penetration is mainly affected by the welding current,the tungsten internal shrinkage and the distance from the welding torch.In this paper,the orthogonal test of five factors and three levels is designed to study the influence of welding speed,welding current,plasma flow rate,tungsten internal shrinkage and welding distance from the workpiece distance on welding quality.The purpose of this paper is to analyze the forming mechanism of stainless steel perforated plasma arc welding and observe the weld shape and test the mechanical properties of the weld.Through the plasma soldering experiments,we got the best parameters of the experiment,the torch distance is 2mm,the welding speed is 7.7cm / min,the current is 100 A,the tungsten inner shrinkage is 2mm.The welds were subjected to wire cutting,tensile test and metallographic test.The shape and microstructure of the joint were observed and the mechanical properties of the weld were analyzed.The results show that the mechanical properties of the welding seam are almost the same as those of the flat welding weld,which is more than 90% of the mechanical properties of the base metal.We get the mechanical properties roughly as follows,after stretching fracture,the maximum force of 62886.9N,extension strength of 875 N / mm2.The ultimate tensile stress is 855.59 mp.However,the effective penetration of the riser weld is higher than that of the flat weld,and the flat weld can only reach 8mm,but the welding seam of the riser weld can reach at least 20 mm.更多还原