以8.0 mm厚的高氮钢板为试验材料, 采用Nd: YAG激光-熔化极活性气体保护焊(Metal Active Gas, MAG)电弧复合焊接方法, 研究了单一成分活性剂(TiO2, B2O3, Cr2O3)对高氮钢激光-电弧复合焊焊缝组织和性能的影响。研究表明, 活性剂能增加焊缝组织的δ-铁素体数量、使晶粒细化、减小奥氏体的晶枝, 对焊缝组织有改善作用。添加活性剂Cr2O3的焊缝组织变化显著, 出现异金属夹杂现象; 活性剂TiO2、B2O3和Cr2O3都能使焊缝区硬度有所提高, 使熔合区硬度有所降低, 其中活性剂B2O3作用下的焊缝熔合区的硬度最小。加活性剂的复合焊焊接接头抗拉强度均比无活性剂复合焊焊接接头的抗拉强度低, 抗拉强度的大小顺序为无活性剂＞活性剂B2O3＞活性剂Cr2O3＞活性剂TiO2, 拉伸断口均为韧窝断口形貌。

Nd:YAG laser- metal active gas(MAG)arc hybrid welding is used to weld the high nitrogen steel plate of 8.0 mm thick.The effects of activating fluxes(TiO2,B2O3,Cr2O3)on microstructure and properties of high nitrogen by laser-arc hybrid welding are studied. The results show that surfactant can increase the quantity of the delta ferrite of the weld microstructure, make the crystal grain refinement, reduce austenitic dendrites so that the weld organization can be improved, and the weld organization of adding surfactant Cr2O3 has changed obviously and appeared the phenomenon of foreign impurity metal. Surfactant TiO2,B2O3,Cr2O3 can improve the weld zone hardness, decrease the hardness of the fusion zone, and that of the fusion zone is the lowest under the action of surfactant B2O3. The tensile strength of the welding joint of hybrid welding with surfactant is lower than that of the welding joint of hybrid welding without surfactant. The size order of the tensile strength is no surfactant> surfactant B2O3> surfactant Cr2O3>surfactant TiO2. All tensile fractography is dimple.