| The Cr15Mn9Ni1N austenitic stainless steel belongs to 200 series stainless steels. Compared with conventional Ni-Cr series austenitic stainless steels, this kind of steel possess some special properties, such as high strength and toughness, excellent corrosion resistance and nonmagnetic porperty. These stainless steel with high Mn content, and adding nitrogen to strengthen. Furthermore, cost of materials can be greatly reduced by taking nitrogen to replace nickel for stabilization of the austenitic structure.However, this kind of steel is differs from welding process solidification and the metallurgy characteristic of Ni-Cr series austenite stainless steels as a result of special chemical composition. Its tendency to solidification hot cracking large than conventional 300-series austenitic stainless steel. In this dissertation,the welding characteristics of this stainless steel were systematically and deeply investigated, and the solidification mode of weld metal,microstructure characteristic,hotcracking tendency in the steels were analyzed and discussed.Select an appropriate welding materials as E309L-16 stainless steel welding rod according to special chemical composition,adjusted this steel's welded joint chemical composition, has guaranteed in the deposited metal the nitrogen and other alloying element content is reasonable,to promotionγ+δmicrostructure formation. Simultaneously formulates the reasonable welding process to solves problems like hotcracking which possibly appears in the welding process. Examines its welding performance through tensile,bending and hardness test as well as metallographic analysis and EPMA,etc. Will provide the direct processing basis for the future of this industrial application.Two different welding method TIG and manual welding were used to analysis of this steel's weld characteristics under different heat input through welding process variables adjustment. Judge that welded joints as the mode of solidifying through judge the shape and locates position ofδ-ferrite. Using metallographic analysis that theδ-ferrites was distributed on the base of autenitics,as lathy ferrite,vermicular ferrite and skeletal ferrite from fusion line to welded joint center. The results of the study showed that the solidification mode of this austenitic stainless steels was FA mode. And massive project practice already confirmed that it can effectively prevent welding hot cracking if the welding metal first precipitation ofδ-ferrite solidification (FA) mode.The solidification crack tendency of weld metals of Cr15Mn9Ni1N austenitic stainless steels were overall quantitatively evaluated by using the tester Trans-Varestraint test device. Observe the welded joints crack case under different restraint situations and quantifying weld solidification cracking. Analysis of results and compared to other stainless steel materials can be seen it has low cracking susceptibility of this nitrogen strengthened austenitic stainless steels.
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