Research On The Microstructures Of The High Nitrogen Steel After Laser-arc Hybrid Welding

In general,the wide applicability of materials depends not only on the properties of the material itself,but also on the stability of the inter-material bonding technique,which often plays a decisive role.As a new type of welding technology,laser-arc hybrid welding makes up for the shortcomings of single laser welding and single arc welding,and combines the advantages of both in the field of industrial production and other fields gradually developed.Based on the excellent performance of high nitrogen steel as test materials,laser and electric arc compound welding sample plate.Using some related experimental instruments and equipment: scanning electron microscope(SEM),energy spectrum analyzer(EDS),optical microscope(OM),X-ray diffraction(XRD),microhardness tester,tensile testing machine and so on after butt welding on the example of processing operations.Through the early stage of the welding test change process parameters of welding current and arc voltage,the different arc energy influence on welding joint quality and performance,so as to optimize the optimum parameters of welding experiment.Experiment is carried out under the optimal welding parameters,observation and analysis of high nitrogen steel welded joint microstructure change,and relevant conclusions,to guide the actual production.The microstructural analysis of the welded joint shows that the welded joint is composed of the base metal,heat affected zone and weld zone.The microstructure of the weld zone is typical dendrite and small amount of equiaxed crystal morphology.The results of EDS analysis show that the content of alloying elements in different microstructures is different.The second phase precipitates in the weld are analyzed by alloy composition,and the results show that the alloy has the effect of welding metallurgy.X-ray diffraction analysis of the welded joints shows that both the base metal and the heat affected zone are austenitic,and the weld zone is accompanied by a small amount of ferritin in addition to austenite.Tensile test results show that the tensile fracture appears in the weld zone,the fracture morphology is typical of the dimple fracture,and the fracture can be found in the second phase particles and the morphology of the characteristics of the weld defects which may result in weak mechanical properties.The property of the weld has a certain relationship with the laser keyhole and the complex heat source instability.The generation of the hot crack of the weld appears in the vicinity of the weld line near the weld line,indicating that the metallurgical and crystal formation has a certain relationship.