Experimental Research On Weldability And Welded Joint Performance Of 10cr13Ni2 Steel

Martensitic stainless steel is characterized by good hardenability.It can be strengthened through the heat treatment process such as quenching and tempering to obtain higher strength,hardness,wear resistance and fatigue resistance,and has a certain degree of corrosion resistance.So it has been widely used in oil,chemical,automobile and aeronautical areas.However,due to the fact that martensitic stainless steel welded joints are prone to cracks,embrittlement and other defects,its application is limited to a large extent.In this paper,the crack sensitivity of the new martensitic steel 10Cr13Ni2 was evaluated by FISCO test.the maximum hardness test in the heat affected zone and the welding crack test of the inclined Y shaped groove,and the effects of three different process conditions on the microstructure,tensile properties and impact toughness of the welded joint of 10Cr13Ni2 steel were tested and analyzed.The corrosion resistance of welded joints was tested in 5%NaCl solution and 5%Na2SO4 solution respectively.(1)The FISCO test showd that when the welding current was increased from 80 A to 120 A,the cracking rate increases and then decreases when the welding current rises from 120A to 140A.Under the condition of this study,the crack rate was the maximum when the current was 120 A.(2)The highest hardness test of heat affected zone showd that the preheating temperature has little effect on the cold crack tendency of the steel from 0 to 250? degrees.Experimental verification of weld crack on oblique Y groove showd that no cold crack occurs at preheating temperature of 150? and 250?.(3)When the preheating temperature was increased from 150? to 250?,the microstructure of the heat-affected zone of the welded joint was mainly martensite and ferrite,and the ferrite changes from an irregular massive distribution to a regular distribution along the fusion line.The microstructure of the weld zone was martensite.With the temperature rised,the organization grew obviously and the columnar characteristics decreased.After preheating at 250?,after tempering at 610?,the welded joint micro structure was tempered sorbite and induced austenite.(4)With the preheating temperature of 150?,the tensile strength and other comprehensive parameters of the samples were the best,and the fracture was plastic fracture,so the tensile property of the samples was the best.Different treatment processes had little influence on the impact toughness of the welded samples,in which the fracture morphology of the preheating temperature is 150? as dimple feature,and the dimple was small and shallow,so the impact toughness of the samples was slightly better.(5)The corrosion resistance of 10Cr13Ni2 steel welded samples in the corrosive medium of 5%(mass fraction)NaCl solution is inferior to that in the corrosive medium of 5%Na2SO4 solution.The corrosion resistance of the weld zone was better than that of the welding heat affected zone.The pitting corrosion of the welded joint specimens occurred in both corrosion media,and the corrosion resistance of the welded joint with preheating at 250? was the best in the two kinds of corrosion medium,and the corrosion resistance of the base metal was the worst.