Comparative Study On Welding Process And Mechanical Properties Of Slag-Free And Slag Self-shielded Flux-Cored Wire

In recent years,The flux-cored wire becomes the greatest potential welding consumables.Moreover,the self-shielded flux cored wire with its characteristics of energy conservation and emissions reduction optimization industry become the mainstream of development direction of flux-cored wire.In this paper,the advantages and disadvantages of the welding properties are discussed by comparing the structure and performance of two self-protected cored wires with slag and slag-free.Respectively for free of slag and slag self-protection flux cored wire welding performance(covering slag and slag,weld metal forming,the spatter rate)and the mechanical properties of deposited metal,toughness,hardness and so on has carried on the systematic study and discussion.Through the macro forming of the two kinds of welding wire,welding parameters,spatter test,slag covering and so on,two kinds of self protection flux cored wire without slag and slag were compared.The results show that the welding parameters of the two kinds of welding wire are the best when the diameter is 1.2mm,and the welding spatter is the smallest when the diameter of the two kinds of flux cored wire and the slag self protective flux cored wire are all in the diameter of 250 A and 25 V.Slag free self shielded flux cored wire is superior to slag self shielded flux cored wire in spatter,slag removal and pore sensitivity.Microstructure of deposited metal of two kinds of welding wire was observed.The results show that the matrix structure of slag free self shielded flux cored wire is mainly composed of martensite,retained austenite and ferrite.The matrix structure of flux shielded flux cored wire with slag is mainly composed of martensite,retained austenite,cementite and acicular ferrite.Grain size of deposited metal with slag self shielded flux cored wire is smaller than that of slag free self shielded flux cored wire.The strength of deposited metal of two kinds of welding wires was measured by universal electronic tensile testing machine.Hardness of deposited metal of two wire was measured by HR-150 hardness tester.The results show that the toughness of the deposited metal with slag self shielded flux cored wire is better than that of the slag free self shielded flux cored wire,and the tensile strength reaches Q235 strength.The hardness of deposited metal with non slag self shielded flux cored wire is 57.9HRC,and the hardness of deposited metal with slag self shielded flux cored wire is 52.2HRC.