The Development Of Self-shielded Flux Cored Wire And The Study Of Weld Performance Of 2205 Duplex Stainless Steel

2205 duplex stainless steel is widely used in petroleum and natural gas transportation,chemical industry,ship and marine equipment because of its excellent performance.In recent years,self-shielded flux cored wire(SSFCW)has been developed rapidly and gradually became a new-type welding materials used in engineering practice for its convenient welding,good welding regulation,full position welding and so on.Through systematic analysis of 2205 duplex stainless steel chemical composition and weldability,combined with the basic requirements of SSFCW in engineering practice,a new-type SSFCW for 2205 duplex stainless steel has been developed.At the same time,the technological properties of the wire,the mechanical properties and corrosion resistance of the welded joint,and the main influencing factors and influencing laws of the above properties were emphatically discussed.TiO2 is beneficial to improve the uniformity of the slag coverage,but it will also lead to the decline of the are stability when content is too high.The CO2 gas produced during the welding process of Li2CO3 can protect the weld metal,and the lithium atom plays an important role in the stability of the arc.With the increase of Fe2O3 content,the problems of spatter and arc instability can be found.Excessive amount of Al2O3 and Fe2O3 will lead to the deterioration of welding slag.The slag removal rate decreases with the increase of basicity and linear expansion coefficient.Ni and Mn elements can increase the content of austenite in the weld;Cr and Mo elements are beneficial to the formation of ferrite.In addition,Mn elements can also promote the formation of acicular ferrite and inhibit austenite growth.The strength and hardness of the weld metal increase with the increase of ferrite content,while the impact absorption work increases with the increase of austenite content.The refinement of the grain can improve the strength and toughness of the weld metal simultaneously.Cr23C6 and Fe7C3 and some oxides,such as MnO and SiO2,exist in the form of second phase,which results in a decrease in the impact energy of the weld metal.The corrosion rate of 2205 stainless steel welded joint in HCl is greater than that in H2SO4.