Effect Of Fluoride Component And Oxide Surface Tension On Spatter In E308LT0-3

With the increasing application of stainless steel,the amount of stainless steel welding material is also increasing.Stainless steel self-shielded flux cored wire has attracted much attention due to its high efficiency,good wind resistance and easy operation.However,at present,stainless steel self-shielded flux cored wire mainly relies on imports,and its own brands are few.Moreover,compared with the foreign advanced wire,the domestic stainless steel self-shielded flux cored wire still has obvious gap in the process performance,which is highlighted by the high spatter rate.Reducing welding spatter is the key and difficult point in the research and development of stainless steel self-shielded flux cored wire.It is related to whether the domestic stainless steel self-shielded flux cored wire can break the foreign monopoly situation.The change of spatter rate of E308LT0-3 welding wire with different fluoride and oxide in the core was studied.The form and causes of droplet transition,spatter and cause were analyzed by high-speed camera,Hannover welding quality analyzer,numerical simulation analysis and so on.A mathematical model for the influence of fluoride on spatter is established,and a mathematical model for the influence of surface tension on spatter is established to provide guidance for practical production.The experimental results show that fluoride generally increase the welding spatter rate,but when fluoride is too small,slag detachability become not bad.The welding wire added with mixed fluoride in the core component is lower than that of adding a single fluoride in spatter rate.When mixing the four fluorides of NaF,MgF₂,BaF₂ and CaF₂ in the proportion of 1:1:2:6,the mixed fluoride can reduce the welding spatter rate at utmost.The spatter rate of the welding wire sample is the lowest,and the large particle spatter ratio is also the least.The experimental result indicated that the spatter will be increased when the surface tension is too large or too small.When the surface tension of the oxide is?330-340?×10^-7J/cm²,the spatter rate can decrease to 2.51%.The droplet transfer mode of stainless steel self-shielded flux cored wire is mainly composed of three types:bridging transfer without arc interruption,short circuit transfer and repelled transfer.The welding wire with moderate surface tension is dominated by the coexistence of arc bridge,which has few spatter in this mode.Bridging transfer without arc interruption is the most ideal metal transfer mode of the stainless steels self-shielded flux cored wire.In bridging transfer without arc interruption,the transfer process is relativity smooth,and the spattering is extremely reduced.