Study On Metallurgical Behaviour Between Ceramic Slag And Metallic Bath In One-sided Welding

One-sided welding is a kind of highly effective welding technology, which has been widely applied to the ships, pressure vessel, bridge and each kind of heavy section structure and equipment. Compared with two-sided welding, it can improve working conditions, saves the process of back gouging, reduce worker’s labor intensity, therefore greatly improve the production efficiency.With basic theory of one-sided welding with backing, type、characteristi、 craftsmanship and property of ceramics backing are discussed. Based on welding metallurgy, the particular welding metallurgy of one-sided welding with backing is expounded. Metal crystalline process are analyzed. By the analysis, a series of ceramics backing of diverse alkalinity are produced.Under different alkalinity ceramics backing, The composition of the weld metal and slag alkalinity are Measured, in order to make certain when alkalinity change, how the amount of Si,Mn and the metallurgy behaviour between bath weld and ceramic slag.Under different welding parameter, compostition of ceramic slag,welding slag and weld metal are measured, the amount of Si,Mn in weld metal and the metallurgy behaviour between bath weld and ceramic slag are analysed.When one-sided welding with ceramic backing, the amount of Si,Mn in weld metal are decided by the following the factors:(1) The components of ceramic backing, because of the components range, Si would transition to molten metal from ceramic slag, and Mn would transtition to ceramic slag from molten, This action would be weaken while ceramic alkalinity increase. Therefore the [Mn]/[Si] in weld metal would increase.(2) The concentration of Si and Mn in welding wire and base metal, the Si and Mn in weld metal related with weld penetration ratio, because the Si and Mn in base metal is lower than in welding wire, the Si,Mn and [Mn]/[Si] in weld metal would drop with weld penetration ratio increase.(3) Welding variables,the Si and Mn transfer efficiency would increase and the weld penetration ratio would decrease with the welding current increase. the Si.Mn and [Mn]/[Si] in weld metal would increase, the Si and Mn transfer efficiency would decrease and the weld penetration ratio would increase with the arc voltage decrease. The Si,Mn and [Mn]/[Si] in weld metal would decrease. The weld penetration ratio would increase with the welding speed increase. The Si,Mn and [Mn]/[Si] in weld metal would decrease.