Optimization Of Bi-free Stainless Steel FCAW Cladding Process

Cladding is one of the important ways to improve the mechanical parts surfaceproperties.It can not only repair the old metal parts，but also overlay a composite layer onthe surface of workpiece．It can give the mechanical parts some special properties，so as toimprove the surface quality,increase the working life and reduce the cost．Bi-free stainless steel FCAW cladding Process parameters have important influenceon the arc stability,appearance of overlaying layer，overlaying quality and overlayingefficiencv obviously．Overlaying current，arc voltage，wire feed speed，shielding, flowrate,wire size, tube to work distance, welding torch swing angle、 Torch angle、preheat/interpass temperature.The objective of this study is to optimize Bi-free stainless steel FCAW claddingProcess of the nuclear pressure equipment of small diameter workpiece and the transitionregion.The study of Bi-free stainless steel FCAW cladding Process parameters on thestability, chemical composition surfacing, surfacing layer and the heat-affected zonemicrostructure and properties were investigated to determine the non-bismuth steel FCAWwelding optimum parameters: Choosing CO2as protective gas, gas flow rate of15~25L/min, flux cored wire diameter of1.2mm, tube to work distance of20mm, Overlayingcurrent180to200,welding voltage28~30V, the welding torch swing angle-10°~0°,welding torch inclination to-10°~0°, welding speed is350~550mm/min, preheating/interlayer temperature100～120℃/160℃~180℃. Bismuth free stainless steelFCAW welding process optimization is successfully applied to the three generation ofAP1000nuclear power plant steam generator pipe inner wall surfacing, the products meetthe technical requirements of users.