Research On Microstructure Control Process Of Duplex Stainless Steel Surfacing

Aiming at the problem that the proportion of duplex stainless steel may be out of balance during welding.In this paper,CMT welding technology is used to weld a layer of transition layer ER304 on Q345 base plate,and a layer of ER2209 surfacing layer is welded on the transition layer.The process parameters of surfacing are systematically studied,and the microstructure and properties after surfacing are analyzed.The results show that:The process parameters of CMT surfacing ER304 are current 120 A,welding voltage 13.7V,welding speed 2mm/s,swing width 7mm,dwell time on both sides 0.1s,welding swing frequency 1Hz,and shielding gas flow 18L/min.When the overlap amount of multi pass welding is 3mm,304 surfacing layer can be obtained without defects and pores in the macro view.The process parameters of CMT surfacing ER2209 are current 122 A,welding voltage 14 V,welding speed 2mm/s and swing width 8mm.The dwell time on both sides is 0.1s,the welding swing frequency is 1Hz,and the gas flow rate is 18L/min.The overlapping amount of multi pass welding is 3mm.ER2209 surfacing layer can be obtained,which has no defect and no pore crack.ER2209 surfacing layer welded by the above process has a good dual phase ratio,α About 48%.The electrochemical corrosion results show that the surfacing layer has good corrosion resistance.Compared with Q345 substrate,the corrosion resistance is greatly improved by 0.249 V.The hardness of the duplex stainless steel surfacing layer prepared with the above parameters is between 215-240 Hv.The welding process was simulated by numerical simulation software.The results show that when the welding heat input increases,the maximum temperature in the weld center increases,the welding compressive stress increases,and the welding deformation increases.In order to reduce the welding deformation,it can be considered to increase the welding speed and reduce the welding heat input when formulating the actual welding process.