Due to the problems that the groove rails need to be repaired in the field during the service process such as wear and fatigue

special welding wire and special automatic welding repair equipment are selected. On the basis of the optimal surfacing welding process parameters explored by the failed orthogonal test of the single-layer surfacing welding

discussing the feasibility of multi-layer welding repair process

and the organization and performance level of surfacing layer. The results show that under the preheating condition of300 ℃

in the heat affected zone of the single-layer welding layer

martensite is inevitable. But with the welding voltage of 31 V

wire feed speed of 220 mm/s

and welding speed of 8 mm/s

the martensite content in the heat-affected zone of the surfacing layer is the lowest. The microstructure of the heat affected zone in these multi-layers are pearlite

and there are no cracks

pores

and other defects in these layers. Welds are well-formed

the microstructure of welds are austenite

and their hardness values are well matched to the parent metal;the polymer damping material properties are not obviously effected by heat generated by welding repair process.Therefore

multi-layer welding repair technology has good process feasibility.