Characteristics of surface remelted hardfacing spheroidal graphite cast iron using the plasma transferred are process

The plasma transferred are (PTA) process was used to obtain a 2-5 mm thickn ess remelted hardfacing layer on the spheroidal graphite cast iron surface. Cementite structure can be observed on the surface layer, exhibiting a sig nificantly high hardness due to rapid solidification, The composition of 3. 54 wt pct carbon and 2.48 wt pct silicon remains fixed throughout the PTA s urface remelting experiment. To study the effect of substrate microstructur e on the remelted hardfacing layer, experimental parameters including spher oidal graphite nodule count and the microstructure of matrix are conducted. Experimental results confirm that the remelted hardfacing layer is accompan ied by a large amount of Fe3C eutectic cementite. If the PTA remelting inpu t current is increased, the volume fraction of eutectic cementite tends to decrease, subsequently decreasing the hardness. An increased spheroidal gra phite nodule count of the substrate tends to decrease the hardness of the r emelted hardfacing layer. The substrate with ferritic matrix shows increase d hardness over a pearlite structure. Furthermore, while the impact angle i s fixed at 30 degrees, the erosion wear resistance increases with the incre asing hardness of the remelted hardfacing layer, but this tendency is contr ary when the impact angle is fixed at 90 degrees.