Microstructure and erosion characteristic of nodular cast iron surface modified by tungsten inert gas

摘要: Abstract The surface of nodular cast iron has been melted and rapidly solidified by Tungsten Inert Gas (TIG) process to produce a chilled structure high hardness better erosion resistance. Welding currents magnitude 100, 150, 200 A at constant voltage 72 have used melt the iron. Microstructural characterization, measurements, wear tests performed on these modified surfaces as well untreated material. characterization shown that melting resulted in complete or partial dissolution graphite nodules resolidification primary austenite dendrites, which undergo further decomposition into ferrite cementite, interdendritic acicular eutectic; their microhardness measured across depth ranged between 600 800 Hv. scale dendrites eutectic became coarser when higher current is used. results also indicated remelting TIG improved resistance three four times. Eroded observations as-received samples showed ductile behavior with maximum rate 30°. fine microstructures obtained rapid cooling formation large amount cementite instead contributed greatly plastic flow consequently samples.