Liquation behavior in the weld HAZ of high Si nodular iron

Abstract

In the present study, liquation behavior including the constitutional liquation phenomena in the weld heataffected zone (HAZ) of nodular cast iron with 4% Si was investigated. The thermal cycle of the weld HAZ was simulated using a Gleeble simulator at various peak temperatures and a fast heating rate of 1000 degrees C/sec was selected to observe the constitutional liquation phenomenon. Differential thermal analysis has shown that the eutectic constituents of gamma + Laves and gamma + Fe3C begin to melt at 1120 degrees C and 1140 degrees C, respectively. Meanwhile, constitutional liquation by gamma/graphite reaction occurred above 1140 degrees C, due to carbon enrichment around the graphite nodules.