Microhardness and Microstructure on Welding of Nodular Cast Iron Grade FCD 500

Abstract

The aim of this research is to study the microhardness and the microstructure of the welds of nodular cast iron by SMAW process utilizing two different patterns of filler metal: one uses only ENiFe-CI and the other employs ENiFe-CI as butter layer and followed by E7016. These investigations represent that the highest hardness occurs in the fusion boundary due to carbide formation; the HAZ composes of the formation of bainite and the bottom of the E7016 weld metal comprises martensite. On the contrary, the base metal and the ENiFe-CI weld metal gives lower hardness because of the formation of pearlite and graphite nodules surrounded by ferrite rings and austenite with ferrite at the sub-grain boundary respectively.