Microstructural factors that determine the weldability of a high Cr-high Si HK 40 alloy

The modified HK 40 heat resistant steel with higher chromium and silicon content has improved resistance to carburization and metal dusting but presents serious weldability problems as the material is fissured during the welding process. In order to know the microstructural factors that determine the weldability of the alloy, several welding repair tests were carried out and the causes that origin cracking during welding process were determined. The purpose of this study was to determine the phases that participate in the cracking and to analyze their effect on the weldability of the alloy.