Abstract
When low chromium steel bars (C 0.43%, Cr 0.99%) are flash-butt-welded, the weld metal and heat affected zone show coarse structure containing martensite and troostite. The degree of decarburization of weld metal is smaller than that of low manganese steel bar.
If these parts are postheated at about 800°C with an electric furnace, the very hard microstructure in these parts, martensite, disappears and fine sorbite or granular cementite appear. Accordingly the improvement of mechanical properties are observed. In the case of postheating with a flash-butt-welder, the postheating at about 800°C is also suitable.
