Spheroidal graphite

Compact, spherulitic graphite precipitates in ductile cast iron produced by targeted magnesium or cerium treatment. This morphology minimizes stress concentrations in the microstructure and drastically increases elongation at break.

Nodular graphite forms when producing ductile cast iron by adding magnesium or cerium to the melt. That's a casting step, not welding. When welding such cast iron, be careful: the heat can break down the nodular graphite and you get hard, crack-prone cementite. So preheat the part, weld with a suitable electrode, and let it cool slowly. If you don't, the workpiece will crack quickly.

MetallurgieSchweißtechnik