Secondary carbide
Secondary carbides form during cooling and increase strength, but too much leads to hot cracking.
Physicochemical Mechanism of Action
Secondary carbides are fine carbides that form during cooling from the supersaturated solid solution. They form through diffusion processes between carbon and iron.
Metallurgical Relevance & Risks in Welding
Secondary carbides increase the strength and toughness of the steel, improving its mechanical properties. However, too high concentrations of secondary carbides can lead to hot cracking, especially if cooling is too fast. This can cause local stresses and cracks in the weld.
Workshop Practice & Action Instructions
To minimize the negative effects of secondary carbides, it is important to ensure controlled cooling. This can be achieved by choosing the right welding process and correct cooling time. For high-carbide steels (e.g., HSS), cool especially carefully to avoid hot cracking.