Cut Edge Hardening
Cutting edge hardening occurs when steels rapidly cool from the austenitic state into the martensitic range. This leads to a local hardness increase at the cut surface.
Physical-Chemical Mechanism of Action
Rapid cooling of austenitic steels creates local martensitic zones near the cut edges. This happens because fast cooling doesn't give enough time to form a uniform structure.
Metallurgical Relevance & Welding Risks
Cut edge hardening can lead to hard, crack-prone cut surfaces. This increases susceptibility to hot cracking and lowers the mechanical properties of the weld. It can also cause wear problems in service.
Workshop Practice & Instructions
To avoid cut edge hardening, control the cooling rate. You can do this by keeping the heat on long enough and carefully cooling the part after welding. For high-carbon steels (e.g., HSS), using cooling water or oil is especially important to regulate the cooling rate.