Lath Martensite Structure

A dislocation-rich, subcrystalline structure of densely packed, parallel martensite laths typically occurring in low- and medium-carbon steels upon rapid quenching. It possesses a high dislocation density to enhance mechanical strength.

Lath martensite forms in unalloyed and low-alloy steels when you cool them too quickly after welding. The structure then becomes hard and brittle, making the weld prone to cracking. To avoid this, you need to slow down the cooling, for example by preheating or controlled post-heating. Once the weld has cooled, stress relief annealing can help make the structure tougher again. Also make sure the carbon content in the steel isn't too high, otherwise the problem gets worse.

MetallurgieSchweißtechnik