← Glossary

Quench crack

Hardness crack is a crack-like defect caused by too rapid cooling during quenching. This leads to extremely high internal stresses in the workpiece.

Physical-chemical mechanism of action

Hardness cracks occur when the weld workpiece cools too quickly. This causes a rapid crystal structure change and forms glass-hard martensite. The strong internal stresses can overstress the material.

Metallurgical relevance & risks in welding

Hardness cracks lead to high mechanical stresses in the workpiece, which can cause cracks and buckling effects. They reduce the toughness and service life of the material.

Workshop practice & action instructions

To avoid hardness cracks, ensure controlled cooling. Use a long quenching time (t8/5 > 25 s) and protect the workpiece from rapid cooling shocks. For high-hardness metals, controlling the cooling rate is especially important.

MetallurgieSchweißtechnik

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