Hot Crack
A hot crack forms during cooling of the melt and is caused by low-melting impurities at grain boundaries.
Physikalisch-chemischer Wirkmechanismus
Hot cracks form when the melt cools quickly and low-melting impurities such as silicon or carbon are concentrated at grain boundaries. These impurities accumulate into microstructures that stress the material and cause cracks.
Metallurgical Relevance & Welding Risks
Hot cracks can lead to severe material failure and significantly shorten the service life of components. They are particularly dangerous when they are not visible or are located in the weld, as they can suddenly propagate under mechanical stress.
Werkstattpraxis & Handlungsanweisungen
To avoid hot cracks, it is important to ensure controlled cooling and a clean weld pool. Use high-melting-point deoxidizers such as silicon or titanium and pay attention to the correct carbon content in the steel. For heavily stressed components, careful control of cooling times is essential.