Thermal Residual Stresses
Thermal residual stresses arise from uneven cooling and different thermal expansion coefficients in a material. They can significantly impair component strength.
Physical-Chemical Mechanism of Action
During cooling of a material, its length changes depending on temperature and chemical composition. When different areas of the material cool at different rates, stresses arise because the rapidly cooled areas expand less than the slower cooled areas.
Metallurgical Relevance & Risks in Welding
These stresses can lead to cracks and deformations, especially when they exceed a critical threshold. They impair the strength of the material and can reduce the service life of components.
Workshop Practice & Actions
To minimize thermal residual stresses, it is important to ensure uniform cooling. This can be achieved by using cooling water or cooling gas. When welding steels with high carbon content (e.g., HSS), controlled cooling in a furnace should be carried out to avoid stresses. The maximum stress range should be kept below 50 MPa.