Transformation residual stress
Transformation residual stress occurs due to time-shifted microstructural transformations and volume jumps during hardening or welding. It leads to stresses that can cause cracks under high pressure.
Physicochemical Mechanism of Action
Transformation residual stress results from locally time-shifted phase transformations and volume changes. During hardening or welding, the crystal structure and volume of the metal change, leading to local stresses.
Metallurgical Relevance & Risks in Welding
These stresses can cause cracks in the weld, especially if not properly balanced. Hard stresses can also impair the toughness and ductility of the material.
Workshop Practice & Instructions
To minimize transformation residual stress, controlled cooling sequences are important. When hardening, cool the material slowly and uniformly. When welding, choosing the right shielding gas and correct welding parameters is crucial. If needed, use stress relief techniques like peening.