Deformation Residual Stress
Residual deformation stresses are internal stresses in the material caused by uneven cold working. They increase hardness and reduce the toughness of the material.
Physicochemical Mechanism of Action
Residual deformation stresses arise when the material is not deformed uniformly. This creates stress zones in the crystal lattice that do not fully relax. These stresses can be reduced by heat treatments such as austenitizing or normalizing.
Metallurgical Relevance & Risks in Welding
Residual deformation stresses can lead to increased hardness and lower toughness, making the material prone to cracking. During welding, this hardness can cause hot cracking or splattering, especially if the stresses are not properly addressed.
Workshop Practice & Instructions
To minimize residual deformation stresses, perform austenitizing after cold working. This involves heating the material above the austenitizing temperature and cooling slowly. When welding, it is important to preheat the weld area and cool uniformly to reduce stresses and prevent cracking.