Induced residual stresses
Induced residual stresses are compressive stresses introduced into materials by mechanical deformation to increase their fatigue life under cyclic loading. They prevent cracks at surface notches.
Physical-Chemical Mechanism of Action
Induced residual stresses are created by mechanical deformation of materials, such as forming or welding. These deformations alter the crystal structure and lead to internal stresses that build up in the material structure.
Metallurgical Relevance & Risks in Welding
These stresses can help prevent cracking at surface notches by deforming the material and making crack initiation harder. However, too high residual stresses can also lead to cracking if they are too high or not introduced correctly. This can happen especially under cyclic loading.
Shop Practice & Action Instructions
To successfully introduce induced residual stresses, the following steps should be observed:
• Use a correct forming technique, such as forming or welding with special processes.
• Ensure that the material temperature during deformation stays below the stress formation temperature point to guarantee a homogeneous stress distribution.
• Monitor the stress distribution and correct the forming technique or material temperature if necessary.