Plastic flow limit
The plastic yield point is the stress value beyond which a metal flows plastically and becomes formable. It separates the elastic from the plastic region.
Physical-Chemical Mechanism of Action
The plastic yield point is the point at which the internal atomic bonds of a metal are so heavily stressed that they can no longer align completely. The atomic structure begins to distort and become malleable.
Metallurgical Relevance & Risks in Welding
When stress exceeds the plastic yield point, micro-deformations occur in the material. This can lead to cracks or distortion and impair the strength of the workpiece. In welding, it is crucial to keep the stress level below this limit to achieve a clean and stable joint.
Workshop Practice & Action Guidelines
To ensure the plastic yield point is not exceeded, the correct stress values must be maintained during welding. This can be achieved by selecting the right welding process and appropriate materials. At high stresses, careful control of temperature and stress state is essential.