Yield Strength

The yield strength is an essential material parameter that specifies the maximum mechanical stress up to which a material is elastically deformable. This means that the material returns to its original shape after the load is removed. If the yield strength is exceeded, plastic deformation occurs, causing the material to undergo permanent changes in shape. In a tensile test, the yield strength is determined by the stress at which the material transitions from elastic to plastic behaviour. Some materials, especially unalloyed or low-alloy steels, exhibit a pronounced yield strength with an upper and lower yield strength. The upper yield point (ReH) is the highest stress before the material begins to flow, while the lower yield point (ReL) is the lowest stress during flow. For materials without a pronounced yield point, the 0.2% elongation limit (Rp0.2) is often used as a substitute value. In stainless steel technology, knowledge of the yield point is crucial for the design and application of components, as it provides information about the load limits of the material.