Yield strength
Yield strength is the maximum stress value at which a material plastically deforms and permanent deformation occurs. It separates elastic (recoverable) from plastic strain.
Physical-Chemical Mechanism of Action
The yield point is the point at which a material reaches its maximum elastic deformation and begins to deform plastically. Below this limit, the material springs back elastically; beyond it, the strain becomes permanent.
Metallurgical Relevance & Risks in Welding
Exceeding the yield point can lead to cracks and distortion. When welding steels, this can occur due to excessively high stress values or too rapid cooling, which coarsens the microstructure and increases hardness.
Workshop Practice & Action Instructions
To avoid exceeding the yield point, pay attention to:
• Properly set stress in the welding equipment (max. 90 % of the yield point)
• Controlled cooling of the weld seam (t8/5 between 10 and 20 seconds)
• Use of appropriate filler materials to reduce stress value