Definition - What does Yield Strength mean?
Yield strength of a material is that point at which the material loses its elasticity and becomes plastic. The point at which the material yields is called the yield point. The yield strength of a pipe depends on the yield strength of its material, the pipe size and wall thickness.
Yield strength is an important factor in designing pipes and its components and depends on the loading conditions that the pipe will be subjected to and the purpose which the pipe will serve. Buried pipes are subject to different loads from within and without including soil pressure, and live and dead loads.
The pipe material should have sufficient yield strength so that it performs in the elastic region.
Trenchlesspedia explains Yield Strength
The yield strength of a material is a predetermined amount of deformation that occurs at a certain stress. When the internal pressure of a pipe reaches the yield strength the pipe will fail under deformation and may even burst. A pipe's configuration, the yield strength of its material, the thickness of the pipe wall and the size of the pipe are all important factors that determine its yield strength. The yield strength is an approximation of a materials elastic limit and if the yield point is not reached, the material will regain its original shape when the stress is removed.
Yield strength represents the maximum limit of safe load application without deforming it permanently.