When we think of steel, we might imagine a fairly standard material. We might also assume that the strength of steel depends only on its thickness. Thickness is indeed a factor, but by itself, it does not tell the whole story.
The strength of steel is determined through mechanical properties, which are obtained by applying standardized tests to the material. For steel pipe production, the mechanical properties of the material are crucial. The right steel material must be chosen as the pipe raw material depending on the intended use of the pipe. For example, in steel constructions, in addition to the pipe dimensions, the material properties must be clearly defined according to the load the pipes will carry.
These tests provide three critical values:
Yield Strength
During a tensile test, the force applied to the material eventually moves it from elastic behavior to permanent deformation. This point is called the yield point. If the force is removed before reaching this point, the material returns to its original shape. The force measured at this point represents the steel’s yield strength. It is expressed in Newtons per square millimeter (N/mm²).
Tensile Strength
During a tensile test, the material stretches until it eventually breaks. The stress value at the moment of fracture is the ultimate tensile strength (maximum tensile stress). It is also expressed in Newtons per square millimeter (N/mm²).
Elongation
Elongation is defined as the maximum permanent increase in length of the tensile specimen. It is expressed as a percentage (%).
