Tensile stress (or tension) is the stress state leading to expansion; that is, the length of a material tends to increase in the tensile direction. The volume of the material stays constant. When equal and opposite forces are applied on a body, then the stress due to this force is called tensile stress.
Considering this, what is the difference between yield stress and ultimate stress?
The material then becomes strain hardened until you reach the ultimate strength and necking starts to occur and the material becomes weaker again until it breaks apart. Yield stress is the stress at which that the material deforms permanently, ultimate tensile stress is the stress at which it breaks.
What is the ultimate strength of a material?
The ultimate strength is the maximum stress that a material can withstand before it breaks or weakens. For example, the ultimate tensile strength (UTS) of AISI 1018 Steel is 440 MN/m2. In general, the SI unit of stress is the pascal, where 1 Pa = 1 N/m2.
Why is the ultimate tensile strength important?
The tensile strength of a metal is essentially its ability to withstand tensile loads without failure. Ductility, on the other hand, measures a material's ability to deform under tensile stresses. This is an important factor in metal forming processes since brittle metals are more likely to rupture.