What is the tensile strength of mild steel?
Tensile strength refers to the maximum amount of stress a material can withstand while being stretched or pulled without breaking. A tensile strength test usually involves taking a sample of the material with a fixed cross-section area, placing it in a tensometer and increasing the force until it breaks. Some materials will break without deforming, and other more ductile materials will stretch a small amount, shrinking at the point where the stress is greatest.
Tensile strength is measured as a force per unit area - the unit being a pascal (Pa)/megapascal(MPa), a newton per square metre (N/m2) or pounds-force per square inch (psi).
Mild steel is a relatively ductile material as it contains a smaller amount of the hardening alloy – carbon – than other carbon steels. It has a low tensile strength of around 400MPa.
What is the yield strength of mild steel?
Yield strength is defined as being the amount of stress applied to a material that will deform it permanently. It is also referred to as a ‘yield point’ because the material will return to its original shape if the amount of stress does not pass the yield point, but if it does exceed the yield point then the material will not return to its original shape and the deformation will be permanent.
Similar to tensile strength testing, yield strength testing is carried out on a small sample of the material with a fixed cross-section area. The sample is pulled out of shape, and a measurement is taken of the level of stress placed on the material. For most steels, indentation hardness correlates with yield strength, and therefore a hardness test can be carried out as an economical alternative to tensile testing.
Like tensile strength, yield strength is measured in pascals (Pa) or megapascals (MPa). Mild steel as an approximate yield strength of 250MPa.