Mechanical properties are the most important use properties of steel, including tensile properties, plasticity, toughness and hardness.
Tensile performance. The indexes of tensile performance include yield strength, tensile strength, yield ratio, elongation, and reduction of area.
Yield refers to the phenomenon that the load no longer increases during the tensile process of the steel sample, but the sample still continues to deform.
Tensile strength refers to the ratio of the maximum load to the original cross-sectional area of the sample before it is broken when the sample is stretched.
The ratio of the yield point (yield strength) of steel to the tensile strength is called the yield ratio. The greater the yield ratio, the higher the reliability of structural parts.
Elongation refers to the percentage of the length of the gauge length to the original gauge length when the metal material is stretched, after the sample is broken.The reduction of area refers to the percentage of the maximum reduction of the cross-sectional area at the neck of the metal sample after it is broken.The greater the elongation and reduction of area, the better the plasticity of the steel.
(2) Cold bending performance. Cold bending performance refers to the ability of steel to resist bending deformation at room temperature, and represents the plasticity of steel under harsh conditions. Cold bending can reveal defects such as stress and impurities inside the steel, and can also be used to inspect the quality of steel welding, and can reveal defects such as cracks and impurities on the bending surface of the weldment.
(3) Impact toughness. Impact toughness refers to the ability of steel to resist impact loads without being damaged.
The impact toughness of steel is an index to measure the quality of steel, especially for the components that often bear the impact of load, such as heavyweight crane beams, etc., the impact toughness must be appraised. The greater the impact toughness, the better the impact toughness of the steel.
(4) Hardness. Hardness refers to the ability of a metal to resist the pressure of a hard object on its surface. Hardness is not a simple physical quantity, but a comprehensive performance index reflecting elasticity, strength, and plasticity.
(5) Fatigue failure. Under the action of alternating stress, steel will suddenly fail when the stress is far lower than the static load tensile strength, and even when it is lower than the static load yield strength, it will break down. This type of damage is called fatigue failure.
