What are the mechanical properties of steel?

Mechanical properties of the material refers to material's mechanical characteristics in the different environment (temperature, medium and humidity), under various loads (tensile, compression, bending, torsion, impact, alternating stress, etc.).So what are the mechanical properties of steel?
Steel mechanical properties are the important indicators to ensure that the steel end-use properties (mechanical properties), it depends on the chemical composition of the steel and heat treatment system. The mechanical properties of steel is refers to the standard of steel yield strength, tensile strength, elongation, impact toughness and cold bending performance, also known as the mechanical properties.
Yield strength
Steel one-way tensile stress - strain curve corresponds to the yield platform in the strength of the known as the yield strength, also known as the yield point, is building an important mechanical properties of the steel.The yield point is the end of the elastic deformation and internal stress doesn't increase the scope of large deformation, forming the ideal elastic-plastic model.Low carbon steel and low alloy steel has obvious yield platform, but not for heat treatment of steel and high carbon steel.
Tensile strength
One-way tensile stress - strain curve of the highest point of the strength, referred to as tensile strength, it is can withstand the maximum stress value of the steel.Because after the steel yield strength it has larger residual deformation, it is more than normal use category structure, so the structure of the tensile strength only as a safety reserve.
Elongation
Specimen fracture elongation is the permanent deformation as a percentage of the original length of calibration.Elongation on behalf of the steel plastic deformation ability before breaking , the ability to protect steel without obvious damage,even if subjected to shear, punching, bending, and tapping local yield when make structure manufacture.The greater the elongation, the plasticity and ductility of the steel, the better.
Yield strength, tensile strength and elongation are the three important mechanics performance of steel.All steel in the steel structure shall meet on the targets of the three norms
Cold bending performance
According to the specimen thickness, in accordance with the relevant provisions under the condition of the diameter of the sample 180 °bend heart, its surface without crack and delamination is the cold bending is qualified.Cold bending property is a comprehensive indicator, cold bending qualified express steel plastic deformation capacity meets the requirements on one hand, on the other hand also said steel metallurgy quality accords with a requirement (particle crystallization and nonmetallic inclusions, etc.). it need to have good cold steel, hot working process performance in Important structure, shall have the qualified cold bending test.
Impact toughness
Impact toughness is the ability to resist impact load steel, it was measured by absorbed total energy when steel broke.Unidirectional tensile test of steel performance is the static performance, toughness is a dynamic performance.Toughness is the comprehensive indicators of steel strength, plasticity, toughness is lower, the greater the chance of brittle failure.Toughness value is highly affected by the temperature, when the temperature is lower than a certain value will fell sharply, thus put forward according to the corresponding temperature requirements.