1. Yield point (σs)
When the steel or sample is stretched, when the stress exceeds the elastic limit, even if the stress does not increase, the steel or sample continues to undergo obvious plastic deformation, which is called yielding, and the minimum stress value when the yielding phenomenon occurs is for the yield point.
2. Yield strength (σ0.2)
The yield point of some metal materials is extremely inconspicuous, and it is difficult to measure. Therefore, in order to measure the yield characteristics of the material, the stress when the permanent residual plastic deformation is equal to a certain value (usually 0.2% of the original length) is specified, which is called the condition.
3. Tensile strength (σb)
The maximum stress value reached by a material during stretching, from initiation to fracture. It expresses the ability of steel to resist breaking. Corresponding to the tensile strength, there are compressive strength, flexural strength, etc.
4. Elongation (δs)
After the material is broken, the percentage of its plastic elongation length to the original sample length is called elongation or elongation.
5. Yield-strength ratio (σs/σb)
The ratio of the yield point (yield strength) of the steel to the tensile strength is called the yield-strength ratio. The larger the yield ratio, the higher the reliability of the structural parts. Generally, the yield ratio of carbon steel is 0.6-0.65, and the low-alloy structural steel is 0.65-0.75, and the alloy structural steel is 0.84-0.86.
6. Hardness
Hardness indicates the ability of a material to resist the pressing of a hard object into its surface. It is one of the important performance indicators of metal materials. Generally, the higher the hardness, the better the wear resistance. Commonly used hardness indicators are Brinell hardness, Rockwell hardness and Vickers hardness.
