1. Yield point (σs)
When a steel or specimen is stretched, when the stress exceeds the elastic limit, even if the stress does not increase any more, and the steel or specimen continues to undergo significant plastic deformation, this phenomenon is called yield, and the minimum stress at which the yield phenomenon occurs is To yield point.
Let Ps be the external force at the yield point s, Fo be the sample cross-sectional area, then the yield point σs = Ps/Fo (MPa), MPa is called megapascal equals N (Newton)/mm2, (MPa = 106 Pa, Pa: Pascal) =N/m2)
2. Yield strength (σ0.2)
The yield point of some metallic materials is extremely inconspicuous and difficult to measure. Therefore, in order to measure the yield characteristics of materials, it is specified that a permanent residual plastic deformation equal to a certain value (generally 0.2% of the original length) is called a conditional stress. Yield strength or short-term yield strength σ0.2.
3. Tensile strength (σb)
The maximum stress value reached by the material from the beginning to the moment of breakage during stretching. It represents the ability of steel to resist fracture. Corresponding to the tensile strength, there are compressive strength, bending strength, and the like.
Let Pb be the maximum tensile force before the material is broken, Fo is the cross-sectional area of ​​the sample, then the tensile strength σb = Pb/Fo (MPa).
4. Elongation (δs)
After the material is broken, the percentage of its plastic elongation length to the length of the original sample is called elongation or elongation.
5. Yield ratio (σs/σb)
The ratio of the yield point (yield strength) and the tensile strength of a steel is called the yield ratio. The larger the yield ratio, the higher the reliability of structural parts, the general yield ratio of the carbon steel is 0.6-0.65, and the low alloy structural steel is 0.65-0.75 alloy structural steel is 0.84-0.86.
When a steel or specimen is stretched, when the stress exceeds the elastic limit, even if the stress does not increase any more, and the steel or specimen continues to undergo significant plastic deformation, this phenomenon is called yield, and the minimum stress at which the yield phenomenon occurs is To yield point.
Let Ps be the external force at the yield point s, Fo be the sample cross-sectional area, then the yield point σs = Ps/Fo (MPa), MPa is called megapascal equals N (Newton)/mm2, (MPa = 106 Pa, Pa: Pascal) =N/m2)
2. Yield strength (σ0.2)
The yield point of some metallic materials is extremely inconspicuous and difficult to measure. Therefore, in order to measure the yield characteristics of materials, it is specified that a permanent residual plastic deformation equal to a certain value (generally 0.2% of the original length) is called a conditional stress. Yield strength or short-term yield strength σ0.2.
3. Tensile strength (σb)
The maximum stress value reached by the material from the beginning to the moment of breakage during stretching. It represents the ability of steel to resist fracture. Corresponding to the tensile strength, there are compressive strength, bending strength, and the like.
Let Pb be the maximum tensile force before the material is broken, Fo is the cross-sectional area of ​​the sample, then the tensile strength σb = Pb/Fo (MPa).
4. Elongation (δs)
After the material is broken, the percentage of its plastic elongation length to the length of the original sample is called elongation or elongation.
5. Yield ratio (σs/σb)
The ratio of the yield point (yield strength) and the tensile strength of a steel is called the yield ratio. The larger the yield ratio, the higher the reliability of structural parts, the general yield ratio of the carbon steel is 0.6-0.65, and the low alloy structural steel is 0.65-0.75 alloy structural steel is 0.84-0.86.