Explanation

Also known as strength limit. An important mechanical property index of materials in engineering design, which gives the maximum tensile stress that materials can withstand. It is obtained by the ratio of the maximum load (F0) before fracture of the tensile specimen to the cross-sectional area S0 of the specimen（ σ B=F0/S0). For plastic materials, σ B represents the resistance of materials to maximum uniform plastic deformation, but it does not represent the fracture resistance of materials. Because the materials can also have local concentrated deformation (necking) after uniform deformation, the real stress at actual fracture will be significantly higher than σ B. For brittle materials without (or very small) uniform plastic deformation, σ B Externally, it can reflect the fracture resistance of materials. materials σ The value of b is easy to determine. For the same materials, the repeatability of the determination is good, and it is very useful in engineering design. At the same time, it is also a mechanical property with more sensitive structure, so it can also be used as one of the quality control indicators of materials. A good rule of experience has been accumulated between the exterior of metallic materials (especially carbon steel) and the Brinell hardness hardness and fatigue strength of materials, which is very useful in engineering design and process control. Of different materials σ B Great changes, such as ordinary carbon steel, alloy steel after certain heat treatment σ B can reach over 2000MPa.

Classification