Tensile test

Tensile test            Tensile test is a series of tests to determine the properties of materials under tensile load, also known as tensile test. It is one of the basic methods of material mechanical property test, which is mainly used to check whether the material meets the specified standards and study the performance of the material.            Tensile test performance index            Tensile test can measure a series of strength and plasticity indexes of materials. Strength usually refers to the ability of material to resist elastic deformation, plastic deformation and fracture under the action of external force. When the material is under tensile load, when the load does not increase, it still continues to produce obvious plastic deformation, which is called yield. The stress at which yield occurs, called yield point or physical yield strength, is expressed in & sigma; s (PA). In engineering, there are many materials without obvious yield point. Generally, the stress value when the residual plastic deformation of materials is 0.2% is regarded as yield strength, which is called conditional yield limit or conditional yield strength, expressed by & sigma; 0.2. The maximum stress value reached by the material before fracture is called tensile strength or strength limit, which is expressed by & sigma; B (PA).            Plasticity refers to the ability of metal materials to produce plastic deformation without damage under load. The commonly used plasticity indexes are elongation and reduction of area. Elongation, also known as elongation, refers to the percentage of the ratio of the total elongation to the original length after the material sample is broken by tensile load, which is expressed by & Delta. The reduction of area refers to the percentage of the ratio of the reduced area of the material sample to the original area after the tensile load is broken, which is expressed by & psi.            Conditional yield limit & sigma; 0.2, strength limit & sigma; B, elongation & Delta; and reduction of area & psi; are four performance indexes that are often measured in tensile test. In addition, the elastic modulus E, the proportional limit & sigma; P, the elastic limit & sigma; E and so on can also be measured.