There is another parameter about yield strength and tensile strength, which may not be known to many people, and this parameter is the yield ratio. The yield ratio is the ratio of yield strength to tensile strength. The range is between 0 and 1. The yield-to-strength ratio is one of the indicators to measure the brittleness of steel. The larger the yield strength ratio, the smaller the difference between the yield strength and tensile strength of the steel, the worse the plasticity of the steel, and the greater the brittleness. Why do you say that, here is to introduce a new indicator - elongation rate. In layman's terms, it is how much the steel is stretched compared to the original after it is broken. This is an important indicator for testing the plasticity of steel. The larger the value, the better the ductility of the steel. When the steel is stretched beyond the yield point, it is impossible for the steel to return to its original size at this time, and the steel is continuously elongated until it breaks. The larger the yield ratio, the smaller the difference between the yield strength and the tensile strength, and the shorter the elongation time of the steel when the loading rate is constant, the lower the elongation. According to the law of conservation of energy, energy can only be converted or transferred. When steel is stretched, in the final analysis, it is the conversion and absorption of energy. Before the yield point, the steel is in the elastic deformation period, and the external tensile force is almost completely offset by the elastic force (converted into elastic potential energy), and the external energy is not absorbed or converted to much, and only a small amount is converted into heat energy. When the yield point is passed, part of the external force is offset by the elastic force (transformed into elastic potential energy), while part is converted into heat energy. The energy of the external force acting on the steel is mainly absorbed during the plastic deformation period. Material failure begins at the yield point. The lower the yield ratio, the longer the time from the beginning of failure to fracture the material, and the higher the yield ratio, the shorter the time from the beginning of failure to fracture the material. Energy is largely converted into heat energy between the yield point and the breaking point.