Introduction to the yield section in the test test of tensile testing machine

Tension testerThe tests performed are tensile testing tests of materials. Our company has made the following detailed description of the yield stage of the tensile machine:

Tension testerAt the beginning of the upward tensile test, when the load reaches Pp, the elongation of the sample is in a positive proportional relationship with the load, that is, the elongation of the equal amount corresponds to the equal amount of load. The Pp value is called proportional limit load. When the load is greater than Pp, the proportional relationship is no longer valid. When the load increases from Pp to Pe, although the sample in this range has deformed and can still return to its original state after the load is unloaded. This range is called the elastic deformation stage, and the Pe value is called the elastic limit load. When the load increases from Pe to Ps, the sample in this range not only deforms, but also cannot return to its original state after the load is unloaded, but a part of the residual deformation is retained, which is called plastic deformation. When the load just reaches Ps, the pointer on the dynamometer dial of the tensile tester begins to stop or rotate backwards, and the tensile curve appears as a "platform" (or waveform segment). When the load does not increase or decrease, the sample continues to elongate. This phenomenon is called yielding, and the Ps value is called yielding limit load.

After the surrender phase,Tension testerThe metal on it began to show obvious plastic deformation, and slip bands appeared on the surface of the sample.