The tensile testing machine's test speed (i.e., the rate at which the specimen stretches when subjected to stress) is one of the key control parameters in material mechanical property testing. The test speed of a tensile strength testing machine is not a matter of "faster, better" or "slower, better." Instead, it must be determined comprehensively based on material properties, testing standards, and actual application scenarios. The core principle is that the speed must match the material's "mechanical response speed" to ensure that the test process truly reflects the material's stress-deformation behavior in actual use.