GB/T 38250-2019 "Metallic materials—Verification of the alignment of fatigue testing machines": This standard is identical to the international standard and was implemented on May 1, 2020. It specifies the method for verifying the alignment of fatigue testing machines using strain measurement devices. It is applicable to dynamic uniaxial tension-compression, pure torsion, and combined tension-torsion fatigue testing machines for metallic materials, and can also be used for static testing machines and non-metallic material testing. By eliminating errors due to inherent defects of the alignment sensor, it evaluates the consistency of the fixture axis using parameters such as maximum bending strain, thereby avoiding additional stresses during loading and ensuring the accuracy of fatigue test results.