This standard specifies the principle, terms, symbols, specimens, testing machines, test conditions, test procedures, test results presentation methods and test reports of metal materials torsional stress fatigue tests. The torsional stress fatigue performance of metal smooth samples with circular cross-section mm ~ 12.5 mm Note: When doing the metal torsional stress fatigue test in a corrosive environment, you can refer to the provisions of 4.2 in GB/T 7733