1　范围本标准规定了金属线材扭转试验方法的原理、符号、试验设备、试样、试验程序和试验报告。本标准适用于测定直径 (或特征尺寸 )为 0 .3～1 0 .0 mm的金属线材在单向或双向扭转中承受塑性变形的能力及显示线材的表面和内部缺陷。2　原理单向扭转　试样绕自身轴线向一个方 1 Scope This standard specifies the principle of metal wire torsion test methods, symbols, test equipment, samples, test procedures and test reports. This standard applies to the determination of diameter (or feature size) of 0 .3 ~ 1 0. 0 mm of metal wire in one way or two-way torsion in plastic deformation ability and display wire surface and internal defects. Principle 2 unidirectional torsional specimen around its axis to one side