根据金属材料均匀塑性变形阶段单位长度塑性伸长相同,以及颈缩变形只在局部长度内发生这一规律,建立了一种用标距小于标准比例试样标距的非标准试样获得标准比例试样断后伸长率的方法。经过试验验证,用该方法测得的断后伸长率与GB/T 228-2002标准规定的方法获得的伸长率相吻合。

On the basis of that the plasticity elongation was equal for the unit length in the process of metallic materials uniform deformation,and the constriction occurred in local length,a new method was builded to acquire the percentage elongation after fracture of standard proportional sample,a short sample whose gauge length was shorter than the standard proportional sample’s was used in the method. After test,the percentage elongation after fracture which was acquired by means of the method was almost identical with that acquired by means of the method provided by GB/T 228-2002.