采用GB/T 4160-2004要求尺寸的拉伸样坯，在预拉伸应变量未达到规定应变量时易出现颈缩和夹持部位断裂现象，导致试验失败。为避免出现上述情况，笔者采用形状和横截面尺寸不同于该标准规定尺寸的拉伸样坯，进行5%和10%的两种应变量的预拉伸，然后对其取样进行系列温度夏比冲击试验。结果表明：拉伸样坯尺寸对试样应变时效冲击试验的结果不存在明显影响；钢铁材料的应变时效拉伸样坯可以不局限于一种横截面尺寸，也可以采用与室温拉伸试验相同的带夹持头部试样。

The pre-stretch specimens, whose dimension conformed to the requirement of GB/T 4160-2004, were easy to neck or break at the clamping section before the pre-stretch strain reached the stipulated strain, and the tests failed. In order to avoid the above situation, the tensile tests with 5% and 10% straining and Charpy impact tests at a series of temperatures were carried out on the specimens whose shape and cross-section dimension were different from those of the standard specimens. The results show that: the dimension of pre-stretch specimens had no significant effect on the results of strain aging sensitivity test; different cross sectional dimensions of pre-stretch specimens could be acceptable during the strain aging sensitivity test of steel materials, such as rectangular specimens with grip ends of the tension test at ambient temperature.