根据GB/T 228.1-2010中断后伸长率的测量方法，选取塑性富余量较小的BW300TP耐磨钢板进行拉伸试验，分析了采用机器测量方法和手工测量方法测得的断后伸长率结果有差异的原因，并对标准提出修订建议。结果表明：因断裂位置偏离标距中心，机器测量的断后伸长率小于手工测量的断后伸长率，可用关系式y=0.850 5x+5.183 8对机器测量的断后伸长率结果进行补偿和修正。建议GB/T 228.1-2010中P7带头试样的平行长度最小值修改为60 mm；取消附录D中矩形截面非比例试样平行长度L_c≥L₀+1.5 √S₀的规定；增加不同试验材料的机器测量断后伸长率的修正方法及修正建议值。

According to GB/T 228. 1-2010 measurement method of elongation after fracture, BW300TP wear-resistant steel plate with small plastic surplus was selected for tensile test, and the reasons for the difference of elongation after fracture measured by machine-measured method and hand-measured method were analyzed, and some suggestions for revising the standard were put forward. The results show that the elongation after fracture measured by machine was less than that measured by hand because the fracture position deviated from the center of gauge length. The formula y=0. 850 5x+5. 183 8 could be used to compensate and correct the elongation after fracture. It is suggested that the minimum parallel length of P7 lead sample in GB/T 228. 1-2010 be modified to 60 mm, cancel the stipulation of parallel length of non-proportional sample with rectangular section in Appendix D L_c≥L₀+1. 5 √S₀, and add the correction method and recommended value of elongation after fracture for machine-measured of different test materials.