C级钢拉伸试样的屈服现象及断后伸长率的可比性

The yield appearance and the final elongation comparability of tensile testing bar made from C-grade casting steel

指出测定C级钢拉伸试样屈服点时，用载荷停顿法或指针法，屈服现象不明显，只有图解法可一次测出未知屈服指标。探讨了以屈服强度σp0.2代替下屈服点σs1并作为屈服阶段唯一指标的可能性。分析得出断后伸长率的可比性原则，讨论了比例因数对断后伸长率的影响。

It was pointed out that in tensile test with specimen of C-grade casting steel,the load-halt method or the judgment from the pointer swing of strain instrument could not give clearly the yield point except the graphical analysis method. Also an investigation was given in the possibility of substituting the conditional yield poing σp0.2 for theoretical yield strength σs1 as the beginning of the yield step. Besides, the comparability of the final elongation and the effect of the gauge length/diameter on the elongation were presented in the paper.