管线钢落锤撕裂试验厚度效应试验研究

Experimental Study on Drop Weight Tear Test Thickness Effect of Pipeline Steel

通过不同壁厚试样落锤撕裂试验(DWTT)研究,指出壁厚对于试验断口剪切面积影响符合Z形曲线规律,随着壁厚的增加,管材韧性降低。在大壁厚和小壁厚范围内,厚度对剪切面积影响较小,剪切面积百分比呈现上下平台。韧脆转变温度随试样壁厚的变化规律服从反Z形曲线规律,随着壁厚的增加,韧脆转变温度逐渐升高,在大壁厚和小壁厚范围内,也存在类似的上下平台区。进一步的分析结果表明,随着温度的降低,剪切面积百分比随试样厚度转变曲线逐渐下降,转变曲线上下两个平台之间的过渡段也逐渐变短。在低温和常温下,厚度对材料韧脆转变的影响较小。低温和常温之间的温度,厚度效应更加明显。

The Z curve relationship between specimen thickness and shear area was obtained through drop-weight tear test （DWTr） with different specimen thicknesses. With the increasing of specimen thickness, the ductile of pipeline steel decreases. Within the limits of specimen thickness large or small, specimen thickness makes less influence on the percent shear area of the fracture surface and two plat- forms of upper and lower, which appear as the Z curve. In transition section of the Z curve, the percent shear area of the fracture surface decreases with the specimen thickness increasing. The relationship be- tween critical ductile-brittle transition temperature and specimen thickness obeys Anti-Z law, which means the ductile-brittle transition temperature increases as specimen thickness increases. Similar upper and low- er platform also exists in the Anti-Z curve when specimen thickness is larger or smaller. Further analysis shows that,with the temperature decreasing, the percent shear area of the fracture surface gradually de- creases along with temperature transition curve, and the transition section of Anti-Z curve also becomes shorter. In conditions of low temperature or normal temperature, the effect of thickness on material ductile- to-brittle transition temperature is less. In the range of low and room temperature, the effect of thickness is more obvious.