不同温度下两种管材应力应变特性的研究

Study on Stress-Strain Behavior of X60 SSAW and ERW X52 Line Pipes

通过对国产X60螺旋埋弧焊管(SSAW)和进口X52直缝电阻焊管(ERW)的温度拉伸试验,研究了两种钢管母材和焊缝的应力应变特性。试验结果表明,两种焊管的屈服强度和抗拉强度随温度的降低而提高,断后伸长率、最大均匀变形断面收缩率、断后断面收缩率以及屈强比随温度降低而降低;两种焊管母材应力应变曲线特征为连续屈服,而焊缝为非连续屈服,存在明显物理屈服现象;X60 SSAW焊管母材与焊缝强度基本相当,X52 ERW焊管母材与焊缝区域存在着较大的强度差异。研究结果表明,在油气管道设计和安全评价时,应充分考虑焊管材料在不同温度下的应力应变行为及母材与焊缝应力应变特性差异。

Tension tests under different temperatures were conducted for X60 SSAW and X52 ERW line pipes. The results indicate that the strength of both pipes increased as test temperature dropped, the plasticity dropped as test temperature decreased. The shape of stress-strain curves of both base metals was continuous yielding, while that of both welds was non-continuous yielding and presented apparent physical yielding. As to X60 SSAW pipes, the strength of base metal and weld was almost the same, but a big difference was found between the base metal and weld of X52 ERW pipes. During oil and gas pipeline design and safety assessment,emphasis should be put on stress-strain behavior of pipe metals under different temperatures and difference of stress and strain behavior between base metal and weld.