X70管线钢显微组织对室温蠕变性能的影响

Effect of microstructure on room temperature creep in a X70 pipeline steel

研究不同显微组织的X70管线钢的室温蠕变现象和室温蠕变对常温拉伸性能的影响。结果表明,在各种保载应力水平下,不同显微组织的X70管线钢都存在室温蠕变现象。当保载应力高于屈服强度时,室温蠕变变形更加明显。在保载应力与屈服强度之比相同的情况下,不同热处理状态的X70管线钢的室温蠕变量差别不大。同时发现当保载应力高于屈服强度时,室温蠕变后材料屈服点的流变应力显著提高。

The effect of microstructure on room temperature creep (RTC) and its influence on subsequent tensile properties were investigated. The results show that the X70 pipeline steel with different microstructure exhibits time-dependent deformation at several stress levels at room temperature. When the stress level is higher than yielding strength (σs) of the steel, RTC deformation is significant. At identical ratio of creep stress to σs, no significant difference in RTC strains is observed for the steel with different microstructure. The occurrence of RTC deformation enhances the subsequent yielding flow stress of the steel.