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通过SEM、TEM和相应的力学性能测试,研究X100级管线钢应变时效前后微观组织及其力学性能的变化。结果表明,在相同的温度、时间条件下时效,随着应变量的增加,针状铁素体和粒状贝氏体组织均发生形变,同时基体上的M/A组织周围形成高密度的位错,成为微裂纹的形核核心,并在温度时效的作用下导致间隙原子的偏聚。应变时效2%后,管体的拉伸强度虽没有较大变化但其均匀伸长率明显降低。应变时效后管体材料的冲击断口上二次裂纹增多,冲击韧性显著降低。
The microstructure and mechanical properties of X100 grade steel before and after strain aging were studied by SEM, TEM and corresponding mechanical properties tests. The results showed that acicular ferrite and granular bainite were deformed with the increase of strain at the same temperature and time, and high density dislocations were formed around the M / A structure on the matrix , Become the nucleus of micro-crack nucleation and lead to the segregation of interstitial atoms under the effect of temperature aging. Strain aging 2%, although the tensile strength of the pipe body without significant changes in its uniform elongation was significantly reduced. After strain aging, the impact of the tube material fracture increased secondary cracks, impact toughness decreased significantly.