显微组织对UOE管线管时效敏感性的影响

Influence of microstructure on aging sensitivity of UOE linepipes

研究了不同组织类型UOE管线管时效后纵向和横向的力学性能变化。结果表明,试验钢经200~250℃时效,纵向和横向的屈服强度和屈强比均有明显增加,并随时效温度升高进一步扩大增幅,横向受时效的影响显著高于纵向。单相贝氏体组织经时效后,屈强比大幅增加,最高可达0.98,表现出了较强的时效敏感性;铁素体＋贝氏体双相组织经250℃时效处理,屈强比增幅相对较小,具有较好的抗时效性能。此外,UOE管线管的时效过程主要受温度控制,时效时间对性能的影响并不显著。

Mechanical property changes of UOE linepipes with different microstructure after aging treatment were investigated. The results show that yield strength and yield ratio of both longitudinal and transverse directions of the tested steel aged in the range of 200-250 ℃increase obviously. Furthermore,the transverse aging sensitivity is much higher than that of the longitudinal. The specimen with single phase of bainite exhibits higher aging sensitivity,and the yield ratio increases notably,up to 0. 98 after 250 ℃ aging. Meanwhile the specimen with dual phases of ferrite and bainite shows better aging resistance. In addition,the aging behavior of UOE linepipe is mainly controlled by aging temperature rather than aging time.