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利用SEM、TEM、EBSD和多功能内耗仪研究了应变量和时效温度对热连轧X100管线钢显微组织和力学性能的影响,及其时效过程的内耗行为。结果表明:应变量小于2%时,仅有块状铁素体发生明显变形;当应变量大于3%时粒状贝氏体呈现出明显变形。随着应变量增加铁素体板条内部位错密度增加,并且形成许多亚结构,大角度晶界数量显著减小,韧性显著下降;随着时效温度升高,抗拉强度和屈服强度都呈上升趋势,应变量对强度的影响大于时效温度的影响。内耗试验证实,X100管线钢时效强化主要归因于游离态的C原子对位错的钉扎作用。
The effects of strain amount and aging temperature on the microstructure and mechanical properties of hot rolled X100 pipeline steel were investigated by means of SEM, TEM, EBSD and multifunctional internal friction instrument. The results show that when the strain is less than 2%, only the bulk ferrite is obviously deformed; when the strain is more than 3%, the granular bainite shows obvious deformation. With the increase of strain, the density of dislocations in the ferrite lath increases and many sub-structures are formed. The number of large-angle grain boundaries decreases remarkably and the ductility decreases significantly. With the increase of aging temperature, the tensile strength and yield strength The upward trend and the dependent variable have greater influence on the intensity than the aging temperature. The internal friction test confirmed that the aging strengthening of X100 pipeline steel was mainly attributed to the pinning effect of dislocation on free C atoms.