【摘要】 采用电化学充氢方法研究了氢对铁素体/贝氏体双相X70管线钢拉伸和疲劳性能的影响；采用扫描电镜(SEM)和电子背散射(EBSD)技术观察了拉伸和疲劳断口的形貌及疲劳断口处的组织。结果表明：氢对双相X70管线钢的强度影响不大，但显著降低钢的塑性，特别是断后伸长率；充氢后拉伸断口由塑性的韧窝断裂转变为脆性准解理断裂；氢显著加速钢疲劳裂纹萌生和裂纹扩展速率，降低疲劳寿命；氢加速位错等缺陷在晶界及铁素体/贝氏体界面处的聚集，导致断裂模式发生变化，从而降低钢的塑性和疲劳寿命。更多还原

【Abstract】 Effect of hydrogen on tensile and fatigue properties of ferrite/bainite dual-phase X70 pipeline steel was studied by electrochemical hydrogen charging method. The morphology of tensile and fatigue fracture surfaces and microstructure near the fatigue fracture surface were observed by means of scanning electron microscopy(SEM) and electron backscatter diffraction(EBSD) technique. The results show that the hydrogen has little effect on the strength of the dual-phase X70 pipeline steel, but significantly reduces its plasticity, especially the elongation. After hydrogen charging, the tensile fracture changes from plastic dimple fracture to brittle quasi-cleavage fracture. Hydrogen significantly accelerates the initiation and propagation rate of fatigue cracks in the steel, reducing fatigue life. Hydrogen accelerates the aggregation of dislocations and other defects at grain boundaries and ferrite/bainite interfaces, which leads to the change of fracture mode, thus reducing the plastic and fatigue life of the steel.更多还原