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应用慢应变速率拉伸试验和扫描电镜(SEM),研究了X80管线钢电化学充氢后的力学性能和断口形貌变化。结果表明:随着充氢电流密度的增大,X80钢中的可扩散氢含量增加,造成伸长率、断面收缩率和冲击吸收能量不断减少,拉伸断口的韧窝变小、变浅,而空洞会增大、增多,空洞边缘出现准解理形貌;电流密度低于5 m A/cm2时,X80钢表面以及其冲击断口无裂纹;电流密度增加至5 m A/cm2以后开始出现裂纹,并且随着电流密度的增加,裂纹开始增大、增多;当电流密度为10 m A/cm2时,冲击断口中出现准解理形貌。
The mechanical properties and fracture surface morphologies of X80 pipeline steel after electrochemical hydrogen charging were studied by slow strain rate tensile test and scanning electron microscope (SEM). The results show that with the increase of hydrogen charging current density, the diffusible hydrogen content in X80 steel increases, resulting in the decrease of the elongation, the reduction of area and the impact absorption energy. The dimples of the tensile fracture become smaller and lighter, While voids will increase and increase, and the quasi-cleavage morphology appears at the edge of cavity. When the current density is lower than 5 m A / cm 2, no cracks appear on the surface of X80 steel and its impact fracture. The current density begins to appear after increasing to 5 m A / cm 2 The cracks begin to increase and increase with the increase of the current density. When the current density is 10 m A / cm 2, quasi-cleavage morphology appears in the impact fracture.