温度对超高强度套管钻井钢拉伸性能及断裂机理影响

Effect of Temperature on Tensile Properties and Fracture Mechanism of Ultra-high Strength Casing Drilling Steel

本文主要通过使用万能试验机、低温试验箱、JSM-6390型扫描电子显微镜,研究了温度对超高强度套管钻井钢拉伸性能的影响,并对其断裂机理进行了分析。结果表明:随着温度增加,套管钻井钢的强度随温度的降低而升高,且与温度具有显著的线性关系,而断面收缩率和总伸长率随着温度的降低没有呈现出显著的降低趋势,表明该钢具有较好的低温特性;同时,随着温度的降低,超高强度套管钻井钢的宏观断口放射区特征总体呈减弱趋势,剪切区比例越来越小,且断面高峰和低谷差值呈增加趋势,纤维区微观形貌的韧窝呈浅化趋势,这是由于材料强度提高,塑性变形能力变差所致。

The influence of temperature on the tensile properties of casing drilling steel was studied by using C64-305 static hydraulic universal testing machine,GDW60-200 high and low temperature test chamber,JSM-6390 scanning electron microscope,and its fracture mechanism was analyzed.The results show that the tensile and yield strengths of ultra-high strength casing drilling steel increase with temperature decreasing and have a significant linear relationship with temperature,while the section shrinkage and total elongation do not show a significant decreasing trend with temperature decreasing,indicating that the steel has good low temperature characteristics;at the same time,with temperature decreasing,the macroscopic fracture radiation zone characteristics of ultra-high strength casing drilling steel generally show a weakening trend,the proportion of shear zone becomes smaller and smaller,and the difference between the peak and trough of the section increases,and the tough nest in the microscopic shape of the fibre zone shows a shallow trend,which is due to the increase of material strength and the deterioration of plastic deformation ability.