【摘要】 以石油天然气设备及机器中广泛使用的几种中、低强度钢为代表,在低温下进行断裂力学J积分和常规力学拉伸、冲击试验,然后,用扫描电子显微镜断口分析技术对断口形貌及有关几何参数进行观察和测量,得到了材料强度、试验温度对裂纹尖端延伸区宽度、高度及钝化角影响的规律,以及这些参数与J积分值之间的关系,最后提出了适合于低温环境的裂纹尖端钝化线方程。更多还原

【Abstract】 In the study, we take some medium, low-strength steels used widely in oil and gas equipments and machines as exponents, to make J-integration tests of fracture mechanics and tension, impact tests of conventiona lmechanics at low temperature. Then the shapes and relative geometric parameters of fractographies are viewed and measured using the techniques of scanning electron microscopes fractography. We have obtained the regularity of height, width and blunting angle of stretched zone of crack tip affected by material strength and testing temperature, and the regularities between these parameters and J-integration value. Finally, the equation of blunting line of crack tip adapted for low temperature environment is proposed.更多还原