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。 In the oil and gas equipment and machinery widely used in several kinds of low-strength steel as the representative, at low temperature fracture mechanics J integral and conventional mechanical tensile and impact test, and then, by scanning electron microscopy fracture analysis of fracture morphology And the related geometrical parameters were observed and measured. The influence of material strength and test temperature on the width, height and passivation angle of the crack tip extension were obtained, and the relationship between these parameters and J integral was obtained. Finally, Environmental Crack Tip Passivation Line Equation.