X80管线钢断裂韧性及失效评估图研究

Research on Fracture Toughness and Failure Assessment Curves of X80 Pipeline Steel

X80管线钢在我国已经开始大规模的应用,其断裂韧性和失效评估曲线是工程应用中安全评定的重要依据。在力学性能测试的基础上,参考材料断裂韧性测试标准,并在试验中采用高K值比法预制疲劳裂纹,利用声发射装置确定裂纹起裂点,测定了X80管线钢母材、焊缝及热影响区的断裂韧性,并在此基础上建立其失效评估曲线,给出了符合三种材料特性的失效评估曲线拟合方程,以便为工程应用提供依据。

API X80 high grade pipeline steel have been used greatly in China, and its fracture toughness and failure assessment curve （FAC） are the essential basis for the safety assessment of engineering application. According to the metallic material fracture toughness test standard, the fracture toughness of base metal, seams and HAZ of API X80 pipeline steel have been tested on the basis of the mechanical property test results. Especially, high K ratio method was applied to precut the fatigue crack, and the sound emission method was used to determine the initiation of crack propagation. Furthermore, the failure assessment curve （FAC） of API X80 pipeline steel was established, and the fitting equations of its base metal, seams and HAZ were suggested in order to provide the foundation of engineering application.