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从国产Ｘ５２输送管上取三点弯曲试样分别对焊缝和母材进行了Ｊ积分和ＣＯＤ测试与分析。结果表明、由于受材料显微组织等的影响，ＪＲ和δＲ阻力曲线差别较大。各试样Ｊ０．０５与Ｊ０．２、δ０．０５与δ０．２相差较大。与不带侧槽试样相比，带侧槽试样裂纹扩展阻力及断裂韧性大幅度下降。采用带侧槽试样可获得下限断裂韧性特征值。在管道设计和安全评价中，为得到偏于安全的结果，可采用带侧槽试样的Ｊ积分和ＣＯＤ特征值如Ｊ０．２或δ０．２。
Three-point bending specimens were taken from domestic X52 pipelines to conduct J-integral and COD test and analysis on the weld and base metal, respectively. The results show that due to the influence of the microstructure of the material, the resistance curves of JR and δR differ greatly. The samples J0.05 and J0.2, δ0.05 and δ0.2 differ greatly. The crack propagation resistance and the fracture toughness of the specimens with side grooves are significantly lower than those without side grooves. The characteristic value of the lower limit fracture toughness can be obtained by using the sample with side grooves. In the pipeline design and safety assessment, J-scores and COD characteristic values such as J0.2 or δ0.2 for side-groove specimens may be used to obtain biased safety results.