气相杂质对临氢环境中L245断裂韧性的影响研究

INFLUENCE OF GAS PHASE IMPURITIES ON FRACTURE TOUGHNESS OF L245 PIPELINE STEEL IN HYDROGEN ENVIRONMENT

  • 摘要: 本文在含不同气相杂质的氢气环境中对管线钢材料L245进行断裂韧性测试,对比研究气相杂质对L245管线钢在氢环境中断裂韧性的影响规律,利用扫描电镜对试样断口进行观察,分析L245在不同气相杂质环境中的断裂模式。结果表明,相较于空气环境中的韧性断裂,4 MPa H2环境中L245发生脆性启裂,断裂韧性特征值降低6.5%;4 MPa H2环境基础上添加100 ppm H2O,受H2O分子竞争吸附和吸附解离共同作用,L245断裂韧性特征值增大约3.9%;4 MPa H2+100 ppm H2O环境基础上,CO2的添加因CO2+H2O的局部电化学析氢作用在一定程度上促进L245氢脆,断裂韧性特征值降低13.5%,而O2的添加则由于竞争吸附作用明显降低L245的氢脆程度,断裂韧性特征值增大13.5%。

     

    Abstract: This article performed fracture toughness testing on L245 pipeline steel in hydrogen environment containing with different gas impurities, comparatively studying the influence of gaseous impurities on the fracture toughness of L245 pipeline steel in a hydrogen-containing environment. Scanning Electron Microscopy (SEM) was utilized to observe the fracture surfaces of the test samples, analyzing the fracture modes of L245 steel in hydrogen environment with different gaseous impurities. The results indicated that, compared to the ductile fracturing in air, L245 exhibited a brittle initiation of cracking in 4 MPa H2 environment, with a decrease in the characteristic values of fracture toughness by 6.5%. as for Adding 100 ppm H2O to the 4 MPa H2 environment, due to the combined effects of competitive adsorption and adsorption dissociation by H2O molecules, the characteristic value of L245 fracture toughness increases by approximately 3.9%. as for 4 MPa H2 +100 ppm H2O environment, the addition of CO2 can promote hydrogen embrittlement of L245 steel due to the local elecrtochemical hydrogen evolution effect of CO2 +H2O, resulting in a decrease in the characteristic value of faracture toughness by 13.5%. Conversely, the addition of O2 significantly reduced the degree of hydrogen embrittlement of L245, with an increase in the characteristic values of fracture toughness by 13.5% due to the competitive adsorption of O2.

     

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