摘要
为了考察低钢级管线钢在中压氢气环境下的氢脆敏感性,采用光滑和缺口试样慢拉伸试验方法,结合宏观和微观断口表征与分析,研究了L245钢在空气和4 MPa氢气中的氢脆敏感性。结果表明:L245钢光滑试样在4 MPa氢气中慢拉伸的抗拉强度、断面收缩率和延伸率的损失率分别为5.2%、4.8%和-0.1%,而缺口试样在4 MPa氢气中慢拉伸的抗拉强度、断面收缩率和拉伸位移的损失率分别达到19.1%、45.6%、15.4%,即发生了氢脆。L245钢光滑试样在空气介质中的慢拉伸断裂方式为韧性断裂;开缺口后起裂源开始于缺口位置,然后以准解理断裂的方式向内部扩展,加速试样断裂过程,但整体仍然表现为韧性断裂。相比之下,当L245钢光滑试样在4 MPa氢气环境中时,会在颈缩位置产生裂纹源;开缺口后,从缺口位置向内部产生的准解理断裂区域显著增加,使得断裂过程急剧加快,而心部则发生了氢致韧断。开缺口后L245钢在4 MPa氢气中的断裂方式为准解理断裂与氢致韧断相结合。
In order to investigate the hydrogen embrittlement sensitivity of the low-grade pipeline steel in medium-pressure hydrogen environ-ment,the hydrogen embrittlement sensitivity of L245 steel in air environment and 4 MPa hydrogen environment was studied by smooth and not-ched slow tensile tests,combined with macroscopic and microscopic fracture characterization and analysis.Results showed that the loss rates of tensile strength,area reduction,and elongation of the L245 steel smooth samples under slow stretching in 4 MPa hydrogen were 5.2%,4.8%,and-0.1%,respectively.However,the loss rates of tensile strength,area reduction and tensile displacement of the notched samples under slow stretching in 4 MPa hydrogen were 19.1%,45.6%and 15.4%,respectively,indicating the occurrence of hydrogen embrittlement.The slow tensile fracture mode of the L245 steel smooth sample in air was ductile fracture.After the notch was opened,the crack source of the smooth samples started at a certain position of the notch and expanded inward in the way of quasi-cleavage fracture,accelerating the fracture process of the sample,but the overall fracture method was still ductile fracture.In contrast,the crack source generated at the necking position when the L245 steel smooth sample was exposed to 4 MPa hydrogen.After the notch was opened,a significant increase in the quasi-cleavage fracture area generated from the notch position towards the interior,which rapidly accelerated the fracture process,and the hydrogen-induced ductile fracture occurred in the center.The fracture mode of L245 steel after notch opening in 4 MPa hydrogen gas was a combination of quasi-cleavage fracture and hydrogen induced ductile fracture.
作者
杜培恩
宋卫臣
刘智
付国强
李拔
汪兵
刘清友
DU Peien;SONG Weichen;LIU Zhi;FU Guoqiang;LI Ba;WANG Bing;LIU Qingyou(Sinopec Petroleum Engineering Corporation,Dongying 257000,China;Central Iron and Steel Research Institute,Beijing 100081,China)
出处
《材料保护》
CAS
CSCD
2023年第7期90-97,共8页
Materials Protection
关键词
氢气
L245钢
缺口
慢拉伸试验
氢脆敏感性
准解理
hydrogen
L245 steel
notch
slow strain rate test
hydrogen embrittlement sensitivity
quasi-cleavage
