共查询到17条相似文献,搜索用时 531 毫秒
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通过紧固圆盘压力试验及缺口慢应变拉伸试验,结合断口分析,对X80管线钢在气态氢环境中的敏感性进行评价,并研究了含氢煤制气环境中X80管线钢的氢脆敏感性随氢含量的变化规律。结果表明:X80管线钢在氦气和氢气环境中的爆破压力比pHe/pH2为1~2,具有一定的氢脆敏感性;在含氢环境中应用时,应当根据使用环境进行进一步的评价;氢分压为0.36 MPa时,X80管线钢的断后伸长率和断面收缩率与在常温常压空气中的结果接近,当氢分压高于0.36 MPa时,随氢含量的升高,X80管线钢的塑性损失增加,断口表现出脆化特征,氢脆敏感性增加。 相似文献
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煤制气中含有一定量的氢气,氢致失效成为输送管线的潜在问题,HAZ的存在增加了氢脆失效的敏感性. 选用X80钢,通过焊接热模拟制备了HAZ试样. 采用高压煤制气环境下的拉伸试验对比研究了X80钢及HAZ各区的氢脆敏感性. 结果表明,经模拟煤制气环境充氢后,X80钢及HAZ各区的性能均稍有降低,氢对材料的性能有一定影响. 粗晶区的氢脆敏感性最高,结合金相和电子背散射衍射分析发现,主要是由于粗晶区在高温作用下发生晶粒长大,致使大角度晶界减少,氢的扩散速率及其在裂纹尖端的富集程度增加,止裂性能变差,断口呈明显的脆性断裂特征. 相似文献
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选择西部管道用大管径X80钢,通过外加阴极保护电位下的慢应变拉伸试验结合阴极极化曲线对比分析了其在新疆农田水饱和土壤及其模拟溶液中氢脆敏感性的变化规律。结果表明,随阴极保护电位的负移,X80钢的断面收缩率和延伸率逐渐降低,氢脆敏感性增加;农田土壤和模拟溶液中阴极保护电位分别达到-1.15V(CSE,下同)和-1.10V时,X80钢发生明显脆断;X80钢在模拟溶液中的氢脆敏感性高于在土壤中。因此利用土壤模拟溶液对X80钢进行氢脆敏感性研究更偏保守,是适宜的。 相似文献
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利用电化学工作站测试了经不同工艺热处理后X80钢在海水模拟液中的极化曲线,并采用慢应变拉伸试验(SSRT)对其在模拟海水环境中进行了应力腐蚀试验。用扫描电镜(SEM)观察试样的断口形貌,并结合腐蚀试验结果分析在模拟海水环境中X80钢的应力腐蚀开裂机理。极化曲线表明未经过热处理的X80钢耐蚀性最差,腐蚀电流密度最大,热处理有效改善了钢样在模拟海水中的耐蚀性能,在回火温度为650 ℃时,腐蚀电流密度最小;SSRT试验结果表明,热处理后试样的断裂强度和伸长率增加,说明应力腐蚀开裂敏感性降低,并且回火温度越高,应力腐蚀开裂敏感性越低;电镜扫描结果显示经热处理后的试样断口出现了韧性断裂特征,宏观断口出现颈缩,微观上也可以观察到韧窝。 相似文献
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采用慢应变速率拉伸实验方法 (SSRT) 结合断口扫描电镜 (SEM) 观察,研究了阴极保护电位对E550钢在海水中氢脆敏感性的影响.结果表明:随着阴极保护电位负移,E550钢在海水中的氢脆敏感性增加,阴极保护电位为-0.95 V (vs SCE) 时,拉伸试样出现脆性解理断裂特征,电位为-1.05 V时,E550钢断口呈明显脆性断裂特征. 相似文献
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目的研究酸性土壤环境中剥离涂层下X80管线钢应力腐蚀行为及机理。方法采用电化学极化曲线测试、慢应变速率拉伸试验和腐蚀形貌扫描电子显微镜观察,对服役于鹰潭土壤环境的X80管线钢在剥离涂层下滞留液中的应力腐蚀行为及机理进行了分析研究。结果 X80管线钢在剥离涂层下的滞留液中具有一定的SCC敏感性,应力腐蚀开裂类型属于TGSCC,敏感性较大位置为近漏点处、剥离区中下部及剥离区底部,且近漏点处滞留液体系中X80钢的SCC机理受阳极溶解(AD)机制控制,剥离区底部滞留液中SCC机理受阳极溶解+氢脆(AD+HE)的混合机制控制。结论服役于酸性土壤中的X80管线钢在外防腐涂层破损后,除开放破损处将发生腐蚀外,剥离涂层下的管线钢还会存在一定的应力腐蚀敏感性。 相似文献
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Qiushi Deng Weimin Zhao Wei Jiang Timing Zhang Tingting Li Yujiao Zhao 《Journal of Materials Engineering and Performance》2018,27(4):1654-1663
Coarse-grained heat-affected zone (CGHAZ) exhibits the highest hydrogen embrittlement (HE) susceptibility, which changes under the influence of thermal cycle. In this study, slow strain rate tension (SSRT) tests were conducted to investigate the HE susceptibility of reheated CGHAZs and the critical hydrogen pressure for fracture failure. Results show that intercritically reheated CGHAZ (ICCGHAZ) possesses the lowest HE resistance. Analyses of HE index and fracture indicate that the critical hydrogen pressure is 3.5 MPa. Microstructure analysis reveals that HE susceptibility is associated with multiple factors, such as phase composition, grain coarsening, HAB density, and MA constituent. Blocky necklace-like MA constituent along prior austenite boundaries plays a predominant role in intensifying the HE susceptibility of ICCGHAZ. 相似文献
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Youngju Kim Jaeki Kwon Daeho Jeong Namsub Woo Masahiro Goto Sangshik Kim 《Metals and Materials International》2014,20(5):851-858
In the present study, the fatigue crack propagation (FCP) tests were conducted on X80 steel in air and artificial seawater (ASW) under various applied potentials to establish optimum and safe working limits of cathodic protection (CP). The slow strain rate test (SSRT) was also conducted on the X80 BM specimens in ASW under CP potential to identify the susceptibility of hydrogen affecting the FCP behavior. The CP potential of ?850 and ?1,050 mVSCE suppressed the environmental effect of seawater on the FCP behavior of X80 BM and WM specimens, showing almost identical da/dN-ΔK curves for both air and ASW environments. The SSRT in ASW under CP potential of ?1,050 mVSCE suggested that the X80 BM specimen steel is susceptible to hydrogen embrittlement, but the effect of hydrogen was believed to be marginal in affecting the FCP behavior of the X80 specimens at a loading frequency of 10 Hz. The FCP behavior of high strength X80 steel is discussed based on the fractographic observation to understand the FCP mechanism in seawater under various CP potentials. 相似文献
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U-bent and notched tensile tests in a 80 °C salt-spray environment were conducted to evaluate the effect of cold rolling at room temperature (CR), warm rolling at 150 °C (WR), and a sensitization at 650 °C/10 h (CRS and WRS) on the hydrogen embrittlement (HE) susceptibility of the 304L stainless steel. The CR specimen exhibited the highest crack growth rate with a greater number of short cracks found in the CRS specimen in U-bent tests. The CR specimen was resistant to HE in notched tensile tests relative to other specimens. Cracking in these specimens was more likely to initiate at the slip bands. 相似文献
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L. W. Tsay W. Y. Chen R. K. Shine R. H. Shine 《Journal of Materials Engineering and Performance》2001,10(3):371-377
This study investigated stress corrosion cracking (SCC) of A588 steel welds as determined by U-bend immersion tests and slow
strain rate tensile (SSRT) tests to evaluate the steel’s cracking susceptibility in various regions of the weldments. The
immersion test results indicated that the fusion zone (FZ) had better corrosion resistance than the other regions in the weld.
It was also demonstrated that the columnar grain boundaries exhibited a higher resistance to corrosion than the grain interior
of the FZ. However, the coarse elongated ferrite in the FZ is susceptible to hydrogen embrittlement (HE), which results in
the formation of microcracks. As a result, a severe degradation of the weld’s tensile properties in the saturated H2S solution was observed. Scanning electron microscope (SEM) fractographs of tensile specimens reveal a cleavage fracture in
the coarse-grained heat-affected zone (CGHAZ) and featherlike rupture in the FZ, both indicating a high sensitivity to HE. 相似文献
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Slow displacement rate tensile tests were carried out to investigate the effect of hydrogen embrittlement (HE) on notched tensile strength (NTS) and fracture characteristics of aged T-200 maraging steel. Hydrogen diffusivity, permeation flux and apparent hydrogen solubility were determined by an electrochemical permeation method, and correlated with the HE susceptibility and microstructures of the specimens. The results indicated that all aged specimens were susceptible to HE in the saturated H2S solution, to different degrees. The susceptibility in the decreasing order of severity was observed to be under-aged, peak-aged, and over-aged conditions. The main trend was that the specimen with the highest diffusivity and permeation flux of hydrogen had the greatest NTS loss. Reverted austenite, if present in the microstructure, acted as irreversible traps for hydrogen and hence, improved the HE resistance. At similar strength and hydrogen solubility level, the more reverted austenite the less susceptibility to HE of specimens was resulted. The detailed microstructures of distinct specimens and their performances in hydrogen-containing environments are discussed. 相似文献