Pipeline transport of hydrogen is one of today’s economic and environmental challenges.In order to find safe and reliable application of both existing gas and build new pipelines,it is essential to carry out tests on...Pipeline transport of hydrogen is one of today’s economic and environmental challenges.In order to find safe and reliable application of both existing gas and build new pipelines,it is essential to carry out tests on full-scale pipeline section,including the potentially more dangerous places than the main pipe,the girth welds.For the investigations,pipeline sections of P355NH steel with girth welds were prepared and exposed to pure hydrogen at twice the maximum allowable operating pressure for 41 days.Subsequently,full-scale burst tests were carried out and specimens were cut and prepared from the typical locations of the failed pipeline sections for mechanical,and macro-and microstructural investigations.The results obtained were evaluated and compared with data from previous full-scale tests on pipeline sections without hydrogen exposure.The results showed differences in the behavior of pipeline sections loaded in different ways,with different characteristics of the materials and the welded joints,both in the cases without hydrogen exposure and in the cases exposed to hydrogen.展开更多
The transient tribological phenomenon and premature lubricant breakdown have been widely observed in metal forming,leading to excessive friction at the contact interfaces.In this research,the transient tribological be...The transient tribological phenomenon and premature lubricant breakdown have been widely observed in metal forming,leading to excessive friction at the contact interfaces.In this research,the transient tribological behaviour of a two-phase lubricant were studied under complex loading conditions,featuring abrupt interfacial temperature,contact load,and sliding speed changes,thus representing the severe interfacial conditions observed in warm/hot metal forming applications.The strong experimental evidence indicates that the evolution of friction was attributed to the physical diminution and chemical decomposition effects.As such,a visco-mechanochemical interactive friction model was developed to accurately predict the transient tribological behaviour of the two-phase lubricant under complex loading conditions.The new friction model exhibited close agreements between the modelling and experimental results.展开更多
基金supported by the European Union and the Hungarian State,co-financed by the European Structural and Investment Funds in the framework of the GINOP-2.3.4-15-2016-00004 project。
文摘Pipeline transport of hydrogen is one of today’s economic and environmental challenges.In order to find safe and reliable application of both existing gas and build new pipelines,it is essential to carry out tests on full-scale pipeline section,including the potentially more dangerous places than the main pipe,the girth welds.For the investigations,pipeline sections of P355NH steel with girth welds were prepared and exposed to pure hydrogen at twice the maximum allowable operating pressure for 41 days.Subsequently,full-scale burst tests were carried out and specimens were cut and prepared from the typical locations of the failed pipeline sections for mechanical,and macro-and microstructural investigations.The results obtained were evaluated and compared with data from previous full-scale tests on pipeline sections without hydrogen exposure.The results showed differences in the behavior of pipeline sections loaded in different ways,with different characteristics of the materials and the welded joints,both in the cases without hydrogen exposure and in the cases exposed to hydrogen.
文摘The transient tribological phenomenon and premature lubricant breakdown have been widely observed in metal forming,leading to excessive friction at the contact interfaces.In this research,the transient tribological behaviour of a two-phase lubricant were studied under complex loading conditions,featuring abrupt interfacial temperature,contact load,and sliding speed changes,thus representing the severe interfacial conditions observed in warm/hot metal forming applications.The strong experimental evidence indicates that the evolution of friction was attributed to the physical diminution and chemical decomposition effects.As such,a visco-mechanochemical interactive friction model was developed to accurately predict the transient tribological behaviour of the two-phase lubricant under complex loading conditions.The new friction model exhibited close agreements between the modelling and experimental results.
