Research on Hydrogen Embrittlement Sensitivity of 321 Stainless Steel and Nickel-based Alloy 825 for Hydrogenation Heat Exchanger
XU Xiuqing1, WANG Wei2,3, CHEN Zhiteng2, LI Yun2, HU Haijun2
1 State Key Laboratory of Performance and Structural Safety for Petroleum Tubular Goods and Equipment Materials, Xi'an 710049, China 2 School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, China 3 Xi'an Aerospace Propulsion Inititute, Xi'an 710049, China
Abstract: As the core equipment of the hydrogenation unit, the safe operation of the hydrogenation heat exchanger is of great significance to the development of petrochemical industry in China. Due to the long-term operation under severe working conditions such as high temperature, high pressure and hydrogen exposure, the hydrogenation heat exchanger is frequently subject to leakage and cracking accidents caused by hydrogen embrittlement, resulting in unplanned shutdown. Therefore, the nickel-based alloys Incoloy 825 and AISI 321 stainless steel for hydrogenation heat exchangers were selected as the research objects. The electrochemical dynamic hydrogen charging slow strain rate tensile test (SSRT) was used. At the same time, the XRD and SEM was used to analyze the change of the samples' physical properties and fractures before and after hydrogen charging. The comparative study on deterioration tendency, fracture behavior and hydrogen resistance under hydrogen environment of two kinds of materials is carried out. As test results shown, (ⅰ) 321 will convert to martensite while 825 produce hydrides under the action of hydrogen;(ⅱ) hydrogen can significantly reduce the plasticity of 321 and 825 materials, and the plastic loss caused by hydrogen will increase with the increase of hydrogen charging current density; (ⅲ)both 321 and 825 show dimple type fractures when stretched in air. With the increase of hydrogen charging current density, 321 transforms into a mixed fracture mode of intergranular cracking and quasi-cleavage type transgranular crac-king, and 825 transforms to quasi-cleavage fracture. In conclusion, under the stress/hydrogen interaction, the austenite with good hydrogen resistance of 321 stainless steel is converted to martensite, so the hydrogen resistance of 321 stainless steel is worse than that of 825 nickel-based alloy.
1 Li Y Z, Li Y T. Chemical Engineering & Machinery, 2020, 47(1), 11(in Chinese). 黎宇仲, 黎荫棠. 化工机械, 2020, 47(1), 11. 2 Zhang Z. Ω ring hydrogenation heat exchanger technology research. Master's Thesis, College of Mechanical Engineering China University of Petroleum, China, 2010(in Chinese). 张峥. Ω环加氢换热器制造技术研究. 硕士学位论文, 中国石油大学, 2010. 3 Hu H J, Li K, Wu W, et al. Journal of Xi'an Jiaotong University, 2016, 50(7), 89(in Chinese). 胡海军, 李康, 武玮,等. 西安交通大学学报, 2016, 50(7), 89. 4 Wu S H. Process Equipment & Piping, 2019, 56(5), 39(in Chinese). 吴松华. 化工设备与管道, 2019, 56(5), 39. 5 Chang P T, Chen W W, Shan G B, et al. Materials Protection, 2019, 52(3), 127(in Chinese). 常培廷, 陈文武, 单广斌, 等. 材料保护, 2019, 52(3), 127. 6 Elkebir O A, Szummer A. International Journal of Hydrogen Energy, 2002, 27(7), 793. 7 Lu X, Wang D, Wan D, et al. Acta Materialia, 2019, 179, 36. 8 Yang Y J, Gao K W, Chen C F. International Journal of Minerals Metallurgy and Materials, 2010, 17(1),58. 9 Xie D G, Li S Z, Li M, et al. Nature Communications, 2016, 7, 168. 10 Kirchheim R. Scripta Materialia, 2009, 62(2), 67. 11 Ferreira P J, Robertson I M, Bimbaum H K. Acta Materialia, 1998, 46(5), 1749. 12 Zhu W Y. Hydrogen embrittlement and stress corrosion cracking, Science Press, China, 2013(in Chinese). 褚武扬. 氢脆和应力腐蚀, 科学出版社, 2013. 13 Fan Y H. Effect of microstructures on the hydrogen embrittlement of stainless steels. Ph.D. Thesis, University of Science and Technology of China, China, 2019(in Chinese). 范宇恒. 不锈钢微观组织结构对其氢脆性能的影响. 博士学位论文, 中国科学技术大学, 2019. 14 Fan Y H, Zhang B, Yi H L, et al. Acta Materialia, 2017, 139, 188. 15 Dai Q X, Cheng X N, Wang A D. Materials Reports, 2002(4), 35(in Chinese). 戴起勋, 程晓农, 王安东. 材料导报, 2002(4), 35. 16 Wang Y F, Wang X W, Gong J M, et al. International Journal of Hydrogen Energy, 2014, 39(25), 13909. 17 Martin M, Weber S, Theisen W. International Journal of Hydrogen Energy, 2013, 38(34), 14887. 18 Zhang L, Wen M, Imade M, et al. Acta Materialia, 2008, 56(14), 3414. 19 Yu C Y. Total Corrosion Control, 2015, 29(8), 11(in Chinese). 余存烨. 全面腐蚀控制, 2015, 29(8), 11. 20 Han G, He J, Fukuyama S, et al. Acta Materialia, 1998, 46(13), 4559. 21 Rozenak P, Bergman R. Materials Science & Engineering A, 2006, 437(2),366. 22 Li J X, Wang W, Zhou Y, et al. Acta Metallurgica Sinica, 2020, 56(4), 444(in Chinese). 李金许, 王伟, 周耀, 等. 金属学报, 2020, 56(4), 444. 23 Fu H, Wang W, Zhao H Y, et al. Corrosion Science, 2020, 162, 108191.