High-speed railway high-strength bolts often suffer from coating corrosion failure during their service period, but the base material remains in a good mechanical state. Direct scrapping would result in huge resource waste. This paper addresses the demand for the reuse of in-service bolts in high-speed railways, systematically studies the corrosion mechanism, and develops a rapid coating cleaning process suitable for retired bolts. Firstly, by analyzing the macroscopic morphology, microstructure, element composition, and coating thickness of bolts that have been in service for 5 years, the corrosion characteristics of in-service bolts were revealed: the average thickness of the zinc coating decreased from 10 μm to 4.5 μm, the corrosion products were mainly iron oxides, and the combined effect of crevice corrosion and discrete current led to accelerated coating failure. Secondly, based on the principle of "prior protection of the base material", a rapid acid cleaning process with the core of thiourea + butynediol + sulfuric acid + nitric acid was developed, and integrated with a hydrogen removal treatment at 200°C for 4 hours. Comparing the three deplating liquid formulations, it was found that deplating solution III could completely remove the old coating without damaging the base material, without "surface roughening" phenomenon, and the reaction process was stable and controllable. The results of magnetic particle inspection, appearance inspection, and hydrogen embrittlement test after cleaning showed that there were no defect indications on the surface and near-surface, the geometric accuracy was maintained well, and the hydrogen embrittlement test (421 N·m, 48 h) was all qualified, proving that the base material strength was not degraded due to the cleaning process. The corrosion analysis and cleaning process established in this study provide reliable technical support for the reuse of in-service bolts in high-speed railways, and have significant economic benefits and engineering application value.

Zixi Nan, Peng Cheng, Decheng Wang, Chenxi Shao. High-speed rail fastener remanufacturing cleaning technology: From corrosion failure to hydrogen embrittlement prevention. Academic Journal of Engineering and Technology Science (2026), Vol. 9, Issue 3: 190-199. https://doi.org/10.25236/AJETS.2026.090325.

[1] Peng Chang, Wang Tiantian, Niu Bu Zhao, et al. Research and Application of Artificial Intelligence Technology in Rail Vehicles: Progress, Challenges and Prospects[J]. Science Fund of China, 2026, 40(01): 139-156.

[2] Editorial Department of China Journal of Highway Engineering. Academic Research Review of Road Subgrade Engineering in China·2025[J]. China Journal of Highway Engineering, 2025, 38(12): 1-153.

[3] Wang Dong. Discussion on the Feasibility of Reusing Bolts for EMU[J]. Urban Rail Transit Research, 2021, 24(02): 46-50.

[4] Zheng Guolong, Liu He, Yang Jiongming, et al. Research on torque coefficient variation of reused bolts for wind turbine generators[J]. Mechanical and Electrical Product Development and Innovation, 2022, 35(01): 124-126+130.

[5] Kai Yang, Yu Bai, Chenting Ding. Off-torque and long-term performance of bolted joints for structural disassembly and reusability[J]. Journal of Constructional Steel Research, 2024, 221

[6] Lei Guanbiao, Li Xinkui, Zhao Yan, et al. Feasibility study on reuse of fastener connections for key components of high-speed trains[J]. Mechanical Engineer, 2021, 48(12): 61-67.

[7] Chai Zhu, Pan Anxia, Yang Mingwei, et al. Feasibility study on bolt reuse of subway bogies[J]. Railway Vehicles, 2025, 63(04): 187-192.

[8] Liu Jing, Zhu Yanping, Zhang Ting, et al. Reuse analysis of outer cover mounting bolts for EMU gearbox grounding devices[J]. Internal Combustion Engine & Parts, 2024(20): 33-35.

[9] Wang Haoyang, Wang Suqian, Dong Weiwei. Reusability analysis of workpiece bolts based on torque and friction coefficient test[J]. Automotive Practical Technology, 2025, 50(19): 78-80+137.

[10] Gai Jie, Wang Yuechen, Yu Yizheng, et al. Research on reuse of Hafen bolts for bottom plate connection of EMU equipment cabin[J]. Journal of Dalian Jiaotong University, 2025, 46(05): 45-50+75.

[11] Zhang Chaoqian, Li Tao, Yang Xiaming, et al. Loosening behavior of blind hole bolted connections under shear excitation[J]. Lubrication and Sealing, 2020, 45(07): 8-15.

[12] Jia Guoyu, Zhuang Jian. Reuse times and fatigue life of high-strength bolts for tower cranes and related problems[J]. Construction Machinery Technology and Management, 1999(04): 19-21.

[13] Wei Yuqin. Theoretical analysis on reusability of high-strength bolts for EMU[J]. Railway Vehicles, 2023, 61(05): 158-161.

[14] Maddison W. Bolted joint preload decay and the effect of multiple reuse[J]. Proceedings of the Institution of Mechanical Engineers, 2023, 237(9): 2213-2224.

[15] Eccles W, Sherrington I, Arnell R D. Frictional changes during repeated tightening of zinc plated threaded fasteners[J]. Tribology International, 2010, 43(4): 700-707.

[16] Wu Minghui, Chen Xuan, Zhai Qinghua, et al. Research progress on wear-resistant surface treatment technology for power connection hardware[J]. Electroplating & Precision Finishing, 2025, 47(10): 112-120.

[17] Yu Wenbin, Pi Zhichao, Xiao Peng, et al. Research progress on electroplated metals on steel surfaces and their properties[J]. Mechanical Manufacturing and Automation, 2024, 53(04): 7-19+36.

[18] Peng Dong, Wu Huilin, Zhou Zhongfeng, et al. Research status and prospect of zinc-based alloying technology on steel surfaces[J]. Surface Technology, 2025, 54(12): 17-36.

[19] Liu Jun, Zuo Gang, Pan Xin, et al. Anti-corrosion application research of fixed offshore photovoltaic support structures[J]. Northwest Hydropower, 2025(04): 24-30.

[20] Liu Zhongyu, Ding Chenxi, Fang Zhen, et al. Research progress on iridium alloy modification for high-temperature protection[J]. Materials Reports, 2025, 39(21): 177-189.

[21] Li Zhengxian, Cheng Fei, Chen Yilin, et al. Resistance spot welding performance of hot-formed high-toughness aluminum-silicon coated steel[J]. Automotive Engineering, 2025, 47(02): 367-375.