摘要
由于良好的力学性能和经济效益,节镍不锈钢在海洋桥梁结构领域具有巨大的应用前景,研究不同腐蚀率下其力学性能及破坏特征具有重要意义。基于外加电流加速腐蚀方法,制备0%、5%、10%、20%腐蚀率的试样,分析不同腐蚀率下试样的表面形貌特征;结合数字图像相关技术,开展准静态条件下的拉伸力学试验,研究不同腐蚀率试样的拉伸力学性能、应变场演变规律及破坏特征;此外,汇总分析了现有文献中不同钢种腐蚀试验结果,对比分析了盐雾腐蚀与外加电流腐蚀下材料力学性能变化差异。结合中心孔洞模型,简化分析了腐蚀后钢材的归一化抗拉强度与孔隙率之间的定量关系。研究结果表明:腐蚀率的提高会导致腐蚀孔深度、尺寸和分布范围不断扩大,且表面形貌由点蚀逐步过渡至坑蚀。当腐蚀率从5%增加到20%时,节镍不锈钢的屈服强度、抗拉强度及延伸率均呈非线性下降。此外,腐蚀率的增大会导致试样拉伸过程中颈缩现象逐渐减弱,应变集中区域主要在腐蚀孔周围,腐蚀试样最终断裂位置均位于较大的腐蚀孔处,破坏模式也由塑性破坏转变为脆性破坏。相比盐雾加速腐蚀,外加电流加速腐蚀方法对钢材的拉伸力学性能影响更为显著,结合理论推导和试验数据进一步验证了腐蚀率增大导致钢材强度降低的结论。研究结果为深入理解跨海桥梁结构钢材的腐蚀行为及其对材料力学性能的影响提供了重要依据,为节镍不锈钢在跨海桥梁结构中的应用提供了参考。
Low-nickel stainless steel has great application prospects in the field of marine bridge structure,benefitting from its good mechanical properties and economic benefits.It is of great significance to study its mechanical properties and failure characteristics under different corrosion rates.Based on the impressed current accelerated corrosion method,the samples with corrosion rates of 0%,5%,10%and 20%were prepared,and the surface morphology of the samples under different corrosion rates were analyzed.Combined with digital image correlation(DIC)technology,tensile mechanical tests under quasi-static conditions were carried out to study the tensile mechanical properties,strain field evolution and failure characteristics of samples with different corrosion rates.In addition,the corrosion test results of different steel grades in the existing literature were summarized and analyzed,and the difference of the mechanical properties of materials under salt spray corrosion and applied current corrosion were compared and analyzed.Combined with the central pore model,the quantitative relationship between the normalized tensile strength and porosity of the steel after corrosion was simplified and analyzed.The results show that corrosion has a significant effect on the surface morphology of low-nickel stainless steel.The increase of corrosion rate can lead to the continuous expansion of the depth,size and distribution of corrosion holes,and the surface morphology gradually transits from pitting corrosion to hole corrosion.When the corrosion rate increases from 5%to 20%,the yield strength,tensile strength and elongation of low-nickel stainless steel decrease nonlinearly.In addition,the increase of the corrosion rate can lead to the gradual weakening of the necking phenomenon during the tensile process of the sample.The strain concentration area is mainly around the corrosion hole.The final fracture position of the corrosion sample is located at the larger corrosion hole.The failure mode is also changed from plastic failure to brittle failure.Compared with salt spray accelerated corrosion,the effect of applied current accelerated corrosion method on the tensile mechanical properties of steel is more significant,combined with theoretical derivation and experimental data,the conclusion that the increase of corrosion rate leads to the decrease of steel strength is further verified.The research results can provide an important basis for further understanding the corrosion behavior of steel and its influence on the mechanical properties of materials,and provide a reference for the application of low-nickel stainless steel in cross-sea bridge structures.
作者
涂壮
张国凯
刘黎旺
刘举
王明洋
TU Zhuang;ZHANG Guokai;LIU Liwang;LIU Ju;WANG Mingyang(School of Safety Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;State Key Laboratory of Disaster Prevention and Mitigation of Explosion and Impact,Army Engineering University of PLA,Nanjing 210007,China)
出处
《铁道科学与工程学报》
北大核心
2025年第5期2218-2228,共11页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(52278504)
江苏省自然科学基金资助项目(BK20220141)。
关键词
节镍不锈钢
电流加速腐蚀
腐蚀率
拉伸力学性能
破坏特征
low-nickel stainless steel
current accelerated corrosion
corrosion rate
tensile mechanical properties
failure characteristic
