摘要
针对贝氏体钢实际应用工况的多变问题,本文研究了贝氏体钢在质量分数为3.5%的NaCl溶液、pH为5的H_(2)SO_(4)溶液和pH为9的NaOH溶液3种环境介质中的电化学腐蚀和腐蚀磨损行为。结果表明:贝氏体钢在NaCl溶液中耐蚀性能最差,自腐蚀电流密度(3.17×10^(-3)A·cm^(-2))高于其他两种溶液两个数量级,其次是H_(2)SO_(4)溶液,最后是NaOH溶液。贝氏体钢在NaCl溶液中腐蚀磨损最严重,由于Cl^(-)的存在,导致钢表面存在明显的腐蚀坑,且摩擦系数、磨损率(8.20 mm^(3)·N^(-1)·m^(-1))及粗糙度(3.42μm)明显高于其他两种溶液环境。贝氏体钢在NaCl溶液中磨损机制最初为磨粒磨损,后续由于腐蚀作用的进一步加强,在剪切力的作用下发生疲劳脱落,磨损机制转变为腐蚀疲劳磨损、磨粒磨损为主的混合作用机制。在NaOH溶液和H_(2)SO_(4)溶液中钢表面腐蚀磨损的程度相对较轻,腐蚀磨损机制主要以磨粒磨损为主。
Bainitic steel,due to its excellent strength,toughness,fatigue resistance,and wear resistance,can meet the stringent requirements of high strength and toughness materials in railway industry applications.Therefore,it has attracted increasing attention for many scientific researchers.However,during service,bainitic steel faces many complex environments,and corrosion and wear,as a common material degradation problem,are inevitable.At present,there are still a few researches on the corrosion and wear performance and electrochemical corrosion mechanism of bainitic steel under different environmental media.Based on this,this article used an electrochemical workstation and a friction and wear tester to study the electrochemical corrosion behaviors and corrosion wear behaviors of bainitic steel in 3.5%NaCl(mass fraction)solution,pH 5 H_(2)SO_(4)solution,and pH 9 NaOH solution.The surface morphologies before and after corrosion were studied using scanning electron microscopy and three-dimensional morphology analyzer.The electrochemical test results showed that the self-corrosion current density of bainitic steel was the smallest in NaOH environment.Combined with impedance spectrum,the capacitance arc radius was the largest and the impedance modulus was the largest,indicating that the corrosion resistance performance was the best in NaOH environment.In NaCl environment,the self-corrosion current density was the highest,combined with impedance spectra,the impedance modulus was the lowest,and the corrosion resistance performance was the worst.The corrosion wear test results showed that bainitic steel had the highest friction coefficient,the lowest wear rate,and the lowest roughness in NaOH environment,indicating that bainitic steel exhibits good lubricity in NaOH environment.Due to the formation of a protective film on the surface from the beginning in NaOH solution,it hindered further corrosion.In H_(2)SO_(4)environment,a protective film would also form on the surface,hindering further corrosion.However,due to the presence of SO_(4)^(2-),the performance was lower than in alkaline environments.In NaCl environment,due to the strong corrosiveness of Cl^(-),the phenomenon of"chlorine embrittlement"occurred.Therefore,the surface of the sample was most severely corroded,with obvious pitting.The friction coefficient was highest,the wear rate was highest,and the roughness was highest in NaCl environment.According to the three-dimensional morphology of the wear track,the wear tracks in all three environments were U-shaped.In H_(2)SO_(4)and NaCl environments,there would be protrusions and corrosion pits on the surface,and the corrosion marks were relatively severe.In NaOH environment,compared to the other two environments,the corrosion was relatively mild.According to the scanning image,the surface of the scratch in NaCl environment was severely corroded,with a large number of corrosion pits,which also confirmed that the increase in pits led to an increase in surface roughness,resulting in an increase in friction coefficient.At the beginning of friction,it was abrasive wear.Subsequently,due to the strengthening of corrosion,some plow grooves inside the wear marks gradually deepened,and NaCl solution accumulated in the plow grooves continuously corroded inward.At the same time,it spread outward from the boundary of the plow grooves,causing the plow grooves to deepen and widen,resulting in a decrease in mechanical strength.Then,under the action of periodic shear forces,fatigue detachment occurred,and the wear mechanism of bainitic steel transformed into a mixed action mechanism mainly consisting of corrosion fatigue wear and abrasive wear.In H_(2)SO_(4)environment,the worn surface was basically a plow groove morphology,with a few deep plow grooves and slight cracks,indicating that the wear mechanism of bainitic steel in H_(2)SO_(4)was mainly abrasive wear.In NaOH environment,the wear marks were relatively smooth and the plow grooves were shallow,but slight corrosion cracks and fragments appeared on the scratch surface,indicating that the wear mechanism of bainitic steel in NaOH was mainly abrasive wear.
作者
吕博
焦振
程丹
郝雪龙
郑春雷
Lv Bo;Jiao Zhen;Cheng Dan;Hao Xuelong;Zheng Chunlei(School of Environmental and Chemical Engineering,Yanshan University,Qinhuangdao 066004,China;National Nonferrous Metals and Electronic Materials Analysis and Testing Center,National Standard(Beijing)Inspection and Certification Co.,Ltd.,Beijing 100088,China;School of Materials Science and Engineering,Yanshan University,Qinhuangdao 066004,China)
出处
《稀有金属》
北大核心
2025年第3期448-456,共9页
Chinese Journal of Rare Metals
基金
河北省重点研发计划项目(20311002D)项目。
关键词
贝氏体钢
环境介质
耐蚀性
腐蚀磨损
bainite steel
environmental media
corrosion resistance
corrosion and wear
