D0I:10.13374/.issn1001-053x.2012.10.004 第34卷第10期 北京科技大学学报 Vol.34 No.10 2012年10月 Journal of University of Science and Technology Beijing 0ct.2012 300M超高强度钢电化学性能及应力腐蚀开裂 孙 敏”肖葵”董超芳”李晓刚四钟平2) 1)北京科技大学新材料技术研究院，北京1000832)北京航空材料研究院，北京100095 ☒通信作者，E-mail:lixiaogang99@263.nect 摘要采用动电位扫描技术和慢应变速率拉伸试验研究了超高强度钢300M在3.5%NCl溶液中的应力腐蚀行为，并利 用扫描电镜观察了不同外加电位下的断口形貌.300M钢在3.5%NaC1溶液中开路电位下的应力腐蚀开裂机制为阳极溶解 型，C1ˉ的存在明显地增加了材料的应力腐蚀开裂敏感性.阳极电位-600V下300M钢溶解速率加快，表现出较高的应力 腐蚀开裂敏感性，断面收缩率损失由开路电路下的52.6%升高至99.5%，裂纹起源于表面点蚀坑处，应力腐蚀开裂为阳极 溶解型机制.阴极电位-800mV下材料处于阴极保护电位范围，表现出较低的应力腐蚀开裂敏感性，强度和韧度与空气中 拉伸的数值相近，开裂机制为阳极溶解和氢致开裂协同作用.在更低电位（低于-950mV)下，300M钢的应力腐蚀开裂机制 为氢致开裂，在氢和拉应力的共同作用下表现出很大的应力腐蚀开裂敏感性 关键词高强钢：应力腐蚀开裂：氢致开裂：电化学 分类号TG172.5 Electrochemical behavior and stress corrosion cracking of 300M ultrahigh strength steel SUN Min”,XIAO Kui”,DONG Chao-fang',IXiao-gamg'▣，ZHONG Ping 1)Institute for Advanced Materials and Technology,University of Science and Technology Beijing,Beijing 100083,China 2)Beijing Institute of Aeronautical Materials,Beijing 100095,China XCorresponding author,E-mail:lixiaogang99@263.net ABSTRACT The stress corrosion cracking (SCC)behavior of an ultrahigh strength steel 300M in a 3.5%NaCl solution was studied by potentiodynamic polarization and slow strain rate tests (SSRT),and the fracture surfaces at different applied potentials were observed by scanning electron microscopy (SEM).The SCC mechanism of 300M steel in the NaCl solution at open circuit potential is attributed to anodic dissolution.Cl"ions significantly increase the SCC sensitivity of 300M steel.At the anodic applied potential of -600 mV the anodic dissolution rate and SCC susceptibility of 300M steel increase,represented by the loss of reduction-in-area at open circuit potential increasing from 52.6%to 99.5%.Cracks generally initiate at corrosion pits and the SCC mechanism remains anodic dissolution.At the cathodic potential of-800mV,300M steel exhibits a lower SCC sensitivity due to cathodic protection.Its strength and toughness values are close to those in air.The SCC is controlled by anodic dissolution and hydrogen induced cracking. When the applied potential is more negative than-950 mV,300M steel exhibits a higher SCC sensitivity.The SCC mechanism is hydrogen induced cracking due to a synergistic action of stress and hydrogen. KEY WORDS high strength steel:stress corrosion cracking:hydrogen induced cracking:electrochemistry 作为结构钢的超高强度钢，其应力腐蚀开裂会 Ramamurthy等B发现4340钢在去离子水中的应 引发重大事故，因此近年来高强度钢的应力腐蚀问 力腐蚀裂纹起源于点蚀坑，在30℃和90℃时的应 题引起了广泛的关注-习.学者对高强度钢的应力 力腐蚀开裂机理均为阳极溶解型.对压力容器用 腐蚀开裂(SCC)进行了大量研究并提出了两种应力 300M钢的研究表明，300M钢的失效方式为氢致 腐蚀开裂机理：阳极溶解型和氢致开裂型. 开裂 收稿日期：2011-1001 基金项目：中央高校基本科研业务费专项(FRF-TP-H1006B):国家自然科学基金资助项目(51171023)第 34 卷 第 10 期 2012 年 10 月 北京科技大学学报 Journal of University of Science and Technology Beijing Vol． 34 No． 10 Oct． 2012 300M 超高强度钢电化学性能及应力腐蚀开裂 孙 敏1) 肖 葵1) 董超芳1) 李晓刚1) ! 钟 平2) 1) 北京科技大学新材料技术研究院，北京 100083 2) 北京航空材料研究院，北京 100095 !通信作者，E-mail: lixiaogang99@ 263． net 摘 要 采用动电位扫描技术和慢应变速率拉伸试验研究了超高强度钢 300M 在 3. 5% NaCl 溶液中的应力腐蚀行为，并利 用扫描电镜观察了不同外加电位下的断口形貌． 300M 钢在 3. 5% NaCl 溶液中开路电位下的应力腐蚀开裂机制为阳极溶解 型，Cl － 的存在明显地增加了材料的应力腐蚀开裂敏感性． 阳极电位 － 600 mV 下 300M 钢溶解速率加快，表现出较高的应力 腐蚀开裂敏感性，断面收缩率损失由开路电路下的 52. 6% 升高至 99. 5% ，裂纹起源于表面点蚀坑处，应力腐蚀开裂为阳极 溶解型机制． 阴极电位 － 800 mV 下材料处于阴极保护电位范围，表现出较低的应力腐蚀开裂敏感性，强度和韧度与空气中 拉伸的数值相近，开裂机制为阳极溶解和氢致开裂协同作用． 在更低电位( 低于 － 950 mV) 下，300M 钢的应力腐蚀开裂机制 为氢致开裂，在氢和拉应力的共同作用下表现出很大的应力腐蚀开裂敏感性． 关键词 高强钢; 应力腐蚀开裂; 氢致开裂; 电化学 分类号 TG172. 5 Electrochemical behavior and stress corrosion cracking of 300M ultrahigh strength steel SUN Min1) ，XIAO Kui 1) ，DONG Chao-fang1) ，LI Xiao-gang1) !，ZHONG Ping2) 1) Institute for Advanced Materials and Technology，University of Science and Technology Beijing，Beijing 100083，China 2) Beijing Institute of Aeronautical Materials，Beijing 100095，China !Corresponding author，E-mail: lixiaogang99@ 263． net ABSTRACT The stress corrosion cracking ( SCC) behavior of an ultrahigh strength steel 300M in a 3. 5% NaCl solution was studied by potentiodynamic polarization and slow strain rate tests ( SSRT) ，and the fracture surfaces at different applied potentials were observed by scanning electron microscopy ( SEM) ． The SCC mechanism of 300M steel in the NaCl solution at open circuit potential is attributed to anodic dissolution． Cl － ions significantly increase the SCC sensitivity of 300M steel． At the anodic applied potential of － 600 mV the anodic dissolution rate and SCC susceptibility of 300M steel increase，represented by the loss of reduction-in-area at open circuit potential increasing from 52. 6% to 99. 5% ． Cracks generally initiate at corrosion pits and the SCC mechanism remains anodic dissolution． At the cathodic potential of － 800 mV，300M steel exhibits a lower SCC sensitivity due to cathodic protection． Its strength and toughness values are close to those in air． The SCC is controlled by anodic dissolution and hydrogen induced cracking． When the applied potential is more negative than #950 mV，300M steel exhibits a higher SCC sensitivity． The SCC mechanism is hydrogen induced cracking due to a synergistic action of stress and hydrogen． KEY WORDS high strength steel; stress corrosion cracking; hydrogen induced cracking; electrochemistry 收稿日期: 2011--10--01 基金项目: 中央高校基本科研业务费专项( FRF--TP--11--006B) ; 国家自然科学基金资助项目( 51171023) 作为结构钢的超高强度钢，其应力腐蚀开裂会 引发重大事故，因此近年来高强度钢的应力腐蚀问 题引起了广泛的关注［1--2］． 学者对高强度钢的应力 腐蚀开裂( SCC) 进行了大量研究并提出了两种应力 腐 蚀 开 裂 机 理: 阳极溶解型和氢致开裂型． Ramamurthy等［3--4］发现 4340 钢在去离子水中的应 力腐蚀裂纹起源于点蚀坑，在 30 ℃ 和 90 ℃ 时的应 力腐蚀开裂机理均为阳极溶解型． 对压力容器用 300M 钢的研究表明，300M 钢的失效方式为氢致 开裂［5］． DOI:10.13374/j.issn1001-053x.2012.10.004