Q345D低合金钢在海洋潮差区的腐蚀规律及电化学行为研究

通过在青岛海域2年实海挂片暴露试验研究Q345D低合金钢和对比材料Q235B普碳钢在潮差区的腐蚀行为。试验结果表明,Q345D钢在实海潮差区1年和2年周期的平均腐蚀速率都小于Q235B钢,且两种钢锈层组成和结构基本类似,但Q345D钢表面锈层较厚,且更致密均匀。通过室内模拟海水周浸腐蚀试验研究两种钢的初期腐蚀行为,通过腐蚀数据的回归拟合分析得出,在腐蚀起始阶段,Q345D钢与Q235B钢的腐蚀倾向差别不大,但随着周浸时间的延长,腐蚀速率逐渐降低,且Q345D钢表现出比Q235B更好的耐全面腐蚀性能。宏观电化学阻抗谱和微区阻抗谱测试结果也证实,Q345D低合金钢形成的腐蚀产物膜层具有比Q235B钢更高的膜层电阻,且能够在更短时间内形成稳定的腐蚀产物膜层。     

不同敏化温度和冷凝液成分对430铁素体不锈钢电化学腐蚀行为影响

利用电化学测量技术,研究不同温度敏化后的430铁素体钢在模拟汽车冷凝液环境中的电化学行为及汽车冷凝液成分变化对430铁素体不锈钢电化学行为的影响。结果表明,850~1 150℃的敏化温度范围内,430铁素体不锈钢随着敏化温度的升高,晶粒度逐渐增大,在模拟汽车冷凝液环境中,零电流电位和电荷转移电阻逐渐降低,耐蚀性下降;430铁素体不锈钢在Cl–分别与SO42–或SO32–共存的条件下,比在Cl–与CO32–共存环境中更容易发生腐蚀,腐蚀速度更高;Cl–存在的溶液中,SO32–具有较大的加速腐蚀作用,且随着SO32–浓度的增加,维钝电流升高,腐蚀过程有逐渐加剧的趋势;Cl–和SO32–共存溶液中,CO32–在一定程度上抑制了430铁素体不锈钢腐蚀过程的进行,降低了腐蚀速度,SO42–加速了腐蚀过程的发生,提高了腐蚀速度。     

船用Q235碳钢的海洋微藻附着诱导微生物腐蚀特性

研究了在含三角褐指藻的人工海水(含藻海水)中,循环光照12h/黑暗12h、光照、黑暗条件下船用Q235碳钢的腐蚀行为,以及腐蚀7d后的电化学性能,并与无藻海水中的进行了对比,分析了三角褐指藻的生命活动对碳钢腐蚀行为的影响。结果表明:在含藻海水中,光照条件下,氧气的去极化反应占主导,碳钢表面发生点蚀,腐蚀产物主要为γ-FeOOH;黑暗条件下,CO_2腐蚀导致碳钢表面发生均匀腐蚀,腐蚀产物主要为FeCO_3;循环光照12h/黑暗12h条件下两种腐蚀方式共同作用,腐蚀产物由γ-FeOOH、Fe_3O_4和FeCO_3组成;与在无藻海水中浸泡7d后的相比,在含藻海水中,不同光照条件下浸泡7d后,碳钢的电荷转移电阻减小,自腐蚀电流密度增大。     

柔性石墨材料硫含量对金属电化学腐蚀影响的试验研究

该文通过柔性石墨材料-金属间电化学腐蚀试验与缝隙腐蚀试验研究,探讨柔性石墨材料的硫含量对金属电化学腐蚀速率的影响。     

油井管杆材料电化学腐蚀试验研究

针对电化学腐蚀对抽油井中管杆偏磨腐蚀的影响,通过对油田常用的5种管杆材料(管材料N80、J55,杆材料20CrMo、 35CrMo和45#钢)在5种油田污水条件下的电极电位和电偶腐蚀电流的测定,对油井管杆配对在油田污水中的腐蚀行为进行了评估.结果表明:根据电位分析,20CrMo的耐蚀性最佳,45#钢则较差;各材料自腐蚀电位差值不大,小于50 mV,可见偶对间腐蚀驱动力较小;偶对间稳定的电偶电流均不超过15 μA/cm2,电偶腐蚀轻微.     

容器用钢应力腐蚀及电化学研究

着重研究316L、16MnR、20钢在H2S介质中的应力腐蚀及应力腐蚀过程中的电化学行为，评定316L、16MnR、20^#在H2S介质中的应力腐蚀开裂的敏感性，测定316L、16MnR、20^#在H2S介质中发生时的电位变化，为在H2S介质中选用抗应力腐蚀容器用钢，及用电化学方法提高H2S介质中容器用钢的抗应力腐蚀性能提供依据。     

不同表面处理对不锈钢SUS304耐微生物腐蚀性能的影响

对焊接的ＳＵＳ３０４不锈钢进行氧化、打磨、酸洗和喷丸等不同处理，研究了不同表面处理对ＳＵＳ３０４不锈钢耐微生物腐蚀性能的影响。在微生物腐蚀试验台中测量了不同表面的试样的开路电压，分析了不同表面处理对电位升的影响。测量了不同表面状态下ＳＵＳ３０４不锈钢的点蚀电位。用俄歇电子能谱（ＡＥＳ）对不同表面进行了分析。得出在不同表面状态下，ＳＵＳ３０４不锈钢耐微生物腐蚀性能由好到差依次是酸洗、喷丸、打磨、原样和氧化。     

海水体系中铝合金微生物腐蚀的研究

就海水体系中硫酸盐还原菌（ＳＲＢ）对铝合金的腐蚀进行了研究,使用扫描电镜以及表面能谱分析方法研究了微生物对铝合金腐蚀的影响。结果表明：硫酸盐还原菌的代谢产物能够破坏铝合金钝化膜,参与腐蚀反应并加速腐蚀的进行。     

腐蚀电化学实验教学中动电位极化测试的应用

通过对等离子弧焊7A52铝合金焊接接头设计动电位极化曲线实验,阐述了动电位扫描极化曲线的测试原理、方法步骤和实验结果的分析拟合,确定了7A52铝合金焊接接头部位腐蚀电位、腐蚀电流及腐蚀极化电阻。论述了极化曲线测试对材料耐蚀性分析的作用及其与电化学反应热力学和动力学参数的关系。通过实验,培养学生对腐蚀实验的兴趣和主动性,提高学生的实际动手操作能力、观察现象、分析问题、探索真理、解决问题以及创新能力。     

ODS钢的电化学腐蚀性能研究

采用PGSTHT30型电化学工作站,对不同种类的ODS钢在1mol/L的硫酸溶液中的电化学腐蚀特性进行了研究,测量了极化曲线和自腐蚀电位,对腐蚀形貌进行了分析。研究表明:弥散强化合金随着Cr含量的增加,能够有效提高耐蚀性。     

Influence of flow conditions on the corrosion of AISI 304L stainless steel

Hydrodynamic and electrochemical noise measurements (ENMs), of AISI 304L stainless steel, were made in a pipe test section of 28 mm inside diameter for a range of flow regimes from laminar to turbulent. Mean flow velocities through the test section were controlled at 0.04, 0.07, 0.11, 0.36, 1.8 and 2.7 m s⁻¹, equivalent to Reynolds numbers of 1000, 2000, 3000, 10 000, 50 000 and 75 000, respectively. Standard hydrodynamic parameters were employed to characterise and evaluate the complex interrelationship between the mass transfer rate of oxygen and momentum transfer through turbulence to the metal/solution interface. For AISI 304L stainless steel, pitting typically occurs in the form of metastable pits which either repassivated before achieving stability or grow to become stable pits. Metastable pitting was evident under all flow regimes. The fluid flow, whether laminar or turbulent, had little overall effect on the nucleation rates of metastable pitting events. Conversely, stable pit growth was most evident during laminar flow immediately before the transition to turbulent flow and close to the critical velocity (∼1.5 m s⁻¹).     

Assessment of the sulfide stress corrosion cracking characteristics in the multi-pass weld of the A106 Gr B steel pipe

Sulfide stress corrosion cracking (SSCC) in crude oil field environment containing hydrogen sulfide (H₂S) has been recognized as a material degradation and damage mechanism. Laboratory data and field experience have demonstrated that extremely low concentration of H₂S may be sufficient to lead to SSCC failure of susceptible materials. In some cases, sulfides may act synergistically with chlorides to produce SSCC failures. SSCC mechanism is a form of hydrogen embrittlement that occurs in high strength steels and in localized hard zones in weld of susceptible materials. In the heat-affected zones adjacent to the weld, there are often very narrow hard zones combined with regions of high residual stress that may become embrittled to such an extent by dissolved atomic hydrogen. On the basis of this understanding, SSCC tests were conducted with smooth specimens of the multi-pass welded ASTM A106 Gr B steel pipe used in the oil industries. And SSCC resistance according to the welding processes was evaluated. From the results, the weld by GTAW+FCAW showed the largest resistance against SSCC. This paper was recommended for publication in revised form by Associate Editor Chongdu Cho Gyuyoung Lee received the M.S. degree in Mechanical Engineering from Sungkyunkwan University in 2003 and 2005, respectively. Currently he is in doctorate course in Sungkyunkwan University. He is currently serving as a Reliability member of the Korean Society of Mechanical Engineers. Lee’s research interests are in the area of welding design, environmental strength of materials, and life prediction and reliability assessment of the industrial facilities.