拉压载荷下焊缝的磁记忆表征及热处理评价

为考察拉、压载荷下焊缝的磁记忆特征,测试Q235钢板焊缝进行拉、压载荷下的磁记忆(MMM)信号,分析焊缝正、反面MMM信号在拉、压载荷下的变化规律,并对比热处理前后MMM信号,研究热处理质量对磁记忆信号的影响.结果表明:拉伸载荷下磁记忆信号较压缩载荷下变化明显,焊缝正面应力集中较大,焊逢的热处理效果可以在磁记忆特征信号...     

干热岩开发中高温水-岩作用下岩石应力腐蚀及多场损伤问题

赋存于地球深部的地热资源,以其储量丰富、清洁再生等优势,有望成为破解我国能源困局,助推“双碳”目标实现的重要途径之一。干热岩(HDR)开发过程中,面临着高温高压环境下水-岩作用问题,在温度场、渗流场、应力场、化学场(THMC)等多场耦合作用下,岩体应力腐蚀效应和疲劳劣化会诱发岩石微裂纹-裂缝扩展、成核与丛集行为,进而影响增强型地热系统(EGS)的热交换效率和地质体稳定性,这也是制约干热岩长期安全开发的瓶颈,亟待突破。通过总结现有干热岩高温高压下多场损伤研究中的实验探索、理论模型、数值分析等多手段跨尺度方法,分析干热岩在高温高压及水环境下的应力腐蚀效应,可阐明循环生产过程中低温工质与高温地质体循环换热下干热岩储层结构演化的动态过程及工程响应,进而揭示THMC多场耦合作用下干热岩储层疲劳劣化损伤机理,为我国深部地热资源高效安全开发提供理论支撑和地质保障;但仍亟待深入开展增强型地热系统的THMC多场耦合作用下岩体应力腐蚀效应的干热岩疲劳劣化机制与长期稳定性研究,如考虑应力腐蚀效应和疲劳损伤的干热岩长期强度评价模型、基于跨尺度疲劳损伤评价的干热岩开发下地质体长期稳定性方法、适应于干热岩储层改造...     

基于DIC和声发射的TC4合金疲劳损伤状态监测方法

钛合金TC4是飞机关键结构件中应用最广泛的材料。为保障飞机在服役过程中安全稳定运行,将数字图像相关(DIC)和声发射技术结合,开展TC4合金疲劳损伤状态监测研究;利用微力拉伸实验系统,对TC4合金进行不同应力水平下的循环加载声发射监测实验。选择试样表面变形不均匀程度参数表征TC4合金疲劳损伤状态,结合加载过程中声发射信号时域经历,分析试件内部微损伤、裂纹开裂及扩展状态下声发射特征参量分布规律。结果表明:利用DIC和声发射技术结合方法,可以实现TC4合金疲劳状态的动态监测及损伤状态的有效表征。     

STRESS CORROSION CRACKING OF AISI 321 STAINLESS STEEL IN ACIDIC SEAWATER

ImooUonONSCCisoneofthemosttwortantcausoffailureofstaiuleSsstalequipmentandfacilitieS.Studiesonunh0refacilitiesshowedthatanaddicchloridesolutionfilmcouldbefo~onthescheeofstalandthatstaiuleSSstalisinaCtivedissolutionstateinaedicchloridesolutionopinetal.,l99O;Gnanamoorthyetal.,l99O).ltisgenerallythoughtxthatSCCcannotoimrwhenthematerialisinaCtiveanodicdissolutionstate,soitsomcewithresultingcasualties(0ldfieldetal.,l99O)arousedattentiont0it.SomeSCCmeCanisrnsproposedpeuang,l988,Newmanctal.,…     

三元复合驱采油污水阻垢缓蚀剂电化学分析

研制适用于三元复合驱采油污水工况条件下的MPM固体缓蚀阻垢剂,分析三元复合驱采油污水中MPM的电化学特性.结果表明:随着温度增加,20#钢在采油污水的腐蚀速率呈增加趋势,极化曲线显示钝化区表面材料在表面高温下处于钝化状态,产生的钝化膜能够降低腐蚀速度.在阻垢缓蚀剂质量浓度相同的情况下,不同温度的电化学阻抗谱在高频区出现容抗弧,显示优良的缓蚀性能.不同质量浓度MPM极化曲线表明,缓蚀率随MPM质量浓度的增加而增大,MPM极值质量浓度为80mg/L.污水体系中的Ca2+、Cl-对缓蚀率产生影响.MPM适用于高质量浓度Ca2+的三元复合驱采油污水处理.     

ELECTROCHEMICAL STUDY ON CORROSION BEHAVIOUR OF STEELS IN SAND WITH WATER

ImooUcr0NCormsinnofsodinconatisnowrognindasaseriousproblemwithlargeere-nondconSequenas.Thecormsionproducofondatthesurfaeeofrenfontin-dutaltenSioninthernaterial,resultinginfraCtureandspillingoftheconcretefromtherenfoot(Madrinaldetal.,l99l).Asaasult,theconCretestructure'sIneCanhalstwthisgreatiytalued.0wingtothephyShaldfultyofconduCtingforchdricalexperiInentsinconare,muCoftheworkintheaasofndanisticdCtendnationsforcormsionofstalincon-~wereconduedinalkalinesolution,generallyofporewatCr(Romirz…     

Electrochemical corrosion behavior of hot dip coating in artificial seawater

INTR0DUCnONAlloycoatingscandetivelyproteCtsteelagainstcormsioninseri0uscormsionenvir-orunent,suchasthedrinesplashandtidalzones-TwoInainhodiptincaldrinumalloycOaingswidelyusedcommroiallyareGalfancoaing(contalningZn-5wt%kl-us)devel-oPedbytheIntemaionaltalZincReenhheZaionandhocoating(c0n-talningZn-55Wt%Al-1.6Wt%Si)develoPedbytheBethlehemSteelCorpOration-Anewrinc-basedalloycOaingdevel0PedbyNortheaStemUniversityisdiscussedinthesPaperbyelecthehendcalmethod.FromSun(l996),welmOWthecorms…     

The influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes in seawater

The high strength low-alloy steels are welded by underwater wet welding with stainless steel electrodes. The micro-structural and electrochemical corrosion study of base metal (BM), weld zone (WZ) and heat affected zone (HAZ) are carried out to understand the influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes, methods used including, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The results indicate that the WZ acts as a cathode and there is no corrosion product on it throughout the immersion period in seawater. The HAZ and BM acts as anodes. The corrosion rates of the HAZ and BM change with the immersion time increasing. In the initial immersion period, the HAZ has the highest corrosion rate because it has a coarse tempered martensite structure and the BM exhibites a microstructure with very fine grains of ferrite and pearlite. After a period of immersion, the BM has the highest corrosion rate. The reason is that the corrosion product layer on the HAZ is dense and has a better protective property while that on the BM is loose and can not inhibit the diffusion of oxygen.     

Electrochemical measurement of steel corrosion in seabottom sediment with “MD” method

The through one year corrosion potential and polarization resistance for 3 kinds of steels in seabottom sediment of Liaodong Bay were measured with the “MD” method. The measurements will have some theoretical and practical values. The theoretical value lies in that the recorded changing process of the practical corrosion case can be basis for indoor discussion and electrochemical research on the corrosion process. The practical value lies in that the obtained data can be basis for designing and controlling electrochemical protection systems. In fact, it is very difficult to measure in situ the corrosion parameters of steels in sea sediment. Contribution No. 2611 from the Institute of Oceanology, Chinese Academy of Sciences. This study is a major project of the Chinese Academy of Sciences.     

Simulation test apparatus for marine corrosion

ＩＮＴＲＯＤＵＣＴＩＯＮＳｔｅｅｌｃｏｎｓｔｒｕｃｔｕｒｅｓａｒｅｓｅｖｅｒｅｌｙｃｏｒｒｏｄｅｄｉｎｍａｒｉｎｅｅｎｖｉｒｏｎｍｅｎｔｇｅｎｅｒａｌｌｙｄｉｖｉｄｅｄｉｎｔｏ5ｃｏｒｒｏｓｉｏｎｚｏｎｅｓｉｎａｃｃｏｒｄａｎｃｅｗｉｔｈｔｈｅｃｏｒｒｏｓｉｏｎｂｅｈａｖｉｏｒｏｆｓｔｅｅｌａｔｓｅａ:ｍａｒｉｎｅａｔｍｏｓｐｈｅｒｉｃｚｏｎｅ,ｓｐｌａｓｈｚｏｎｅ,ｔｉｄａｌｚｏｎｅ,ｓｅａｗａｔｅｒｚｏｎｅａｎｄｓｅａｍｕｄｚｏｎｅｓ.Ｐｒｏｔｅｃｔｉｖｅｍｅａｓｕｒｅｓｆｏｒｔｈｅｓｅｃｏｒｒｏ…     

Surface modification of ZrO2 nanoparticles with styrene coupling agent and its effect on the corrosion behaviour of epoxy coating

The surface of ZrO2 nanoparticles was modified by styrene coupling grafting method to improve the dispersion and interaction of the nanoparticles with the epoxy coating in which the modified ZrO2 nanoparticles were used as an additive. The grafting performance and microstructure of the nano- ZrO2/epoxy coating were analyzed by Fourier transformation infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The corrosion behavior of the nano-ZrO2/epoxy coating on mild steel was evaluated in neutral 3.5 wt% NaC1 solution using electrochemical impedance spectroscopy （EIS）. Both the coating capacitance and coating resistance fitted by the equivalent circuit from EIS were used to evaluate the protective performance of the coating towards the mild steel. The results show a superior stability and efficient corrosion protection by the modified ZrO2 nanoparticles. The epoxy coating containing 2 wt% modified ZrO2 nanoparticles exhibited the best corrosion performance among all the coating specimens. This research may provide an insight into the protection of mild steel using modified epoxy coatings.     

STUDY ON THE CORROSION PEAK OF CARBON STEEL IN MARINE SPLASH ZONE

lNTRODUCTI0NSincetheoonceptofrnarinesplashzone(MSZ)wasfirstproposedbyHumble,rnanyresearchesprovedthatthecorrosionofsteelinthesplashzoneisthemostseriousinthemarineenvironninetandthatthisMSZcorrosionhasapeak(Zhu,l995).Howevertheenvironmentalfactorscatisingthecorrosionpeakwasnotkn0wnthen(Niat0,l975,Atsushi,l994)andtherangeoftheMSZwasnotyetdeariydefinedopzkaki,l985).ThispaperexplainsthemaincauseofthecormsionpeakanddefinestheexaCtrangeoftheMSZinsomeofChina'sharbours.MATERIALSANDMET…     

Study on rust layers on steel in different marine corrosion zone

IrmODUCnONTheMossbaureffect(ME)isalsoknOWnasrecoil-thenuclearresonaneabsorp-hon.MossbaursPeCboscoPy(MS)haspIDvedtobeaveryuSefultecheqUeforstudytngcormsionPimessesandcedon-cts.TheInainadvantagsofMSincormsionre-enhare:(l)thenon-deStrutivechateroftheteCboqUe;(2)possibilltyforquali-tativeandqUanitativephaanalsis;(3)uSehassinidenificationofPOOrlycrystal-lizedoramorphouscormsionpnhats.WththedeVfoPmntofInarineresomees,InansteelconstrUctionswerebulltatsea'MSwasusedforanalfongcormsion~t…