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1

Raseroka, Mantsaye S. "Controlled chloride cracking of austenitic stainless steel." Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-07032009-120615/.

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2

Wong, T. M. "Stress corrosion cracking in a high strength steel." Thesis, University of Canterbury. Engineering, 1986. http://hdl.handle.net/10092/6429.

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This thesis falls into four fields of study. The first is a survey of relevant literature concerning the many theories of stress corrosion cracking and hydrogen embritt1ement. This includes descriptions of the mechanisms of stress corrosion cracking (SCC) and outlines electromechanical processes and stress - sorption theory. Four widely accepted mechanisms for environment assisted cracking are also outlined. They are, 1) Embritt1ement resulting from accumulated hydrogen at embritt1ement sites, 2) Lowering of surface energy by adsorption of hydrogen, 3) Hydrogen interaction with dislocations, and 4) Lowering of the binding energy by interaction of hydrogen. The literature survey is a significant part of this thesis. The overall objective of the survey is to review a series of current SCC tests on high strength steels. The principal findings from these previous studies are summarized, they provide concrete evidence for the conclusion that SCC of high strength steels is due to hydrogen embrittlement. The second part of the project deals with the development of a stress corrosion loading clevis suitable for testing compact tension specimens. Three existing constant load rigs were developed, and equipment was designed for the successful operation of the rigs. Corrosive environment was applied to the standard compact tension specimen using a novel circulation system based on a magnetic plate stirrer. Corrosive solution (3.5% NaCl) was stirred by the magnetic plate, and the vortex created by the magnetic stirrer was used to create a pumping head. The third area of work dealt with the testing of compact tension specimens of ULTIMO 200 steel using the developed apparatus. The experimental procedures used are based on the application of linear elastic fracture mechanics to stress corrosion cracking. The fourth area of work carried out was to perform slot length calibration experiments on CT specimens by using strain gauges. The results indicated that the specimens pre-cracked in air with a higher dynamic load gave higher threshold stress intensities (KIscc ) than those pre-cracked in air with a lower dynamic load. An electron microscope study indicated evidence of a largely inter granular fatigue crack having occurred in the specimens pre-cracked with a high dynamic load.
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3

Gedeon, Steven Anthony. "Hydrogen assisted cracking of high strength steel welds." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14842.

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4

Saithala, Janardhan R. "Pitting and stress corrosion cracking of stainless steel." Thesis, Sheffield Hallam University, 2007. http://shura.shu.ac.uk/20311/.

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An investigation has been performed to determine the pitting resistance of stainless steels and stress corrosion cracking of super duplex stainless steels in water containing chloride ions from 25 - 170°C. The steels studied are 12% Cr, FV520B, FV566, 304L, Uranus65, 2205, Ferallium Alloy 255, and Zeron 100. All these commercial materials used in very significant industrial applications and suffer from pitting and stress corrosion failures. The design of a new experimental setup using an autoclave enabled potentiodynamic polarisation experiments and slow strain rate tests in dilute environments to be conducted at elevated temperatures. The corrosion potentials were controlled using a three electrode cell with computer controlled potentiostat. The experimental programme to determine pitting potentials was designed to simulate the service conditions experienced in most industrial plants and develop mathematical model equations to help a design engineer in material selection decision. Stress corrosion resistance of recently developed Zeron100 was evaluated in dilute environments to propose a mechanism in chloride solutions at high' temperatures useful for the nuclear and power generation industry. Results have shown the significance of the composition of alloying elements across a wide range of stainless steels and its influence on pitting. Nitrogen and molybdenum added to modern duplex stainless steels was found to be unstable at higher temperatures. The fractographic results obtained using the scanning electron microscope (SEM) has given insight in the initiation of pitting in modem duplex and super duplex stainless steels. A mathematical model has been proposed to predict pitting in stainless steels based on the effect of environmental factors (temperature, chloride concentration, and chemical composition). An attempt has been made to identify the mechanism of SCC in Zeron100 super duplex stainless steel. The proposed empirical models have shown good correlation between predicted pitting potential values with experimental results. It has been shown that the SCC mechanism in Zeron100 supports the slip assisted anodic dissolution model of SCC. The relationship between pitting and stress corrosion in dilute environments is established and empirical equations have been proposed to determine the damage region for wide range of stainless steels.
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5

Johnson, David H. "Lüders bands in RPV Steel." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/8039.

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The R6 procedure is used for the prevention and prediction of crack behaviour and other defects in the reactor pressure vessel(RPV). The RPV material is an upper-bainitic, low alloy steel structure, which deforms inhomogeneously when yielding. The current codes that are used to design and calculate the fracture, within an RPV, assume that the material yields continuously as the size of the L¨uders strain is less than 2%. However, the work of Wenman et al[1] has shown that the inclusion of a L¨uders band during calculations can reduce the residual stress in a material, when compared to standard work-hardening models and, consequently, reduces the amount of conservatism. The objective of the research was to determine whether Wenman’s finding could be generalised and therefore initiate a re-evaluation of R6 procedure, when looking into materials that yield discontinuously. This required further investigation into L¨uders bands, such as using failure assessment diagrams (FADs). The findings from FADs showed that at the temperature range for an RPV steel at -155±C for different micro-structures (assuming that the material deforms homogeneously), this reduced the amount of conservatism. However, at fracture toughness values more representative of room temperature behaviour, the converse was true. That is, assuming a discontinuous yield point reduced the amount of conservatism. It was also shown that the tempered martensite structure could be used as an alternative to the current upper bainitic, low alloy steel that is used in RPVs. Further insight is gained into the nature of a L¨uders band, by developing a theoretical model that showed explicit relations between L¨uders strain and the mean free-path(ferrite path), dislocation density and the grain-size. It was also shown that an explicit relation between the L¨uders strain and carbon content was possible from known data, which a new parameter Á was derived, and is the derivative of the work-hardening exponent with respect to the lower yield stress.
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6

Ghasemi, Rohollah. "Hydrogen-assisted stress corrosion cracking of high strength steel." Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-50416.

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In this work, Slow Strain Rate Test (SSRT) testing, Light Optical Microscopy (LOM) and Scanning Electron Microscopy (SEM) were used to study the effect of micro-structure, corrosive environments and cathodic polarisation on stress corrosion cracking (SCC) of two grades of high strength steels, Type A and Type B. Type A is manufactured by quench and tempered (Q&T) method. Type B, a normalize steel was used as reference. This study also supports electrochemical polarisation resistance method as an effective testing technique for measuring the uniform corrosion rate. SSRT samples were chosen from base metal, weld metal and Heat Affected Zone (HAZ). SSRT tests were performed at room temperature under free corrosion potential and cathodic polarisation using 4 mA/cm2 in 1 wt% and 3.5 wt% NaCl solutions. From the obtained corrosion rate measurements performed in 1 wt% and 3.5 wt% NaCl solutions it was observed that increased chloride concentration and dissolved oxygen content enhanced the uniform corrosion for all tested materials. Moreover, the obtained results from SSRT tests demonstrate that both Q&T and normalized steels were not susceptible to SCC in certain strain rate(1×10-6s-1) in 1 wt% and 3.5 wt% NaCl solutions under free corrosion potential. It was con-firmed by a ductile fracture mode and high reduction in area. The weld metal of Type A with acicular ferrite (AF), pro-eutectoid (PF) and bainite microstructure showed higher susceptibility to hydrogen assisted stress corrosion cracking compared to base metal and HAZ. In addition, typical brittle intergranular cracking with small reduction in area was observed on the fracture surface of the Type A due to hydrogen charging.
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7

Singh, Preet Mohinder. "Stress corrosion cracking of carbon steel and inconel 600." Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328104.

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8

McNutt, Steven A. "Stress relief cracking in copper-precipitation strengthened HSLA-100 steel." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/23410.

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Approved for public release; distribution is unlimited
The US Navy is currently developing a new family of high-strength , low-alloy steels which derive a significant portion of their strength from copper precipitation. These highly weldable steels require little or no preheat. resulting in substantial cost savings. The first of these steels. HSLA-80, has been certified for ship construction, but recent studies have indicated some susceptibility to stress relief cracking in weldments. HSLA-100, a modification of HSLA-80, is now being considered for several higher-strength naval structures. Stress-relief cracking has not been studied previously in this steel and is the subject of investigation in this work. The steel weldments were loaded below their yield strength, heated to temperatures of 550°-650° C, and permitted to stress relieve for one hour. At all temperatures, the steel exhibited susceptibility to stress relief cracking in certain stress ranges. Optical and scanning electron microscopy exhibited intergranular cracking which always traversed the coarse-grained region of the heat-affected zone. Auger and transmission electron microscopy indicated high concentrations of alloying elements at the grain boundaries. Stress-relief cracking was associated with the diffusion of alloying elements to the prior austenite grain boundaries.
http://archive.org/details/stressreliefcrac00mcnu
Captain, Canadian Forces
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9

Bhattacharya, Ananya. "Stress corrosion cracking of duplex stainless steels in caustic solutions." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26491.

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Thesis (Ph.D)--Materials Science and Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Singh, Preet M.; Committee Member: Carter, W. Brent; Committee Member: Gokhale, Arun, M.; Committee Member: Neu, Richard; Committee Member: Sanders, Thomas H., Jr.. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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10

Mozhi, T. Arul. "The effect of nitrogen on sensitization and stress corrosion cracking of AISI 304 stainless steels /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487265143147533.

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11

Ulbinas, Darius. "Cracking and stiffness analysis of steel fiber reinforced concrete members." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130211_185704-20674.

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In last decades, fibre reinforcement is widely used in many countries as ad-ditive for concrete and cement mortar mixture for production of structures. Fibre reinforcement applications in Lithuania are often restricted to production of concrete floor for different purposes. Whereas, in other countries (USA, Japan, Germany and other) application area of fibre reinforcement is much wider, for example: bridge deck, thin-walled structures for special constructions (tunnels, reservoirs, etc), covering of roadway, airport landing strip, pipelines, pile foundation. Application of fibre reinforcement is considered as one of the most important development area of structural construction in the world. Fibre reinforcement significantly improves service properties of concrete. Fibre reinforcement does not have considerable influence on concrete compressive strength, however it significantly changes fracture characteristics of tensile concrete. Fracture of non-reinforced tensile concrete is brittle, whereas with fibre reinforcement–plastic. This is due to restraining of tensile deformations by distributed fibres. Fibre reinforcement influence on concrete member is more effective than bar reinforcement, as tensile deformations are restrained in the whole volume of tensile zone. Whereas, tensile deformations in a RC member are restrained in the specific interaction area of reinforcement and concrete. Main advantages of fibre reinforcement are slow crack propagation, greater tensile and... [to full text]
Jau kelis dešimtmečius plieno plaušas visame pasaulyje plačiai taikomas kaip priedas betono ir cementinio skiedinio mišiniams, naudojamiems statybinių konstrukcijų gamybai. Lietuvoje dispersinis armavimas dažniausiai naudojamas betonuojant įvairios paskirties pastatų grindis. Tuo tarpu, kitose pasaulio šalyse (JAV, Japonijoje, Vokietijoje ir kt.) dispersinė armatūra naudojama daug plačiau, pvz.: tiltų perdangoms, plonasienėms specialiųjų statinių (tunelių, rezervuarų ir t. t.) konstrukcijoms, kelių dangoms, oro uostų pakilimo takams, vamzdynams, poliniams pamatams ir t. t. Dispersinės armatūros taikymas visame pasaulyje laikoma viena iš prioritetinių statybinių konstrukcijų vystymosi sričių. Dispersinis armavimas neturi didesnės įtakos gniuždomajam betono stipriui, tačiau lemia visiškai skirtingą tempiamojo betono suirimo pobūdį. Nearmuoto tempiamojo betono suirimas yra trapus, tuo tarpu dispersiškai armuoto – plastinis. Tai lemia dispersiškai pasiskirsčiusio plaušo sukeliamas tempimo deformacijų suvaržymas. Dispersinio armavimo poveikis betoniniam elementui yra daug efektyvesnis nei strypinės armatūros, kadangi tempimo deformacijos varžomos visame tempiamosios zonos tūryje. Tuo tarpu klasikiniame gelžbetoniniame elemente tempimo deformacijos varžomos tik tam tikrame armatūros ir betono sąveikos plote. Lėtesnis plyšių vystymasis, didesnis atsparumas smūgiams ir nuovargiui bei plastiškumas yra pagrindiniai veiksniai, lemiantys dispersiškai armuotų gelžbetoninių konstrukcijų... [toliau žr. visą tekstą]
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12

Albores-Silva, Octavio E. "Atmospheric stress corrosion cracking and pitting of austenitic stainless steel." Thesis, University of Newcastle Upon Tyne, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.579513.

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The atmospherically-induced stress corrosion cracking (AISCC) of austenitic stainless steel type AISI 316L was investigated using a U-bend technique, under conditions relevant for storage of intermediate level radioactive waste drums. The specimens were obtained from an actual '500 litre' drum with a wet-bead blasted surface finish. Using MgCI2 as contaminant salt, it was found that at the characteristic equilibrium relative humidity a threshold deposition for AISCC occurrence is found above chloride-ion contamination levels of 10 and 25 µg cm-2 at 50 and 30 °C, respectively. Higher contamination levels were required to produce cracking at room temperature or with the increase of relative humidity to 60 %. The AISCC severity was related to the spatial characteristics of the electrolyte film. Above 100 µg cm-2, crack depth seems to be controlled by the electrolyte thickness as it determines the diffusion path of oxygen to the cathodic surface. Below 100 µg cm-2, crack depth is affected predominantly by the formation of a discontinuous electrolyte film which results in smaller anodic/cathodic domains. Transition from cracking to pitting corrosion with tunnel appearance was observed as test temperature was decreased from 30 °C to room temperature, except at high chloride deposition levels. The results indicate that AISCC occurrence can be limited by restriction of chloride deposition, control of RH away from the deliquescence point of relevant salts and control of temperature. Using an X-ray diffraction technique, it was found that the drum's surface residual stresses are compressive and would provide a degree of protection against AISCC. However, tensile residual stresses can be found in non-blasted areas and in sections of the drum welds. Exposure of corrosion coupons and U-bend specimens III an underground environment that potentially resembles a geological disposal facility did not cause any significant pitting or AISCC after 1.75 years of exposure. This was correlated to a low chloride deposition and a high average RH that would have maintained the hygroscopic deposits in a dilute condition.
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13

Fang, Peijun. "Weldability and hydrogen relationships in super duplex stainless steel." Thesis, Robert Gordon University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260057.

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14

Quigley, James R. "Analysis of distortion-induced fatigue cracking of a trapezoidal steel box girder bridge including retrofit investigation." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 171 p, 2009. http://proquest.umi.com/pqdweb?did=1885755711&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Thesis (M.C.E.)--University of Delaware, 2009.
Principal faculty advisors: Michael J. Chajes and Harry W Shenton III, Dept. of Civil & Environmental Engineering. Includes bibliographical references.
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15

White, David. "Factors influencing the hydrogen content of steel weld metals." Thesis, University of Leeds, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366360.

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16

Gómez, Navarro Miguel. "Concrete cracking in the deck slabs of steel-concrete composite bridges /." Lausanne : EPFL, 2000. http://library.epfl.ch/theses/?nr=2268.

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17

Stratford, G. C. "Type IV cracking in 1¼Cr - ½Mo low alloy steel welds." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639124.

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Service experience has shown the main form of medium to long term damage and failure in low alloy steel weldments to be "TYPE IV" creep cracking in the intercritically transformed region of the heat affected zone (HAZ). This research programme aimed to define the fabricational, loading and microstructural factors which lead to this form of damage. Research welds, which were an accurate model of the geometry and microstructure of steam pipe weldments, were fabricated in tubular testpieces using standard welding techniques. The welds were subjected to a post-weld heat treatment (PWHT) of 700oC or 750oC for two hours. Whilst the heat treatment reduced the hardness of the welds, significant changes in microstructure were only seen in the 750oC PWHT weld. Uniaxial creep tests were performed on base metal and cross-weld specimens. Post-weld heat treatment increased the creep deformation and reduced the failure life of base metal specimens. For cross-weld specimens in the as-welded condition, the susceptibility for low ductility TYPE IV failure in the HAZ was invariably found to be linked to the sub-surface development of creep cavities and cracks. All specimens tested in the as-welded condition failed in a low ductility TYPE IV mode. For all cross-weld specimens, the susceptibility to low ductility failure was linked to factors which affect the base metal ductility, such as PWHT and test temperature. Thus, specimens with a PWHT of 750oC or those with a PWHT of 700oC tested at a temperature greater than 580oC were found to fail in a high ductility manner in the base metal region. Tubular specimens were tested at elevated temperature under internal pressure and applied end-load conditions. Results showed that deformation and fracture were dependant on temperature and axial stress and that sub-surface TYPE IV damage had developed in the HAZ of 700oC PWHT welds.
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18

Scatigno, Giuseppe Giovanni. "Chloride-induced transgranular stress corrosion cracking of austenitic stainless steel 304L." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/51506.

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Stress corrosion cracking (SCC) of austenitic stainless steels has been a known failure mode for more than 80 years and it continues to be a major cause of concern in the nuclear industry. The so-called nuclear grades, such as 304L, contain low levels of C and are therefore hard to sensitise, which is a major problem with high C grades, and these low C grades mainly fail by transgranular SCC. The effect of cold work (CW) has long been known to have a detrimental effect on SCC performance of a stainless steel component. CW is readily introduced in engineering components, through manufacturing history, or implementation, i.e. welding and hammering during fitting. The aim of this thesis is to systematically assess the role of CW in Cl-induced atmospheric SCC in 304L grade austenitic stainless steel. 304L is widely used in the nuclear industry, for both the primary cooling system of nuclear power plants and dry casks for interim storage of spent nuclear fuel. CW was applied in uniaxial tension to levels of 0, 0.5, 1, 2, 5 10, 20, and 40%. The specimens were loaded in a jig to produce a uniform stress of 60 MPa on the top surface and corroded under atmospheric conditions at 75°C, 70% relative humidity, using MgCl2, for 20 days. The role of applied stress (from 60-180 MPa), on SCC susceptibility was investigated at a fixed level of CW (chosen as 10% CW after preliminary experiments) using indicators such as crack density. Secondary and transmission electron microscopy, electron back-scattered diffraction, focused ion beam and secondary ion spectroscopy were the main characterisation techniques used. The maximum susceptibility to SCC was observed between 0.5-5% CW, while 20 and 40% CW did not exhibit cracking. The characterisation of the samples tested provided evidence that Cl is found ahead of the crack tip, whereas oxygen is not, which was never previously observed in the literature. Secondary ion mass spectroscopy and transmission electron microscopy were both used to observe and study the presence of Cl. Simulations such as SRIM and Casino 3.2 were used to confirm that the findings were not a technique artefact. Evidence of dealloying was also observed during the characterisation. Dealloying has long been deemed unlikely in Cl-SCC of austenitic stainless steel, but recent work showed that this may also be an available mechanism for SCC as more and more of the characteristics features of dealloying are observed. The dealloying signs observed were: nanoporosity, found on fracture surfaces; severe striations, heavy dissolution of slip planes; element migration (areas of light and dark contrast in back scattered electron images, dictated by the migration of Cr); cleavage failure; Cr and Ni migration around the crack. The role of salt loading was investigated. Different levels of salt deposition were tested in order to obtain an engineering threshold for salt deposition, namely: low ( < 5.70 x 10-3 g cm-2), medium (5.70 x 10-3–1.42 x 10-2 g cm-2) and high ( > 1.42 x 10-2 g cm-2). A linear relationship was observed between level of salt deposited and both crack density and corrosion area. However, more work is necessary to obtain a threshold.
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19

Kyle, Nathan Lawrence. "Subsidence Cracking of Concrete Over Steel Reinforcement Bar in Bridge Decks." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/33129.

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It is known that subsidence cracking may cause premature deterioration of concrete slab structures in salt laden environments. Chlorides from either deicing salts or marine environments may cause chloride-induced corrosion of the reinforcing steel resulting in spalling of the cover concrete. Concrete specimens with 16 mm (# 5) diameter bars were cast with various cover depths, bar spacing and two concrete mixture types to determine the influence that epoxy coated reinforcement, cement type and bar spacing may have on the probability of subsidence cracking in bridge deck slabs. It was determined that there is not a significant difference in the probability of cracking of concrete between concrete cast with epoxy coated reinforcing steel and bare reinforcing steel. Concrete subsidence cracking was found to be dependent upon the clear cover depth and cement type.
Master of Science
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20

Al-Rabie, Mohammed. "Observations of stress corrosion cracking behaviour in super duplex stainless steel." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/observations-of-stress-corrosion-cracking-behaviour-in-super-duplex-stainless-steel(51f53ed4-7bdc-469a-8ff7-7dfd9ff56339).html.

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The new generation of highly alloyed super duplex stainless steels such as Zeron 100 are preferable materials for industrial applications demanding high strength, toughness and superior corrosion resistance, especially against stress corrosion cracking (SCC). SCC is an environmentally assisted failure mechanism that occurs due to exposure to an aggressive environment while under a tensile stress. The mechanism by which SCC of duplex stainless steel is expected to suffer depends on the combination of electrochemical and the mechanical interaction between austenite and ferrite in the duplex alloys. The main aims of this work are to study the suitability of digital image correlation (DIC) to monitor the initiation and propagation of SCC and to understand how the microstructure of duplex stainless steel influences the kinetics of crack initiation and growth. The combined analysis of DIC, SEM and EBSD was used to study the relative crack propagation and the effect of interphase boundaries on crack growth as well. Cracking was initiated beneath saturated MgCl2 droplets in an atmospheric environment at 80°C and relative humidity of 30-33%. As-received and 10% cold rolled samples (with two orientations transverse and longitudinal to the loading direction) were subjected to an applied strain of 0.03 under displacement controlled tests. Regular optical observations were recorded of the droplets and their surrounding area. DIC analyses used the differentiation of the displacement fields to obtain the apparent surface strains used to detect crack initiation and propagation, and to measure crack opening displacements. It was found that DIC was efficiently observed the strain developments and the displacements in observed surfaces outside of the droplets but it could not identify or quantify the initiation of the cracks inside the droplets because of the mobility of the salt film and the high amount of the corrosion products formed which obscure the vision under the droplets. In addition, results showed that early stage microcracks were initiated in α phase and α/γ interfaces and propagated preferentially in the ferrite phase. Also, SCC initiation and propagation was accelerated by cold rolling and the grains orientations were of major effects on the retardation of crack propagation which was more severe in the transverse rolling direction. Also, there was no relation established between the strain level and the density of pitting in either phase.
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21

Aboalriha, Wajdi. "Prediction of cracking in steel joint subjected to high cyclic strains." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25963.

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During earthquakes, structures can be subject to many cycles of high strain. This can lead to cracking and a serious reduction in strength in comparison with the usual assumption of maintained strength during ductile cycling. This study reviews various methods for the prediction of cracking and compares them with results available in the literature. Crack prediction can be performed using one of the three basic methodologies: stress-life theory, strain-life theory, and the crack growth approach. These techniques are developed to determine the number of cycles to failure. Stress life theory is suitable when elastic stresses and strains are considered. However, for the components having nominal cyclic elastic stresses but local plastic deformation, local strain-life theory is used for predicting the fatigue life. In this work, the behaviour of a fully welded steel connection subjected to cyclic displacement loading, is analysed using the strain-life theories. Based on the results, it can be concluded that: FE modelling, in conjunction with strain life equations can approximately estimate the cycles to failure at the observed crack location on a beam framing into the connection. However the more highly stressed area in the connections "panel zone" did not crack in the experiments, perhaps because of the more complex stress field and defect orientation to the tensile stresses in this location. The connection was improved by adding triangular bracing gussets, in the plane of the beam and column webs. The FE model showed that stress and strain were decreased and the high strains moved from the panel zone to the gussets.
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22

Kivisäkk, Ulf. "Influence of hydrogen on corrosion and stress induced cracking of stainless steel." Doctoral thesis, KTH, Korrosionslära, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12436.

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Hydrogen is the smallest element in the periodical table. It has been shown in several studies that hydrogen has a large influence on the corrosion and cracking behaviour of stainless steels. Hydrogen is involved in several of the most common cathode reactions during corrosion and can also cause embrittlement in many stainless steels. Some aspects of the effect of hydrogen on corrosion and hydrogen-induced stress cracking, HISC, of stainless steels were studied in this work. These aspects relate to activation of test specimens for uniform corrosion testing, modification of a test cell for dewpoint corrosion testing and the mechanism of hydrogen-induced stress cracking. The results from uniform corrosion testing of superduplex stainless steels indicated that there is a large difference between passive and activated surfaces in hydrochloric acid and in lower concentrations of sulphuric acid. Hence, initial activation of the test specimen until hydrogen evolution can have a large influence on the results. This may provide another explanation for the differences in iso-corrosion curves for superduplex stainless steels that have previously been attributed to alloying with copper and/or tungsten. In concentrated sulphuric acid, potential oscillations were observed; these oscillations activated the specimen spontaneously. Due to these potential oscillations the influence of activation was negligible in this acid. An experimental set-up was developed for testing dewpoint corrosion of stainless steels in a condensate containing 1 % hydrochloric acid. There was an existing experimental set-up that had to be modified in order to avoid azeotroping of the water and hydrogen chloride system. A separate flask with hydro chloric acid was included in the experimental set-up. The final set-up provided reasonably good agreement with field exposures in contrary to much higher corrosion rates in the original set-up. Relaxation and low temperature creep experiments have been performed with several stainless steels in this work. The aim was to understand how creep and relaxation relates to material properties and the relative ranking between the tested materials. For low temperature creep with a load generating stresses below the yield strength, as well relaxation at stress levels above and below the yield strength, the same ranking with respect to changes in mechanical properties of the steel grades was found. For low temperature creep with a load level above the yield strength, the same ranking was not obtained. This effect can most probably be explained by annihilation and generation of dislocations. During low temperature creep above the yield strength, dislocations were generated. In addition, low temperature creep experiments were performed forone superduplex stainless steel in two different product forms with differentaustenite spacing in the microstructure. The superduplex material experienced low temperature creep at a lower load level for the material with large austenite spacing compared to the one with smaller austenite spacing. Also this differenceis influenced by dislocations. In a material with small austenite spacing the dislocations have more obstacles that they can be locked up against. Studies of the fracture surfaces of hydrogen induced stress cracking, HISC, tested duplex stainless steels showed that HISC is a hydrogen-enhanced localised plasticity, HELP, mechanism. Here a mechanism that takes into account the inhomogeneous deformation of duplex stainless steels was proposed. This mechanism involves an interaction between hydrogen diffusion and plastic straining. Due to the different mechanical properties of the phases in a superduplex stainless steel, plastic straining due to low temperature creep can occur in the softer ferrite phase. A comparison between low temperature creep data showed that for the coarser grained material, HISC occurs at the load levelwhen creep starts. However, in the sample with small austenite spacing, HISC did not occur at this load level. Microhardness measurements indicated that the hydrogen level in the ferrite was not high enough to initiate cracking in the coarser material. The proposed mechanism shows that occurrence of HISC is an interaction between local plasticity and hydrogen diffusion.
QC20100618
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23

Goodman, Lindsey R. "Stress corrosion cracking of X65 pipeline steel in fuel grade ethanol environments." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45790.

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In recent years, the demand for alternatives to fossil fuels has risen dramatically, and ethanol fuel has become an important liquid fuel alternative globally. The most efficient mode of transportation of petroleum-based fuel is via pipelines, and due to the 300% increase in ethanol use in the U.S. in the past decade, a similar method of conveyance must be adopted for ethanol. Low-carbon, low-alloy pipeline steels like X52, X60, and X65 comprise the existing fuel transmission pipeline infrastructure. However, similar carbon steels, used in the ethanol processing and production industry, were found to exhibit stress corrosion cracking (SCC) in ethanol service. Prior work has shown that contaminants absorbed by the ethanol during distillation, processing or transport could be the possible determinants of SCC susceptibility; 200 proof ethanol alone was shown not to cause SCC in laboratory studies. To ensure the safety and integrity of the pipeline system, it was necessary to perform a mechanistic study of SCC of pipeline steel in fuel grade ethanol (FGE). The objective of this work was to determine the environmental factors relating to SCC of X65 steel in fuel grade ethanol (FGE) environments. To accomplish this, a systematic study was done to test effects of FGE feedstock and common contaminants and constituents such as water, chloride, dissolved oxygen, and organic acids on SCC behavior of an X65 pipeline steel. Slow strain rate tests (SSRT) were employed to evaluate and compare specific constituents' effects on crack density, morphology, and severity of SCC of X65 in FGE. SCC did not occur in commercial FGE environments, regardless of the ethanol feedstock. In both FGE and simulated fuel grade ethanol (SFGE), SCC of carbon steel was found to occur at low water contents (below 5 vol%) when chloride was present above a specific threshold quantity. Cl- threshold for SCC varied from 10ppm in FGE to approximately 1 ppm in SFGE. SCC of carbon steel was inhibited when oxygen was removed from solution via N2 purge or pHe was increased by addition of NaOH. During SSRT, in-situ¬ electrochemical measurements showed a significant role of film rupture in the SCC mechanism. Analysis of repassivation kinetics in mechanical scratch tests revealed a large initial anodic dissolution current spike in SCC-causing environments, followed by repassivation indicated by current transient decay. In the deaerated environments, repassivation did not occur, while in alkaline SFGE repassivation was significantly more rapid than in SCC-inducing SFGE. Composition and morphology of the passive film on X65 during static exposure tests was studied using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results showed stability of an air-formed native oxide under static immersion in neutral (pHe = 5.4) SFGE, and dissolution of the film when pHe was decreased to 4.3. XPS spectra indicated changes in film composition at high pHe (near 13) and in environments lacking sufficient water. In light of all results, a film-rupture anodic-dissolution mechanism is proposed in which local plastic strains facilitates local breakdown of the air-formed oxide film, causing iron to dissolve anodically. During crack propagation anodic dissolution occurs at the crack tip while crack walls repassivate preserving crack geometry and local stress concentration at the tip. It is also proposed that SCC can be mitigated by use of alkaline inhibitors that speed repassivation and promotes formation of a more protective Fe(OH)3 film.
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24

Sutton, Benjamin James. "Solidification Behavior and Hot Cracking Susceptibility of High Manganese Steel Weld Metals." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366302517.

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25

Anyanwu, Ezechukwu John. "Low Alloy Steel Susceptibility to Stress Corrosion Cracking in Hydraulic Fracturing Environment." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1398948610.

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26

Mginqi, Lungile Ngubekhaya. "Evaluation of stress corrosion cracking of high-nitrogen Cr-Mn stainless steel." Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/17932.

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Includes bibliographical references.
The stress corrosion cracking susceptibility of an experimental high nitrogen Cr-Mn stainless steel, known as Cromanite ™, and conventional AISI 304 stainless steel were investigated in order to compare their stress corrosion performance in solutions where AISI 304 stainless steel is known to be susceptible. Slow strain rate tests (SSRT) were performed on solution treated specimens a t30°C in aerated aqueous sodium chloride (NaCI) solution containing hydrochloric acid (HCI) of varying concentration at open circuit potentials. Static tests in the form of bent-beam tests were performed on both solution treated and aged specimens in 3M NaCI solution containing 0.05 M HCI. Potentiodynamic scans and Tafel plots were used to assess corrosion behaviour and corrosion rate respectively, while the electrochemical potentiokinetic reactivation (EPR) method was used to quantify the degree of sensitisation for the materials. The SSRT revealed poor corrosion behaviour of Cromanite TM in the presence of hydrochloric acid. Whilst AISI 304 could be examined for stress corrosion cracking at HCI concentrations up to 0.5 M HCI, Cromanite ™ exhibited corrosion rates which were too fast to permit assessment of stress corrosion susceptibility at HCI concentrations of 0.15 M or above. SCC started in a salt solution containing 0.05M HCI for AISI 304 while Cromanite TM cracked in both salt solution (3M NaCI) and in 0.05 M HCI +3M NaCI. The bent-beam test performed on solution treated specimens revealed no evidence of cracking for both alloys after 100 days of exposure; however, Cromanite ™ suffered substantial mass loss after this period. While aged Cromanite TM suffered intergranular cracking after only 25 days in the test solution, no cracking was observed for the aged AISI 304 after 75 days.
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27

Kearns, M. A. "Electrochemical behaviour of segregants in relation to stress corrosion cracking of 3.5NiCrMoV steel." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233261.

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28

Gulbrandsen, Stephani. "Stress corrosion cracking of 316L austenitic stainless steel in high temperature ethanol/water environments." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/47815.

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There has been an increase in the production of bio-fuels. Organosolv delignification, high temperature ethanol/water environments, can be used to separate lignin, cellulose, and hemicelluloses in the bio-mass for bio-fuel production. These environments have been shown to induce stress corrosion cracking (SCC) in 316L stainless steel. Previous research has been done in mixed solvent environments at room temperature to understand SCC for stainless steels, but little is known about the behavior in high temperature environments. Simulated organosolv delignification environments were studied, varying water content, temperature, pHe, and Cl- content to understand how these constituents impact SCC. In order for SCC to occur in 316L, there needs to be between 10 and 90 volume % water and the environment needs to be at a temperature around 200°C. Once these two conditions are met, the environment needs to either have pHe < 4 or have more than 10 ppm Cl-. These threshold conditions are based on the organosolv delignification simulated environments tested. SCC severity was seen to increase as water content, temperature, and Cl- content increased and as pHe decreased. To prevent failure of industrial vessels encountering organosolv delignification environments, care needs to be taken to monitor and adjust the constituents to prevent SCC.
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29

Lou, Xiaoyuan. "Stress corrosion cracking and corrosion of carbon steel in simulated fuel-grade ethanol." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37279.

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Today, ethanol, as well as other biofuels, has been increasingly gaining popularity as a major alternative liquid fuel to replace conventional gasoline for road transportation. One of the key challenges for the future use of bioethanol is to increase its availability in the market via an efficient and economic way. However, one major concern in using the existing gas-pipelines to transport fuel-grade ethanol or blended fuel is the potential corrosion and stress corrosion cracking (SCC) susceptibility of carbon steel pipelines in these environments. Both phenomenological and mechanistic investigations have been carried out in order to address the possible degradation phenomena of X-65 pipeline carbon steel in simulated fuel-grade ethanol (SFGE). Firstly, the susceptibilities of stress corrosion cracking of this steel in SFGE were studied. Ethanol chemistry of SFGE was shown to have great impact on the stress corrosion crack initiation/propagation and the corrosion mode transition. Inclusions in the steel can increase local plastic strain and act as crack initiation sites. Secondly, the anodic behavior of carbon steel electrode was investigated in detail under different ethanol chemistry conditions. General corrosion and pitting susceptibility under unstressed condition were found to be sensitive to the ethanol chemistry. Low tendency to passivate and the sensitivity to ethanol chemistry are the major reasons which drive corrosion process in this system. Oxygen plays a critical role in controlling the passivity of carbon steel in ethanol. Thirdly, the detailed study was carried out to understand the SCC mechanism of carbon steel in SFGE. A film related anodic dissolution process was identified to be a major driving force during the crack propagation. Fourthly, more detailed electrochemical impedance spectroscopy (EIS) studies using phase angle analysis and transmission line simulation reveal a clearer physical picture of the stress corrosion cracking process in this environment. Fifthly, the cathodic reactions of carbon steel in SFGE were also investigated to understand the oxygen and hydrogen reactions. Hydrogen uptake into the pipeline steel and the conditions of the fractures related to hydrogen embrittlement were identified and studied.
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30

Manning, Ryan Daniel. "Analysis of underbead cracking in underwater wet weldments on A516 grade 70 steel." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA357618.

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Thesis (M.S. in Mechanical Engineering) Naval Postgraduate School, September 1998.
"September 1998." Thesis advisor(s): Alan G. Fox. Includes bibliographical references (p. 37). Also available online.
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31

Wildash, Clint. "Microstructure factors affecting hydrogen induced cold cracking in high strength steel weld metal." Thesis, University of Leeds, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364642.

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32

Kucz, Daniel Allen. "Analysis of distortion-induced fatigue cracking in a steel trapezoidal box girder bridge." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 177 p, 2009. http://proquest.umi.com/pqdweb?did=1885755701&sid=9&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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33

Yang, Dong. "Factors affecting stress assisted corrosion cracking of carbon steel under industrial boiler conditions." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24809.

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Thesis (Ph.D.)--Mechanical Engineering, Georgia Institute of Technology, 2008.
Committee Co-Chair: Preet M. Singh; Committee Co-Chair: Richard W. Neu; Committee Member: Hamid Garmestani; Committee Member: Timothy Patterson; Committee Member: W. Steven Johnson.
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34

Cao, Liu. "Corrosion and Stress Corrosion Cracking of Carbon Steel in Simulated Fuel Grade Ethanol." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1345141634.

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35

Xie, Yi. "Chloride-Induced Stress Corrosion Cracking in Used Nuclear Fuel Welded Stainless Steel Canisters." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469132001.

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36

Scott, Allan Nye. "The influence of binder type and cracking on reinforcing steel corrosion in concrete." Doctoral thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/5001.

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Includes bibliography.
Two of the main factors affecting the durability of reinforced concrete structures are the level of chlorides required to initiate corrosion and the subsequent rate of penetration of chloride ions through concrete. The primary focus of the current work is the study of how cement extenders impact on the corrosion characteristics of embedded steel in concrete. The investigation was limited to those materials commonly used in South Africa (slag, fly ash,and condensed silica fume) and performed under laboratory conditions at 30°C.
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37

Gupta, Jyoti. "Intergranular stress corrosion cracking of ion irradiated 304L stainless steel in PWR environment." Thesis, Toulouse, INPT, 2016. http://www.theses.fr/2016INPT0031/document.

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L’IASCC est un mécanisme de fissuration intergranulaire par corrosion sous contrainte (IGCSC) induite par l'irradiation. C’est un phénomène complexe qui peut avoir une influence significative sur le temps et le coût de maintenance des composants internes du coeur des réacteurs à eau pressurisée (REP) et est donc un sujet d'intérêt. Des études récentes ont proposé d'utiliser l'irradiation aux ions (protons) comme une alternative à l'irradiation neutronique afin d’améliorer la compréhension du mécanisme. L'objectif de cette thèse est d’étudier la sensibilité à la fissuration de l’acier austénitique SA 304L irradié aux ions ainsi que les facteurs contribuant à cette fissuration. Deux types d’irradiations aux ions ont été menées (fer et aux protons). Ces deux irradiations ont générées des défauts ponctuels dans la microstructure représentatifs de ceux crées par les neutrons provoquant ainsi le durcissement de l’acier austénitique 304L. Matériel (non irradié et le fer irradié) n'a montré aucune sensibilité à la fissuration intergranulaire sur la soumission à un essai de traction lente SSRT (Slow Strain Rate Test) commencer avec une vitesse de déformation de 5 × 10-8 s-1 jusqu'à 4% de déformation plastique dans un environnement inerte. Il est montré que les deux types d’irradiation aux ions (fer et protons) augmentent la sensibilité à la fissuration intergranulaire du matériau après un essai de SSRT dans un environnement simulé de REP à 340 ° C. La corrélation entre la sensibilité de fissuration et le degré de localisation de la déformation plastique a été étudiée. L’impact de l'irradiation aux ions fer sur l'oxydation du 304L a été aussi étudié grâce à des essais effectués pendant 360 h dans un milieu REP à 340 ° C. Les résultats de cette thèse indiquent que la fissuration intergranulaire de l'acier inoxydable 304L en milieu REP peut être étudiée en utilisant l'irradiation Fe malgré sa faible profondeur de pénétration dans le matériau. Par ailleurs, il est montré que le comportement vis-à-vis de la fissuration est similaire entre une irradiation aux protons et au fer, et ceux malgré une localisation de la déformation moins importante pour ces derniers. Par conséquent, l’irradiation au fer est utilisée pour étudier l'impact de la préparation de surface et des chemins de déformation sur la sensibilité de la fissuration intergranulaire de l’acier 304L
IASCC is irradiation – assisted enhancement of intergranular stress corrosion cracking susceptibility of austenitic stainless steel. It is a complex degrading phenomenon which can have a significant influence on maintenance time and cost of PWRs’ core internals and hence, is an issue of concern. Recent studies have proposed using ion irradiation (to be specific, proton irradiation) as an alternative of neutron irradiation to improve the current understanding of the mechanism. The objective of this study was to investigate the cracking susceptibility of irradiated SA 304L and factors contributing to cracking, using two different ion irradiations; iron and proton irradiations. Both resulted in generation of point defects in the microstructure and thereby causing hardening of the SA 304L. Material (unirradiated and iron irradiated) showed no susceptibility to intergranular cracking on subjection to SSRT with a strain rate of 5 × 10-8 s-1 up to 4 % plastic strain in inert environment. But, irradiation (iron and proton) was found to increase intergranular cracking severity of material on subjection to SSRT in simulated PWR primary water environment at 340 °C. Correlation between the cracking susceptibility and degree of localization was studied. Impact of iron irradiation on bulk oxidation of SA 304L was studied as well by conducting an oxidation test for 360 h in simulated PWR environment at 340 °C. The findings of this study indicate that the intergranular cracking of 304L stainless steel in PWR environment can be studied using Fe irradiation despite its small penetration depth in material. Furthermore, it has been shown that the cracking was similar in both iron and proton irradiated samples despite different degrees of localization. Lastly, on establishing iron irradiation as a successful tool, it was used to study the impact of surface finish and strain paths on intergranular cracking susceptibility of the material
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38

Stratulat, Alisa. "Micromechanics of stress corrosion cracking in 304 stainless steel and Ni Alloy 600." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:3c150765-b2b1-4f54-95aa-36d294a99acc.

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The current thesis takes a step forward into understanding the intergranular stress corrosion cracking (IGSCC) by applying a relatively new micro-mechanical technique to look at the crack growth rate of individual grain boundaries in 304 stainless steel (SS) and to measure fracture toughness for different grain boundaries in Ni Alloy 600. In addition, a model is tested and proposed that could predict crack initiation in 304 SS. Pentagonal cross-section cantilevers 5 μm wide by 25 μm long were milled at individual grain boundaries in both 304 SS and Ni Alloy 600. The cantilevers milled in 304 SS were tested in-situ in a customised stage, using the nanoindenter. Crack growth rate was measured for two different cantilevers to be approximately 40 μm/s (K = 1.1 MPa(m)^(1/2)) and 120 μm/s (K = 1.7 MPa(m)^(1/2)). Cantilevers were milled in Ni Alloy 600 for three different samples: samples that were exposed to simulated pressurized water reactors (PWR) environment for 4500 h, for 1500 h and un-oxidised samples. The fracture toughness calculated for the fractured cantilevers in samples that were exposed for 4500 h was measured to be between 0.73 and 1.82 MPa(m)^(1/2). No intergranular fracture occurred in the samples that were exposed for 1500 h and in the un-oxidised samples. The grain boundary misorientation was measured for the tested cantilevers but no direct correlation was observed between the misorientation angle and the fracture toughness. A Schmid-modified grain boundary stress (SMGBS) model previously used to study the intergranular behaviour of irradiated 316L steel in supercritical water was applied to predict crack initiation in 304 stainless steel. The model was successfully applied and accurately predicted crack initiation. To extend the model, sensitisation was also included. In addition, different areas of the specimen, including the initiation site were analysed using High resolution electron backscatter diffraction (HR-EBSD) technique to measure the geometrically necessary dislocations (GNDs) density. It was observed that the boundary average GNDs is lower for the intact boundaries and higher for the cracked grain boundaries.
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39

Je, Hwanil. "Stress Corrosion Cracking Behavior of Oxide Dispersion Strengthened Ferritic Steel in Supercritical Pressurized Water." Master's thesis, Kyoto University, 2013. http://hdl.handle.net/2433/180448.

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40

Grover, Parmeet S. "Creep-fatigue crack growth in Cr-Mo-V base material and weldments." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/19540.

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41

Sowards, Jeffrey William. "Development of a chromium-free consumable for joining stainless steel." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1237845645.

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42

Brady, Michael P. "Evaluation of laser surface melting to mitigate chloride stress corrosion cracking in an austenitic stainless steel." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03122009-040851/.

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43

Hays, Richard A. "Surface residual stress effects on stress corrosion cracking/hydrogen embrittlement behavior of AISI 4340 steel." Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/80148.

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A series of experiments was performed in an attempt to measure the effects of surface residual stresses on the stress corrosion cracking/hydrogen embrittlement (SCC/HE) behavior of AISI 4340 steel. Stress corrosion tests were performed under load control on cylindrical and notched tensile specimens in acidified 3.5% NaCl solution. The electrochemical potential of the specimens was maintained at -0.7 V versus a saturated calomel reference electrode. Time to failure for specimens tested at various applied and residual stress levels was measured. Stress relieved specimens as well as specimens containing mechanically induced residual stresses were tested. Residual stresses were estimated using Neuber's rule and were measured using an x-ray diffraction technique. In all cases, the sum of the applied and residual stresses was greater than zero. Test results showed the initiation of SCC/HE cracks to be insensitive to the effects of surface residual stresses under the conditions evaluated. This is probably a result of the total time to failure criterion used to evaluate the SCC/HE tests. The extremely aggressive environment used in these experiments apparently led to rapid crack initiation, even in specimens containing compressive residual stresses. Another possible explanation of the insensitivity of this series of tests is crack initiation in the interior of the specimens below the depth of the mechanically induced residual stresses.
Master of Science
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44

Phung-on, Isaratat. "An investigation of reheat cracking in the weld heat affected zone of type 347 stainless steel." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1188419315.

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45

Patel, Akshay Mahesh. "Growth of small fatigue cracks in PH 13-8 Mo stainless steel." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/18185.

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46

Yang, Di. "Cyclic stress effect on stress corrosion cracking of duplex stainless steel in chloride and caustic solutions." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42811.

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Duplex stainless steel (DSS) is a dual-phase material with approximately equal volume amount of austenite and ferrite. It has both great mechanical properties (good ductility and high tensile/fatigue strength) and excellent corrosion resistance due to the mixture of the two phases. Cyclic loadings with high stress level and low frequency are experienced by many structures. However, the existing study on corrosion fatigue (CF) study of various metallic materials has mainly concentrated on relatively high frequency range. No systematic study has been done to understand the ultra-low frequency (10-5 Hz) cyclic loading effect on stress corrosion cracking (SCC) of DSSs. In this study, the ultra-low frequency cyclic loading effect on SCC of DSS 2205 was studied in acidified sodium chloride and caustic white liquor (WL) solutions. The research work focused on the environmental effect on SCC of DSS 2205, the cyclic stress effect on strain accumulation behavior of DSS 2205, and the combined environmental and cyclic stress effect on the stress corrosion crack initiation of DSS 2205 in the above environments. Potentiodynamic polarization tests were performed to investigate the electrochemical behavior of DSS 2205 in acidic NaCl solution. Series of slow strain rate tests (SSRTs) at different applied potential values were conducted to reveal the optimum applied potential value for SCC to happen. Room temperature static and cyclic creep tests were performed in air to illustrate the strain accumulation effect of cyclic stresses. Test results showed that cyclic loading could enhance strain accumulation in DSS 2205 compared to static loading. Moreover, the strain accumulation behavior of DSS 2205 was found to be controlled by the two phases of DSS 2205 with different crystal structures. The B.C.C. ferrite phase enhanced strain accumulation due to extensive cross-slips of the dislocations, whereas the F.C.C. austenite phase resisted strain accumulation due to cyclic strain hardening. Cyclic SSRTs were performed under the conditions that SCC occurs in sodium chloride and WL solutions. Test results show that cyclic stress facilitated crack initiations in DSS 2205. Stress corrosion cracks initiated from the intermetallic precipitates in acidic chloride environment, and the cracks initiated from austenite phase in WL environment. Cold-working has been found to retard the crack initiations induced by cyclic stresses.
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47

Needham, William Donald. "Stress corrosion cracking and hydrogen embrittlement of thick section high strength low alloy steel." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/10945/22123.

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An experimental study was conducted to evaluate the corrosion performance of weldments of a high strength low alloy(HSLA) steel in a simulated seawater environment. This steel, designated HSLA80, was developed by the United States Navy for use in ship structural applications. Stress corrosion CRACKING(SCC) and hydrogen embrittlement(HEM) were investigated by conducting 42 Wedge-Opening load(WOL) tests as a function of stress intensity and corrosion potential and 33 Slow Strain Rate(SSR) tests as a function of strain rate and corrosion potential. The corrosion potentials were chosen to simulate the environmental conditions of free corrosion, cathodic protection and hydrogen generation. The results from this investigation indicated that HSLA 80 base metal and weldments were susceptible to hydrogen assisted cracking(HAC) in a seawater environment under conditions of continuous plastic deformation and triaxial stress in the presence of hydrogen. The heat-affected zone of the weldment was found to be the most susceptible portion of the weld joint. A lower bound was established for the critical stress intensity for stress corrosion cracking for HSLA 80 base metal and weldments.(Theses)
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48

Morlock, Florian. "Evaluation of stress corrosion cracking in sensitized 304 stainless steel using nonlinear Rayleigh waves." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53025.

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This research uses nonlinear Rayleigh surface waves to characterize stress corrosion cracking (SCC) damage in sensitized 304 Stainless Steel (304 SS). 304 SS is widely used in reactor pressure vessels and fuel pipelines, where a corrosive environment in combination with applied stress due to high internal pressures can cause SCC. SCC poses great risk to these structures as it initiates cracks late in the lifetime and often unexpectedly. The initiated microcracks grow and accumulate very quickly to form macroscopic cracks that lead to material failure. Welds and the nearby heat affected zones (HAZ) in the vessels and pipework are particularly affected by SCC as welding induces sensitization in the material. SCC damage results in microstructural changes such as dislocation movement and microcrack initiation that in the long term lead to reduced structural integrity and material failure. Therefore, the early detection of SCC is crucial to ensure safe operation. It has been shown that the microstructural changes caused by SCC can generate higher harmonic waves when excited harmonically. This research considers different levels of SCC damage induced in samples of sensitized 304 SS by applying stress to a specimen held in a corrosive medium (Sodium Thiosulfate). Nonlinear Rayleigh surface waves are introduced in the material and the fundamental and the second harmonic waves are measured. The nonlinearity parameter that relates the fundamental and the second harmonic amplitudes, is computed to quantify the SCC damage in each sample. The results obtained are used to demonstrate the feasibility of using nonlinear Rayleigh waves to characterize SCC damage.
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49

Sui, Gaoyi. "Some aspects of stress corrosion cracking of Type 316 stainless steel steam generator tubes." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481644.

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50

Hunt, Christopher Paul. "Influence of residual elements on the intergranular stress corrosion cracking of carbon manganese steel." Thesis, University of Surrey, 1987. http://epubs.surrey.ac.uk/847543/.

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Abstract:
The Influences of five common tramp elements P, S, Sn, Cu, and Ni at typical residual levels on the intergranular stress corrosion cracking (IGSCC) of a typical mild steel. (0.15%C, 0.8%Mn and 0.05%Si), are studied in nitrate solutions and a mixture of carbonate and bicarbonate solutions. The relative effects of these impurities are examined in terms, of the electrochemical properties of unstressed material, of the IGSCC susceptibility in a constant strain rate test, and of the grain boundary and surface oxide compositions via surface analysis. Results show that in general only phosphorus can be detrimental. A slight beneficial effect is apparent for Cu in both electrolytes. Phosphorus has small adverse effects in certain narrow potential regions in the NH[4]NO[3] electrolyte. These occur just above the free corrosion potential and above the active-passive transition (1100 mV). There are no detrimental effects due to the impurities in the carbonate/bicarbonate electrolyte. The negligible effects of impurities occurs in spite of impurity concentrations at the grain boundaries being significantly enhanced above the bulk to 10%. as confirmed by Auger electron spectroscopy. Hence, the IGSCC susceptibility is shown to be dominated by the carbon present in the steel. XPS measurements indicate that carbon is present throughout the oxide, and importantly up to the electrolyte interface. IGSCC susceptibility is thought to occur principally by a breakdown in the oxide integrity, which leads to prolonged chemical attack. This mechanism is attibuted to the action of carbon and possibly the impurities, however under certain conditions some secondary mechanisms are needed to account for ail the effects due to the impurities. These include improved passivation by reaction products and a remedial influence on the detrimental effect of carbon.
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