Showing papers on "Carbon steel published in 1998"

Effect of Microstructure on Corrosion of Steels in Aqueous Solutions Containing Carbon Dioxide

Abstract: The influence of microstructure on the corrosion rate of steels in a carbon dioxide (CO2)-containing aqueous solution was measured experimentally as a function of pH, temperature, and part...

Factors Controlling Naphthenic Acid Corrosion

Abstract: A laboratory study was conducted to elucidate the influence of chemical and physical parameters on corrosion of type 1018 carbon steel (CS, UNS G10180)and 5% Cr-0.5% Mo steel in oils conta...

Heat Transfer across Mold Flux Film in Mold during Initial Solidification in Continuous Casting of Steel

Abstract: Analysis of heat transfer near the meniscus in mold for continuous casting of steel has been carried out by taking into account conductive and radiative thermal resistances of infiltrated mold flux film and thermal resistance at the copper mold/solidifying mold flux film interface. Mold fluxes in commercial use for casting low and medium carbon steel are selected for this study. Thermal conductivities, absorption coefficients and interfacial thermal resistances of these fluxes have been determined in our previous work by laser flash method, high temperature cell FTIR test and contacting thermal resistance test, respectively. Calculation with these data shows that the heat transfer is strongly influenced by the interfacial thermal resistance. Slow cooling required for casting surface crack sensitive medium carbon peritectic steel slabs can be achieved by making the interfacial thermal resistance high, which is attainable by use of basic mold fluxes with high rate of crystallization. A flux film thicker than 0.25 mm for the low carbon steel or 0.4 mm for the medium carbon steel is also found to be a requisite to prevent the occurrence of longitudinal surface cracks. Reasonably high interfacial thermal resistance and a proper flux film thickness are essential to reduce the surface defects and to increase the speed of continuous casting of these steel slabs.

Corrosion Inhibition of a Mild Steel by Aniline and Alkylamines in Acidic Solutions

Abstract: Corrosion inhibition of a mild steel in acid solutions by alkylamines (ALK-AM) and aniline hydrochloric (ANL-HCl) salts was investigated in the presence of sodium sulfate (Na2SO4) and sodium chloride (NaCl) using a potentiostat, a contact-angle goniometer, a scanning electron microscope (SEM), a Fourier transform infrared spectrometer (FTIR), and an atomic force microscope (AFM). Results showed chloride ions (Cl−) had a pronounced effect on inhibition of amines and ANL for corrosion of mild steel. In the presence of Cl− ions, cationic types of surfactants (ALK-AM and ANL) were attached to the surface through formation of chloride precipitate at the surface. In the absence of the organic inhibitors, corrosion initiated along grain boundaries of ferrite and pearlite structures. In the presence of the organic inhibitor, however, the steel surface was covered by an organic salt precipitation, and the corrosion rate was reduced significantly.

Analytical characterization of the passive film formed on steel in solutions simulating the concrete interstitial electrolyte

Abstract: Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) were used to study the effect of chloride (Cl−) and fly ash on behavior of the passive film formed on steel in ...

Microstructure Analysis of Coupons Exposed to Carbon Dioxide Corrosion in Multiphase Flow

Abstract: Carbon dioxide (CO2) corrosion products formed on low-carbon steel test coupons exposed to multiphase flows of CO2-oil-salt water mixtures were analyzed. The effects of flow, temperature, ...

Effect of precorrosion on the performance of inhibitors for CO2 corrosion of carbon steel

Abstract: Four commercially available, water soluble corrosion inhibitors for CO corrosion have been tested in the laboratory on carbon steel specimens that were corroded for up to 18 days in the medium prior to inhibitor addition. The tests were performed at 20-50 °C, pH 5, 1 bar CO, 1-3 w% NaCl in glass cells and a glass loop. The results show that inhibitor performances were impaired with increasing precorrosion time and increasing temperature. The resulting corrosion attack was localised within deep pits. The detrimental effect is influenced both by the nature of the steel and the inhibitor composition. The inhibitor failure is related to the formation of a cementite layer at the steel surface.

Microstructure/property relationships in dissimilar welds between duplex stainless steels and carbon steels

Abstract: The metallurgical characteristics, toughness and corrosion resistance of dissimilar welds between duplex stainless steel Alloy 2205 and carbon steel A36 have been evaluated. Both duplex stainless steel ER2209 and Ni-based Alloy 625 filler metals were used to join this combination using a multipass, gas tungsten arc welding (GTAW) process. Defect-free welds were made with each filler metal. The toughness of both the 625 and 2209 deposits were acceptable, regardless of heat input. A narrow martensitic region with high hardness was observed along the A36/2209 fusion boundary. A similar region was not observed in welds made with the 625 filler metal. The corrosion resistance of the welds made with 2209 filler metal improved with increasing heat input, probably due to higher levels of austenite and reduced chromium nitride precipitation. Welds made with 625 exhibited severe attack in the root pass, while the bulk of the weld was resistant. This investigation has shown that both filler metals can be used to join carbon steel to duplex stainless steels, but that special precautions may be necessary in corrosive environments.

Effects of plastic strain and strain path on youngs modulus of sheet metals

Abstract: The effects of plastic strain and strain path on Young’s modulus of sheet metals are experimentally investigated using low carbon steel, stainless steel, aluminium, copper and brass sheets of 1 mm thickness. These sheets are firstly deformed to different plastic strains under a few strain paths from balanced biaxial stretching to uniaxial tension. Then, a small uniaxial tension test specimen is cut from each deformed sheet and Young’s modulus is measured using electrical-resistance strain gauges glued to both surfaces of the specimen. The experimental results show that Young’s moduli of the low carbon steel and stainless steel sheets decrease with increasing plastic strain, while those of aluminium, copper and brass sheets hardly change with the plastic strain. In all materials, however, the effect of the strain path on Young’s modulus is not necessarily evident. It is confirmed that Young’s modulus of the low carbon steel sheet can be recovered to the initial value of undeformed sheet by a subsequent annealing. In addition to Young’s modulus, the effects of the plastic strain and the strain paths on Poisson’s ratio of these materials are also shown.

Steel slag: applications for amd control

Abstract: In both laboratory and field studies, steel slags were found to generate exceptionally high levels of alkalinity over extended periods. Steel slags also have high neutralization potentials and can be used as alkaline amendments to acid-producing materials. This paper discusses the alkalinity-generating capacity of steel slags, their metal leaching potential and applications for acid mine drainage control. Results indicate that steel slags can provide highly concentrated alkaline recharge to acid mine wastes. Proper design and sizing offers the potential for a low- to zero-maintenance method for treating acid mine drainage (AMD) within the spoil pile itself. Since slags form around the melting point of iron, >2,700 o F, most compounds which have a low boiling point have been driven off. Most of the residuals are encased as oxides or in a calcium-alumino-silicate glassy matrix. Fortunately, the matrix is soluble and releases calcium and manganese oxides which drive the pH above 10. Since slag is a glass in its coarser form (e.g. -1/8 in.) it will, unless compacted, maintain high permeability regardless of how much water has passed through it. Unlike lime, steel slags do not absorb CO 2 from the air and convert back to relatively insoluble calcite: Ca (OH) 2 + CO 2 fiCa CO 3 +H 2 O. This is an extremely important property, since it means slag will generate high levels of alkalinity even after years of open storage. STEEL SLAG: WHAT IS IT? Technically, slag is nearly any solid which melts and forms a silicate glass during a metal refining process. In the power industry, slag is ash which melts and sticks to the walls or pipes of the boiler. In the base-metal industry, slags result from the smelting of various ores of copper, zinc, lead, etc. These slags can have high concentrations of heavy metals. In this paper, we are only discussing slags from the steel-making process. In making steel, iron ore or scrap metal is melted in combination with limestone, dolomite or lime. Pure iron is soft, bends easily under loads, and has limited uses. Small amounts of carbon, nickel, manganese, and other elements turn iron into various alloys of steel. There are hundreds of grades of steel ranging from basic carbon steel to high grade stainless. Steel making begins by reducing any metal oxides in the melt to pure iron metal, while scavenging ions such as aluminum, silicon, and phosphorous. The later three elements are bad news for steel as they cause it to become weak, brittle, or otherwise difficult to roll into sheet in a predictable way. For that matter, they make it nearly impossible to make anything useful out of iron. (Even though iron is much more readily available, its impurities caused bronze to become the metal of choice for tools after stone became obsolete.) Fortunately, our ancestors discovered that ironis imperfections could be controlled by adding limestone or dolomite. These calcium compounds mix with aluminum, silicon and phosphorous to form slag. Slag then floats to the top of the melt, is poured off, and sent to disposal. Slag starts its life at about 2,700 o F and cools almost immediately.

Mechanism of Cathodic Disbonding of Three-Layer Polyethylene-Coated Steel Pipe

Abstract: The mechanism of cathodic disbonding of three-layer polyethylene (PE)-coated steel pipe composed of liquid epoxy primer, adhesive PE, and a PE protective layer at an elevated temperature was investigated in sodium chloride (NaCl) solution. Cathodic disbonding tests were carried out to determine the route by which the substances reached the disbonding front under various conditions. Tested parameters included coating thickness, dissolved oxygen, NaCl concentration, and cathodic potential. The cathodic disbonding radius (r) decreased with increased PE thickness. Both oxygen and water migrating through the coating strongly affected cathodic disbonding. Oxygen migrated not from the interface between coating and steel at the holiday (defect) but through the PE coating to the disbonding front. Sodium did not migrate through the PE coating but through the interface between the coating and steel. Therefore, the decrease of r with increased coating thickness was caused by retardation of water and oxygen m...

Study of the interfacial phenomena during friction surfacing of mild steel with tool steel and inconel

Abstract: Friction surfacing was carried out with tool steel (AISI 01) and inconel 600 consumables on mild steel 1020 substrate in an argon atmosphere. Inconel bonded strongly with the substrate and there was evidence of interfacial compound formation between the substrate and coating. For tool steel coatings, a sharp boundary between the substrate and coating was observed by scanning electron microscopy. X-ray fluoroscopic imaging also revealed this boundary. Mechanical interlocking between the coating and the substrate appears to be insignificant so adhesion between the coatings and the substrate may be caused by solid-phase bonding. For friction surfacing of both tool steel and inconel, a nominal contact pressure as high as 21.8 MPa was required to obtain an adherent coating of uniform quality. © 1998 Chapman & Hall

The corrosion performance of steel and reinforced concrete in a tropical humid climate. a review

Abstract: systematic study of atmospheric corrosion behavior of steel and reinforced concrete was carried out in a tropical, humid, marine-coastal and rural-urban test sites, located in the Gulf of Mexico, and the Peninsula of Yucatan, in Southeastern Mexico. The temperature and relative humidity complex, time of wetness, principal contaminants (S02 and air-borne salinity) and pluvial precipitation are related to the steel corrosion mechanism and the formation of corrosion products. Regression analysis kinetics equations are presented. An electronic sensor was developed for monitoring the temperature and time of wetness of metal surface and the performance of concrete exposed in the tropical environment. The corrosivity of the marine-coastal and rural-urban atmospheres is classified according to ISO 9223-92. The atmospheric parameters and chloride deposition rate correlate well with the corrosion potential and current, time of curing, water/cement ratio and chloride (+) This review is based on articles authored by L. Veleva, P. Castro, et al., published in international journals and listed in the references. The chapter on the Gulf of Mexico was contributed by G. Hernandez Duque. M. Schorr edited the review.

Mesa Corrosion Attack in Carbon Steel and 0.5% Chromium Steel

Abstract: Local breakdown of protective corrosion films may result in rapid local attack or mesa corrosion attack during CO{sub 2} corrosion of carbon steel. The factors affecting formation and local breakdown of protective corrosion films were studied in a series of flow loop experiments performed at 40--80 C with pH 5.8, 1.8 bar CO{sub 2} partial pressure, high iron content in the water and flow rates 0.1--7 m/s. Carbon steels with or without chromium and nickel additions up to 1% were tested. Addition of 0.5% chromium in the steel was found to reduce the tendency for severe mesa attack in carbon steels during CO{sub 2} corrosion significantly. Deep mesa attack did not occur in steels with 0.5--1% Cr in experiments at 80 C and pH 5.8. Protective corrosion films reform more easily in the chromium containing steels, making localized attack less dangerous in chromium containing steels than in unalloyed carbon steels.

Prediction of Erosion-Corrosion Penetration Rate in a Carbon Dioxide Environment with Sand

Abstract: In oil and gas wells producing carbon dioxide (CO2) with saturated water, carbon steel piping can corrode rapidly depending upon the nature of the hydrocarbon phases produced and on flow and environmental parameters. In some CO2 environments, a protective iron carbonate (FeCO3) scale can form on carbon steel piping walls and reduce corrosion rates to within acceptable design limits. If sand also is being produced, protective scales can be removed or prevented from forming on piping walls at points where sand particles entrained in the flow stream impinge the walls. When this happens, bare metal corrosion is enabled at these impingement points, and corrosion rates again reach high levels. This process involves both erosion and corrosion mechanisms and often is referred to as “erosion-corrosion.” In some cases, pitting occurs at impingement points, resulting in extremely high penetration rates. In the present work, a laboratory flow loop circulating a CO2-saturated sodium chloride (NaCl) solution a...

Determination of the oxygen reduction products on ASTM A516 steel during cathodic protection

Abstract: The electrochemistry of steel in aerobic and anaerobic aqueous alkaline solutions was studied with or without forced convection to investigate the cathodic processes occurring on steel exposed by defects in polymer coated steel pipe. The results are relevant to the mechanistic understanding of the effect of cathodic protection on the disbonding of fusion bonded epoxy (FBE) coatings on steel. Moderate (pH9.8) and strongly (pH14) alkaline aqueous solutions were used to simulate the water layers at the cathodically polarized steel surface on the soil-side of buried pipe. A rotating gold ring and steel disc electrode (RRDE) in alkaline aqueous electrolyte equilibrated with 1atm oxygen over solution was used to measure the rotation rate dependent current for the electroreduction of oxygen, O2, on an ASTM A516 steel disc and the resulting peroxide generation, which was determined by monitoring the oxidation current on the gold ring. An appreciable fraction of the oxygen reduction current on the steel disk gave rise to peroxide generation over a wide range of potentials, from −0.2 to −0.9V vs SCE in 1M KOH. The observation of peroxide generation is noteworthy, because oxidizing agents, such as peroxide and its decomposition products, superoxide and hydroxy radical, can degrade the polymers used for coating pipelines. As result, oxidative degradation of polymer or interfacial compounds may be a cause of the accelerated disbonding observed for protective coatings on steel pipelines under cathodic protection.

Electrode erosion and coating properties in pulsed air arc deosition of WC-based hard alloys

Abstract: WC-based hard alloys were deposited from a slab source anode on to low carbon steel and pure Ti substrates using a pulsed air arc. The depositions were conducted with a series of pulses with current amplitudes of 75 A, 300 A, and 500 A, a pulse duration of 150 μs, and a pulse repetition rate of 100 Hz. The influence of the electrode material, discharge energy and deposition time on the electrode erosion rate, mass transfer direction, and the wear resistance and friction coefficient of the coatings was investigated. Anodic and cathodic mass change characteristics depended on both the anode and cathode materials. Using a steel cathode and a WC anode, depositions of the anode material always formed on the cathode. For the same WC anode but a Ti cathode, coatings only formed locally in the craters of the eroded cathode. The anodic mass loss when using the steel cathodes was about a factor of 3 larger than when using the Ti cathodes. The microhardness of the coated substrates was larger by factors of 5–12 than the uncoated Ti and low carbon steel substrates. The coatings increased the wear resistance of the steel and Ti substrates by factors of 4.3 and 1.4, respectively. The poorer performance of the coated Ti substrates is attributed to the intensive erosion of the Ti cathodes (compared to the steel cathodes) and the discontinuous nature of the coatings (i.e. only in the erosion caters).

Hybrid steel cord for tyre

Abstract: The invention concerns a hybrid steel cord comprising, in contact with one or several carbon steel wire(s), at least one stainless steel wire with its microstructure containing less than 20 % of martensite ( % in volume). The invention also concerns the use of at least one stainless steel wire in a steel cord comprising carbon steel wires, to improve by contact the fatigue-fretting-corrosion strength of theses carbon steel wires, and thereby the fatigue life of the steel cord itself. The invention further concerns cords as per the invention for reinforcing plastic and/or rubber articles and plastic and/or rubber articles reinforced with such cords, in particular tyre treads or body plies of such tyre treads.