Showing papers by "Bethlehem Steel published in 1998"

Characterization of Iron Oxides Commonly Formed as Corrosion Products on Steel

Abstract: For fundamental studies of the atmospheric corrosion of steel, it is useful to identify the iron oxide phases present in rust layers. The nine iron oxide phases, iron hydroxide (Fe(OH)2), iron trihydroxide (Fe(OH)3), goethite (α-FeOOH), akaganeite (β-FeOOH), lepidocrocite (γ-FeOOH), feroxyhite (δ-FeOOH), hematite (α-Fe2O3), maghemite (γ-Fe2O3) and magnetite (Fe3O4) are among those which have been reported to be present in the corrosion coatings on steel. Each iron oxide phase is uniquely characterized by different hyperfine parameters from Mossbauer analysis, at temperatures of 300K, 77K and 4K. Many of these oxide phases can also be identified by use of Raman spectroscopy. The relative fraction of each iron oxide can be accurately determined from the Mossbauer subspectral area and recoil-free fraction of each phase. The different Mossbauer geometries also provide some depth dependent phase identification for corrosion layers present on the steel substrate. Micro-Raman spectroscopy can be used to uniquely identify each iron oxide phase to a high spatial resolution of about 1 µm.

Structure of Protective Rust Layers Formed on Weathering Steels by Long-term Exposure in the Industrial Atmospheres of Japan and North America

Abstract: A protective and adherent rust layer develops on weathering steels during outdoor exposure. This layer acts as a barrier which slows further corrosion, thus enabling weathering steel to be used in structural applications without painting. To aid in understanding the mechanism of protective rust formation, studies have been made on the composition and microstructure of these layers. The present study was jointly conducted on Japanese weathering steel exposed in the industrial environment of Amagasaki, and US weathering steel exposed in the industrial environment of Bethlehem. The rust layers were studied by use of optical microscopy, electron microscopy with X-ray fluorescence, X-ray diffraction, and micro-Raman spectroscopy. The results of this collaboration show that, in general, the rust layers formed during long-term exposure are composed of one or more alternating layers of goethite and lepidocrocite, with scattered patches of maghemite and/or magnetite.

Retractable humidity sensor for use in corrosion test chambers

Abstract: A sensor probe device for monitoring atmosphere within a chamber. The device includes a housing that extends through a wall of the chamber being monitored, and a tubular sleeve that is movably captured within the housing. The sleeve includes an open end for receiving a sensor probe, and a closed end having a plurality of radially spaced apertures that extend through the sleeve wall. The apertures provide an open ribbed portion that exposes the enclosed sensor probe to chamber atmosphere when the sleeve portion is inserted into the chamber. A drive mechanism is attached to either extend the open ribbed portion of the sleeve outward from its shielded position within the housing to an extended position within the chamber, or retract the sleeve portion from the chamber back into its shielded position within the housing. An air supply is provided to inject forced air into the sleeve to maintain sensor probe integrity by purging contaminates through a drain in the sleeve wall, and an external air wipe nozzle is attached to the closed end of the sleeve to provide an air flow along the sleeve to prevent chamber atmosphere from entering the sleeve through the radially spaced apertures.

In vitro stability predictions for the bone/hydroxyapatite composite system.

Abstract: Electroacoustic measurements of the zeta (ζ) potential as a function of pH were collected and used to probe the nature of the ionic contributions to the bond formed between synthetic hydroxyapatite (HA) and bone. HA powder and wet bone powder were dispersed into an electrolyte solution comprised of physiologic saline (0.154M NaCl), electroacoustic measurements collected, and the ζ potential calculated as a function of pH. The ζ potential and particle size then were used to calculate the stability of the composite dispersion, where stability is the ability of a particulate suspension to remain unagglomerated. The stability was used to predict the homo- (HA to HA and bone to bone) versus heterocoagulation (HA to bone) behaviors for the HA/bone system. Although single component bone and HA demonstrated stability against agglomeration, the HA/bone interaction was determined to be unstable for all pH levels tested, including pH 7.4, the normal in vivo pH. These results establish one factor responsible for the observed physicochemical bonding between bone and HA noted by many in the orthopedic community. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 412–416, 1998.

Atmospheric corrosion resistance of skyward- and groundward-exposed surfaces of zinc- and 55% Al-Zn alloy-coated steel sheet

Abstract: Zinc-coated (galvanized) and 55% Al-Zn alloy-coated steel sheet was tested for atmospheric corrosion resistance for 20 years in rural (Saylorsburg, Pennsylvania), industrial (Bethlehem, Pennsylvania), moderate marine (250-m [880-ft] lot, Kure Beach, North Carolina), and severe marine (25-m [80-ft] lot, Kure Beach, North Carolina) environments. Corrosion losses were determined separately for skyward- and groundward-exposed surfaces and compared to results for conventional two-sided coupons, which gave only an average of skyward and groundward surfaces. Results were fitted to exponential equations of the form C = ATB, where C is the corrosion loss, T is time, and A and B are constants. Coating lives were estimated based upon extrapolation of these equations to the time to reach a corrosion loss equal to the coating thickness. On average, the estimated life of a skyward-exposed 55% Al-Zn alloy coating was 12 times that of a galvanized coating of equal thickness (25 μm).

System and method for minimizing slag carryover during the tapping of a BOF converter in the production of steel

Abstract: A system and method for detecting molten slag in a tap stream between a steel making basic oxygen furnace (BOF) and corresponding ladle. BOFs are used in the manufacture of steel. An infrared (IR) imaging or detecting device is used to image/view the BOF-to-ladle tap stream, the steam transmitting energy indicative of whether molten steel and/or slag is in the stream at a given time. The imaging device uses mainly long IR wavelengths (e.g. wavelengths of from about 8 to 14 μm) when imaging the molten tap stream, because these wavelengths are less susceptible to being blocked or absorbed by airborne gases and particles frequently found in BOF environments. In certain embodiments, all IR wavelengths other than those greater than about 8 μm are filtered out and are not used to detect slag in the tap stream.

Gas appliance with automatic gas shut-off device responsive to flame outage

Abstract: A gas appliance is provided for producing an open flame. The gas appliance includes an elongated gas tube, a gas inlet, a nozzle, a flame sensor, a gas shut-off valve, and a protective member. The gas tube has a proximal end and a distal end. The gas inlet is located near the proximal end, for connection to a source of combustible gas. The nozzle is located at the distal end, for expelling the combustible gas to produce the open flame. The flame sensor detects the open flame and communicates its absence or presence to the gas shut-off valve. The gas shut-off valve has a valve inlet, a valve outlet, a control input, and the over-ride mechanism. The valve inlet is connected to the gas inlet. The valve outlet is connected to the proximal end of the elongated gas tube. The control input is responsive to absence of the open flame as detected by the flame sensor so that the gas shut-off valve automatically closes when the flame is absent to keep the combustible gas from flowing from the valve inlet through the valve outlet. The over-ride mechanism is manually actuatable to over-ride the control input by opening the valve inlet to the valve outlet even if the flame is absent. The protective member is arranged around at least one of the flame sensor and the gas shut-off valve to protect these components. A method is provided for discharging combustible gas into the open flame in a manner dependent upon the presence of the open flame.

Method for recycling iron bearing sludges in a steelmaking operation

Abstract: The invention is directed to a process for dehydrating wet BOF scrubber sludge to produce a steelmaking revert having an improved flow rate when handled in a recycle stream. Wet sludge is combined with hot BOF slag to provide a slag/sludge mixture. The wet sludge causes the mixture to have a moisture content greater than 10 % water by weight, and the hot slag, having a temperature below the molten liquid state, vaporizes the water in the mixture and reduces the moisture content to about 4 % water by weight or less. The dehydrated mixture has improved flow rate properties when it is recycled as a steelmaking revert.

Prediction of responses to different powdering tests on a galvanneal-coated steel substrate or different tests on other substrates, using computer-based systems and methods

Abstract: Computer-based systems and methods of determining product parameters, performing process control, and/or classifying products are provided. These computer-based systems and methods analyze previous responses to different iterations of one or more tests and, based on this analysis, predict responses to future tests. The predictions are based on a classification and regression tree analysis. Also provided are computer-based systems which are pre-programmed with the results of at least one such analysis and which perform product parameter determination, process control, and/or product classifications based upon those results. The methods and computer systems are particularly well-suited for use in the context of manufacturing galvanneal-coated steel products (e.g., strips, sheets, plates, rods, wires, and the like), though it is understood that the methods and computer systems are not limited to use on such semi-finished products or their methods of manufacture. To the contrary, these methods and computer systems can be successfully applied to processes of manufacturing any product irrespective of its form. Coated and uncoated products can be manufactured according to the subject methods and systems. The methods and systems also can be applied to the manufacturing of substrates other than steel (e.g., aluminum), regardless of whether those substrates are coated, uncoated, or semi-finished.

Method for magnetically filtering wastewaters containing oil-coated mill scale

Abstract: Electro-magnetic filter apparatus and method of operating to separate and remove oily magnetic solids from wastewaters. The filter apparatus includes a filter assembly having an electro-magnetic coil that encircles a canister. The canister has an interior space defined by a wall surface and a first perforated baffle spaced apart from a second perforated baffle. The interior space contains a ferromagnetic matrix comprising split ring lock washers. The feed side end portion of the canister communicates with the wastewater source that contains the oily magnetic solids, a wash-water supply, a pressurized air supply and a disposal stream. The discharge side end portion of the canister communicates with a recycling stream, the disposal stream and the wash-water supply. A feed side valve arrangement selectively introduces the wastewater into the feed side end portion of the canister during filtering operations, and selectively injects a pressurized air/wash-water mixture from the wash-water and pressurized air supply into the feed side end portion of the matrix canister during up-flow backwashing operations. The ferromagnetic matrix is fluidized by the pressurized air/wash-water mixture the during the up-flow backwashing. A discharge side valve arrangement selectively discharges clean effluent through the recycling stream during filtering or introduces water, from the wash-water supply, into the discharge end portion of the matrix canister during down-flow backwashing.

Apparatus for measuring coating thickness on a substrate and method thereof

Abstract: The invention is directed to a method and apparatus for determining coating thickness on a substrate. The apparatus comprises a jig and fixture combination where the jig includes a moveable stop that fixes a position for placing a substrate specimen in the fixture, and where the fixture includes an inclined plane for receiving the substrate specimen at a predetermined angle θ that slopes in a downward direction to engage the moveable stop. A clamp that holds the substrate specimen at a fixed position against moveable stop and inclined plane when said fixture is separated from said jig to determine coating thickness on the substrate. The method for determining coating thickness using the combination jig and fixture arrangement includes placing and clamping a substrate specimen at a predetermined position in the fixture in response to a bound fixed by the moveable stop of the jig, grinding a measuring surface along a portion of the substrate specimen that is clamped in the fixture, and repositioning the substrate specimen to place the measuring surface prepared by grinding in a plane parallel to the focal plane of a measuring device used to determine coating thickness.

Surface segregation of phosphorus, carbon, and sulfur in commercial low-carbon grades of steel

Abstract: Surface segregation behavior of solute atoms has been studied on low-carbon steels used in producing galvannealed sheet steels for automotive body panel applications. Samples of cold-rolled low-carbon steels with different amounts of carbon and phosphorus in solution were heated in a vacuum chamber and their surface chemistries analyzed by Auger electron spectroscopy. For the steels studied here, one or more of the elements carbon, phosphorus, and sulfur accumulated significantly at the surface within a temperature window of 300 to 973 K. As the temperature was increased, carbon appeared on the surface first, followed by phosphorus, and then sulfur. Each succeeding segregating element displaced the previous one from the surface. The free solute concentration in the bulk and the temperature were critical factors controlling the amount of solute accumulation at the surface. Once segregated, the solute atoms remained on the surface as the samples cooled. Carbon and/or boron in steels retarded the transport of phosphorus to the surface. The implications of these findings in understanding the galvannealing behavior of these steels are discussed.

Method of recycling iron-bearing waste material back into a basic oxygen furnace

Abstract: The invention is directed to a process for dehydrating and recycling back into a BOF converter wet BOF scrubber sludge to produce a steelmaking revert having an improved flow rate when handled in a recycle stream. Wet sludge is combined with hot BOF slag to provide a slag/sludge mixture. The wet sludge causes the mixture to have a moisture content greater than 10% water by weight, and the hot slag, having a temperature below the molten liquid state, vaporizes the water in the mixture and reduces the moisture content to about 4% water by weight or less. The dehydrated mixture has improved flow rate properties when it is recycled as a steelmaking revert.

Apparatus and method for cooling a basic oxygen furnace trunnion ring

Abstract: A method and apparatus for cooling a BOF trunnion ring by vaporization. A water mist is injected into the interior space of the trunnion ring where it is vaporized upon contact with a hot interior surface. The heat transfer of vaporization cools the trunnion ring, and hot water vapor is vented into the atmosphere.

Use of ISO Guides 25, 30, 31, 34, 35, and 9001 in re-engineering Bethlehem Steel Corporation's analytical chemistry reference materials program

Abstract: Many certified reference materials are needed to calibrate and control analytical measurement processes in integrated steel works It is beyond the scope and capacity of most national laboratories to supply all of these needs Yet, the demand for these materials is steadily increasing as more steel producers update their quality systems in preparation for ISO 9000 registration and/or ISO Guide 25 laboratory accreditation assessments This paper describes how the Bethlehem Steel Corporation updated its reference materials program to meet its internal needs and offers a model for use by others in improving their programs

Wastewater treatment process for vacuum degasser effluent

Abstract: A system and method for disposing of vacuum degasser contaminants which includes adjusting the pH, in a reactor vessel, of a vacuum degasser underflow stream to precipitate lead and zinc into particulate matter. The solids are then concentrated in a thickener to produce an underflow stream that is communicated to a holding vessel to settle. The overflow from the thickener is filtered through a sand filter and discharged to meet applicable NPDES permit limits. Lime is added to the slurry in the holding vessel to further settle the solids, to aid in filtration, and to prevent leaching of lead from the filter cake during TCLP testing. An overlaying supernatant is decanted from the holding vessel and returned to the reactor vessel for further treatment. Limestone is added to the underflow stream. The resulting slurry is dewatered to produce a friable, nonhazardous filtrate cake and a filtrate. The filtrate is directed back to reactor vessel prior to discharge for further treatment.