Showing papers by "Bethlehem Steel published in 1999"

Distribution of aluminum in hot-dip galvanized coatings

Abstract: Hot-dip galvanized panels of low-carbon (LC) and interstitial-free (IF) steels were produced in a laboratory simulator with an average coating mass of 60 g/m2. Three pot aluminum levels were used, viz., 0.10 pct (by wt), 0.15 pct, and 0.18 pct. Metallography, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize coating and base steel microstructures. Wet chemical analysis and scanning transmission electron microscopy (STEM) were employed for compositional analyses. The aluminum content of the melt was found to be the predominant factor influencing the distribution of Al in the coating. At 0.18 pct melt aluminum, Al is partitioned between the aluminide inhibition layer at the coating-steel interface (∼80 pct) and the zinc overlay (∼20 pct). At 0.15 pct, it is partitioned among the aluminide layer (∼75 pct to 80 pct), zinc-iron (FeZn13, ζ) intermetallic layer (∼5 pct to 15 pct), and the coating overlay (∼10 pct). At 0.10 pct, the aluminum is divided almost equally between the overlay and the zinc-iron intermetallics. At the two lower aluminum levels is the distribution marginally influenced by the steel grade. The ζ was found to not preferentially nucleate at the ferrite grain boundaries. When both the aluminide and ζ occurred at the coating-steel interface, the ζ particles appeared near discontinuities and thinner regions in the aluminide layer. The coating, relative to the melt, is enriched in aluminum because of its concentration in the aluminide and in the zinc-iron intermetallics. This enrichment increases with melt aluminum through an increase in the aluminum content of the aluminide layer and not of its thickness. In addition, a few tens-of-nanometers-thick layer enriched in aluminum, oxygen, and iron is observed on the outer surface of all coatings. The aluminum content in this layer also increases with an increase in the melt aluminum, but it contributes negligibly to the coatings’s content because of its extreme thinness.

Method of making a weathering grade plate and product therefrom

Abstract: A method of making a weathering grade steel plate includes the steps of casting, hot rolling, and accelerated cooling using a modified weathering grade alloy composition. The composition employs effective levels of manganese, carbon, niobium, molybdenum, nitrogen, and titanium. After the casting, the slab or ingot is heated and rough rolled to an intermediate gauge plate. The intermediate gauge plate is controlled finish temperature rolled and subjected to accelerated cooling. With the controlled alloy chemistry, rolling and cooling, the final gauge plate exhibits continuous yielding and can be used for applications requiring a 70 KSI minimum yield strength, a 90-110 KSI tensile strength, and a Charpy V-notch toughness greater than 35 ft-lbs. at −10° F. in plates up to 4.0″ thick.

Method of making an as-rolled multi-purpose weathering steel plate and product therefrom

Abstract: A method of making a weathering grade steel plate includes the steps of establishing a minimum yield strength plate thickness target from one of 344MPa (50KSI) up to 10.16cms (4'), 447MPa (65KSI) up to 3.81cms (1.5'), and 481MPa (70KSI) up to 3.17cms (1.25'). A modified weathering grade alloy composition is cast into a slab employing effective levels of manganese, carbon, niobium, vanadium, nitrogen, and titanium. The cast slab is heated and rough rolled to an intermediate gauge plate. The intermediate gauge plate is controlled rolled and subjected to one of air cooling or accelerated cooling depending on the minimum yield strength and thickness target. With the controlled alloy chemistry, rolling and cooling, the final gauge plate exhibits discontinuous yielding and can be used for applications requiring a 481MPa (70KSI) minimum yield strength in plate thicknesses up to 3.17cms (1.25'), a 447MPa (65KSI) minimum yield strength in plate thickness up to 3.81cms (1.50') and a 344MPa (50KSI) minimum yield strength for plates as thick as 10.16cms (4').

Connection for a lightweight steel frame system

Abstract: The invention is directed to a lightweight steel frame system having end nailed connections where lightweight steel structural members frame into support members. The end nailed connection is made by driving fasteners through the support member and directly into the connection end of a lightweight steel structural member without the need for using additional connection hardware. Where the lightweight steel structural member is a roof or floor truss, the support member may include a leveling member to facilitate positioning each roof truss at an elevation set point to produce a level roofline along the finished structure.

License plate cosmetic corrosion test of automotive coated steel sheet

Abstract: A new standard laboratory test (SAE J2334) for evaluation of the cosmetic corrosion resistance of autobody steel sheet has been developed through the joint efforts of the Society of Automo...

1999 F.N. Speller Award Lecture: Extending the Limits of Growth Through Development of Corrosion-Resistant Steel Products

Abstract: The costs of corrosion have been estimated at ∼ 4.2% of the gross domestic product (GDP) or ∼ $330 billion in 1997 for the United States. However, when the potential effects on extending r...

Mathematical model for nitrogen control in oxygen steelmaking

Abstract: A mathematical model was developed to quantify the effects of different operational parameters on the nitrogen content of steel produced during oxygen steelmaking. The model predicts nitrogen removal by the CO produced during decarburization and how the final nitrogen content is affected by different process variables. These variables include the type of coolants used (scrap, direct reduced iron (DRI), etc.), the sulfur content of the metal, combined gas blowing practices, and the nitrogen content in the hot metal, scrap and oxygen blown. The model is a mixed control model that incorporates mass transfer and chemical kinetics. It requires a single parameter that reflects the surface area and mass-transfer coefficient that is determined from the rate of decarburization. The model also computes the rate of decarburization and the change in surface active elements, such as sulfur and oxygen, that affect the rate of the nitrogen reaction. Nitrogenization of steel in the converter is also predicted with the model. The computed results are in good agreement with plant data and observations.

The similitude of fatigue damage principle: Application in S-N curves-based fatigue design

Abstract: The current procedures of fatigue design of ship structural components via application of S-N diagrams based on the test results of typified welded joints physically are not complete and may need in adjustment. The main base for discrepancies of actual and S-N-modeled fatigue behavior of structural details is formed by the fairly approximate following the principles of identity of material fatigue damage in fatigue assessment of structural details. The identity of fatigue damage in both, hull details and specimens may be limited by the initial phase of fatigue process, mostly within the stress concentration zone, specifically since the local conditions are assessed in fatigue analysis and in fatigue design of ship hull structures. To retain the current format of fatigue design a procedure of reduction of design S-N curves is developed considering the «informative part of fatigue process, completed with the adjustment which accounts for the possible mismatch in conditions for fatigue damage in laboratory specimens and structural details. The method is based on application of the local strain approach to fatigue assessment of both, the specimen and the detail. The adjustment suggests estimation of the ratio of fatigue lives of these and, respectively, correction of the reduced appropriate S-N diagram. The loading history of the detail comprises the feasible modes of loading and the service conditions, while the loading history of a specimen is related to the principal loading mode in a particular structure. A possible difference in fatigue properties of base-line specimen and structure materials may be considered.

Fiber optic sensor and method of use thereof to determine carbon content of molten steel contained in a basic oxygen furnace

Abstract: The invention is directed to a gas cooled fiber-optic cable apparatus for use in a hostile environment, for instance adjacent a metallurgical furnace, and a method using the apparatus to determine carbon content of molten steel. The fiber-optic cable includes a radiation collection end comprising a manifold chamber that surrounds the fiber-optic cable filaments used to collect radiant energy emitted from the furnace flame. The manifold includes a tip portion having an orifice to expose the filaments to the radiant energy, and a gas supply attached to the manifold to inject a cooling gas into the chamber. The orifice provides a discharge for expelling the cooling gas from the manifold chamber at a high velocity purge to prevent foreign matter from entering the chamber. The gas cooled fiber-optic cable transmits collected radiant energy to a radiation sensor. The sensor converts the energy into voltage signals and the signal information is processed to determine carbon content of steel contained in the metallurgical furnace.

Off-gas hood for a basic oxygen furnace and method of repair

Abstract: The invention is directed to water-cooled furnace hoods that exhaust gases away from a work area, and in particular, it is directed to an off-gas hood for use with a basic oxygen furnace (BOF). The furnace hood includes an assemblage of panels fastened together to form a flue positioned above a BOF at a location to receive gases generated by the furnace. Each panel includes an inlet header for receiving cooling water, an outlet header for discharging cooling water, and a plurality of tubes, such as a tube-bar-tube membrane, extending between the inlet and outlet headers to distribute cooling water between the headers. Jumper pipes extend between outlet headers and inlet headers located in adjacent panels. The jumper pipes distribute cooling between adjacent panels and thereby provide a continous flow of cooling water along the length of the flue. The invention is also directed to a method of replacing the panels located in the assemblage of panels that make up the flue.

Fiber-optic sensor and method to determine carbon content of molten steel in a basic oxygen furnace

Abstract: The invention is directed to a gas cooled fiber-optic cable apparatus for use in a hostile environment, and a method using the apparatus to determine carbon content of molten steel. The fiber-optic cable includes a radiation collection end comprising a manifold chamber that surrounds the fiber-optic cable filaments. The manifold includes a tip portion having an orifice to expose the filaments to the radiant energy, and a gas supply attached to the manifold to inject a cooling gas. The orifice provides a discharge for expelling the cooling gas from the manifold chamber at a high velocity purge to prevent foreign matter from entering the chamber. The fiber-optic cable transmits collected energy to a sensor. The sensor converts the energy into voltage signals and the signal information is processed to determine carbon content of steel contained in the metallurgical furnace.

Process of agglomerating high carbon dusts and a substantially non-dusting high carbon composition therefrom

Abstract: The invention is directed to a process for agglomerating high-carbon dust, such as kish. The process comprises the steps of providing a supply of the high-carbon dust, applying a suifactant and water to the high-carbon dust, and applying a bonding agent to the high-carbon dust so that the high-carbon dust becomes agglomerated. The process provides a product having favorable characteristics. A substantially non-dusting high-carbon composition, for example, can be provided. The high-carbon composition comprises high-carbon dust, a surfactant, and a bonding agent in an amount by weight between about {fraction (1/20,000)} and about {fraction (1/200)} of the weight of the high-carbon dust. The high-carbon dust, surfactant, and bonding agent are agglomerated to form a clay-like material. A kish agglomerating system also is provided. The system comprises a kish storage container, a mixing tank, and a transport mechanism. The mixing tank has an agitator adapted to mix kish, surfactant and bonding agent so that the kish, surfactant and bonding agent become agglomerated. Also provided is a kish collection and treatment vessel. The vessel comprises a wall structure, a closure device, and a treatment applicator. The wall structure defines outer boundaries of a kish collection cavity. The treatment applicator has an inlet outside of the kish collection cavity and at least one outlet in communication with the kish collection cavity to permit treatment of any kish in the kish collection cavity even when the closure device is in the closed position.

Revert manufactured from iron-bearing waste material

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.

Penalty-based sequencing strategy implemented within a knowledge-based system

Abstract: A hot dip coating line (HDCL) is used to coat steel coils with a corrosion-resistant coating. The sequencing of the coils going into a HDCL is important to ensure that the required coating quality of each coil is achieved and that production through the facility is maximised. In this paper, the logic used in a knowledge-based sequencing system for a HDCL will be outlined. Also, how the original knowledge-based system logic was modified to include a penalty-based heuristic sequencing strategy that resulted in much-improved HDCL coil sequences will be discussed. The enhanced version of this system has been in routine use since January 1994.

Method and system for improving the efficiency of a basic oxygen furnace

Abstract: A method is provided for improving the efficiency of a basic oxygen furnace operation and/or regulating its rate of molten iron consumption to accommodate interruptions in downstream production. The method comprises the steps of combining a wet scrubber sludge with hot slag to provide a slag/sludge mixture, commencing a steelmaking operation of the basic oxygen furnace (BOF), and introducing the slag/sludge mixture into the BOF during the steelmaking operation so that the BOF produces a desired quantity and quality of steel in a manner that is more efficient than without the slag/sludge mixture. Also provided is a system for improving the efficiency of a BOF operation. The system comprises a mixer and an introduction mechanism. The mixer is connected to a source of wet scrubber sludge and a source of hot slag. The mixer is adapted to combine the wet scrubber sludge with the hot slag to provide a slag/sludge mixture. The introduction mechanism is adapted to transport the slag/sludge mixture from the mixer to a BOF and is adapted to introduce the slag/sludge mixture into the BOF during a steelmaking operation of the BOF. The mixer and introduction mechanism are operable in conjunction with the BOF so that the BOF produces a desired quantity and quality of steel in a manner that is more efficient than without the slag/sludge mixture. Improvements in efficiency include reduced heat cycle times, reduced oxygen blow times, reduced demand for raw materials outside of the slag/sludge mixture, reduced disposal and transportation costs, and increased productivity.

Method for refurbishing a coke oven doorjamb

Abstract: A method [and apparatus] for refurbishing eroded portions in coke oven doorjambs including refurbishing apparatus having a framework attached to the coke oven structure adjacent the doorjamb. The framework supports a carriage that is simultaneously moveable in an "X" axis direction and a "Y" axis direction within the boundary so that a machine[-cutting] tool, attached to the carriage, can be moved from one position directly to another position within the framework boundary. [The machine-cutting tool is positioned to make cutting] The machine tool is moved directly to selected positions within the boundary to make machining passes along new metal that is fused into the eroded portions of the coke oven doorjamb.