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U.S. STEEL DUQUESNE WORKS HAER No. PA-115 (Page 175) IV. Steel Conditioning Office, and Storage Building: Laid out on a north-south axis and built onto the eastern outside wall of the building at its southern end is a 18*-0" wide x 220'-0" x 12'-0" high long brick lean-to. The building houses the steel conditioning office, the grinder storage room, the tool storage room, locker room, and wash room. Construction date: 1943. V. QuttiPQr Electrical gufr-5tation: Laid out on a north-south axis, a 140'-0" wide x 270'-0" long sixty-nine kv sub-station is located 70'-0" north of the steel conditioning building and 42'-0" east of the electric furnace building. A one story, 20 , -0" wide x 30'-0" long control building is located in the northeast corner of the sub-station. Construction date: 1943. HISTORY Electric furnace steelmaking at Duquesne began in 1917 with the installation of an Heroult 20-ton tilting furnace in the furnace building of Open Hearth Number Two. Located at the northern end of the building in line with the open hearth furnaces, the electric furnace was serviced by existing auxiliary equipment. It originally was used only for deoxidizing and desulphurizing basic open hearth steel. Many special alloy open hearth heats were finished in this manner because the electric furnace made it possible to produce a more homogeneous product. The process began by teeming a ladle of molten steel from an open hearth heat into the charging ladle of the electric furnace. The charge was then transported by a dinky running over a narrow gauge track to the furnace where it was poured through a portable spout attached to the water cooled charging door of the furnace. As the charge was being poured, a sample of it was taken for chemical analysis in order to determine the proper amount of carbon (in the form of anthracite) and manganese to be added. After analysis, the materials were added to the furnace as the pouring was completed. With the completion of charging, the furnace's three graphite electrodes were adjusted to a point just above the bath and the current was turned on. The bath was heated by the direct arc method. That is, the current was passed through an electrode into the bath and back from the bath to the next electrode. Because the charge initially froze over the top, especially in low carbon steels, nothing was done until it was completely melted. When melted, a
U.S. STEEL DUQUESNE WORKS HAER No. PA-115 (Page 176) slag mixture consisting of four parts lime and one part fluorspar or clean sand was added. Several samples of the slag were taken in the period after the mixture was added. As the heat proceeded, the color of the slag samples taken varied between shades of brown, and contained varying amounts of manganese oxide, indicating the stage of deoxidation or levels of iron oxide being reduced. A slag sample which was decidedly brown in color meant that deoxidation was well under way. At this point a second slag mixture consisting of proportioned amounts of lime, fluorspar, sand, and coke dust was added to the bath. The addition of this mixture made the slag less vitreous thereby creating a tendency for it to slake or disintegrate. At the same time the color of the slag began to fade. Deoxidation was judged complete and preparations were made to finish the heat when a sample of the slag disintegrated upon becoming cold, while the color turned gray. The heat was finished by adding whatever alloys were required in the batch. In order to give these alloys time to thoroughly mix with the steel, a period of approximately thirty minutes was allowed to pass before the heat was tapped. After a final sample was taken to determine if the condition of the slag was satisfactory, the furnace was tapped. Tapping consisted of tilting the furnace on its rockers toward a teeming ladle set in a pit below the tapping spout on the pouring aisle of the building. A special skimmer, attached to the pouring spout of the furnace, separated the slag from the steel as it was being poured into the ladle. Subsequent to tapping, the ladle was carried over by a E.O.T. crane to the platform where the steel was teemed into ingot moulds. 1 Full fledged use of the electric furnace process for melting down steel scrap did not take place at Duquesne until World War II when an alloy steel plant was built by the Defense Plant Corporation (D.P.C.). The new facility, which was part of an effort to increase production for war time needs, was designed to work in conjunction with a newly constructed heavy forging plant built by the D.P.C. at the nearby Homestead Works. Consisting of electric furnace, heat treating, and steel conditioning facilities, part of the plant was built on land occupied by the city of Duquesne's First Ward, which had been located between the upper and lower works. The electric furnace building originally contained two side door charged 70-ton furnaces and one side door 35-ton capacity furnace. All of the furnaces contained a basic (magnesite brick) lining. Electric furnace alloy steelmaking at Duquesne followed the precepts of the "cold melt process." The process employed the direct arc method and was conducted in two stages. During the
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Installation Date: 1955. U.S. STEEL
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cooling tower has a capacity of 190
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