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Melting
Steel remelting
To reach aerospace standards, even sophisticated alloys must be refined further by remelting under rigorously controlled conditions. Latrobe metallurgists have perfected chemistries and melt strategies for complex, high performance materials.
We employ a full range of advanced technologies, including vacuum induction melting (VIM), vacuum arc remelting (VAR) and electroslag remelting (ESR).
 The first step in producing any of our alloys is melting raw material in our electric arc furnace, which produces master heats ranging from 25 to 35 tons (22.680 to 31.752 t). After a quick check of the chemical composition to verify the alloy mix, we transfer the heat to the AOD vessel for refinement.
We alloy steel in an argon-oxygen decarburization (AOD) vessel. The operators of our computer controlled 32-ton (29.030-t) AOD unit program a unique combination of constituents based on the chemical composition of the steel coming from the electric arc furnace and the desired properties of the finished alloy. Periodic sampling monitors the progress of the heat’s chemical composition. After AOD refining, we bottom-pour the heat into ingots that can weigh from 1,000 to 55,000 pounds (0.453 to 24.948t t). Typically, they undergo further refinement by vacuum induction melting (VIM) and vacuum arc remelting (VAR).
 We operate one of the largest vacuum induction melting (VIM) installations in the world. It can produce high purity heats as large as 60,000 pounds (27.216t t) while meeting the most stringent aerospace requirements. In a computer controlled process that can take up to 24 hours, electromagnetic eddy currents liquefy alloys, ridding them of inclusions and optimizing their chemical composition. Still in a vacuum, the metal flows into molds, where it solidifies into electrodes that will be remelted and further purified in a VAR furnace.
With 13 vacuum arc remelt (VAR) furnaces, we offer one of the largest VAR batteries devoted specialty steels in the USA. We produce the largest VAR ingots made in North America — up to 45 inches (1.145 mm) in diameter, weighing as much as 55,000 pounds (24.948 t). In a VAR furnace, an electric arc remelts electrodes produced by either our VIM or AOD operations. Controlled melting and solidification in a vacuum ensures consistent chemistry and microstructure for high resistance to fracture and fatigue.
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