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EDSGN Kick Off Meeting – 2/27/2012 Steelmaking Basics and Project Overview. R. Zellers. Steelmaking Process Map - Iron. Steelmaking Process Map - Refining. Basic Oxygen Furnace – Raw Materials. Fluxes Coolant Fuel. BOF - Reactions. Decarburization
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EDSGN Kick Off Meeting – 2/27/2012Steelmaking Basics and Project Overview R. Zellers
Basic Oxygen Furnace – Raw Materials Fluxes Coolant Fuel
BOF - Reactions • Decarburization 2C + O2 2CO (reaction occurs in bath, CO to off gas) 2CO + O2 2CO2 (reaction occurs above bath, CO2to off gas) • Silicon Oxidation Si + O2 SiO2 (reaction occurs in bath, SiO2 to slag) • Manganese Oxidation Mn + O2 MnO • Aluminum Oxidation 4Al + 3O2 2Al2O3 + HEAT!
Chemistry of “Open” Steel • C 0.04% • Mn 0.1% • Cr 0.01% • Cb 0.00% • Al 0.00%
BOF – Order of Reactions – Ellingham Diagram Fe + O2 FeO2 Cr: 1/2 C + O2 CO2 Mn: 1/3 Si: All Energy 2C + O2 2CO 4Cr + 3O2 2Cr2O3 Al: All 2Mn + O2 2MnO Si + O2 SiO2 Ca: All 2Ca + O2 2CaO 4Al + 3O2 2Al2O3 Temperature
Alloying – Why & Where? • Aluminum – Deox, aluminum-nitride grain refining • Carbon – Strengthener • Calcium – Inclusion modification, castability • Chrome – Hardening, corrosion resistance • Columbium (Niobium) – Grain refining • Manganese – Strengthener, heat treatment hardening BOF during tap – Good mixing, allows for “settling” Ladle met facility – Greater control
Alloy CalculationExample: LCAK Mn addition • Aim: 0.5% • Already in steel from BOF: 0.1% • Needed from alloy: 0.4% • Heat Size: 440,000 lb • HC Mn: 78% Mn, 90% Recovery (note: “pure alloy” in project) Calculation: (0.4% Mn/steel) * (440,000 lb steel) = 1760 lb Mn (1760lb Mn) / (78% Mn/HC Mn * 90% Recovery) = 2500 lb HC Mn
Project Part 1 – No Off Chemistries • Separate advanced high strength steel (AHSS) from scrap autos • Use mix of AHSS and low carbon aluminum-killed (LCAK) scrap to make LCAK heat Part 2 – Cost Savings • Utilize AHSS scrap to make line pipe heat • Calculate addition alloys needed