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Injection metallurgy and lf

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Injection metallurgy and Laddle furnace

Injection metallurgy and Laddle furnace

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    Injection metallurgy and lf Injection metallurgy and lf Presentation Transcript

    • INJECTION METALLURGYINJECTION METALLURGYAND LADLE FURNACEAND LADLE FURNACEN. PRAKASANME METALLURGY
    • INJECTION METALLURGYINJECTION METALLURGY
    • Injection methods effectively reduce sulphurcontent.In this method, a strong desulphurizingreagent in the form of fine powder is injected(through a lance) in the refined steel bathalong with an inert gas (Argon) as carrier.Injection reagent may be Metallic like Calcium,Magnesium or the other form like Lime,Calcium carbide, Calcium silicide andMagnesium coke.INJECTION METALLURGYINJECTION METALLURGY
    • INJECTION METALLURGYINJECTION METALLURGY
    • Ladle Capacity:• 40 T – 300 TCycle time:• About 20-50 minutes depending upon theaim and final chemistry.Injection rate:• The injection rate varies between 2 -4 kg/tonof meltINJECTION METALLURGYINJECTION METALLURGY
    • A ladle with deoxidized (killed) molten steel istransported to the injection stand and placedunder a cover, through which the injectionlance is lowered and immersed into the melt.Desulfurization agents are injected in argonstream. Argon bubbles produce stirring ofthe molten steel and the slag promotesdesulfurization.Stirring also provides thermal and chemicalhomogenization of the melt.INJECTION METALLURGYINJECTION METALLURGY
    • The more interfacial area of contact of particleswith the steel bath leads to very efficientinteraction of the reagent with the bath.The treated steel is covered by a layer ofdesulfurizing slag having high solubility ofsulfur and capable to absorb sulfides formedas a result of active agents injection.Desulphurization takes place in a short time ofabout 8 – 10 minutes and the bath looses30 – 35oC temperature.INJECTION METALLURGYINJECTION METALLURGY
    • When the desulphurizing agents are injectedinto molten steel in form of a cored wirecontaining powder of desulphurizing agentstirring by argon bubbling from the porous plugmounted in the ladle bottom is used.Fumes formed during the operation areextracted through the cover.TN (Thyssen Niederrhein) injection system ismore popular.INJECTION METALLURGYINJECTION METALLURGY
    • Benefits of Ladle desulphurization by injectionof active agents:• Sulphur removal (desulfurization);• Temperature and chemical homogenizing;• Non-metallic inclusions removal.• The effective desulphurization allows toachieve ultra-low concentrations of sulfur insteel (0.0002%) and decreases sulphideinclusions, thereby improves Toughness andElongation of the Steel.INJECTION METALLURGYINJECTION METALLURGY
    • Ladle Furnace (LF)Ladle Furnace (LF)
    • Molten steel in a ladle is treated (refined) in adevice called Ladle Furnace (LF).It is capable of carrying out Vacuum treatment,slag refining, Injection etc,Primary functions of LF are:• Reheating of liquid steel through electricpower conducted by graphite electrodes.• Homogenization of steel temperature andchemistry through inert gas stirringLadle Furnace (LF)Ladle Furnace (LF)
    • Primary functions of LF are:• Formation of a slag layer that• Protects refractory from arc damage,• Concentrates and transfers heat to theliquid steel,• Trap inclusions and metal oxides,• Provide the means for desulphurization bysynthetic slag or by injection metallurgy.Ladle Furnace (LF)Ladle Furnace (LF)
    • Primary functions of LF are:• The slag is primarily modified by the additionof CaO or CaF2.• The slag is basic and its typical compositionrange is CaO: 50-56%, MgO: 7-9%,SiO2: 6-12%, Al2O3: 20-25%.• LF has the ability to make alloying additions.• LF Provide a means for dephosphorization.Ladle Furnace (LF)Ladle Furnace (LF)
    • Capacity:• 10 T - 25 T - DC Ladle Furnace• 15 T - 150 T - AC Ladle FurnaceCycle time:• About 40-50minutes depending upon the aimand final chemistry and desired temperaturerise.Ladle Furnace (LF)Ladle Furnace (LF)
    • Slag forming materials used for injection:Ladle Furnace (LF)Ladle Furnace (LF)
    • The ladle is transferred to the Ladle Furnacestand where it is placed under a coverequipped with three graphite electrodesconnected to a three-phase arc transformer.The ladle bottom has a porous refractory plug,which is connected to the argon supply pipe atthe Ladle Furnace stand.The LF stand is also equipped with an additionhopper mounted on the cover and a lance forinjection of desulfurizing agents.Ladle Furnace (LF)Ladle Furnace (LF)
    • During the treatment process argon is blownthrough the bottom plug for continuous metalstirring.Molten steel treated in Ladle Furnace iscovered by a layer of desulphurizing slag.When the graphite electrodes are submergedinto the ladle, the slag protects the ladle liningfrom overheating produced by the electric arcs.The arcs are capable to heat the steel at therate about 3°C/min.Ladle Furnace (LF)Ladle Furnace (LF)
    • Stirring results in,• distribution of heat produced by the arcs,• chemical homogenization• desulfurization of the steel by the slag.Fumes formed during the operation areextracted through the cover.Alloying elements may be added through theaddition hopper.Besides refining operations Ladle Furnace (LF)may serve as a buffer station beforeContinuous casting.Ladle Furnace (LF)Ladle Furnace (LF)
    • Advantages of Ladle Furnace (LF):• Increase productivity• Decreasing refining time of EAF• Decreasing tapping temperature at EAF• Precise temperature control• Improved inclusions control and cleanlinessof the steel.Ladle Furnace (LF)Ladle Furnace (LF)
    • Benefits of Ladle Furnace (LF):• Sulfur removal (desulfurization);• Controllable reheating by electric power;• Alloying;• Temperature and chemical homogenizing;• Non-metallic inclusions removal (Oxygentcontent upto 30ppm can be attained).Ladle Furnace (LF)Ladle Furnace (LF)
    •  Introduction to Modern Steel Makingby Dr.R H Tupkary Iron Making and Steel Makingby Ahindra Ghosh, Amit Chatterjee Lecture 23 : Injection Ladle Metallurgy _Class notes IIT Madras. Ladle Refining_ www.substech.comREFERENCES :REFERENCES :