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Metal Preparation |
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Ordinary cast iron contains graphite in the form of flakes, many of which are interconnected and create discontinuities in the structure. As a result, cast iron is brittle. |
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In ductile iron, the graphite is spherical in shape and this dramatically reduces the area of interface between iron and graphite, imparting properties like strength, toughness, ductility etc. While retaining the corrosion resistance property of cast iron. Ductile iron is a versatile engineering material, which enables engineers to design not only for performance but also for economy. |
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Carefully selected raw materials are melted in medium frequency induction furnaces. The molten metal is subjected to magnesium treatment under controlled conditions in order to change the graphite to spheroids or nodules. The spheroidised molten metal is then used for casting in a mechanized moulding line. |
Casting Process in the Vacuum Lost Foam Casting Technique. |
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First an exact replica of the fitting is made with ‘Styrofoam’, popularly known as thermocole.
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This replica is moulded in special machines and acts as the pattern for the casting. The patterns are then buried in sand in special moulding box fitted on conveyor.
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When hot metal is poured in the mould the Styrofoam pattern vaporizes and the metal takes the shape of the fitting by filling up the cavity.
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Castings are taken out from the moulds after metal solidification and cooling. Shot blasting, fettling and cleaning operations are then carried out.
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Then castings (fittings) are subjected to hydrostatic testing at prescribed pressures
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Tested fittings are then cement lined inside, and coated with zinc rich paint and given a bituminous finishing coat from outside.
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At every stage of manufacture, the products are inspected and tested to maintain conformance to specifications and high level of quality.
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The ' Lost Foam ' process used for manufacturing of D.I. fittings, is a much advanced technique and it scores over other conventional process on the following accounts: |
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Casting process in much faster resulting in higher productivity.
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No need of core setting. So no question of core displacement resulting in uneven thickness.
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Much lower chances of having pinhole, slag inclusion of blowhole.
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Maintains high dimensional tolerance, which is so vital for proper fitment and leak-tightness. The castings have excellent finish.
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In Flanged Fitting no drilling hole is necessary as all the holes are cored
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Mini_blast furnace: |
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Electrosteel's mini-blast
furnace represents a critical backward
integration initiative in the company's
value chain. The blast furnace was commissioned
in September 1996 with an initial installed
capacity of 1,09,00 MT with the objective
to produce pig iron for the company's captive
consumption. In 2003-04 pig iron production
increased from 1,78,367 MT in 2002-03 to
1,79,461 MT , at 89,73 percent capacity
utilisation: |
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Captive power plant: |
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A captive power plant based on blast furnace gas gives Electrosteel: a stable supply of electricity , a reduced dependence on the State electricity grid and a low energy cost, leading to predictable and cost-effective production schedule.
The company's captive generation facility accounted for 31.90 percent of its requirement. Its 3 MW captive power plant (TG) was upgraded to 3.75 MW through improvements in the turbine and boiler. This captive power availability was reinforced through three diesel generator sets of 1.1 MW each. The excess requirement of 12 MW was sourced from the CESC grid.
OVer the foreseeable future, the company expects
to augment its electricity requirements through
its proposed coke oven plant at Haldia where
the waste gases generated from the coke manufacturing
process will be utilised to generate power. This
is expected to enhance the company's power generation
capacity to 80 per cent of its requirement.
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Thickness: |
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The wall thickness 'e' of fittings is calculated as a function of the nominal diameter 'DN' by using the formula given below with the following values for K.
E = K (0.5 + 0.001 DN)
Ductile iron Fittings are made with K12 thickness, Where K = 12.
Thus e = 6 + 0.012 DN.
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