DUCTILE IRON FOUNDARY PRACTICE
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Transcript of DUCTILE IRON FOUNDARY PRACTICE
Presented by:RAJKUMAR S WAGMARE
1MS15MS101st sem. M.Tech MSE
M.S.RAMAIAH INSTITUTE OF TECHNOLOGY BANGALORE (AUTONOMOUS INSTITUTE,AFFILIATED TO VTU)
“DUCTILE IRON FOUNDARY PRACTICE”
MMSE 24 seminar5th MAY, 2016
Department of Mechanical Engineering, M S RAMAIAH INSTITUTE OF TECHNOLOGY, BENGALURU-560054, Karnataka, India
RAJKUMAR S WAGMARE 1MS15MSE10
contents Introduction Melting practice Desulfurization methods Composition control Magnesium treatment Inoculation , Casting and solidification Engineering properties Austempered Ductile iron(ADI) Applications Conclusion References
Introduction Foundries produce castings that are close to the final product
shape, i.e., “near-net shape ” components. Castings are produced by pouring molten metal into moulds ,
with cores used to create hollow internal sections. After the metal has cooled sufficiently, the casting is
separated from the mould and undergoes cleaning and finishing techniques as appropriate.
Molten metal is prepared in a variety of furnaces, the choice of which is determined by the quality,quantity and throughput required
Spheroidal graphite cast iron, also referred to as ductile iron These spheroids are obtained directly during solidification of castings and
no by any heat treatment Ductile iron is a family of cast graphitic irons which possess high strength
ductility and resistance to shock. Annealed cast ductile iron can be bent, twisted or deformed without fracturing. Its strength, toughness and ductility
DUCTILE IRON
Introduction
Ductile iron crankshaft
Ductile iron automotivesteering knuckle
DESULPHURIZATION
Introducing magnesium it is necessary to bring the sulphur atleast upto 0.03%
is to remove all the sulphur possible for best spheroidizing resultHigher sulphur content will also result in increase of the consumption of magnesium alloys
For successful desulphurization, the following basic factors are desirable in the processes.a) Intimate contact between molten metals and the Desulphurizing agent
b) Reaction duration
c) Simple removal of sulphur bearing slags after desulphurization
d) Temperature control
e) Fume control
f) Minimum refractory maintenance
g) Ease of handling and feeding of de-sulphurizing agent
Cont…. Methods of desulphurization Reducing slag in furnace the metal can be effectively desulphurized One of the oldest and simplest methods of desulphurization is the addition
of soda ash to the molten metal when poured into the ladle Fusite method- sodium carbonate is added from 0.5-1% by wt of molten metal Co2 and Na2O Combines with sulphur form a complex compound which
comes as a slag to the top of the ladle which can be remobed
CONT…
Flour spur(CaF2) method- flourspar is added to MM in ladle which reacts with sulphur and forms
ahighly basic slag which settles on top of the MM Calcium carbide method Calcium carbide can be injected in the powder form along a carrier gas
like nitrogrn into moletn metal It reacts withsulphur to form calcium sulphide which goes as a slag
Composition control in DI Sulphur content of CI low as possible below 0.01% Carbon-3.2% to 4%, Si-1.8% to 3%, Manganese-0.25-0.5% Phosphorus-0.08 max, Sulphur-0.015% Residual magnesium-0.03 to 0.07% Carbon equivalent upto 4.6
MAGNESIUM TREATMENT
SANDWICH METHOD
PLUNGING METHOD
T-NOCK METHOD
INJECTION PROCESS
INOCULATION Inoculation is the addition of small quantities of materials to molten metal iron which
will bring about remarkable enhanced properties in the iron without appreciable changing the composition of the iron
Inoculants are silicon based inoculants Include ferrosilicate ,silicon carbide,cal-silcide,graphite etc Inoculation alters the solidification process Increases the degree of nucleation of the iron Prevents chill formation and undesirable graphite formWhy foundaries use inoculants To improve machinability To ensure that castings meet customer requirements
INOCULATION OF DUCTILE & GREY IRON
The main purpose of inoculation is to achieve best mechanical properties and optimum machinability characteristics by:
1. Control of graphite structure.2. Elimination or reduction of chill/carbide.3. Reduction of casting section sensitivity DUCTILE INOCULATION Optimum nodule shape Degree of nodularity Improves nodule count Prevention of formation of carbides Increases ferrite content.
Austempered Ductile Iron (ADI) Austempered ductile iron is obtained by heat treating the ductile iron in
salt bath of sodium chloride, potassium chloride and barium chloride at the temperature of 830C.
It was austempered at 350 - 420oC and later salt bath using sodium nitrate and potassium nitrate.
ADI nominally has the chemical composition Fe, 3.6 C, 2.50 Si, 0.5 Mn, 0.032 Mg, 0.05S, 0.114 P wt.%,
Austempered Ductile Iron (ADI) Austempered Ductile Iron (ADI) is a ferrous, cast material with a high strength-to-weight ratio
and good dynamic properties. The application of the Austempering process to ductile iron produces a material called
Austempered Ductile Iron (ADI) that has a strength-to-weight ratio that exceeds that of aluminum.
ADI Exihibites a microstructure consisting of graphite nodules like bainitic matrix Pesence of bainitic in the matrix gives Increased toughness Good wear resistance Fatique and impact strength to the material Vibration damping ability
APPLICATIONS ADI is used in many branches of industry as
machine‐building, civil engineering, transport, military industry, mining etc.
It is applied mainly to casting for dynamically loaded components, e.g. gear and traversing wheels, crankshafts of cars, vans and trucks, swivel pins, rail brakes, pressure pipes in oil industry etc.
References