This document summarizes a presentation on ductile iron foundry practice given by Rajkumar S Wagmare. It discusses various aspects of ductile iron production including melting, desulfurization, composition control, magnesium treatment, inoculation, casting, properties and applications. Austempered ductile iron is also introduced, which involves heat treating ductile iron to produce a bainitic matrix that increases toughness, wear resistance, and fatigue strength. Common applications of ductile and austempered ductile iron include automotive and machine components that require high strength and durability under dynamic loads.

1. Presented by:
RAJKUMAR S WAGMARE
1MS15MS10
1st
sem. M.Tech MSE
M.S.RAMAIAH INSTITUTE OF TECHNOLOGY
BANGALORE
(AUTONOMOUS INSTITUTE,AFFILIATED TO VTU)

2. “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

3. contents
 Introduction
 Melting practice
 Desulfurization methods
 Composition control
 Magnesium treatment
 Inoculation , Casting and solidification
 Engineering properties
 Austempered Ductile iron(ADI)
 Applications
 Conclusion
 References

4. 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

5.  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

6. Introduction
Ductile iron crankshaft
Ductile iron automotive
steering knuckle

7. DESULPHURIZATION
Introducing magnesium it is necessary to bring the sulphur atleast upto 0.03%
is to remove all the sulphur possible for best spheroidizing result
Higher 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

8. 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

9. 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

10. 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

11. MAGNESIUM TREATMENT

12. SANDWICH METHOD

13. PLUNGING METHOD

14. T-NOCK METHOD

15. INJECTION PROCESS

16. 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 form
Why foundaries use inoculants
 To improve machinability
 To ensure that castings meet customer requirements

17. 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


18. 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.%,

19. 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

20. APPLICATIONS
 ADIis use d in m any branche s o f industry as
m achine building , civile ng ine e ring , transpo rt,‐
m ilitary industry, m ining e tc.
 It is applie d m ainly to casting fo r dynam ically
lo ade d co m po ne nts, e . g . g e ar and trave rsing
whe e ls, crankshafts o f cars, vans and trucks,
swive lpins, railbrake s, pre ssure pipe s in o il
industry e tc.

21. References