cast iron · 2018-08-31 · cast iron • cast iron is a cast ferrous based materials with the...
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CAST IRON
MATERIAL TEKNIK (MAT)
Cecep Ruskandi
Cast Iron• Cast iron is a cast ferrous based materials with
the carbon content greater than 2% and also contain elements such as Si, Mn,P and S.
• Cast irons are classified into :
- Gray cast iron (GG / FC)
- Nodular cast iron (GGG / FCD)
- Chilled cast iron (GH)
- Malleable cast iron (GT)
Gray cast iron (GG/FC)
• It has gray fracture appearance.
• Good machinability and castability
• This cast iron contains flake graphite which cause the iron to be brittle.
• The application : housing engine, crankcase etc.
• Designation :
GG (DIN) or FC (JIS) followed by digits which represent the tensile strength.
example : GG 25
Flake Graphite
Gray Cast Iron Products
Exhaust manifoldhousing
Brake drum
rotorArts
Door knocker
Body valve
Nodular Cast Iron• This cast iron contains spheroidal graphite which
cause the iron to be ductile. so called S.G Iron• High toughness, strength and elongation,
therefore this metal also called ductile iron• This iron also has a good wear resistance• Application : crankshaft, gears, transmission gear,
roll, pump, steering knuckls, valves etc.• Designation :
GGG (DIN) or FCD (JIS) followed by digits which represent the matriks content.example : GGG 70
Nodular Graphite
The Group of Ductile Iron
• Ferritic Ductile Iron, which is high impact resistance, relatively good thermal conductivity , high magnetic permeability, good machineability.
• Pearlitic Ductile Iron, which is high strength and hardness, moderate ductility and impact resistance, lower thermal conductivity and magnetic permeability but good machineability
• Ferritic-Pearlitic Ductile Iron, with its properties is in between ferritic and pearlitic ductile iron.
The Group of Ductile Iron (con’t)
• Martensitic Ductile Iron or quench &tempered iron.
In the "as-cast" condition the alloy is hard andbrittle, and seldom used. However, TEMPEREDMARTENSITE has very high strength and wearresistance. A 930°F (500°C) tempering resultsin 300 HB, a 1110°F (600°C) tempering in 250HB hardness.
The Group of Ductile Iron (con’t)
• Austenitic Ductile Iron
They are never chosen for strength alone. Theoutstanding features are good corrosion andoxidation resistance, magnetic properties,strength and dimensional stability at elevatedtemperatures. (Also known as Ductile Ni-Resist).
The Group of Ductile Iron (con’t)
• Austempered Ductile Iron- ADI is almost twice as strong as the regular ASTM grades ofDuctile Iron whilst still retaining high elongation andtoughness characteristics
- It also offer wear resistance and high strength
The remarkable properties of ADI are developed by a closelycontrolled heat treatment operation (austempering) which
develops a unique matrix structure of bainitic ferrite (60%) andretained (high carbon) austenite.
Application of Ductile Iron
Malleable Cast Iron (GT –DIN)• Malleable irons are cast white, that is, their as-cast
structure consists of metastable carbide in a pearliticmatrix
• The castings must then be annealed to convert carbides into rossette graphite.
• There are two types of malleable iron, blackheart and whiteheart.
• Malleable irons have a good weldability, machinability and ductility.
• Application : automotive parts, agricultural components, valves etc.
Whiteheart malleable cast iron (GTW)
• In the whiteheart process, the white, as-cast iron is decarburised during annealing leaving a structure of iron carbide in a metallic matrix.
• Annealing is performed in an oxidising atmosphere improving weldability
Blackheart malleable cast iron (GTS)
• In the Blackheart process, the white, as-cast iron is annealed to develop graphite cluster.
• Annealing is performed in a non-oxidising atmosphere
Malleable cast iron products
Chilled Cast Iron• These irons have a white fracture appearance due to
rapid cooling or very small amount of Si content.
• The microstructure consists of carbide causing the iron has a high hardness but very brittle.
• This irons have a very good wear resistance
• The chilled cast irons are generally applied for components which require a high wear resistance properties such as roll mill, crusher etc.
Chilled cast iron products
Rolls