MATERIAL TEKNIK (MAT) CAST IRON. Cecep Ruskandi

Transcription

1 MATERIAL TEKNIK (MAT) CAST IRON Cecep Ruskandi

2 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)

3 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

4 Flake Graphite

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6 Gray Cast Iron Products Exhaust manifold housing Brake drum rotor Arts Body valve Door knocker

7 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

8 Nodular Graphite

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10 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.

11 The Group of Ductile Iron (con t) Martensitic Ductile Iron or quench & tempered iron. In the "as-cast" condition the alloy is hard and brittle, and seldom used. However, TEMPERED MARTENSITE has very high strength and wear resistance. A 930 F (500 C) tempering results in 300 HB, a 1110 F (600 C) tempering in 250 HB hardness.

12 The Group of Ductile Iron (con t) Austenitic Ductile Iron They are never chosen for strength alone. The outstanding features are good corrosion and oxidation resistance, magnetic properties, strength and dimensional stability at elevated temperatures. (Also known as Ductile Ni- Resist).

13 The Group of Ductile Iron (con t) Austempered Ductile Iron - ADI is almost twice as strong as the regular ASTM grades of Ductile Iron whilst still retaining high elongation and toughness characteristics -It also offer wear resistance and high strength The remarkable properties of ADI are developed by a closely controlled heat treatment operation (austempering) which develops a unique matrix structure of bainitic ferrite (60%) and retained (high carbon) austenite.

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15 Application of Ductile Iron

16 Malleable Cast Iron (GT DIN) Malleable irons are cast white, that is, their as-cast structure consists of metastable carbide in a pearlitic matrix 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.

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18 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

19 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

20 Malleable cast iron products

21 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.

22 Rolls Chilled cast iron products