piston material selection

Case Study for Applied Material Science for the Selection of materials in automobile piston

1. Kumaraguru College Of Technology P15CCT102/ APPLIED MATERIALS ENGINEERING Presented By, RAGHUL ( 17MCC006 ) GAUTHAM (17MCC007)

2. MATERIAL SELECTION FOR PISTON

3. Piston: A piston is a cylindrical engine component that slides back and forth in the cylinder bore by forces produced during the combustion process. The piston acts as a movable end of the combustion chamber . Its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod.

4. Piston materials: The most commonly used Piston materials are Cast Iron Aluminium Alloys Cast iron pistons are used for moderately rated engines with piston speed below 6m/s. Aluminium alloy pistons are used for highly rated engines with piston speed above 6m/s.

5. Cast Iron: Cast iron is a group of iron-carbon alloys with a carbon content greater than 2 %. Carbon (C) ranging from 1.8–4 wt%, and silicon (Si) 1–3 wt% are the main alloying elements of cast iron. Types of Cast Iron Grey cast iron White cast iron Malleable cast iron Ductile cast iron

6. Cast Iron Characteristics : It is hard. Brittle. Non-malleable (i.e. it cannot be bent, stretched or hammered into shape). M ore fusible than steel. V ery good in compression.

7. Aluminium alloys: Aluminium alloys (or aluminum alloys) are alloys in which aluminium (Al) is the predominant metal . The typical alloying elements are copper, magnesium, manganese, silicon, tin and zinc. Cast aluminium alloys yield cost-effective products due to the low melting point.

8. Aluminum Alloy Characteristics: High operating temperatures Outstanding corrosion resistance Lightweight Very good strength and hardness Good stiffness and strength-to-weight ratio Excellent EMI and RFI shielding properties Excellent thermal conductivity High electrical conductivity Good finishing characteristics Full recyclability

9. Applications for Aluminum:  Aluminum castings improve automotive fuel efficiency by contributing to weight saving requirements Aluminum is used in a broad range of networking and infrastructure equipment in the telecom and computing industries because RF filter boxes and housings require heat dissipation In handheld devices, aluminum castings provide EMI/RFI shielding, rigidity, and durability with minimal weight Because of aluminum’s excellent electrical performance and shielding properties, even in high-temperature environments, die cast aluminum is ideal for electronic connectors and housings

10. Properties PROPERTIES ALUMINIUM CAST IRON Atomic Number 13 26 Crystal Structure FCC FCC Melting Point (°C) 660.2 1204 Boiling Point (°C) 2480 2862 Mean Specific Heat (0-100°C) ( J/ g o C ) 0.900 0.444 Thermal Conductivity (0-100°C) (cal/ cms.°C ) 0.57 0.163 Electrical Resistivity at 20°C ( Ω.cm ) 2.69 9.61 Density (g/cm 3 ) 2.6898 7.874 Poissons Ratio 0.34 0.29 Young's modulus 70 211 Brinell hardness 160-550 200-1180

11. Advantages of Aluminium over cast iron: High thermal conductivity (approx 3 times that of cast iron L ess variation in temperature from the crown to the piston rings. Density of aluminium is about one third that of cast iron. Therefore light weight construction and less inertia forces.

12. Conclusion: Piston material and design contribute to the overall durability and performance of an engine . Cast aluminium alloy is lightweight and has good structural integrity and low manufacturing costs . The light weight of aluminium reduces the overall mass and force necessary to initiate and maintain acceleration of the piston . This allows the piston to utilize more of the force produced by combustion to power the application . Hence Aluminium Alloy is used for Pistons.

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