The Geara International

Cylinder Liner/Cylinder Sleeves : Casting of these components is done in grey cast iron of G-4000 Grade. In such a way so as to achieve pearlitic structure free from ferrite and graphitic (max upto 2-3%). They are casted by centrifugal casting process so as to achieve compact structure and high strength as well as desired wear resistance, hardness and tensile strength. Each and every batch of casting is tested at the time of pouring as well as afterward completely in the in-house laboratory to maintain chemical composition, mechanical properties and metallography of the end products so as to meet the exact requirement of metallurgical norms. These casting of cylinder liners are further machined in our well equipped machinery plant having latest special purpose machines, CNC turning center and hydraulically operated honing machines to achieve plateau honing configuration.

The cylinder liner forms the cylindrical space in which the piston reciprocates. The reasons for manufacturing the liner separately from the cylinder block (jacket) in which it is located are as follows:-

The liner can be manufactured using a superior material to the cylinder block. While the cylinder block is made from a grey cast iron, the liner is manufactured from a cast iron alloyed with chromium, vanadium and molybdenum. (cast iron contains graphite, a lubricant. The alloying elements help resist corrosion and improve the wear resistance at high temperatures. The cylinder liner will wear with use, and therefore may have to be replaced. The cylinder jacket lasts the life of the engine.

At working temperature, the liner is a lot hotter than the jacket. The liner will expand more and is free to expand diametrically and lengthwise. If they were cast as one piece, then unacceptable thermal stresses would be set up, causing fracture of the material. Less risk of defects. The more complex the casting, the more difficult to produce a homogenous casting with low residual stresses.

The Liner will get tend to get very hot during engine operation as the heat energy from the burning fuel is transferred to the cylinder wall. So that the temperature can be kept within acceptable limits the liner is cooled.

Cylinder Blocks/ Cylinder Barrels for tractor engines & marine engines, two wheeler, three wheeler engines & high power industrial engines. Cylinder block/barrels are casted in shell molding process. These shell molding are done on automatic shell molding machines, core shooters and further these shell are joined on hydraulically operated shell joining pin closers. The metallurgical and chemical composition are maintained so as to achieve ASTM with G-4000 Grade. The casting of these blocks/barrels are machined in the machine shop equipped with precision CNC turning center, hydraulically operated NC controlled honing machines,so as to get plateau honing in the Bore. The hardness of the cylinder barrels varies from 190-220 BHN strictly as per international AE standard. The usage of hardened liners with plateau finish improves the engine life, lowers lube oil consumption and improves fuel efficiency.

Pistons are mostly made from Eutectic Aluminum Silicon alloy with excellent properties as low thermal expansion coefficient duty heat treated after casting for proper microstructure and hardness 70-80 hrb to achieve good mechanical properties to work in hot conditions. Pistons are machined with close tolerances as per requirements.

Type Of Pistons

Al-Fin: Top ring carrier with Austenitic special Iron casted rings [ Non-magnetic ] popularly known as Al-Fin type , to provide high wear resistance for longer life than normal pistons. This ring groove means higher degree of wear resistant. These pistons are recommended for Heavy Duty Diesel Engines with turbo charge.

Al-Fin Piston with Cooling Channels: Pistons have cooling channel and are used where high operating temperatures occur. With free flow of oil through this channel keeps the Piston Crown and Ring Belt cool.

Steel Strut Design: Pistons casted with Steel Struts for smooth running with long life. This piston has cast in Steel Strut between the skirt of pin-hole. Such pistons are for high Operating durability & are specially used in passenger Cars.

Steel Belt Piston: This Piston is also casted in Steel Belt with their high Strength. These pistons are suitable for high speed Diesel Engines.

Mono Metal Pistons (Quadra Piston): These pistons are casted all round Steel jacket, casted in the piston which is used in high speed Diesel Engines.

Sp. Steel Strut Design: Pistons casted with special shaped Steel Belts / Struts to achieve nearly uniform thermal expansion and to reduce fitting clearance.

Cylinder Heads are manufactured by shell molding process in graded cast iron in grade-20 melting through induction furnace so as to get all required metallurgical specifications and chemical compositions and further machined and each piece tested for leakage on process of hydraulic pressure.

These are usually made of grey Cast-Iron, suitable for wet-sleeved and non-sleeved engines. Direct Injection and Petrol Cylinder Heads are available.

These are provided with fitments like Valve-Guides, Valve-Seats or also supplied without the fitments.

All Valve Guides are individually casted in grey cast iron alloyed with chromium-nickle-manganese so as to maintain required metallurgical and chemical compositions with hardness ranging from 210-230 BHN. The machining of inner diameter to outside diameter may be maintained in close tolerance of 0.08 mm.

Valves- are nitrided to increase the exhaustion strength, Chrome plated to increase the wear resistance and Stellited (Seat hard Faced) to get high hot hardness at the seat.

Valves Seats- These are produced by centrifugal cast process to obtain closed grain dense structure to meet their functional properties.

Valve Tappets- are made in “Chilled Cast IRON in shell moulds.

Connecting Rods are made from steel forgings, but malleable or spheroid-graphite iron casting or sinter forgings are beginning to be used for smaller engines. These normally have either serrated or groove-and-tongue joints. Split half-shell thin-wall bearings are incorporated in the big-end housing bore.

The plain journal bearing (shell bearing liners) consist of a low carbon-steel cylindrical backup strip on to which the principal bearing material is cast or roll-bonded. This combination is known as bi-metal bearing. It is essential to thinly overlay a soft anti-friction alloy.

Synchronizer Rings are the high tech components used in the gearboxes of all light commercial, heavy trucks & cars. They are manufactured in aluminum, manganese bronze metal(copper base alloy)close die forging process on screw friction process of 100 Tons to 200 Tones capacity. The metallurgical features and chemical compositions are maintained as per International standards required by various Original Equipment manufacturers like Bajaj Tempo Ltd, Pune, Telco Ltd, Mahindra & Mahindra Ltd. Further forgings of those synchronizer rings are machined on CNC turning center so as to maintain consistency in mechanical parameters. The hardness of these components is maintained in the range of 80-90 Rockwell no.