Title of Invention	A SYNCHRONISER HUB USED IN AUTOMOBILES FOR MANUAL TRANSMISSION AND THE PROCESS OF ITS MANUFACTURE
Abstract	The present invention provides for Powder Metallurgy component Synchroniser Hub used in automobiles for manual transmission, comprising an enhanced level of carbon content on its surface with fully pearlite microstructure and Pearlite-Ferrite structure in the core. The present invention also provides for a process for the manufacture of said Synchroniser Hub.

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A SYNCHRONISER HUB USED IN AUTOMOBILES FOR MANUAL TRANSMISSION AND THE PROCESS OF ITS MANUFACTURE FIELD OF INVENTION The present invention provides for Powder Metallurgy component Synchroniser Hub used in automobiles for manual transmission, comprising a Pearlite microstructure with enhanced level of carbon content on its surface and Pearlite and Ferrite microstructure in the core. The present invention also provides for a process for the manufacture of said Synchroniser Hub. BACKGROUND AND PRIOR ART REFERENCES Many powder metallurgy components are used in application where they come in contact with other moving parts. Under these conditions, surface wear resistance is an important property, which the components must possess to perform well during application and with good core toughness. To achieve the dual properties, generally the PM components are heat treated in equipment such as a Sealed Quench Furnace after sintering the components. One disadvantage with such a process is the cost involved for the extra operation. The other disadvantage is that, the components are quenched in oil after austenising them and this causes distortion in the component. Hence, such components require further expensive operations such as grinding to meet the final pre-determined dimensions resulting in cost escalation. An alternative method, which is currently coming in vogue, is Sinter Hardening. In this method, hardening is achieved by increasing the alloying elements such as Ni, Cr, Mo, Mn and Cu in the PM components and forced cooling the parts to room temperature after sintering. The cooling rate is increased by improving heat transfer; either by increasing the volume flow of gas or by having improved cooling through an annular water cooling jacket. The equipment is expensive and addition of metals such as Mo escalates part cost. By this process the parts are hardened throughout the section of the component as against case hardening which is ideally suited for application involving moving parts. In the prior art mentioned above, two separate furnaces are used; one for sintering and other for re-heating and oil quenching the parts. Patent AppUcation US 4,106,931 deals with an alternative protective gas based on nitrogen based atmospheres to prevent and or minimise surface decarburization, reduce additions of hydrocarbons and methods thereby to sinter products in this atmosphere. The carbon intrusion by this method is in the Hot Zone. This patent application US 4,106,931 uses only general ferrous materials. References: 1. Astaloy CrM: New generation powder from Hoganas, Powder Metallurgy, 1998, Vol41,No4,pp 232-233, 2. A.B.Davala, A.H.Graham, R.J.Causton. Effect of process Conditions upon Sinter-hardening Response of PM Alloy FLC-4608. Industrial heating, September 1998, pp 111-120. 3. J.M. Capus. Sinter hardening offers high strength at lower cost. Metal Powder Report, September, 1997 pp 17-18 4. C. Lindberg, U. Engstrom, P. Endel. Sintered High strength materials.(pM-7). Private Publication, ppl-8. 5. F.Chagnon, Y. Trudel. Designing Low Alloy Steel Powders For Sinter hardening Applications. Private Publication pp 1-10. 6. D. Warga, C. Lindberg. Efficient Sintering and Hardening in the Conveyor belt sintering furnace. Proceedings of 1993 Powder Metallurgy World Congress, Part-2. pp 983-986. 7. Howard Ferguson. Guidelines for Heat Treating Powdered Metal Parts. ASM, The Heat Treating Source Book 1986, pp 162-167. 8. P. Johnson, W.Q. Judge and H.S. Nayar. Microstructures, quality control of P/M parts heat treated under various atmospheres. ASM, The Heat Treating Source Book 1986, pp 168-174 OBJECTS OF THE INVENTION The main object of the present invention is to provide for a Synchroniser Hub component comprising an enhanced level of carbon content on its surface to form a Pearlite microstructure with Pearlite and Ferrite microstructure in the core. The present invention also provides for a process for the manufacture of said Synchroniser Hub. Another object of the present invention is to manufacture a Synchroniser Hub for manual transmission of automobiles (Cars and Commercial vehicles) with substantial Pearlite microstructure on the surface. Yet another object of the present invention is to have a Pearlie and Ferrite microstructure in the core of the Synchroniser Hub. Yet another object of the present invention is to have a Pearlite and Ferrite microstructure in the core of the Synchroniser Hub. Yet another object of the invention relates to manufacture of components requiring good surface wear characteristics using similar materials and process. STATEMENT OF THE INVENTION The present invention relates to a synchronizer hub, for manual transmission in automobiles, the said synchronizer hub comprising: a core having a Pearlite and Ferrite micro structure; and a surface having a fully Pearlite micro structure as a result of treatment of the synchronizer hub in an enriched carbon atmosphere so that penetration of the carbon extending to about 1 mm below the surface of the synchronizer hub; wherein the material composition of the said synchronizer hub component having Nickel 1-5%, Copper 1- 5% and Carbon 0.2-0.8% in the form of Graphite Powder and remaining Iron. The present invention also relates to A process for the manufacture of a synchroniser hub for the manual transmission of automobiles, said process comprising: i. providing a suitable die and filling the die with an alloy powder material comprising a nominal composition of Ni 1-5%, Cu 1-5%) and C 0.2-0.8%) in the form of graphite powder and remaining Iron; ii. compacting the powder material to achieve a predetermined shape of the synchroniser Hub using suitable tooling comprising die, punches and core rods; iii. sintering the compacted hub in a N2/H2 protective gas atmosphere at a constant temperature; iv. treating the hub in the cooling zone of the furnace; V. enriching the cooling zone with the carbon containing gases; vi. enhancing the carbon content on the surface of the said synchroniser hub; and vii. creating a fully Pearlite structure on the surface of the synchroniser hub, Pearlite and Ferrite structure in the core, sufficient for the present application. SUMMARY OF THE INVENTION The present invention provides for a Synchroniser Hub having high surface wear resistance and good core toughness. The present invention also provides for a process to sinter low carbon PM component Synchroniser Hub and enrich the components immediately after sintering by providing an atmosphere. which is rich in carbon. Carbon enrichment of the atmosphere enhances the carbon level on the surface of the part. This ensures a surface with high wear resistance and a core with a lower carbon having good toughness. DETAILED DESCRIPTION OF THE INVENTION Accordingly, the present invention provides a synchronizer hub, for manual transmission in automobiles, the said synchronizer hub comprising: a core having a Pearlite and Ferrite micro structure; and a surface having a fully Pearlite micro structure as a result of treatment of the synchronizer hub in an enriched carbon atmosphere so that penetration of the carbon extending to about 1 mm below the surface of the synchronizer hub; wherein the material composition of the said synchronizer hub component having Nickel 1-5%, Copper I- 5% and Carbon 0.2-0.8% in the form of Graphite Powder and remaining Iron. An embodiment of the present invention, wherein a Synchroniser Hub comprises a fully Pearlite structure on the surface with a thickness in the range of 20 to 150 microns. Another embodiment of the present invention, wherein the synchronizer hub comprises a Pearlite and Ferrite structure in the core. Yet another embodiment of the present invention, wherein the core of the Synchroniser Hub having Pearlite and Ferrite structure in the core with about 0.3% Carbon content. Still another embodiment of the present invention, wherein the surface hardness achieved is in the range of 170 to 300 HV5. Further, another embodiment of the present invention, wherein the core toughness achieved is in the range of 120 to 150 HV5. Yet another embodiment of the present invention, wherein said Synchroniser Hub comprises reduced distortion property requiring no corrective measures. The present invention also provides for a novel process for the manufacture of the Synchroniser Hub for use in manual transmission of automobiles, said process comprising: (i) providing a suitable die and filling the die with an alloy powder material comprising a nominal composition ofNi 1-5%, Cu 1-5%) and C 0.2-0.8%) in the form of graphite powder and remaining Iron; (ii) compacting the powder material to achieve a predetermined shape of the Synchroniser Hub using suitable tooling comprising die, punches and core rods; (iii) sintering the compacted hub in a N2/H2 protective gas atmosphere at a constant temperature; (iv) treating the hub in the cooling zone of the furnace; (v) enriching the cooling zone with the carbon containing gases; (vi) enhancing the carbon content on the surface of the said Synchroniser Hub; and (vii) creating a fully Pearlite structure on the surface of the Synchroniser Hub, Pearlite and Ferrite structure in the core, sufficient for the present application. An embodiment of the present invention, wherein sintering of said Synchroniser Hub is at an elevated temperature of about 1120 ""C. Yet another embodiment of the present invention, wherein said N2-H2 gas atmosphere comprises about 90% Nitrogen and about 10% Hydrogen gas by volume. Still another embodiment of the present invention, wherein synthetic gases produced from Nitrogen, Methanol or Endothermic gas produced from cracking LPG are used, in a nominal composition of about 20% Carbon Monoxide and about 40% Hydrogen and a balance comprising Nitrogen. Another embodiment of the present invention, wherein minute additions of Hydrocarbon gases, selected from LPG, Propane or Methane are used in the cooling zone for Carbon enrichment up to 3.5% by volume. Still another embodiment of the present invention, wherein cooling rates in the cooling zone is less than 2"^C/second. Yet another embodiment of the present invention, wherein the Synchroniser Hub is cooled in annular water-cooled jackets with protective gas atmosphere. Still another embodiment of the present invention, wherein treating the sintered product in a cooling zone by carbon diffusion by introducing said Hydrocarbon gas at 900 to 800 °C. BRIEF DESCRIPTION OF THE ACCOMPANYING DIAGRAMS Figure 1 depicts the surface mircostructure of the Synchronizer Hub, wherein it is observed that the surface microstructure is mostly Pearlite. Figure 2 depicts the Core microstructure of the Synchronizer Hub, wherein it is observed that the core microstructure is Ferrite and Pearlite. ADVANTAGES OF THE PRESENT INVENTION 1. The present invention provides for surface carbon enrichment of products for the purpose of enhancing surface properties of products. 2. The present invention focuses on carbon enrichment in the cooling zone and the distinct phase transformations that occur on the surface and core of the products. The point of carbon intrusion in the furnace is in the cooling zone. 3. The present invention takes advantage of specific materials other than the general ferrous materials used in the prior arts, and carbon enrichment to achieve distinct surface properties like hardness that offers a novel idea whereby, the products can be made using conventional equipment and processes thereby reducing cost of manufacturing. Further, advantages of the present invention over the prior art references are provided below in the form of tables: We Claim: 1. A synchronizer hub, for manual transmission in automobiles, the said synchronizer hub comprising: a core having a Pearlite and Ferrite micro structure; and a surface having a fully Pearlite micro structure as a result of treatment of the synchronizer hub in an enriched carbon atmosphere so that penetration of the carbon extending to about 1 mm below the surface of the synchronizer hub; wherein the material composition of the said synchronizer hub component having Nickel 1-5%, Copper 1-5% and Carbon 0.2-0.8%) in the form of Graphite Powder and remaining Iron. 2. The synchronizer hub as claimed in claim I, wherein the fully Pearlite structure at the surface of the hub having a thickness in the range of 20 to 150 microns. 3. The synchronizer hub as claimed in claim 1, wherein the core of the synchronizer hub having Pearlite and Ferrite structure with about 02-0.6% carbon content. 4. The synchronizer hub as claimed in claim 1, wherein the surface having the hardness in the range of 170 to 300 HV5. 5. The synchronizer hub component as claimed in claim 1, wherein the core having the toughness in the Range of 120 to 150 HV5. 6. The synchronizer hub as claimed in claim 1, wherein said synchronizer hub has reduced distortion property. 7. A process for the manufacture of a synchroniser hub for the manual transmission of automobiles, said process comprising: i. providing a suitable die and filling the die with an alloy powder material comprising a nominal composition of Ni 1-5%, Cu 1-5% and C 0.2-0.8%) in the form of graphite powder and remaining Iron; ii. compacting the powder material to achieve a predetermined shape of the synchroniser Hub using suitable tooling comprising die, punches and core rods; iii. sintering the compacted hub in a N2/H2 protective gas atmosphere at a constant temperature; iv. treating the hub in the cooling zone of the furnace; V. enriching the cooling zone with the carbon containing gases; vi. enhancing the carbon content on the surface of the said synchroniser hub; and vii. creating a fully Pearlite structure on the surface of the synchroniser hub, Pearlite and Ferrite structure in the core, sufficient for the present application. 8. The process as claimed in claim 7, wherein the sintering of said synchronizer hub is performed at an elevated temperature of about 1120oC. 9. The process as claimed in claim 7, wherein said protective N2-H2 gas atmosphere comprises 90% Nitrogen and 10% Hydrogen gas by volume. 10. The process as claimed in claim 7, wherein the said carbon containing gas is a synthetic gas and produced from nitrogen, methanol or endothermic gas which is produced from cracking LPG. 11. The process as claimed in claim 10, wherein the carbon containing gases having a composition of about 20%o carbon monoxide, about 40%) hydrogen and balanced is nitrogen; 12. The process as claimed in claim 7, wherein the carbon containing gases enrich the component up to 3.5%) by volume. 13. The process as claimed in claim 7, wherein the cooling rates in the cooling zone is less than 2C. 14. The process as claimed in claim 7, wherein the cooling said synchronizer hub is cooled in annular water-cooled jackets with protective gas atmosphere. 15. The process as claimed in claim 7 to 14, wherein the sintered hub is treated in the cooling zone for carbon diffusion by introducing said hydrocarbon gases at 900 to 800°C. 16. The synchronizer hub for manual transmission in automobiles substantially as herein described with reference to drawings and examples. 17. A synchronizer hub and a process for manufacturing a synchronizer hub substantially as herein described with reference to the accompanying drawings and examples.

Documents:

0888-mas-2001 abstract-duplicate.pdf

0888-mas-2001 abstract.pdf

0888-mas-2001 claims-duplicate.pdf

0888-mas-2001 claims.pdf

0888-mas-2001 correspondence-others.pdf

0888-mas-2001 correspondence-po.pdf

0888-mas-2001 description (complete)-duplicate.pdf

0888-mas-2001 description (complete).pdf

0888-mas-2001 drawings-duplicate.pdf

0888-mas-2001 drawings.pdf

0888-mas-2001 form-1.pdf

0888-mas-2001 form-13.pdf

0888-mas-2001 form-19.pdf

0888-mas-2001 form-26.pdf

0888-mas-2001 form-3.pdf

0888-mas-2001 form-5.pdf