MANUFACTURING OF BEARINGS THROUGH POWDER METALLURGY

Presented by : Akash Deep 16MT001338

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CONTENTS

1. Sintered Metal Self Lubricating Bearings2. Flow Chart Showing Various Steps Involved in Manufacturing of

Bearing3. Powder Production Methods and Additives4. Compaction of powder5. Sintering6. Post Sintering Operations- Sizing and Impregnation7. References

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SINTERED METAL SELF LUBRICTING BEARING Bearings which are manufactured from

powder metallurgy are called sintered metal self contact bearings.

No need of supplying continuous lubricant oils. Bush when heated due to friction release oil

stored in interconnected pores. Oil forms hydrodynamic layer due to wedge

action. On cooling, reabsorption takes place due to

capillary action. Fig-1 Sintered metal bronze bearing[4]

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Production of Cu Powder, Tin powder, Graphite powder

Mixing of Elemental Powder

Compaction

Sintering

Sizing

Impregnation

Bearing

FLOW CHART FOR PRODUCTION OF SELF LUBRICATING BEARING

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POWDER PRODUCTION METHODS

It involves production of copper(90%), tin(9%), and graphite(1%).

Cu powder- Electrolytic deposition Sn powder- Electrolytic deposition or Atomization. For Cu powder, Anode - Crude copper Cathode - Finished Al plate Electrolyte - Copper sulphateAt anode : Cu → + 2eAt cathode : → Cu Graphite is added to improve

pressing characteristics. Fig-2 Cu powder production

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COMPACTION OF POWDERS

It includes Densification of powder particles.

No heating.

For compaction, Automated compaction presses (Die Compaction) are used.

Compaction pressure: 275MPa to 480MPa.

Compact obtained is called Green compact.

The process involves three stages:

71) Powder Filling 2) Applying Pressure 3) Ejection of Compact from Die[3]

Punch

Die

Punch

PowderGreen Compact

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SINTERING

It includes consolidating the green compact under controlled condition of temp. and time.

Sintering Furnace used: Continuous Mesh Belt Furnace. Atmosphere : Hydrogen gas Atmosphere (Reducing) Sintering type : Liquid phase sintering. It is done in three stages:

1) Burn off zone or Preheat zone (400⁰C - 450⁰C)

2) Sintering zone (800⁰C – 850⁰C)

3) Cooling zone.

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Fig-3 Schematic diagram of Continuous type Sintering Furnace[3]

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POST SINTERING OPERATIONS

1. Sizing:- •To control the dimensions of bearings within tolerances. •Done by forcing the part into a die of smaller dimensions and forces.

2. Impregnation:- •Refers to the filling of pores in the part with oil. •Technique used is combination of vacuum and pressure. It involves: ▪ Sintered part placed in basket and subjected to vacuum. ▪ Oil is introduced & external pressure of 4-5 atm is applied. ▪ pressure is brought to 1 atm & excess oil is drained. • Oils used are synthetic hydrocarbon & silicone oil.

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REFERENCES1. J.K. Khare, Abhay Kumar Sharma, Ajay Tiwari, Anmol A. Talankar “Wear and Friction

Analysis of Sintered Metal Powder Self Lubricating Bush Bearing”. International

Journal of Mechanical, Aerospace, Industrial and Manufacturing Engineering vol8,

pp-1491-1494 (2014)

2. Daniel Ogbuigwe “Sintering of Copper Based Porous Bearings”.Ryerson University,

Toronto, Ontario, Canada (2012)

3. P.C. Angelo, R. Subramanium “Powder Metallurgy: Science, Technology and

Applications”(May 2013)

4. http://

www.industrytap.com/ggb-extends-range-self-lubricating-sinter-bronze-sinter-iron-

bearings/20682