Powder MetallurgyPowder Metallurgy

SUBMITTED BY INDRESH KUMAR BAIS ROLL NO. 11031M02018

OutlineOutline

IntroductionIntroduction

Powder ManufacturingPowder Manufacturing

Powder Metallurgy ProcessPowder Metallurgy Process

SinteringSintering

Other Powder Metal ProcessesOther Powder Metal Processes

Powder Metal ProductsPowder Metal Products

Powder Metallurgy DesignPowder Metallurgy Design

IntroductionIntroduction

Powder metallurgy is a Powder metallurgy is a processprocess by by which fine powdered materials are which fine powdered materials are blended, pressed blended, pressed into a into a desired desired shapeshape, and then , and then heated to bond heated to bond surfacessurfacesTypically used when Typically used when large large amounts amounts of of small, intricate parts small, intricate parts withwith high precision high precision are required are requiredLittle material waste Little material waste and and unusual unusual mixtures mixtures can be utilizedcan be utilizedUsed for parts in the automotive Used for parts in the automotive industry, household appliances, industry, household appliances, and recreational equipmentand recreational equipment

Powder MetallurgyPowder Metallurgy

MetalMetal

PowderPowder

Metal ProductMetal Product

Examples of Powder Examples of Powder Metal ProductsMetal Products

GearsGears

CamsCams

CranksCranks

BearingsBearings

Roller bearing cagesRoller bearing cages

HousingsHousings

Light bulb filamentsLight bulb filaments

Sprinkler mechanismsSprinkler mechanisms

Powder Metallurgy Powder Metallurgy ProcessProcess

Powder ManufacturingPowder Manufacturing

Conversion of molten metal to Conversion of molten metal to powderpowder

AtomizationAtomization

Powder Metal MaterialsPowder Metal Materials

ElementalElemental

A pure metal, most commonly A pure metal, most commonly iron, aluminum or copperiron, aluminum or copper

PrealloyedPrealloyed

An alloy of the required An alloy of the required composition, most commonly composition, most commonly copper alloys, stainless steel copper alloys, stainless steel or high-speed steelor high-speed steel

Powder ManufacturingPowder Manufacturing

Other methods of producing Other methods of producing powder:powder:

- Chemical reduction of Chemical reduction of particulate compoundsparticulate compounds

- Electrolytic depositionElectrolytic deposition- Pulverization or grinding of Pulverization or grinding of

brittle materialsbrittle materials- Thermal decompositionThermal decomposition- Precipitation from solutionsPrecipitation from solutions- Condensation of metal vaporsCondensation of metal vapors

Atomization

Atomization is accomplished by forcing a molten metal stream through an orifice at moderate pressures. A gas is introduced into the metal stream just before it leaves the nozzle, serving to create turbulence as the entrained gas expands (due to heating) and exits into a large collection volume exterior to the orifice. The collection volume is filled with gas to promote further turbulence of the molten metal jet. On Earth, air and powder streams are segregated using gravity or cyclonic separation. Most atomised powders are annealed, which helps reduce the oxide and carbon content. The water atomized particles are smaller, cleaner, and nonporous and have a greater breadth of size, which allows better compacting. The powders produced through this method are normally of spherical or pear shape. Usually, they also carry a layer of oxide over them.

Blending and MixingBlending and Mixing

BlendingBlending

Combining powders of the same material Combining powders of the same material but possibly different particle sizesbut possibly different particle sizes

MixingMixing

Combining powders of different materialsCombining powders of different materials

CompactionCompaction

High pressure is applied to squeeze High pressure is applied to squeeze the powder into the desired shapethe powder into the desired shape

SinteringSintering

Heats the powder below the melting Heats the powder below the melting point to allow solid-state diffusion point to allow solid-state diffusion and bond the particles togetherand bond the particles together

SinteringSintering

Other Powder Metal Other Powder Metal ProcessesProcesses

Cold Isostatic PressingCold Isostatic Pressing

Hot Isostatic PressingHot Isostatic Pressing

Injection MoldingInjection Molding

Powder RollingPowder Rolling

Powder ExtrusionPowder Extrusion

Plasma SprayingPlasma Spraying

Injection MoldingInjection Molding

The powder is mixed with a binder The powder is mixed with a binder and molded, and the binder is and molded, and the binder is removed before sinteringremoved before sintering

Powder RollingPowder Rolling

Powder is compressed in a rolling mill Powder is compressed in a rolling mill to form a stripto form a strip

Powder Metal ProductsPowder Metal Products

1.1. Porous or permeable Porous or permeable productsproducts

2.2. Products of complex shapesProducts of complex shapes3.3. Products made of materials Products made of materials

that are difficult to machine or that are difficult to machine or have high melting pointshave high melting points

4.4. Products which require the Products which require the combined properties of combined properties of multiple materialsmultiple materials

5.5. Products in which powder Products in which powder metallurgy produces superior metallurgy produces superior propertiesproperties

Powder Metallurgy Powder Metallurgy DesignDesign

1.1. The shape must permit removal The shape must permit removal from the diefrom the die

2.2. The shape should not have thin The shape should not have thin walls or sharp cornerswalls or sharp corners

3.3. The shape should permit the The shape should permit the construction of strong toolingconstruction of strong tooling

4.4. The shape of the part should be The shape of the part should be within the thickness range for within the thickness range for which the powder can be properly which the powder can be properly compactedcompacted

5.5. The part should have as few The part should have as few changes in section thickness as changes in section thickness as possiblepossible

Powder Metallurgy Powder Metallurgy AdvantagesAdvantages

1.1. Elimination/reduction of Elimination/reduction of machiningmachining

2.2. High production ratesHigh production rates

3.3. Complex shapes can be Complex shapes can be producedproduced

4.4. Wide composition variations Wide composition variations are possibleare possible

5.5. Wide property variations are Wide property variations are possiblepossible

6.6. Scrap is eliminated or Scrap is eliminated or reducedreduced

Powder Metallurgy Powder Metallurgy DisadvantagesDisadvantages

1.1. Inferior strength propertiesInferior strength properties

2.2. Relatively high die costRelatively high die cost

3.3. High material costHigh material cost

APPLICATIONAPPLICATION

••Bearing and filteringBearing and filtering

••Complex shape Complex shape

componentscomponents

••Automotive Automotive

componentscomponents

••Grinding wheelGrinding wheel