Powder Powder MetallurgyMetallurgy

-- An insight An insight

By

GAUTAM SHARMAGAUTAM SHARMA1DA07ME023

DEPARTMRNT OF MECHANICAL ENGG.

DR.AMBEDKAR INSTITUTE OF TECHNOLOGY

BANGALORE-56

Powder Metallurgy (P/M)

•Introduction•History •General Summary of the Science of P/M

1.powder production2.powder compaction3.sintering/ infiltration

•Powder metallurgy products•Applications and market•Feasibility•Conclusions

Introduction

Powder metallurgyPowder metallurgy is the manufacturing process used is the manufacturing process used to fabricate finished products by the method of compaction of to fabricate finished products by the method of compaction of metal powders and further processing to achieve reqd. metal powders and further processing to achieve reqd. properties.properties.

Current feasible examples of its use are:Current feasible examples of its use are: Connecting rods of bugatti and jaguarsConnecting rods of bugatti and jaguars Use in Automotive industryUse in Automotive industry Nacelle frame of F-22 raptorNacelle frame of F-22 raptor Precision equipments and biomedical industryPrecision equipments and biomedical industry

History Early 3000 B.C. – a crude form of powder Early 3000 B.C. – a crude form of powder metallurgy in Egypt metallurgy in Egypt Early 20th Century –copper coins and Early 20th Century –copper coins and medallions, and tungsten wiresmedallions, and tungsten wires1920s – tungsten carbide cutting-tool tips, 1920s – tungsten carbide cutting-tool tips, self-lubricating bearingsself-lubricating bearings1960s – full-density products emerged.1960s – full-density products emerged.1970s – high-performance superalloy 1970s – high-performance superalloy components: aircraft turbine engine parts.components: aircraft turbine engine parts.1980s – the commercialization of rapidly–1980s – the commercialization of rapidly–solidified and amorphous powders and the solidified and amorphous powders and the development of P/M injection molding development of P/M injection molding technologytechnology After 2000- growing dependence of After 2000- growing dependence of automotive and precision industry.automotive and precision industry.

General Summary of The Science of P/M

STEPSSTEPS::

• a) Powder Productiona) Powder Production• b) Powder Consolidationb) Powder Consolidation• c) Sinteringc) Sintering• d) Finishing operationsd) Finishing operations

Powder Production

AtomizationAtomization

o Electrolytic, precipitationElectrolytic, precipitationo Mechanical Mechanical o Chemical, reductionChemical, reduction

Powder Production

Powder Production

Disintegration of liquid stream by a second fluidDisintegration of liquid stream by a second fluid

• Gas AtomizationGas Atomization– Spherical powder particlesSpherical powder particles– Good "flowability"Good "flowability"

• Water Atomization:Water Atomization:– Irregular powder particlesIrregular powder particles

– Good compactabilityGood compactability

Powder Production by Atomization

Atomization Schematics

Water Atomization Induction Coil Gas Atomization

Water Water

Powder Production

Powder Production

Vertical Gas Atomizer

Powder shapes and sizes

Chemical: Sponge Iron-Chemical: Sponge Iron-Reduced Ore Reduced Ore

Electolytic: CopperElectolytic: Copper Mechanical: Milled Mechanical: Milled Aluminum Powder Aluminum Powder Water Atomization : Iron Water Atomization : Iron Gas Atomization: Nickel-Gas Atomization: Nickel-

Base Hardfacing AlloyBase Hardfacing Alloy

Powder Production

Gas Atomized

Silver Alloy

Powder Production

WaterAtomized Copper Alloy

Powder Production

Impart shape to net or near net to powder mass

Net Shape:•Die Compaction•MIM (Metal Injection Molding)

Near Net Shape:•CIP (Cold Isostatic Pressing)•Hot Pressing•Extrusion•Rolling

Powder Consolidation

Consolidation

Powder Consolidation

– Use water atomized powder (irregular shape)Use water atomized powder (irregular shape)– Rigid tooling: tool steel, WC/CoRigid tooling: tool steel, WC/Co– Pressures up to 60 tons/square inchPressures up to 60 tons/square inch– Production > 10,000 parts Production > 10,000 parts – High tolerance, 0.001 "/" possibleHigh tolerance, 0.001 "/" possible– High productivityHigh productivity– Controlled porosity, density (85% to 90%)Controlled porosity, density (85% to 90%)

Die Compaction

•Axis-symmetric•No undercuts•No off-axis attributes•L/D <5

Powder Consolidation

MIM (Metal Injection Molding)

• Plastic Injection Molding + Powder Metallurgy (P/M)

• Complex Shapes• High density metal parts (> 95%)• Economy of Scale (high productivity)• Good tolerance, .003 "/" possible, .005-.008 "/" typ.

Competes with investment casting

and discrete machining

Powder Consolidation

Schematic Of MIM

Powder Consolidation

Sintering

Heat treatment to promote

Metallurgical integrity Metallurgical Bonding Densification (shrinkage) Pore Elimination

Sintering

Sintering furnace

Sintering

Infiltration

Infiltration is the process wherein a slug of low melting point Infiltration is the process wherein a slug of low melting point metal is placed against the sintered parts and then the metal is placed against the sintered parts and then the assembly is heated to a temperature sufficient to melt the slug. assembly is heated to a temperature sufficient to melt the slug. The slug infiltrates the pores, to produce a pore free part The slug infiltrates the pores, to produce a pore free part having good density and strength.having good density and strength.

Advantages of infiltration are that high strength and density is Advantages of infiltration are that high strength and density is achieved and pores are filled up, reducing corrosion. Some achieved and pores are filled up, reducing corrosion. Some bearing materials are formed in this way.bearing materials are formed in this way.

infiltration

Powder Metallurgy Products Porous or permeable products

Oil-impregnated bearings Products of complex shapes that would require considerable machining

when made by other processescomplex shapes such as pawls, cams, and small activating

levers Products made from materials that are difficult to machine or with high

melting pointstungsten lamp filaments and tungsten carbide cutting tools

Products where the combined properties of two or more metals are desired

bearings made of graphite combined with iron or copper Electrical contacts often combine copper or silver with tungsten,

nickel or molybdenum Products here the powder metallurgy process produces clearly superior

propertiesIn areas of critical importance such as aerospace applications

Products

P/M. Applications and Markets

Automotive applicationsAutomotive applications Aerospace applicationsAerospace applications Advanced compositesAdvanced composites Magnetic materialsMagnetic materials Metalworking toolsMetalworking tools A variety of biomedicalA variety of biomedical

and dental applicationsand dental applications

Applications

Porous Metals

Oil-impregnated Porous Bronze Bearings

Metal filters

Applications

Automotive Industry

Automotive gears

Journal bearings

Connecting rods

Applications

CERMET cutting tools(Ceramic-Metal composite)

Microstructure: ceramic particles in metal matrix

Cermet-tipped saw blade for long life

Cermet cutting inserts for lathe

Applications

Biomedical and Others:

KNEE CAPS WITH KNEE CAPS WITH LUBRICATIONLUBRICATION

HIGH DENSITY GOLF HIGH DENSITY GOLF STICKSSTICKS

OTHER HIGH PRECISION OTHER HIGH PRECISION AND SURGICAL AND SURGICAL EQUIPMENTSEQUIPMENTS

Applications

Better material utilizationBetter material utilization

Fewer tool setsFewer tool sets

Reduction of secondary machining Reduction of secondary machining operationsoperations

– Large end bearing bore and mating flatsLarge end bearing bore and mating flats– Eliminate balancingEliminate balancing– Cost saving in case of large production Cost saving in case of large production

volumevolume

P/M Press-Sinter-Forge vs. Power Forge

Applications

Feasibility of P/M ProductsCasting, Forging, Machining, P/M, etc:

Which method to choose?

Quality, Quantity, Tolerance, Geometry, Material, Environment,

Labor quantity, Skill level, Equipment,Etc…

But MOST IMPORTANTLY…..

LOWEST

COST!

Potential cost saving

Part ( in production of F-Part ( in production of F-22 raptor)22 raptor)

Weight( kg)Weight( kg) Cost Cost saving saving

(%)(%)ForgedForged P/MP/M Final partFinal part

Fuselage braceFuselage brace 2.82.8 1.11.1 0.80.8 5050

Engine mount supportEngine mount support 7.77.7 2.52.5 0.50.5 2020

Arrestor hook supportArrestor hook support 79.479.4 25.025.0 12.912.9 2525

Nacelle frameNacelle frame 143143 8282 24.224.2 5050

Conclusions

Advantages:Advantages: Elimination or reduction of Elimination or reduction of

machiningmachining High Production RatesHigh Production Rates Complex Shapes can be Complex Shapes can be

ProducedProduced Wide Variations in Wide Variations in

Compositions are PossibleCompositions are Possible Wide Variation in Wide Variation in

Properties are AvailableProperties are Available Scrap is Eliminated or Scrap is Eliminated or

ReducedReduced

Disadvantages:Disadvantages: Inferior Strength PropertiesInferior Strength Properties Relatively High Die CostRelatively High Die Cost High Material CostHigh Material Cost Design LimitationsDesign Limitations Density Variations Produce Density Variations Produce

Property VariationsProperty Variations Health and Safety HazardsHealth and Safety Hazards