SND Powder Metallurgy
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Transcript of SND Powder Metallurgy
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A Seminar onAdvanced Technology in Powder Metallurgy
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Advanced Technology in PowderMetallurgy
• Introduction
• Process
• Efect o density on various mechanical
properties.• Advanced Technology
• Applications
• Advantages
• Limitations
• onclusion
• !eerences
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Powder MetallurgyPowder metallurgy is a "ranch ometallurgy which deals with the
production o metal and non metalpowders and su"se#uentlymanuacture o components "y
using these powders.
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Flowchart of Powder Metallurgy Process.
Producing metal powders o suita"le si$e% shape and purity.
&lending and mi'ing o powders
ompacting
Presintering
Sintering
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() Production o Metal Powders *Methods
(. Atomi$ation
+. !eduction
,. Electrolysis-. rushing
. Milling
/. ondensation o metal vapours
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!ange o particle si$es
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Automisation
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Automisation
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Automisation
• A high pressure steam or li#uidimpinges on the molten metal which ispassed through ori0ce causing it to
automise into 0ne particles.• Sometimes inert gas is used to get pure
powder.
• 1igh #uality powders o Aluminum%"rass% iron% stainless steel% tool steel%super alloys are produced commercially
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!eduction
• The compound o metals are reduced with2 and 1+ gas in controlled atmosphere
• The reduced product is crushed and ground
to get metal powder.• e. a. Tungsten o'ide * Tungsten powder
Iron hloride * Iron powder
• Metal powders o"tained * opper% Iron% Tungsten% Moly"denum% 3ic4el.
• 5ery convenient% economical% and 6e'i"lemethod% so it is widely used.
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Electrolysis
• The process is similar toelectroplating
• In this process anode and cathodeare placed in the electrolyte "ath.
• 1igh intensity current detoriatesanode and cathode is deposited "ypure copper powder.
• The cathode plates are ta4en out andscraped of to collect copper powder.
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Electrolysis
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ElectrolysisIron Powder opper Powder
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rushing
• Totally mechanical process.
• &rittle metal or alloy can "e easilycrushed.
• It re#uires crushing machinery li4estamps% hammers% 7aw crusher etc.
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rushing Process
8aw rusher 9yratory rusher !ollrusher
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Milling
• This is also mechanical process.
• :sed whenever large amount o powder is to "eproduced.
• :sed or hard% sot% ductile or "rittle materials.• It re#uires "all mill% impact mill% eddy mill% orvorte' mill.
• A "all mill is widely used which is hori$ontal
"arrel shaped container holding num"er o "allswhich "eing ree to tum"le a"out as thecontainer rotates.
• Then crush or grind to get 0ne powder.
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Milling
This contains cylindrical vessel rotating hori$ontally
along the a'is. Length o the cylinder is more or lesse#ual
to diameter. The vessel is charged with the grinding
media. The grinding media may "e made o hardened
steel% or tungsten car"ide% ceramics li4e agate%porcelain%
alumina% $irconia. ;uring rolling o vessel% the grinding
media < powder particles roll rom some height. This
process grinds the powder materials "y impact =collision < attrition.
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Milling process &all Mill 5i"ratory &all Mill
Attrition Mill
!od Mill 1ammer MillPlanetary Mill
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ondensation
• :sed or metal powder li4e >inc%admium% Magnesium.
• In this process the metal can "e"oiled and the vapours o the moltenmetals are condensed to give metalpowder.
• :sed only or small scale production.
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+) &lending < mi'ing oPowders
• ;iferent powders along with lu"ricant mi'ed in a "allmill. Lu"ricants are added to reduce riction during thepressing operations. This reduces die wear and lowersthe pressure re#uired or pressing.
• Ater mi'ing the re#uired properties li4e heatresistance% riction% weight and hardness can "eo"tained.
• &lending types – ;ry method
– ?et method@ Li#uid medium li4e alcohol% acetone% "en$ene ordistilled water are in wet milling.
Advantages o wet mi'ing () !educes dust. +) Avoidse'plosion ha$ards% ,) Prevents surace o'idation.
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,) ompacting
• ompacting means pressing the powdersinto their semi0nished orm o desiredshape.
• Powders are compacted "y using highpressure.
• ompacting methods
() ;ie pressing
+) !oll pressing
,) E'trusion
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;ie pressing
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!oll compacting
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E'trusion
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Presintering
• ?hen some machining is re#uiredthen presintering operation isemployed "eore sintering operation.
• Bor presintering the compacted partsare heated or a short time at atemperature considera"ly "elow the
sintering temperature.
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Sintering
• Sintering is done to get re#uired strengthand hardeness in the 0nished product.
• Sintering consists o heating a compacted
parts in a urnace to a temperature "elowmelting point o the ma7or constituent in acontrolled atmosphere.
• Sintering is process o "onding solid "odies
"y atomic orces.• Sintering gives re#uired shape to the
component.
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Secondary operations
• In many cases% the powderedproducts may "e used as sinteredcondition% "ut in other cases where
desired surace 0nish% tolerance% ormetal structure can "e o"tained "ycertain additional secondary
operations.(. Si$ing +. oining ,.
Machining
-. Impregnation . In0ltration /.
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(. Si$ing
• Sintering process produces somedistortions and alteration in si$e.
• To ma4e it dimensionally correct%place in die and repressed.
• Si$ing improves surace 0nish also.
• A slight change in density occursater si$ing operation.
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+. oining
• The sintered part is repressed in thedie to reduce the void space andimpart re#uired density.
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,. Machining
• Beatures as thread% under cuts%grooves etc are not o"tained atersintering process.
• Such machining is done aterpresintered operations.
• &oring% turning% drilling% tapping etc
can "e done on the presintered partsusing tungsten car"ide tools.
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-. Impregnation
• Sintered porous parts may "eimpregnated with oil% grease or wa'to give sel lu"rication properties.
• Sintered parts may "e impregnatedwith plastic also. – Improves corrosion resistance
– Improves machina"ility. – Introduce pressure tightness.
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. In0lteration
• A part is 0rst pressed and sintered romiron powder which gives CC density.
• Then a replicaFin0ltrant) o copper is
placed over the part.• It is heated in urnace.
• The in0ltrant melts and enters in
porous parts gives (GG density.Advantage It increases strength% hardness
and density.
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C. 1eat Treatment
• Sintered parts are heat treated to improve – ?ear resistance
– 9rain structure
– 1ardness – Strength
• 1eat treatment processess – Stress relieving% ar"urising% ar"onitriding%
3itriding% Through hardening% Inductionhardening%
Precipitation hardening.
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/. Plating
• r Plating * Impart pleasing appearance
• 3i plating * Protect rom corrosion resistance.
• Sn plating * Improves rictional characteristics.
• u and Ag plating * Improves electricalconductivity.
• 3ote@ &eore plating the parts are impregnated
with plastic% so electrolyte is not entrapped inporous structure.
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Efect o ;ensity on ;uctility and Toughness o Be3 P=M alloy
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Efect o ;ensity on Strengtho Be3 P=M alloy
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Advanced Technology in PowderMetallurgy
(. Improvement in or mechanical properties.
a. &y Increasing powder compressi"ility=homogeneity%dust and ha$ard reduction.
–. &etter particle si$e distri"ution.
–. Atomisation no$$le geometry
–. 1ighpressure water atomi$ation
–. 5acuum induction melting% degassing and pouringurnaces to replace the common ones.
–. To enhance the sintered steels homogeneity and toreduce dust% the traditional elemental powdermi'tures are "eing replaced% in spite o their lowestcost.
Advanced Applications or Metal
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Advanced Applications or MetalPowders
Application Metals Uses
A"rasives Be% Sn% >n leaning% a"rasive wheels
Aerospace Al% &e% 3" 8et engines% heat shields
Automotive u% Be% ? 5alve inserts% "ushings% gears
Electrical=electronic Ag% Au% Mo ontacts% diode heat sin4s
1eat treating Mo% Pt% ? Burnace elements%thermocouples
8oining u% Be% Sn Solders% electrodes
Lu"rication u% Be% >n 9reases% a"rada"le seals
Magnetic o% Be% 3i !elays% magnets
Manuacturing u% Mn% ? ;ies% tools% "earings
Medical=dental Ag% Au% ? Implants% amalgams
Metallurgical Al e Si Metal recovery% alloying
3uclear &e% 3i% ? Shielding% 0lters% re6ectors
2Hce e#uipment Al% Be% Ti Electrostatic copiers% cams
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Advanced Technology in PowderMetallurgy
". Improving the die 0lling and lu"ricationprocesses.
• A high 0lling density and uniormity over the
cross section o the die cavity is essential orgood #uality parts o"taining.
• :se o agitating eedshoes or vi"ratory eeders.
• :se organic "inder.
• A good lu"rication during compaction plays ama7or role in o"taining a high and uniormdensity.
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Advanced Technology in PowderMetallurgy
c. Advanced compaction methods
• ?arm compaction up to (GG
allowing ahigher densi0cation at the same appliedpressure.
• 1igh velocity compaction leading to higher
density "y a hydraulically operatedhammer.
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Advanced Technology in PowderMetallurgy
d. 1igh Temperature Sintering• 1igher densi0cation.
• &etter homogeni$ation• Batigue resistance and toughness "eing
improved.
• &ut it leads to the crystal grain growthand higher cost.
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Advanced Technology in PowderMetallurgy
+. E'tending PM capa"ility o comple' partsprocessing.
a. Powder In7ection Molding.
• Powder In7ection Molding FPIM) com"ines the polymer in7ectiontechnology with powder metallurgy. &y in7ection o a powder"inder mi'ture Feedstoc4) in a die cavity% theoretically anyshape can "e reali$ed.
a. Selective Laser Sintering.
• In each layer and "etween two successive layers% a laser"eam% "y a computer controlled se#uential displacement incoordinates% 7oints particles upon a program to reali$e there#uired cross section o the part or that layer. The process isrepeated until the whole part is "uiltJ% layer"ylayer.
A li ti P d
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Applications o PowderMetallurgy
(. Porous products * porous "earings% 0lters
+. Electrical contacts in automo"ile industry
,. ran4shat drive% camshat sproc4et
-. Piston rings% "ra4e liners% connecting rods.. ;oor mechanism.
/. Sintered gears F?ithout much manuacturing)
C. !eractory parts e.a. Tungsten in electric"ul"% 0lament in K ray tu"e% cathode%anode% control grid.
A li ti d
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Applications o powdermetallurgy
D. ?ire drawing dies% wire guides% deep drawing%stamping% "lan4ing tools% roc4 drilling "its Fmadeo tungsten car"ide)
. 3on porous "earings% electric motor "rushes.
(G.Military and deense applications in roc4ets%missiles% cartridge cases% "ullets etc.
((.Atomic energy applications in various uelsystem% control rod systems and radiation
re6ectors.
(+.Parts in cloc4s% timing devices% typewriters%calculators% permanent magnets.
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Powder Metallurgy@
ermet cutting tools
FeramicMetal composite)
www.kyocera-yashica.com.br
www.moldma4ingtechnology.com
www.tool"arn.com
Microstructure@ ceramic particles in metal matri'
ermettipped saw "lade or long lie
ermet cutting inserts or lathe
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www.parmaco.com
Slightly porous appearance
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oee.nrcan.gc.ca
P=M netshape gears are common% save machining time
Metal 0lters
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Powder Metallurgy@Porous Metals
2ilimpregnated Porous &ron$e &earingsnic.sav.sk
www.hd"earing.com
www.ondrives.com
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Borged on let P=M on right
Powder Metallurgy@ onnecting !ods
www.dpsperormance.com
d d l i i 9
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Powdered Metal Transmission 9ear
• ?arm compaction method with (/Gton press• Teeth are molded net shape@ 3o machining• :TS N (%GGG psi• ,G cost savings over the original orged part
www.chipm.com
Powdered Metal Tur"ine "ladedis4 F"lis4J)@ ( pieceO
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Powdered Metal Tur"ine "lade dis4 F "lis4 )@ ( pieceO
www.ml.arl.a.mil
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onventional Borging vs. Borging o Powdered Metal "lan4 F+nd op)
;e9armo
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P=M Tungsten Light"ul" Bilament@GG hrs at +GG°
?ire is creep resistant% note acets on closeup are evaporated ?.
Advantages o Powder
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Advantages o PowderMetallurgy
(. Machining is not re#uired.
+. ;imensional accuracy and surace 0nish.
,. More cleaner and #uieter applications
-. 1igh production rates.
. 3o wastage.
/. omple' shape can "e produced.
C. Longer lie o components.D. E'cellent reproduci"ility.
Advantages o Powder
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Advantages o PowderMetallurgy
. P=M is only method to produce porousproducts.
(G.S4illed wor4er is not re#uired.
((.Impossi"le parts li4e tungsten car"ide can"e produced "y P=M process.
(+.:se o diamond in industry is due to P.M only.
(,.3o need to study phase diagram.
Limitations o Powder
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Limitations o PowderMetallurgy(. 1igh Production ost .
+. 1igh Tooling ost.,. omplicated products can not "e produced.
-. Poor Physical properties.
. Large si$ed products can not "e produced due to
re#uirement o large presses./. E'treme care should "e ta4en in handling pyrophoric
FBire E'plosive) powders li4e Mg% Th% >r
C. To'ic powders li4e :% &e% Th should "e handled
careully.D. 3ot economical or small scale production.
. an not o"tained any speci0c alloy.
(G.;ensity may vary.
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onclusion
• The powder metallurgy product can"e improved – &y improving mechanical and physical
properties li4e ductility% toughness%strength% homogeneity etc.
– &y using modern manuacturingtechni#ues li4e in7ection mounding%Selective Laser Sintering etc.
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ReferencesMaterial Science < Metallurgy "y 2. P.hanna
Material Science < Metallurgy "y ;r. 5. ;.odgire
;e9armo@ E.P. ;e9armo et al% Materials andProcesses in Manufacturing% ?iley% +GG,.
www.parmaco.com
www.kyocera-yashica.com.br
www.moldma4ingtechnology.com
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uestions Please