Oee.nrcan.gc.ca P/M net-shape gears are common, save machining time Powder Metallurgy (P/M) Method:...
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oee.nrcan.gc.ca P/M net-shape gears are common, save machinin owder Metallurgy (P/M) thod: Make fine metal powders and sort Mix powders to get “alloy” • Iron alloys most common, also Bronze Compaction • Powder is pressed into a “green compact” • 20,000-100,000psi pressure • Still very porous, ~70% density • May be done cold or warm (higher density) Sintering • Controlled atmosphere: no oxygen • Heat to .75*Tmelt • Particles bind together • Part shrinks in size • Density increases, up to 95% • Strength ~=~ Density M (vs. Casting): Mass produce small steel parts, net-shape Less waste Unusual “alloys” Range of densities, porosity (adv or disadv) Less energy use But: Smaller parts and less complexity (2.5D)
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Transcript of Oee.nrcan.gc.ca P/M net-shape gears are common, save machining time Powder Metallurgy (P/M) Method:...
oee.nrcan.gc.ca
P/M net-shape gears are common, save machining time
Powder Metallurgy (P/M)
Method:• Make fine metal powders and sort• Mix powders to get “alloy”
• Iron alloys most common, also Bronze• Compaction
• Powder is pressed into a “green compact”• 20,000-100,000psi pressure• Still very porous, ~70% density• May be done cold or warm (higher density)
• Sintering• Controlled atmosphere: no oxygen• Heat to .75*Tmelt• Particles bind together• Part shrinks in size • Density increases, up to 95%• Strength ~=~ Density
P/M (vs. Casting):• Mass produce small steel parts, net-shape• Less waste• Unusual “alloys”• Range of densities, porosity (adv or disadv)• Less energy use• But: Smaller parts and less complexity (2.5D)
Powder Metallurgy
www.parmaco.com www.buau.com.au
Slightly porous appearance is common
Range of particle sizes
Powder Metallurgy: Cermet cutting tools(Ceramic-Metal composite)
www.kyocera-yashica.com.br
www.moldmakingtechnology.com
www.toolbarn.com
Microstructure: ceramic particles in metal matrixCermet-tipped saw blade for long life
Cermet cutting inserts for lathe
Powder Metallurgy: Porous Metals
Oil-impregnated Porous Bronze Bearingsnic.sav.sk
www.hd-bearing.com
www.ondrives.com
Metal filters
Forged on left; P/M on right
Powder Metallurgy: Connecting Rods
www.dps-performance.com
Powdered Metal Transmission Gear
• Warm compaction method with 1650-ton press• Teeth are molded net shape: No machining• UTS = 155,000 psi• 30% cost savings over the original forged part
www.chipm.com
Powdered Metal Turbine blade-disk (“blisk”): 1 piece!
www.ml.afrl.af.mil
Conventional Forging vs. Forging of Powdered Metal blank (2nd op)
DeGarmo
References
DeGarmo: E.P. DeGarmo et al, Materials and Processes in Manufacturing, Wiley, 2003.
