sintering1 2 14
TRANSCRIPT
![Page 1: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/1.jpg)
Powder Blending/Mixing Compacting
Sintering
Powder Metallurgy (P/M)
Particulate Processing of Metals and Ceramics
![Page 2: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/2.jpg)
Powder Metallurgy (P/M)
The Characterization of EngineeringPowders
Production of Metallic Powders Conventional Pressing and Sintering Alternative Pressing and Sintering
Techniques Materials and Products for P/M
![Page 3: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/3.jpg)
Powder Metallurgy (P/M) ?Metal processing technology in which parts
are produced from metallic powders• Usual PM production sequence:
Pressing - powders are compressed into desired shapeto produce green compact• Accomplished in press using punch-and-die
tooling designed for the partSintering – green compacts are heated to bond the
particles into a hard, rigid mass• Performed at temperatures below the melting
point of the metal
![Page 4: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/4.jpg)
Why Powder Metallurgy isImportant ?
• P/M parts can be mass produced to netshape or near net shape, eliminating orreducing the need for subsequentmachining
• P/M process wastes very little material - ~97% of starting powders are converted toproduct
• P/M parts can be made with a specifiedlevel of porosity, to produce porous metalparts– Examples: filters, oil‑impregnated bearings and gears
![Page 5: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/5.jpg)
Illustration
![Page 6: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/6.jpg)
Incandescent bulbs
![Page 7: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/7.jpg)
windshield penetrator sabot stabilizing fin propellant
Kinetic Energy PenetratormaterialsTungsten Heavy Alloy (WHA) Typical composition (wt.%): 90W-7Ni-3Fe Liquid Phase sintered 1500°C melting point of binder alloy (Ni-Fe) ~1465°Crequirements• high density• dimensional precision
Kinetic Energy Armour Piercing Penetrator
![Page 8: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/8.jpg)
![Page 9: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/9.jpg)
P/M for Automobiles
![Page 10: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/10.jpg)
P/M Connecting Rods
![Page 11: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/11.jpg)
Gears
![Page 12: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/12.jpg)
Medical Radiation Shielding
Tungsten Heavy Alloy
![Page 13: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/13.jpg)
Cutting tool inserts
Earlier, high speed steel (HSS) which was manufactured by casting route was used for cutting applications. Such steels are called cutting tool steels. However, they cannot be used by cutting at high speeds wherein the temperature can exceed 600°C. For still higher cutting output, hardmetals or cemented carbides [WC-(6-10 wt.%)Co] is used. Such alloys are consolidated by liquid phase sintering.
![Page 14: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/14.jpg)
P/M Work Materials
• Mostly used for bulk ceramic components• Other P/M metals include copper, nickel,
and refractory metals such asmolybdenum and tungsten
• Metallic carbides such as tungsten carbideare often included within the scope ofpowder metallurgy
![Page 15: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/15.jpg)
Engineering Powders
A powder can be defined as a finely dividedparticulate solid
• Engineering powders include metals andceramics
• Geometric features of engineeringpowders:– Particle size and distribution– Particle shape and internal structure– Surface area
![Page 16: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/16.jpg)
Milled Ti Powder
![Page 17: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/17.jpg)
Electrolytic Cu Powder
![Page 18: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/18.jpg)
Screen Mesh
!
PS =1
MC" tw
![Page 19: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/19.jpg)
Particle Shapes in PM
![Page 20: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/20.jpg)
Inter-particle Friction and FlowCharacteristics
Angle of Repose
![Page 21: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/21.jpg)
Inter-particle Friction and FlowCharacteristics
![Page 22: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/22.jpg)
Production of MetallicPowders
• In general, producers of metallic powdersare not the same companies as those thatmake PM parts
• Any metal can be made into powder form• Three principal methods by which metallic
powders are commercially produced1. Atomization2. Chemical3. Electrolytic
• In addition, mechanical methods areoccasionally used to reduce powder sizes
![Page 23: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/23.jpg)
High velocity gas stream flows throughexpansion nozzle, siphoning molten metal frombelow and spraying it into container
Gas Atomization Method
![Page 24: Sintering1 2 14](https://reader034.vdocuments.us/reader034/viewer/2022051503/58a14d6a1a28abbe3c8b494b/html5/thumbnails/24.jpg)
Iron Powders for P/M
50 µm