UHMW (Ultra High Molecular Weight Polyethylene)
UHMW is an acromym for Ultra High Molecular Weight Polyethylene. Most commonly reffered to as UHMW. It is famous for its abrasive resistance, toughness, and low cost. It is also FDA and NSF compliant. It’s natural color is white, but is available in black and other colors at special request. Typical applications include sleeve and flanged bearings for high wear industrial and manufacturing bearing applications. Custom and standard profiles exist for conveying environments. UHMW is easily machined into custom components. Though it is easily machined with standard metal working equipment, UHMW has a very high coefficient of thermal expansion making it difficult to hold close tolerance dimensions. Its main attributes are impact and abrasion resistance. Its self-lubrication properties and low cost makes UHMW a great choice for many demanding bearing and wear applications.
UHMW is available in many filled varieties, including glass, oil, MS02, thereby enhancing its bearing and wear properties to extreme levels.
Specification | Test | Value | Units |
Density, 73°F | D792 | .93 | gm/cm^{3} |
Tensile Strength @ Yield, 73°F | D638 | 5800 | psi |
Tensile Modulus of Elasticity, 73°F | D638 | 120,000 | psi |
Tensile Elongation (at break), 73°F | D638 | 200 | % |
Flexural Strength, 73°F | D790 | psi | |
Flexural Modulus of Elasticity | D790 | 110,000 | psi |
Shear Strength, 73°F | D732 | psi | |
Compressive Strength – Ultimate | 750 | psi | |
Compressive Strength at 2% Deformation | D695 | psi | |
Compressive Strength at 10% Deformation | D695 | 1,000 | psi |
Deformation Under Load | % | ||
Compressive Modulus of Elasticity, 73°F | D695 | ||
Compressive Strength ⊥ to Laminate (Modulus) | 750 | psi | |
Compressive Strength ⊥ to Laminate (Yield) | 750 | psi | |
Compressive Strength ⊥ to Laminate (Ultimate) | 750 | psi | |
Hardness, Durometer (Shore “D” scale) | D2240 | 68 | |
Hardness, Rockwell (Scale as noted) | D785 | Rockwell M | |
Izod Impact, Notched @ 73°F | D256 Type A | No Break | ft.lbs/in. of notch |
Coefficient of Friction (Dry vs Steel) Static | PTM55007 | .15-.20 | |
Coefficient of Friction (Dry vs Steel) Dynamic | PTM55007 | .10-.14 | |
Maximum Static Bearing Load (P) | PTM55007 | 750 | psi |
Maximum Unlubricated No Load Bearing Velocity (V) | PTM55007 | 15 | ft/minute |
Maximum Limiting PV (Unlubricated) | PTM55007 | 750 | psi x ft/min. |
Wear Factor “K” x 10^{-10} | PTM55010 | Cubic in.-min/ft.lbs.hr | |
Sand Wheel Wear/Abrasion Test | 100 | UHMW=100 | |
Minimum Mating Surface Hardness | 20 | Rockwell (Brinnell) | |
Coefficient of Linear Thermal Expansion | E-831(TMA) | 11 | in/in/°F x 10^{-5} |
Coefficient of Thermal Expansion // to Laminates | E-831(TMA) | 11 | in/in/°F x 10^{-5} |
Coefficient of Thermal Expansion I to Laminates | E-831(TMA) | 11 | in/in/°F x 10^{-5} |
Softening Point | 180 | °F | |
Heat Deflection Temperature 264 psi | D648 | °F | |
Embrittlement Temperature | °F Min. | ||
Continuous Service Temperature in Air | 180 | °F Max. | |
Short Term Service Temperature | 200 | °F Max. | |
Tg-Glass Transition (Amorphous) | D3418 | °F | |
Melting Point (Crystalline) Peak | D3418 | °F | |
Thermal Conductivity | F433 | BTU-in/(hr/ft^{2}°F) | |
Dielectric Strength Short Term | D149 | Volts/mil | |
Volume Resistivity | D257 | ohm/cm | |
Surface Resistivity | D257 | ohm/cm | |
Dielectric Constant, 106 Hz | D150 | 2.3-2.35 | |
Dissipation Factor, 106 Hz | D150 | <.5 x10^{-3} | |
Flammability @ 3.1mm(1/8 in.) UL94 | UL94 | HB | |
Arc Resistance | seconds | ||
Water Absorption, Immersion 24 Hours | D570 (2) | Nil | % |
Water Absorption, Immersion Saturation | D570 (2) | Nil | % |
Machinability Rating | 3 | 1=easy, 10=difficult | |
Rod Diameter Availability (Off the Shelf) | .50 | 10 | inches |
Sheet Thickness Availability (Off the Shelf) | .125 | 3.5 | inches |
Characteristics / Attributes | Excellent Abrasion and Impact Resistance, Easily Machined, Low Cost |