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.

Specification Test Value Units
Specific Gravity, 73°F D792 .93 -
Tensile Strength @ Yield, 73°F D638 3050 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 80  
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/ft2°F)
Dielectric Strength Short Term D149   Volts/mil
Volume Resistivity D257 1017 ohm/cm
Surface Resistivity D257 1017 ohm/cm
Dielectric Constant, 106 Hz D150    
Dissipation Factor, 106 Hz D150    
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) 1 .50-10 inches
Sheet Thickness Availability (Off the Shelf) .25 .25-3.0 inches
Characteristics / Attributes Excellent Abrasion and Impact Resistance, Low Cost