DuPont™ Vespel® SP-21
Graphite-enhanced grade with low-friction properties
DuPont™ Vespel® SP-21 is graphite-enhanced with low-friction properties for use with or without lubrication in various applications. Vespel® SP-21 has maximum physical strength, elongation, and toughness. Available as custom parts or stock shapes.
DuPont™ Vespel® SP-21 is available as isostatically molded billet and unidirectionally pressed slab specified as Type II, Class 1M and Type II, Class 1P respectively per ASTM 6456-10 / MIL-R-46198. Vespel® SP-21 is specified as Class 2 per AMS 3644G.
STANDARD SIZES
| PLAQUE |
Dimensions:
5 in x 5 in – 10 in x 10 in |
Thickness:
0.062 in – 2 in |
| ROD |
Outside Diameter:
0.125 in – 6 in |
OPTIONS AVAILABLE
| COLOR |
Dark Brown |
Length, width, thickness, and diameter tolerances vary by size, by manufacturer, brand, and grade. Vespel® SP-21 is also available in bar.
Typical Properties OF DuPont™ Vespel® SP-21 Polyimide
| |
ASTM
Method |
Units |
SP-21
15% Graphite |
| Mechanical |
Tensile strength
23°C (73°F) |
D1708 / D638 |
MPa (kpsi) |
65.5
(9.5) |
Tensile strength
260°C (500°F) |
D1708 / D638 |
MPa (kpsi) |
37.9
(5.5) |
Elongation at break
23°C (73°F) |
D1708 / D638 |
% |
4.5 |
Elongation at break
260°C (500°F) |
D1708 / D638 |
% |
3.0 |
Flexural modulus
23°C (73°F) |
D790 |
MPa (kpsi) |
3,790
(550) |
Flexural modulus
260°C (500°F) |
D790 |
MPa (kpsi) |
2,550
(370) |
Compressive stress at
10% strain, 23°C (73°F) |
D695 |
MPa (kpsi) |
133
(19.3) |
Deformation under
13.8 MPa (2,000 psi) load |
D621 |
% |
0.10 |
| Friction |
|
|
|
Coefficient of friction at
PV = .875 MPa m/s
(25,000 psi-ft/min)* |
|
|
0.24 |
Coefficient of friction at
PV = 3.5 MPa m/s
(25,000 psi-ft/min)* |
|
|
0.12 |
Static coefficient
of friction in air* |
|
|
0.30 |
| PV limit (unlubricated)** |
|
MPa-m/s
(kpsi ft/min) |
12.3
(350) |
| Other Properties |
|
|
|
Coefficient of thermal
expansion
23–300°C (73–572°F) |
E831 |
µm/m/K
(10-6 in/in-°F) |
49 (27) |
| Hardness |
D785 |
Rockwell E |
25–45 |
Water absorption
24 hr at 23°C (73°F) |
D570 |
% |
0.19 |
*Versus carbon steel, steady state, unlubricated, in air, thrust bearing. **PV limits for any material vary with different combinations of pressure and velocity as well as other conditions.
Need more information about this material? Use our interactive plastic properties table
The information set forth herein is furnished free of charge, is based on technical data that DuPont believes to be reliable, and represents typical values that fall within the normal range of properties. This information relates only to the specific material designated and may not be valid for such material used in combination with other materials or in other processes. It is intended for use by persons having technical skill, at their own discretion and risk. This information should not be used to establish specification limits nor used alone as the basis of design. Handling precaution information is given with the understanding that those using it will satisfy themselves that their particular conditions of use present no health or safety hazards and comply with applicable law. Since conditions of product use and disposal are outside our control, we make no warranties, express or implied, and assume no liability in connection with any use of this information. As with any product, evaluation under end-use conditions prior to specification is essential. Nothing herein is to be taken as a license to operate or a recommendation to infringe on patents.
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