The following table shows a selection of frequently used values of the coefficients for static friction µ0 (static coefficient) and sliding friction µ (also called friction values).
| static coefficient µ0 dry | lubricated | kinetic friction µ dry | lubricated | |
|---|---|---|---|---|
| Aluminium alloy- Aluminium alloy | 0,15…0,60 | |||
| Brake lining-Steel | 0,50…0,60 | 0,20…0,50 | ||
| Chrome-Chrome | 0,41 | |||
| Copper-Copper | 0,60…0,70 | |||
| Iron-Iron | 1,0 | |||
| Leather sealing-Metal | 0,60 | 0,20 | 0,20…0,25 | 0,12 |
| Nickel-Nickel | 0,39…0,70 | |||
| POM-H -- PA6.6 | 0,5 | |||
| POM-H slide modified -- PA6.6 slide modified | 0,14 | |||
| POM-H -- PE-HD | 0,3 | |||
| POM-H -- PE-HD slide modified | 0,15 | |||
| S235JR-S235JR polished | 0,15 | |||
| Steel-Copper | 0,23…0,29 | |||
| Steel-Gray cast iron | 0,18…0,24 | 0,10 | 0,17…0,24 | 0,02…0,21 |
| Steel-Ice | 0,027 | 0,014 | ||
| Steel-Lead | 0,50 | |||
| Steel-PA | 0,32…0,45 | 0,10 | ||
| Steel-PTFE | 0,04…0,22 | |||
| Steel-“S”green | ~0,20 | |||
| Steel-Steel | 0,45…0,80 | 0,10 | 0,40…0,70 | 0,10 |
| Steel-Tin | 0,60 | |||
| Steel-White metal | 0,21 | |||
| Wood-Metal | 0,50…0,65 | 0,10 | 0,20…0,50 | 0,02…0,10 |
| Wood-Wood | 0,40…0,65 | 0,16…0,20 | 0,20…0,40 | 0,04…0,16 |
Explanations of the material names
PA: Polyamid
PE: Polyethylen
POM: Polyoxymethylen
PTFE: Polytetrafluoräthylen or Polytetrafluorethylen
S235JR: Material number 1.0038
“S” green: PE-based plastic, also known as Murtfeldt “S” green, standard material for sliding guides
White metal: Alloys of lead and tin
Here are some engineering mechanics exercises regarding friction.
