Friction coefficients
| Material 1 | Material 2 | Static dry | Static lubricated | Dynamic dry | Dynamic lubricated |
|---|---|---|---|---|---|
| Steel | Steel | 0.5 | 0.1 | 0.4 | 0,1-0,05 |
| Steel | Cast iron | 0.2 | 0.1 | 0.18 | 0,1-0,05 |
| Steel | Cu-Sn alloy | 0.2 | 0.1 | 0.1 | 0,06-0,03 |
| Steel | Pb-Sn alloy | 0.15 | 0.1 | 0.1 | 0,05-0,03 |
| Steel | Polyamide | 0.3 | 0.15 | 0.3 | 0,12-0,03 |
| Steel | PTFE | 0.04 | 0.04 | 0.04 | 0.04 |
| Steel | friction lining | 0.6 | 0.3 | 0.55 | 0,3-0,2 |
| Steel | Wood | 0.55 | 0.1 | 0.35 | 0.05 |
| Wood | Wood | 0.5 | 0.2 | 0.3 | 0.1 |
| Cast iron | Cu-Sn alloy | 0.25 | 0.16 | 0.2 | 0.1 |
| Rubber | Cast iron | 0.5 | 0.45 | ||
| Rolling element | Steel | 0,003-0,001 | |||
| Aluminum | Aluminum | 1,05-1,35 | 0.3 | 1.4 | |
| Aluminum | Mild steel | 0.61 | 0.47 | ||
| Brass | Cast iron | 0.3 | |||
| Bronze | Cast iron | 0.22 | |||
| Cast iron | Cast iron | 1.1 | 0.15 | 0.07 | |
| Copper | Stainless steel (304) | 0.23 | 0.21 | ||
| Glass | Glass | 0,9-1 | 0,1-0,6 | 0.4 | 0,09-0,12 |
| Glass | Metal | 0,5-0,7 | 0,2-0,3 | ||
| Graphite | Graphite | 0.1 | 0.1 | ||
| Graphite | Steel | 0.1 | 0.1 | ||
| Nylon | Nylon | 0,15-0,25 | |||
| Polystyrene | Polystyrene | 0.5 | 0.5 | ||
| Polystyrene | Steel | 0,3-0,35 | 0,3-0,35 | ||
| Steel | Brass | 0.35 | 0.19 | ||
| Mild steel | Brass | 0.51 | 0.44 | ||
| Mild steel | Cast iron | 0.18 | 0.23 | 0.13 | |
| Teflon | Steel | 0.04 | 0.04 | 0.04 | |
| Titanium Alloy | Aluminium Alloy | 0.41 | 0.38 | ||
| Titanium Alloy | Titanium Alloy | 0.36 | 0.3 | ||
| Titanium Alloy | Bronze | 0.36 | 0.27 |
The friction coefficient depend on several factors: contact pressure, surface roughness, temperature, sliding velocity, type of lubricant and level of contamination.
Static coefficients of friction are higher than the dynamic or kinetic values.