Convert Square millimetres per hour to Square millimetres per second
Convert Square millimetres per hour (mm²/h) to Square millimetres per second (mm²/s) instantly and accurately.
Conversion Formula
mm²/s = mm²/h × 0.0002777777778
About Square millimetres per hour
The square millimetre per hour (mm²/h) equals 1/3 600 000 000 m²/s, the smallest practical thermal diffusivity unit. It is used in very slow heat-transfer processes such as diffusion through frozen soils or phase-change materials studied over many hours. Heavy clay soils can show diffusivity values of 1-2 mm²/h. 1 mm²/h = 1e-6/3600 m²/s.
About Square millimetres per second
The square millimetre per second (mm²/s) equals 1 × 10⁻⁶ m²/s and is the standard unit in materials engineering and the laser-flash diffusivity method (ASTM E1461, ISO 22007-4). Metals span roughly 2-180 mm²/s; polymers 0.07-0.2 mm²/s; ceramics 0.3-10 mm²/s. Numerically identical to the kinematic viscosity unit (cSt) in SI context. 1 mm²/s = 1 × 10⁻⁶ m²/s.
Quick Reference Table
| Square millimetres per hour (mm²/h) | Square millimetres per second (mm²/s) |
|---|---|
| 1 mm²/h | 0.000277778 mm²/s |
| 2 mm²/h | 0.000555556 mm²/s |
| 5 mm²/h | 0.00138889 mm²/s |
| 10 mm²/h | 0.00277778 mm²/s |
| 25 mm²/h | 0.00694444 mm²/s |
| 50 mm²/h | 0.0138889 mm²/s |
| 100 mm²/h | 0.0277778 mm²/s |