Summary
Thermal contact conductance is required to evaluate heat transfer through the interface of two materials and is dependent on a range of material and interface properties. This article provides a brief summary of these properties and a list of thermal contact conductance for a selection of metal-metal pairs.
Definitions
| : | Thermal contact conductance $(W/m^2.\degree C) |
Introduction
Thermal contact conductance is the thermal conductivity of the interface between two contacting surfaces and is dependent on the surface roughness, material properties, interface temperature and interface pressure.
Thermal contact conductance is typically determined by measuring the heat flux and temperature change across the interface of two materials while simultaneously maintaining a constant load (pressure) on the two materials. However characterisation of the thermal contact conductance in industrial settings can be difficult as when two materials are fastened together by bolts, screws of rivets the pressure profile at the interface is often non-uniform.
Thermal Contact Conductance Data
Below are some values for the thermal contact conductance of a selection of metal-metal pairs.
| Material | Roughness (μm) | Temperature (K) | Pressure (atm) | h₍c₎ (W/m²·°C) |
|---|---|---|---|---|
| Stainless steel 416 – Stainless steel 416 | 2.54 (Ground) | 90–200 | 0.3–2.5 | 3,800 |
| Stainless steel 304 – Stainless steel 304 | 1.14 (Ground) | 20 | 4–7 | 1,900 |
| Aluminium – Aluminium | 2.54 (Ground) | 150 | 1.2–2.5 | 11,400 |
| Copper – Copper | 1.27 (Ground) | 20 | 1.2–20 | 143,000 |
| Copper – Copper | 3.81 (Milled) | 20 | 1–5 | 55,500 |
| Stainless steel – Aluminium | 20–30 | 20 | 10 | 2,900 |
| Stainless steel – Aluminium | 20–30 | 20 | 20 | 3,600 |
| Stainless steel – Aluminium | 1.0–2.0 | 20 | 10 | 16,400 |
| Stainless steel – Aluminium | 1.0–2.0 | 20 | 20 | 20,800 |
| Steel Ct-30 – Aluminium | 1.4–2.0 (Ground) | 20 | 10 | 50,000 |
| Steel Ct-30 – Aluminium | 1.4–2.0 (Ground) | 20 | 15–35 | 59,000 |
| Steel Ct-30 – Aluminium | 4.5–7.2 (Milled) | 20 | 10 | 4,800 |
| Steel Ct-30 – Aluminium | 4.5–7.2 (Milled) | 20 | 30 | 8,300 |
| Aluminium – Copper | 1.3–1.4 (Ground) | 20 | 5 | 42,000 |
| Aluminium – Copper | 1.3–1.4 (Ground) | 20 | 15 | 56,000 |
| Aluminium – Copper | 4.4–4.5 (Milled) | 20 | 10 | 12,000 |
| Aluminium – Copper | 4.4–4.5 (Milled) | 20 | 20–30 | 22,000 |