Thermal Conductivity of Type 304 Stainless Steel
| Value | 16.2 W/(m·K) |
| Status | Measured: ± 1 W/(m·K) (0.062 relative) |
| Source | ASM Handbook, Vol. 1: Properties and Selection — Irons and Steels |
| Categories | Material PropertiesEngineering & Trade |
| milliwatt per meter-kelvin | 16,200 mW/(m·K) |
| BTU inch per hour square foot Fahrenheit | 112.32224 BTU·in/(h·ft²·°F) |
| watt per meter-kelvin | 16.2 W/(m·K) |
| watt per meter-Celsius | 16.2 W/(m·°C) |
| kilocalorie per hour meter Celsius | 13.938815 kcal/(h·m·°C) |
| BTU per hour-foot-Fahrenheit | 9.3601869 BTU/(h·ft·°F) |
| watt per centimeter-kelvin | 0.162 W/(cm·K) |
| calorie per second centimeter Celsius | 0.038718929 cal/(s·cm·°C) |
| kilowatt per meter-kelvin | 0.0162 kW/(m·K) |
Learning zone
The 18 % chromium and 8 % nickel that make 304 corrosion-resistant also make it a poor conductor: 16 W/(m·K) against 50 for carbon steel and 401 for copper. Unusually among metals, stainless conductivity rises with temperature, reaching about 21 W/(m·K) at 500 °C.
This is a design driver, not a footnote. Stainless heat-exchanger plates and tubes are made thin (0.4–0.6 mm in plate exchangers) precisely to keep the wall resistance small. It is also why stainless cookware needs an aluminium or copper core to avoid hot spots, why stainless welds distort so readily — heat piles up at the arc instead of spreading — and why a stainless vacuum flask outperforms a steel one. Combine the low conductivity with a thermal expansion coefficient 50 % higher than carbon steel and you get the classic stainless problem: steep local temperature gradients producing large thermal stresses, the root of many cracked pipe attachments and failed dissimilar-metal joints.