When designing a mechanical component, mechanical strength is not the only parameter to consider. The thermal conductivity of steel plays a decisive role, especially for components that operate at high temperatures or under heavy friction (as in automotive or hydraulic applications).
Understanding how heat travels through the metal is essential to avoid distortion, overheating and premature failure.
What is thermal conductivity?
Put simply, it is a material’s ability to transfer heat. It is measured in watts per metre-kelvin (W/m·K). A high value means the material dissipates heat quickly; a low value means it tends to retain it (insulating).
Carbon steel vs stainless steel: the differences
Not all steels behave the same way:
Carbon steels: generally have higher thermal conductivity (around 50 W/m·K). They are ideal where heat must be dissipated quickly to avoid “hot spots” that could weaken the structure.
Stainless steels (e.g. AISI 304/316): have much lower thermal conductivity (around 15 W/m·K). This makes them excellent for corrosion resistance, but calls for care during machining, because the heat generated by the tool tends to stay in the part and can affect its tolerances.
Impact on machining
Conductivity also has a direct effect on the production process. During milling or turning, a material with low conductivity (such as stainless steel) requires specific cutting parameters and plenty of coolant to protect tool life and surface quality.
How to choose the right material
The choice depends on the final application:
- Heat exchangers or brakes: require high conductivity.
- Structural components in corrosive environments: stainless steel takes priority, with heat management addressed at the design stage.
At T.M.G., we help our customers select the most suitable material, balancing mechanical, thermal and cost requirements for every project.