Materials / Related reference
Read the interval before using the coefficient.
A coefficient is tied to a material and a temperature range. Linear and volumetric expansion are different quantities.
A source-scoped reference example
| Source product | Linear coefficient | Interval | Evidence boundary |
|---|---|---|---|
| Kaiser 6061 rod and bar | 23.6 µm/m/K 13.1 µin/in/°F as published | 20–100 °C 68–212 °F | Typical physical-property row; temper and test method not separately specified for this coefficient. Confirm applicability to the actual product. |
This single documented example replaces the former generic material table. It does not establish values for every aluminum product, steel, polymer or low-expansion glass.
Read the 6061 identity and condition scope →Use this source example in the length calculator →
Carries the published coefficient, full temperature interval and source. Enter your original length; confirm product applicability separately.
Convert the coefficient in the correct direction
One kelvin of temperature difference equals one degree Celsius; one degree Fahrenheit of difference equals 5/9 K. Therefore α per °F = α per K × 5/9, and α per K = α per °F × 9/5. The length ratios µm/m and µin/in both mean parts per million.
For the same underlying coefficient, 23.6 × 5/9 = 13.111…; the producer rounds its imperial value to 13.1. Keep the original precision visible.
Read the type of expansion data
A mean coefficient covers a stated interval. An instantaneous coefficient applies locally at a temperature; a curve of relative length change has its own reference length. NIST’s historical 6061-T6 cryogenic curve is referenced to 293 K and covers 4–300 K. It must not be treated as a constant 20–100 °C coefficient.
Use geometry to determine what changes
For freely expanding coaxial parts, diametral clearance is expanded hole diameter minus expanded shaft diameter. A hole generally grows with its freely heated body. The direction of a clearance change depends on both components and temperatures. Joint preload requires restraint, stiffness and thermal conditions; this coefficient table does not predict its direction.
Sources and scope
Reviewed 23 October 2026. Process explanations and public standard summaries do not establish a treatment recipe or certify a supplied part.
Kaiser Aluminum 6061 Rod and Bar — page 2, typical physical properties
KA-RBH-6061-8.10, page 2, typical physical properties: 23.6 µm/m/K over 20–100 °C. The coefficient row does not separately specify temper or test method. This is a typical source example, not a batch guarantee or a value for every 6061 product.
Open source ↗NIST — Engineering Metrology Toolbox FAQ
Temperature effects and the need for material-appropriate expansion data in dimensional measurement.
Open source ↗NIST — Aluminum 6061-T6 cryogenic data
Historical dataset, no longer updated. The linear-expansion model covers 4–300 K and is referenced to length at 293 K; it is not a constant coefficient for elevated temperatures.
Open source ↗