Thermal expansion & shrink-fit calculator
The tool computes linear thermal expansion and the shrink-fit heating temperature using the expansion coefficient of the selected material (editable by grade/temperature).
How to use
- Enter the calculation conditions
Enter the dimensions, loads, speeds or operating conditions requested by the form.
- Run the calculation
The tool applies the formulas shown on this page to the entered values.
- Review the result
Review the resulting specification and checks, then verify them against the cited source, current standard and real operating conditions before use.
Core formula
ΔL = α·L·ΔT; shrink fit: ΔT = (δ + c)/(α·D), T_heat = T₀ + ΔT
Example using default values
steel α=12×10⁻⁶, L=1000, ΔT=60 → ΔL = 0.72 mm
Source: Materials handbooks (Machinery's Handbook / MatWeb); Shigley's Mechanical Engineering Design — shrink fitting.
Frequently asked questions
Where does the expansion coefficient α come from?
α is a materials-handbook value around 20 °C (steel ~12, stainless ~17, aluminum ~23, brass ~19, cast iron ~10.5, ×10⁻⁶/°C). Actual α varies with grade and temperature range, so the field is editable.
How hot is safe for shrink fitting?
Heat only the outer part and keep below the steel's tempering temperature (typically ≤ 200–250 °C) to avoid softening; keep aluminum lower. Fit quickly, then let it cool naturally.
Does blocked expansion create stress?
Yes. If both ends are clamped, blocked expansion creates thermal stress σ = α·E·ΔT; and the interference after cooling creates stress per thick-cylinder theory — both must be checked separately.
MINATA — minatavn.com