Braze Joint Clearance: Preserve the Gap at Joining Temperature

Retain the joining condition

Lucas Milhaupt explains that brazing clearance must account for expansion at joining temperature, especially between dissimilar components. Room-temperature clearance alone can leave that condition unresolved. Primary reference: Lucas Milhaupt technical explanation.

Use actual material expansion information for a real assessment. The following comparison expressly assumes constant fictional coefficients and uniform temperature; it gives no recommended clearance or material pairing.

Calculate an invented sleeve gap

Assume sleeve inner diameter 20.10 mm, plug diameter 20.00 mm and temperature rise 500 K. Give them fictional expansion coefficients 16×10⁻⁶/K and 10×10⁻⁶/K respectively. Their modeled hot diameters are 20.2608 mm and 20.1000 mm.

Diametral clearance therefore changes from 0.1000 to 0.1608 mm. Radial clearance is half that value: 0.0804 mm at the modeled hot condition. The two clearance conventions must not share one unlabeled number. No source material example or allowable gap is reproduced.

Keep geometry and evidence connected

Record both diameters, coefficient basis, temperature condition and clearance convention. Preserve whether the surfaces actually share the assumed temperature during joining. A temperature gradient or changing coefficient requires a different analysis.

Ask which hot-condition gap the proposed filler and joint evidence support. This worksheet prevents an apparently consistent assembly dimension from concealing the thermal condition that matters to the actual joining route.

Customer Questions

Primary References

These references support the technical principles discussed in this guide. The worked examples and review questions are educational.

• Primary reference: Lucas Milhaupt technical explanation