Invar planning tools
Two checks to run before you write the RFQ. Both use typical handbook values and run in your browser. Nothing is sent. The growth check on the home page answers the simpler question of whether you need Invar at all.
Alloy selector
Enter the temperature range the part lives in, the length that must hold and the tolerance on it. The tool computes the growth of each alloy over that range using a typical mean CTE for the band and tells you which alloys stay inside your tolerance and which have other limits.
| Material | Mean CTE used | Growth | Fits |
|---|
Mean CTE for the band is interpolated from typical handbook curves, see the specs reference. Super Invar is flagged below about −60 °C, Invar 36 and Super Invar above 100 °C. Kovar and Alloy 42 are the only sealing alloys. The mill cert for your heat lot governs.
Stress relief and allowance planner
Enter the finished size, the tightest tolerance and the heat treatment your drawing calls for. The tool suggests a roughing allowance, the stages the shop is likely to quote and a typical furnace plan. It is a planning aid for reading a quote, not a process sheet.
| Stage | What to expect |
|---|
Typical cycles for Invar 36: stress relief 315 to 345 °C for 1 to 2 h. Full cycle: 830 °C anneal, water quench, 315 °C 1 h, 95 °C 24 to 48 h. Kovar sealing parts: wet hydrogen anneal 900 to 1100 °C. The drawing or spec governs. Read the stress relief guide.