Heat-treatment Furnace / Induction Hardener

Selection criteria

Temperature uniformity, atmosphere / carbon potential, quench control.

Supply chain

Heat-treatment furnaces come from European specialists (Ipsen, Aichelin) and many Chinese furnace makers; small parts are often sent to commercial heat treaters. Ask for temperature-uniformity surveys and atmosphere / carbon-potential control records.

Buyer FAQ

What temperature uniformity should I require from a furnace?

For quench-and-temper of shafts and gears, ±10 °C across the working zone is a common requirement; precision work uses AMS 2750 Class 2–3 (±6 to ±8 °C). Ask for a recent temperature uniformity survey (TUS) and system accuracy tests (SAT). For automotive supply chains, a CQI-9 assessment is the usual benchmark.

Through-hardening or induction hardening for motor shafts?

Most motor shafts in C45 or 40Cr steel are quenched and tempered to roughly 220–280 HB for strength and machinability. Bearing seats, splines or keyways that wear can then be induction-hardened locally to 50–58 HRC with a 1–3 mm case. Induction hardening is fast, localised and causes less distortion than full hardening.

How do I control distortion and cracking after heat treatment?

Control quench media temperature, agitation and polymer concentration, and load long shafts vertically. Check shaft runout after hardening, typically 0.05 mm or less before grinding, with straightening as needed. Inspect critical parts for quench cracks by magnetic particle testing and check for decarburisation on metallographic samples.

Where it is used