Austempering
Austempering is an isothermal heat treatment process in which steel or ductile iron is austenitised and then quenched into a salt bath held at a temperature above the martensite start point, where it is held until transformation to bainite is complete. The process produces a bainitic microstructure with an outstanding combination of strength, toughness, and ductility — superior to conventional quench-and-temper treatments at equivalent hardness levels.
Our process advantage
Our controlled isothermal salt bath process ensures uniform transformation throughout the section, delivering consistent bainitic microstructure with significantly reduced distortion and cracking risk compared to conventional oil quenching — particularly beneficial for complex-geometry and thin-section components.
Why choose Austempering?
High toughness
Bainitic structure delivers superior impact resistance vs martensite at same hardness
Reduced distortion
Isothermal quench minimises thermal gradients and dimensional change
Fatigue strength
Excellent for cyclic loading applications like springs and stamped parts
Eliminates tempering
Single-stage treatment — no separate tempering operation needed
Process specifications
| Resulting microstructure | Lower bainite |
| Quench medium | Molten salt bath (isothermal) |
| Applicable materials | Medium/high-carbon steels, Alloy steels, Ductile iron |
Industries served
- Automobile
- Defence
- General Engineering