Heat Resistant Alloys
NAS 660
- JISSUH 660
- UNSS66286
- DIN/ENー
A-286 Alloy
A precipitation hardening stainless steel, NAS 660 (SUH 660, UNS S66286) maintains superior strength at high temperatures up to 700℃, surpassing austenitic stainless steels. With a higher nickel content than Type 304, NAS 660 also includes such elements as titanium and aluminum for hardening. Age hardening is used to precipitate γ' phase [Ni3 (Al, Ti)] making this an extraordinarily strong metal at high temperatures. Nippon Yakin supplies this product in plate, sheet, and strip forms.
| Chemical Composition | 25Ni-15Cr-1Mo-2Ti-0.3V-0.2Al |
|---|---|
| Product shape |
 Coil Sheet Plate |
Weldability | Spot, TIG, MIG and shield metal arc welding can be used on thin NAS 660 sheets under similar conditions to austenitic stainless steels. |
| Heat Treatment | NAS 660 is a precipitation hardening alloy. Its strength is increased through aging after solution heat treatment. Two stages of heat treatment are generally carried out, as follows: ・Solution heat treatment: 980℃; oil or water cooling ・Age hardening: 720℃ × 16hr; air cooling After solution heat treatment, either oil or water cooling is required, though air cooling is better for thinner metal. Note that it is important to use a suitable temperature and holding time for aging to obtain the target strength. |
| Machinability | Compared to standard austenitic stainless steels, NAS 660 has somewhat superior machining properties. Although a high-speed steel tool can be used, we recommend the use of a sintered carbide tool, and suggest combining a slower feed rate with a greater cutting depth. |
| Applications | NAS 660 is an excellent choice when high-temperature strength is required such as jet engines, gas turbines and turbo charger components. |