This specification2 covers hot-finished or cold-finished precipitation hardening iron base superalloy bars, forgings, and forging stock for high-temperature service. The mechanical properties of these alloys are developed by suitable solution treating and precipitation hardening treatments. Two grades of iron base alloy are covered. Selection will depend upon design, service conditions, mechanical properties, and elevated temperature characteristics.
| Grade 660 (UNS S 66286)A | Grade 662 (UNS S 66220)A | |||
|---|---|---|---|---|
| Ladle Analysis Range, % | Check Analysis Over or Under | Ladle Analysis Range, % | Check Analysis Over or Under | |
| Carbon | 0.08 max | 0.01 over | 0.08 max | 0.01 over |
| Manganese | 2.00 max | 0.04 over | 1.50 max | 0.04 |
| Silicon | 1.00 max | 0.05 over | 1.00 max | 0.05 |
| Phosphorus | 0.040 max | 0.005 over | 0.040 max | 0.005 over |
| Phosphorus | 0.030 max | 0.005 over | 0.030 max | 0.005 over |
| Chromium | 13.50–16.00 | 0.20 | 12.00–15.00 | 0.15 |
| Nickel | 24.00–27.00 | 0.20 | 24.00–28.00 | 0.20 |
| Molybdenum | 1.00–1.50 | 0.05 | 2.50–3.50 | 0.10 |
| Titanium | 1.90–2.35 | 0.05 | 1.55–2.00 | 0.05 |
| Copper | ... | ... | 0.50 max | 0.03 over |
| Aluminum | 0.35 max | 0.05 over | 0.35 max | 0.05 over |
| Vanadium | 0.10–0.50 | 0.03 | ... | ... |
| Boron | 0.0010–0.010 | 0.0004 under 0.001 over |
0.0010–0.010 | 0.0004 under 0.001 over |
A New designation established in accordance with Practice E527 and SAE J 1086.
| Grade 660 | Grade 662 (bars) | Grade 662 (forgings)A | |
|---|---|---|---|
| Heat treatmentB | solution + precipitation harden | solution + precipitation harden | solution + precipitation harden |
| Tensile strength, min: psi [MPa] | 130 000 [895] | 130 000 [895] | 125 000 [860] |
| Yield strength (0.2 % offset), min: psi [MPa] | 85 000 [585] | 85 000 [585] | 80 000 [550] |
| Elongation in 4D min, % | 15 | 15 | 15 |
| Reduction of area min, % | 18 | 18 | 18 |
| Brinell hardness | 248 min | 248 min | 248 min |
A The elongation of tensile specimens machined tangentially from near the center of large disk forgings over 50 in.2 [320 cm2 ] in cross section may be as low as 10 %. The reduction of area may be as low as 12 %.
| Grade | Solution Treatment | Precipitation Hardening Treatment A |
|---|---|---|
| 660 | Type 1 1650 ± 25°F [900 ± 15°C], hold 2 hr, oil or water quench | 1300 to 1400°F [705 to 760°C], hold 16 h, air cool or furnace cool |
| 660 | Type 2 1800 ± 25°F [980 ± 15°C], hold 1 h, oil or water quench | 1300 to 1400°F [705 to 760°C], hold 16 h, air cool or furnace cool |
| 662 | 1750 to 1900°F [955 to 1040°C] hold 1 h, min, oil or water quench | 1250 to 1400°F [675 to 760°C], hold 5 h, min, slow cooling in 5 h, min to 1200 ± 15°F [650 ± 10°C], hold 20 h, min, air cool or furnace cool |
A Times refer to the minimum time material is required to be at temperature.