Nickel Alloy 925
INCOLOY alloy 925 is used in various applications requiring a combination of high strength and corrosion resistance. Because of the alloy’s resistance to sulfide stress cracking and stress-corrosion cracking in “sour” (H2S containing) crude oil and natural gas, it is used for down-hole and surface gas well components including tubular products, valves, hangers, landing nipples, tool joints and packers. The alloy is also useful for fasteners, marine and pump shafting and high-strength piping systems.
| Weight% | Ni | Cr | Fe | Mo | Cu | Ti | Al | Mn | Si | Nb | C | S |
| Alloy 925 | 42 – 46 | 19.55 – 22.5 | 22 min | 2.5 – 3.5 | 1.5 – 3.0 | 1.9 – 2.4 | 0.1 – 0.5 | 1.0 max | 0.5 max | 0.5 max | 0.03 max | 0.03 max |
Heat Treatment
Solution annealing in preparation for age hardening should be done at 1800-1900°F (980-1040°C) for a minimum of 30 min and a maximum of 4 h. Cool at a rate equivalent to air cooling, or faster, for sizes of 1 in (25 mm) or under. Water quench all sizes over 1 in (25 mm). The following age-hardening treatment is normally used: 1350-1380°F (732-749°C)/6-9 h, FC to 1150°F (621°C), hold at 1150°F (621°C) ± 15°F (8°C) for a total aging time of 18 h. Cool at a rate equivalent to air cooling, or faster.
INCOLOY alloy 925 is designated as UNS N09925. Designations and specifications for the product include NACE MR-01-75, ASME Boiler and Pressure Vessel Code Case 2218 Section VIII Division 1, and Special Metals Corporation internal specification HA 46. Alloy 925 is available as tube, round bar, flat bar and forging stock.
