Incoloy® 925 (UNS N09925)
Age-hardened 825: an iron-nickel alloy with 140 ksi strength, sour-gas and chloride resistance and NACE approval — the economical downhole and wellhead fastener alloy.
What Incoloy 925 is.
Incoloy 925 is the age-hardenable version of Incoloy 825. It keeps 825's nickel-iron-chromium base with molybdenum and copper, which resist sulfide stress cracking, chlorides and reducing acids, and adds titanium and aluminium for gamma-prime hardening to 140 ksi. It is NACE listed for sour service at up to 38 HRC and costs less than the nickel-base 718 and 725, so it is widely used for tubing hangers, packers, valve stems and wellhead bolting.
We machine 925 studs, bolts, nuts and components from certified B637 bar, aged and hardness controlled to the NACE limit, with PMI on every lot.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | — | 0.03 |
| Manganese | Mn | — | 1.0 |
| Silicon | Si | — | 0.5 |
| Phosphorus | P | — | 0.03 |
| Sulfur | S | — | 0.03 |
| Chromium | Cr | 19.5 | 22.5 |
| Molybdenum | Mo | 2.5 | 3.5 |
| Niobium | Nb | — | 0.5 |
| Titanium | Ti | 1.9 | 2.40 |
| Aluminium | Al | 0.1 | 0.5 |
| Copper | Cu | 1.5 | 3.0 |
| Nickel | Ni | 42.0 | 46.0 |
| Iron | Fe | 22.0 | — |
Values per ASTM B637-16 Tables 1 and 3 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Mechanical properties.
| Condition and nominal diameter (in.) | Tensile strength, min (ksi) | Yield strength 0.2% offset, min (ksi) | Elongation, min (%) | Reduction of area, min (%) | Hardness |
|---|---|---|---|---|---|
| Cold worked, solution annealed and aged — ⅝ to 3 in. | 140 | 105 | 18 | 25 | 38 HRC max |
| Hot worked, solution annealed and aged — 1 in. and over | 140 | 110 | 18 | 25 | 38 HRC max |
Values per ASTM B637-16 Tables 1 and 3 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Specifications that apply.
How Incoloy 925 ships from Houston.
- Studs and stud bolts
- Hex and heavy hex bolts
- Nuts and washers
- Socket head cap screws
- Machined components from certified bar
Incoloy 925 fasteners we make.
Every item is manufactured to your drawing or standard in Incoloy 925, imperial or metric, with an EN 10204 3.1 certificate.
What is Incoloy 925?
925 is what 825 becomes when it is given something to harden with. Titanium and aluminium precipitate as gamma prime on ageing and roughly double the yield strength, while the base chemistry keeps the resistance to hydrogen sulfide, chlorides and sulfuric and phosphoric acids that made 825 a sour-service standard. With more iron and less nickel than 718 or 725 it is the lower-cost member of the age-hardened sour-service family, and it is stocked in the sizes wellhead and downhole hardware need.
Testing, certification and marking
- Tensile and hardness tested per heat-treat lot
- Grade or alloy symbol and manufacturer's identification on every piece
- EN 10204 3.1 material test report with heat number and chemistry; 3.2 witness available
- PMI verification standard on nickel alloys
Incoloy® 825 (UNS N08825)
The acid and sour-gas alloy: nickel-iron-chromium with molybdenum and copper for sulfuric and phosphoric acid, chlorides and hydrogen sulfide — for chemical plant, pollution control and oilfield fasteners.
ASTM B637Inconel® 725 (UNS N07725)
Age-hardened 625: the corrosion resistance of Inconel 625 with 150 ksi strength, NACE listed for sour service — the subsea and downhole fastener alloy.
ASTM B637 bar · AMS 5662 / 5663 · API 6A CRAInconel 718 (UNS N07718)
The premier high-strength nickel superalloy — 185 ksi tensile and 150 ksi yield from cryogenic temperatures to 1200 °F, with corrosion and sour-gas resistance to match.