Project Description

Incoloy 925 N09925 round bar
Incoloy® 925 (N09925) round bar

Overview

N09925 (Incoloy® 925, UNS N09925) is an age-hardenable nickel-iron-chromium superalloy with controlled additions of molybdenum, copper, titanium, and aluminum. Developed by Special Metals Corporation, it combines the aqueous corrosion resistance of Incoloy 825 with substantially higher mechanical strength achieved through PH (gamma-prime Ni₃(Al,Ti) precipitation). Primary industries served are oil & gas (downhole sour-service), marine engineering, and chemical processing.

Equivalent Grades

Standard Grade / Designation Scope
UNS N09925 Primary designation
ASTM B805 / B637 Wrought products / bar & forgings
AMS AMS 5661 Bar, wire, forgings (aerospace)
W.Nr (EN/DIN) 2.4858 European Werkstoffnummer
JIS NCF 925 Japanese industrial standard
ISO / NACE NACE MR0175 / ISO 15156-3 Sour service qualification (H₂S)
ASME Code Case 2218 Sec. VIII Div. 1 pressure vessels
GB (China) NS2401 / H09925 Chinese national standard

Applications

Oil & Gas (downhole / wellhead): completion tubing, production casing, downhole packers, landing nipples, tool joints, wellhead valve bodies, Christmas tree flanges, flow tees, SSSVs, tubing hangers, mandrels, choke bodies.

Marine: propeller shafts, pump shafts, seawater pump casings, marine fasteners (bolts, studs, nuts), subsea connectors and fittings.

Chemical Processing: heat exchanger tubing, scrubber internals, piping and flanges in H₂SO₄ / H₃PO₄ service, pollution control vessels, springs and fasteners in corrosive environments.

Supply Forms & Sizes

Form Typical Size Range Delivery Condition
Round bar Ø 6 – 500 mm Annealed or annealed + aged
Flat bar T 5 – 80 mm, W up to 300 mm Annealed or aged
Plate / Sheet T 2 – 100 mm Annealed
Seamless tube / pipe OD 6 – 300 mm Annealed or aged
Wire Ø 0.5 – 10 mm Annealed
Forging stock Custom geometry Aged per ASTM B637

Chemical Composition

Per ASTM B805 / UNS N09925  (wt %)

Ni Cr Fe Mo Cu Ti Al C Mn Si Nb
Min 38.0 19.5 22.0 2.5 1.5 1.9 0.1 — — — —
Max 46.0 23.5 bal. 3.5 3.0 2.4 0.5 0.03 1.0 0.5 0.5

Mechanical Properties

Solution anneal: 980–1040 °C / 0.5–4 h → AC (≤25 mm) or WQ (>25 mm)
Age: 732–749 °C / 6–9 h → FC to 621 °C / total 18 h → AC

Condition UTS (MPa) YS 0.2% (MPa) El. (%) RA (%) Hardness CVN −60°C (J)
Solution Annealed (typical) 685 271 56 — 76 HRB —
Annealed + Aged (min, ASTM B637) ≥ 965 724 – 965 ≥ 18 ≥ 25 26 – 38 HRC ≥ 47

Values per ASTM B637 / SMC internal spec HA 46. NACE MR0175 hardness cap: 38 HRC max.