Project Description

Introduction

N09935 nickel alloy round bar
N09935 Nickel Alloy Round Bar

UNS N09935 (trade name: AF935) is a precipitation-hardenable nickel-iron-chromium-molybdenum CRA superalloy. It is a higher-molybdenum, niobium-bearing derivative of Alloy 925 (N09925), specifically engineered for HPHT sour-service downhole environments containing H₂S, CO₂, and chlorides. Age hardening delivers a minimum yield strength of 110 ksi (758 MPa). The alloy is fully qualified to NACE MR0175 / ISO 15156 for resistance to SSC and SCC. Primary industries: oil & gas production, chemical processing, and marine/offshore engineering.

Similar Grades

Alloy UNS Key Standards Note
Alloy 925 N09925 ASTM B805; API 6ACRA; ISO 13680 Direct precursor; lower Mo, no Nb
Alloy 718 N07718 ASTM B637; ASTM B670; W.Nr. 2.4668 Higher strength; Nb–Ti hardened
Alloy 725 N07725 ASTM B637; ASTM B805 625-base; high Mo + Nb; comparable YS
Alloy 716 N07716 ASTM B805; API 6ACRA Sour-service PH alloy; slightly lower Ni

No direct equivalent exists in EN/DIN, JIS, or GOST. Proprietary designation: AF935 (ATI Specialty Alloys & Components).

Applications

Oil & Gas Downhole: Production tubing, wellhead components, tubing hangers, production packers, safety valves, mandrels, subsea flowline connectors, HPHT completion hardware, downhole tools.

Chemical & Refining: Process valves, heat exchanger tubes, reactor internals, piping handling mineral acids (H₂SO₄, HCl, H₃PO₄) and high-chloride media.

Marine/Offshore: Subsea tree bodies, riser components, umbilical terminations, subsea connector assemblies.

Supply Forms & Sizes

Form Typical Size Range Delivery Condition
Round Bar – Forged Ø 80–1200 mm Annealed / Age-hardened
Round Bar – Rolled Ø 10–300 mm Annealed / Age-hardened
Flat Bar / Plate Custom width & thickness Hot/cold rolled, annealed
Tube / Pipe Per API 5CRA / ISO 13680 Seamless, cold-worked & aged
Wire Ø 0.1–16 mm Cold drawn, annealed

Chemical Composition

Per UNS N09935 / NACE MR0175 / ISO 15156 qualification, wt.%

Ni Fe Cr Mo Ti Cu Nb Al C max
38.0 min Bal. 19.5–22.0 3.0–5.0 1.8–2.5 1.5–3.0 ≤0.50 ≤0.50 0.05

Also: Mn ≤1.0%, Si ≤0.50%, S ≤0.03%, P ≤0.03%.

Mechanical Properties

Condition: Solution annealed + age hardened — typical aging: 732 °C / 8 h → furnace cool to 621 °C / 8 h → air cool (AC). Room temperature.

Property Typical Value Min. Requirement
Tensile Strength (UTS) 862–965 MPa (125–140 ksi) 862 MPa (125 ksi)
0.2% Yield Strength 758–896 MPa (110–130 ksi) 758 MPa (110 ksi)
Elongation (A₅₀) 18–25% 15%
Reduction of Area 50–65% —
Hardness 28–36 HRC (277–352 HV) ≤40 HRC (NACE MR0175 limit)