Project Description

Introduction

N09946 Alloy 945X round bar
N09946 / Alloy 945X

UNS N09946, marketed as INCOLOY® Alloy 945X®, is a precipitation-hardenable nickel-iron-chromium superalloy engineered for the oil & gas industry. It delivers ultra-high strength alongside outstanding resistance to SCC, SSC, pitting, and crevice corrosion in H₂S-rich sour environments. Approved under NACE MR0175 / ISO 15156-3 up to Level VII severity, it is the alloy of choice for HPHT downhole and subsea service.

Similar Grades

Alloy UNS Key Standards Remark
INCOLOY 945 N09945 API 6ACRA; NACE MR0175/ISO 15156-3 Parent alloy; lower strength (YS 125 ksi min)
INCONEL 718 N07718 ASTM B637; AMS 5662 / AMS 5664; API 6ACRA Most common Ni PH alloy; lower corrosion class
INCONEL 725 N07725 ASTM B805; API 6ACRA; NACE MR0175 Improved corrosion vs. 718; similar downhole use
INCOLOY 925 N09925 ASTM B805; API 6ACRA; NACE MR0175 Ni-Fe-Cr-Mo-Cu; lower strength, good corrosion resistance

No established equivalents in EN, DIN, JIS, or GOST. Governed primarily by API 6ACRA and NACE MR0175/ISO 15156-3.

Applications

Downhole

  • Casing & production tubing
  • Wellhead hangers & mandrels
  • Landing nipples
  • Packers & packer mandrels
  • Subsurface safety valves
  • Gas lift valves
  • Perforating guns
Surface & Subsea

  • Gate valves & choke valves
  • Subsea connectors & flanges
  • Studs, bolts & nuts (fasteners)
  • Pump shafts & impellers
  • Compressor components
  • Process vessel nozzles & fittings

Supply Forms & Dimensions

Form Size Range
Round Bar Ø 12.7 – 560 mm (0.5″ – 22″)
Flat Bar / Forging Custom cross-section; large ingot sizes available
Plate / Sheet 3 – 100 mm thick × up to 2000 mm wide
Seamless Tube / Pipe OD 12.7 – 273 mm, custom wall thickness
Wire / Filler Wire Ø 0.5 – 12.7 mm; AWS A5.14 ERNiFeCr-3

Chemical Composition

Per UNS N09946 / API 6ACRA (wt %)

Element Min % Max %
Nickel (Ni) 45.0 55.0
Chromium (Cr) 19.0 22.0
Iron (Fe) Balance
Molybdenum (Mo) 3.0 4.0
Niobium (Nb) 2.5 3.5
Copper (Cu) 1.5 3.0
Titanium (Ti) 0.5 2.5
Aluminum (Al) 0.01 0.50
Carbon (C) — 0.030
Sulfur (S) — 0.010

Mechanical Properties

Per API 6ACRA — Solution Annealed + Age Hardened (minimum values)

Grade / Condition UTS (ksi / MPa) YS (ksi / MPa) Elongation (%) Hardness (HRC)
140K — SA + Age 155 / 1069 140 / 965 ≥ 15 ≤ 42
150K — SA + Age 165 / 1138 150 / 1034 ≥ 12 ≤ 44
160K — CW + Age 175 / 1207 160 / 1103 ≥ 10 ≤ 46

NACE MR0175/ISO 15156-3 Level VII approved. Max hardness 46 HRC per NACE limit. SA = Solution Annealed; CW = Cold Worked.