Project Description

Alloy 400 (UNS N04400), also designated W.Nr. 2.4360 / EN NiCu30Fe, is a binary nickel-copper solid-solution alloy containing approximately 67% Ni and 31.5% Cu. First commercialized in 1905, it remains one of the most widely used CRA materials in upstream and downstream oil & gas operations. At SHUNFU METAL, Alloy 400 pipes are produced via vacuum induction melting (VIM) followed by electroslag remelting (ESR) to ensure exceptional ingot cleanliness and compositional homogeneity. Every heat is subject to 100% positive material identification (PMI), ultrasonic testing, eddy current inspection, and hydrostatic pressure testing prior to dispatch.

Equivalent & Similar Grades to Alloy 400

The table below compares Alloy 400 with nickel-copper and high-performance nickel-base alloys sharing overlapping service envelopes in petroleum environments.

Alloy UNS EN / W.Nr. DIN GB GOST JIS Key ASTM Ni %
Alloy 400 N04400 2.4360 / NiCu30Fe 2.4360 H04400 / NS6400 МНЖМц 28-2.5-1.5 NW 4400 B165 / B725 / B127 63 min
Alloy K-500 N05500 2.4375 / NiCu30Al 2.4375 NS6500 — NW 5500 B865 63 min
Cu-Ni 90/10 C70600 2.0872 / CuNi10Fe1Mn 2.0872 BFe10-1-1 МНЖ 10-1-1 C 7060 B466 / B467 9-11
Cu-Ni 70/30 C71500 2.0882 / CuNi30Mn1Fe 2.0882 BFe30-1-1 МНЖ 30-1-1 C 7150 B466 / B467 29-33
Alloy 625 N06625 2.4856 / NiCr22Mo9Nb 2.4856 NS3306 ХН75МБТЮ NCF 625 B444 / B705 58 min
Alloy C-276 N10276 2.4819 / NiMo16Cr15W 2.4819 NS3304 ХН65МВУ NW 0276 B622 / B619 57 bal

Oil & Gas Applications of Alloy 400 Pipe

Alloy 400 is qualified per NACE MR0175 / ISO 15156 for sour service and is approved by ASME Boiler & Pressure Vessel Code for service up to 480 °C. Key petroleum applications include:

HF Alkylation Piping & Heat Exchanger Tubes

Standard material in refinery HF alkylation units for acid rerun piping, overhead condensers, and reboiler tubing—resists HF across full concentration range at sub-boiling temperatures.

Crude Oil Distillation Overhead Condensers

Transfer lines and condenser tubes in crude unit overhead systems handling naphthenic acid, H2S, and chloride-laden condensates.

Seawater Intake & Firewater Pipework

Offshore platform seawater lift piping, firewater ring mains, and cooling water lines—immune to chloride SCC and biofouling-resistant in marine service.

Wellhead & Christmas Tree Components

Valve stems, seat rings, gate and ball valve internals, and instrument tubing for HP/HT wellhead assemblies—NACE MR0175 qualified.

Sour Gas Injection Lines & Downhole Instrument Tubing

Capillary and hydraulic control lines in sour gas wells; downhole pressure and chemical injection umbilicals rated to NACE MR0175 Level VII.

Brine & Produced Water Evaporator Tubes

Evaporator and crystallizer tubing in produced water treatment and salt production—resists both chloride pitting and scaling at elevated temperatures.

Subsea Manifold Valve & Control System Tubing

Hydraulic and methanol injection tubing in subsea production manifolds—excellent crevice corrosion resistance in oxygen-depleted seawater environments.

Sour Water Stripper Overhead Piping

Overhead vapour lines and condenser tubes in refinery sour water stripper (SWS) units handling wet H2S, NH3, and cyanide species.

Acid Gas Removal (AGR) Amine Unit Piping

Rich/lean amine piping, reclaimer tubing, and heat exchanger bundles in gas sweetening units—resists amine degradation and carbonate SCC.

Alloy 400 Pipe Supply Range — SHUNFU METAL

Alloy 400 seamless CRA pipe
SHUNFU Alloy 400 Seamless Pipe

SHUNFU METAL stocks and manufactures Alloy 400 pipe in both seamless and welded configurations to ASTM B165, ASTM B725, ASTM B163, and ASME SB-165 specifications. All products are supplied with EN 10204 3.1 certification and are traceable to heat number.

  • Seamless Pipe: OD 4 mm – 219 mm (⅟” – 8″), WT 0.5 mm – 20 mm
  • Welded Pipe: OD 5 mm – 1219 mm (⅟” – 48″), WT 1.0 mm – 15 mm
  • Large OD Thick-Wall: OD 10 mm – 600 mm, WT 2.5 mm – 100 mm
  • Capillary Tube: OD 0.4 mm – 16 mm, WT 0.1 mm – 3.0 mm
  • Schedule Range: SCH 5S, SCH 10S, SCH 40S, STD, SCH 80S, SCH 160, XXS per ASME B36.10 / B36.19
  • Length: Up to 12 m (random, double random, or cut length)
  • End Finish: Plain end, beveled end, threaded
  • Surface Condition: Annealed & pickled, bright annealed, cold-drawn, polished
  • Certification: NACE MR0175 / ISO 15156, API 6ACRA, VdTÜV 263, MIL-DTL-23227

Chemical Composition of Alloy 400 (ASTM B165)

Alloy 400 is essentially a Ni-Cu binary alloy with controlled iron and manganese additions. Unlike superaustenitic or Ni-Cr-Mo alloys, it derives its corrosion resistance from the high nickel-copper matrix rather than from chromium passivation.

Ni Cu Fe Mn C Si S
≥63.0 28.0–34.0 ≤2.50 ≤2.00 ≤0.30 ≤0.50 ≤0.024

All values in weight percent (wt%). The high nickel content (>63%) provides immunity to chloride SCC, while the 28–34% copper confers outstanding resistance to reducing acids, seawater, and HF environments. SHUNFU METAL verifies every heat with optical emission spectroscopy (OES) and inert gas fusion analysis for carbon and sulfur content.

Mechanical Properties of Alloy 400 Pipe (Annealed)

Properties at room temperature for solution-annealed condition (870–980 °C / 1600–1800 °F, followed by air or water quench). Alloy 400 is a solid-solution alloy that hardens only through cold working—no precipitation hardening response.

Property Metric Imperial
Tensile Strength, Rm 550 MPa min 80 ksi min
Yield Strength, Rp0.2 240 MPa min 35 ksi min
Elongation (2″ / 50.8 mm) 40% min 40% min
Hardness 60–80 HRB / 110–150 HBW 60–80 HRB
Elastic Modulus 182 GPa 26.4 × 106 psi
Density 8.80 g/cm3 0.318 lb/in3
Melting Range 1300–1350 °C 2370–2460 °F
Service Temperature −196 to +480 °C (ASME) −320 to +900 °F

SHUNFU METAL performs solution annealing in computer-controlled furnaces with batch-level temperature recording. Each lot is mechanically tested for tensile, hardness, and flattening/flaring properties per ASTM B165. Intergranular corrosion testing per ASTM G28 and grain-size metallographic examination are conducted on representative samples. Cold-drawn tempers (F55, F70) delivering yield strengths up to 650 MPa are also available for high-strength applications.