UNS N06625 Inconel Bars

Product Description

UNS N06625 (widely known as Inconel 625 / DIN 2.4856 / NiCr22Mo9Nb) is arguably the most widely used and versatile of all the nickel-chromium superalloys.

The fundamental engineering advantage of Inconel 625 bars over options like Inconel 718 or 713C is that it achieves high mechanical strength without relying on specialized precipitation heat treatments. Instead, it is a solid-solution strengthened alloy where substantial amounts of Molybdenum (8.0–10.0%) and Niobium (3.15–4.15%) are dissolved within the nickel-chromium atomic matrix, directly stiffening the lattice structures.

Technical Specifications & International Equivalents

Chemical Composition (Weight %)

• Nickel (Ni): 58.0% Minimum

• Chromium (Cr): 20.0 – 23.0% (Provides premium resistance to oxidation/pitting)

• Molybdenum (Mo): 8.0 – 10.0% (Stiffens matrix; blocks localized chloride pitting)

• Niobium + Tantalum (Nb + Ta): 3.15 – 4.15% (Acts as primary interstitial strengthener)

• Iron (Fe): 5.0% Maximum

• Cobalt (Co): 1.0% Maximum

• Carbon (C): 0.10% Maximum

Bar Profiles & Manufacturing Ranges

Because of its superb ductility, Inconel 625 is readily produced into multiple heavy-duty profiles, generally stocked or processed in the Annealed or Grade 1 condition (for optimum strength and grain control below 650°C) or the Solution-Annealed / Grade 2 condition (optimized for long-term creep resistance above 650°C).

1. Round Bars & Precision Rods

• Size Configurations: Typically produced from tiny wire/rod stock (3 mm) up to massive forged structural sections (800 mm).

• Finishes: Cold-drawn centerless ground & polished, smooth turned, or hot-rolled pickled/sandblasted.

• Applications: Subsea mooring cables, propeller shafts, valve stems, downhole instrumentation housings, and high-temperature aerospace exhaust framing.

2. Hex, Square, & Flat Bars

• Hex / Square Bars: Ranging from 2 mm up to 100 mm across flats (A/F). Highly valued for machining high-integrity hex nuts, union joints, heavy clamping studs, and manifolds.

• Flat Bars: Available in thicknesses from 2 mm up to 100 mm, and widths reaching 500 mm. Ideal for fabricating specialized industrial structural supports, furnace hangers, and marine brackets.

Key Performance Characteristics

• Immunity to Pitting & Crevice Corrosion: The combined action of Chromium and Molybdenum makes Inconel 625 practically immune to chloride-ion stress-corrosion cracking, sea-water pitting, and organic acids.

• Temperature Spectrum: Retains remarkable mechanical integrity from extreme cryogenic temperatures up to 982°C (1800°F).

• Exceptional Fatigue Strength: Possesses high corrosion-fatigue limits, making it the premier choice for marine splash-zone components experiencing constant cyclic mechanical stress.

Mechanical Properties (Typical Annealed Values)

• Density: $8.44 \text{ g/cm}^3$ ($0.305 \text{ lb/in}^3$)

• Melting Range: 1290°C – 1350°C (2350°F – 2460°F)

• Tensile Strength: $\ge$ 827 MPa (120 ksi)

• Yield Strength (0.2% Offset): $\ge$ 414 MPa (60 ksi)

• Elongation at Break: $\ge$ 30% to 40%

• Hardness: $\le$ 287 HB (Brinell)

Fabrication, Machining, & Welding Notes

• Welding Capability: Unlike 713C, Inconel 625 features exceptional weldability. It can be joined with standard processes (GTAW, SMAW) without requiring post-weld stress reliefs or hardening cycles. Use matching filler metals: Inconel Filler Metal 625 (AWS A5.14 ERNiCrMo-3) or Welding Electrode 112 (AWS A5.11 ENiCrMo-3).

• Machining Work-Hardening: It work-hardens instantly under cutting forces. Heavy, positive feeds must be maintained with low cutting speeds to prevent the tool from riding or polishing the surface. High-grade carbide tooling with aggressive coolant geometry is highly recommended.