Inconel 625 Round Bar Suppliers, Manufacturer & Exporter in India
Jade Special Metals is a certified manufacturer, supplier, and exporter of INCONEL® 625 Round Bars, serving critical industries across the globe. Our Inconel 625 Bar Stock conforms to ASTM B446 / ASME SB446 and carries full mill certification to EN 10204 3.1, ensuring complete traceability from melt to finished product.
We supply Alloy 625 Round Bars across a size range of 3 mm to 800 mm diameter, in conditions including annealed, hot-finished, and cold-drawn — available in standard lengths or custom cut-to-size. With a deep inventory of UNS N06625 / W.Nr. 2.4856 products and an established export network, Jade Special Metals guarantees reliable supply with competitive lead times, regardless of project scale or geography.
Quick Section Links
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- What is Inconel 625 Round Bar?
- Types of Inconel 625 Round Bars
- Inconel 625 Round Bar Specifications
- Inconel 625 Round Bar Chemical Composition (ASTM B446)
- Inconel 625 Round Bar Mechanical Properties
- Equivalent Grades for Inconel 625 Round Bar
- Corrosion Resistance — A Technical Overview
- Inconel 625 Round Bar Surface Finish Options
- Inconel 625 Round Bar Weight Chart
- Inconel 625 Bar Tolerances
- Applications of Inconel 625 Round Bars
- Why Choose Jade Special Metals for Inconel 625 Round Bars?
- FAQ — Inconel 625 Round Bars
- Related Products
What is Inconel 625 Round Bar?
Inconel 625 (UNS N06625, W.Nr. 2.4856) is a nickel-chromium-molybdenum-niobium superalloy engineered for service in environments that would rapidly degrade conventional stainless steels or lower-grade nickel alloys. The alloy was originally developed for high-strength steam-line piping and has since become a workhorse material across aerospace, subsea, chemical processing, and nuclear sectors.
Metallurgical Basis of Strength
Unlike precipitation-hardened superalloys such as Inconel 718 or Waspaloy, Alloy 625 derives its mechanical strength entirely through solid-solution strengthening. The molybdenum and niobium atoms dissolved in the nickel-chromium matrix create lattice distortions that impede dislocation movement, providing substantial strength without the need for aging heat treatments. This greatly simplifies procurement and fabrication.
- Niobium (Nb / Columbium): Stabilises the alloy against sensitisation during welding and elevated-temperature service, and contributes significantly to solid-solution hardening.
- Molybdenum (Mo): Enhances resistance to pitting and crevice corrosion in reducing acid environments (particularly hydrochloric and phosphoric acids) and in chloride-bearing media.
- Chromium (Cr): Forms a tenacious passive oxide film that confers resistance to oxidising environments and high-temperature scaling up to approximately 1000°C (1832°F).
- Nickel (Ni): Provides the austenitic matrix, conferring toughness at cryogenic temperatures and immunity to chloride-ion stress-corrosion cracking (SCC) — a failure mode that severely limits 300-series stainless steels.
Temperature Performance
Inconel 625 retains useful mechanical properties over an exceptionally broad thermal window:
| Temperature Range | Condition |
|---|---|
| −196°C (Cryogenic) | Excellent toughness; no ductile-to-brittle transition |
| Ambient to 600°C | High strength and fatigue resistance |
| 600°C – 816°C | Moderate strength; excellent oxidation resistance |
| Up to 982°C (1800°F) | Oxidation-resistant; strength diminishes — Graded as Grade 2 (High Temperature) per ASTM B446 |
Engineering Note: ASTM B446 distinguishes two grades — Grade 1 (solution-annealed for corrosion service) and Grade 2 (annealed at higher temperature for improved creep resistance in elevated-temperature applications). Specify the correct grade at the time of order.
Types of Inconel 625 Round Bars
Inconel 625 Square Bar
Inconel 625 Hex Bar
Inconel 625 Flat Bar
Inconel 625 Forged Bars
Inconel 625 Bright Bars
Inconel 625 Polished Bars
Inconel 625 Cold Drawn Bars
Inconel 625 Hot Rolled Bars
Inconel 625 Peeled Bars
Inconel 625 Rectangular Bar
Inconel 625 Hollow Ring Bar
Inconel 625 Threaded Bar
Inconel 625 Round Bar Specifications
| Parameter | Details |
|---|---|
| Standard | ASTM B446, ASME SB446 |
| Designation | UNS N06625, W.Nr. 2.4856 |
| Common Names | Inconel 625, Alloy 625, Nickel Alloy 625 |
| Grades | Grade 1 (Corrosion Service), Grade 2 (High Temperature Service) |
| Forms | Round, Square, Hex, Flat, Forged, Hollow, Threaded |
| Diameter Range | 3 mm to 800 mm |
| Length | 1 to 6 metres; custom cut-to-length available |
| Finish | Black (as-rolled), Bright Polished, Rough Turned, Peeled, Matt |
| Condition | Annealed, Hot-Finished (HF), Cold-Drawn (CD) |
| Certification | Mill Test Certificate (MTC) as per EN 10204 3.1 |
| Testing | NDE (UT/ET), Hardness (HRB/HRC), Tensile, IGC (ASTM A262 Practice C), Pitting (ASTM G48) |
Inconel 625 Round Bar Chemical Composition (ASTM B446)
| Element | Min % | Max % |
|---|---|---|
| Nickel (Ni) | 58.00 | — |
| Chromium (Cr) | 20.00 | 23.00 |
| Molybdenum (Mo) | 8.00 | 10.00 |
| Niobium + Tantalum (Nb+Ta) | 3.15 | 4.15 |
| Iron (Fe) | — | 5.00 |
| Carbon (C) | — | 0.10 |
| Manganese (Mn) | — | 0.50 |
| Silicon (Si) | — | 0.50 |
| Phosphorus (P) | — | 0.015 |
| Sulphur (S) | — | 0.015 |
| Aluminium (Al) | — | 0.40 |
| Titanium (Ti) | — | 0.40 |
| Cobalt (Co) | — | 1.00 |
Note: The combined Nb+Ta content is the key differentiator of Alloy 625. The niobium level is tightly controlled to ensure weld stability and resistance to sensitisation in heat-affected zones (HAZ), making this alloy one of the most weldable of all nickel superalloys.
Inconel 625 Round Bar Mechanical Properties
| Property | Grade 1 (Annealed) | Grade 2 (High-Temp Annealed) |
|---|---|---|
| Density | 8.44 g/cm³ | 8.44 g/cm³ |
| Melting Range | 1290–1350°C (2354–2462°F) | 1290–1350°C |
| Tensile Strength (UTS) | 930 MPa (135,000 psi) min | 827 MPa (120,000 psi) min |
| 0.2% Proof Strength (YS) | 517 MPa (75,000 psi) min | 414 MPa (60,000 psi) min |
| Elongation | 30% min | 30% min |
| Hardness | ≤ 240 HB | ≤ 220 HB |
| Modulus of Elasticity | 208 GPa | 208 GPa |
| Specific Heat Capacity | 410 J/kg·K | 410 J/kg·K |
| Thermal Conductivity | 9.8 W/m·K (at 24°C) | 9.8 W/m·K |
| Coefficient of Thermal Expansion | 12.8 µm/m·°C (21–93°C) | 12.8 µm/m·°C |
Fabricator’s Note: Cold-drawn Inconel 625 bars exhibit higher tensile and yield strength than annealed bars due to work hardening. For applications requiring post-machining stress relief, solution annealing at 1093°C followed by rapid quench restores full corrosion resistance.
Equivalent Grades for Inconel 625 Round Bar
| Standard | Designation |
|---|---|
| UNS | N06625 |
| Werkstoff Nr. | 2.4856 |
| EN | NiCr22Mo9Nb |
| JIS | NCF 625 |
| BS | NA 21 |
| GOST | ХН75МБТЮ |
| AFNOR | NC22DNb4M |
| ISO | NiCr22Mo9Nb |
Corrosion Resistance — A Technical Overview
Inconel 625’s corrosion resistance stems from the synergistic effect of its alloying elements operating across multiple degradation mechanisms:
- Aqueous Corrosion The alloy demonstrates outstanding resistance to seawater, brine, and hypochlorite solutions at both ambient and elevated temperatures. Its pitting resistance equivalent number (PREN), calculated as Cr% + 3.3×Mo%, exceeds 45, far surpassing super duplex stainless steels (PREN ~40).
- Acid Resistance Alloy 625 resists attack in a wide range of acids including:
- Dilute and concentrated nitric acid (oxidising) — chromium passive film
- Hydrochloric acid (reducing, up to ~5% at ambient temperature) — molybdenum effect
- Phosphoric acid — particularly in fertiliser and food-grade processing
- Acetic, formic, and citric acids — relevant in pharmaceutical applications
- Stress Corrosion Cracking (SCC) Immunity Unlike austenitic stainless steels (e.g., 316L), which are highly susceptible to chloride SCC above ~60°C, Inconel 625 is essentially immune due to its high nickel content. This makes it the alloy of choice for offshore and marine applications.
- High-Temperature Oxidation Alloy 625 resists scaling and carburisation up to ~1000°C in air and oxidising combustion gases, supported by chromium oxide (Cr₂O₃) scale formation.
- Intergranular Corrosion Niobium stabilisation prevents chromium carbide precipitation at grain boundaries during welding or heat treatment, eliminating sensitisation and susceptibility to intergranular attack (IGA) — verified via ASTM A262 Practice C or ASTM G28 Method A testing.
Inconel 625 Round Bar Surface Finish Options
| Code | Description | Typical Range |
|---|---|---|
| HF | Hot Finished (as-rolled/forged) | — |
| HRAP | Hot Rolled, Annealed & Pickled | — |
| RT / P&T | Rough Turned / Peeled & Turned | 3.2–6.3 µm |
| ST | Smooth Turned | 1.6–3.2 µm |
| CD | Cold Drawn | 0.8–3.2 µm |
| CG | Centreless Ground | 0.4–0.8 µm |
| BD / P | Bright Drawn / Polished | ≤ 0.4 µm |
| PR | Peeled & Reeled | 0.8–1.6 µm |
| CF | Cold Finished | 0.4–1.6 µm |
| SRE | Slit Rolled Edge | — |
Inconel 625 Round Bar Weight Chart
| Diameter (mm) | Diameter (in) | Weight (kg/m) | Weight (lbs/ft) |
|---|---|---|---|
| 3 mm | ~1/8″ | 0.055 | 0.037 |
| 6 mm | ~1/4″ | 0.223 | 0.150 |
| 8 mm | ~5/16″ | 0.398 | 0.267 |
| 10 mm | ~3/8″ | 0.620 | 0.417 |
| 12 mm | ~1/2″ | 0.889 | 0.598 |
| 16 mm | ~5/8″ | 1.578 | 1.061 |
| 20 mm | ~3/4″ | 2.470 | 1.660 |
| 25 mm | ~1″ | 3.871 | 2.600 |
| 30 mm | ~1-3/16″ | 5.548 | 3.729 |
| 40 mm | ~1-1/2″ | 9.872 | 6.634 |
| 50 mm | ~2″ | 15.414 | 10.360 |
| 60 mm | ~2-3/8″ | 22.205 | 14.920 |
| 75 mm | ~3″ | 35.762 | 24.020 |
| 100 mm | ~4″ | 63.340 | 42.560 |
Formula: Weight (kg/m) = (D² × 0.006165) — where D = diameter in mm, using density of 8.44 g/cm³
Inconel 625 Bar Tolerances
(As per ASTM B446, BS 970-3, ISO ‘h’ Series)
Cold-Drawn Bar Tolerances
| Section | Diameter / Width (mm) | Tolerance |
|---|---|---|
| Round | ≥6 to ≤18 | +0 / −0.070 mm |
| Round | >18 to ≤30 | +0 / −0.085 mm |
| Round | >30 to ≤50 | +0 / −0.100 mm |
| Round | >50 to ≤80 | +0 / −0.120 mm |
| Square & Hex | ≥6 to ≤18 | +0 / −0.090 mm |
| Square & Hex | >18 to ≤30 | +0 / −0.110 mm |
| Square & Hex | >30 to ≤50 | +0 / −0.130 mm |
| Square & Hex | >50 to ≤80 | +0 / −0.160 mm |
Bright Round Bar Tolerances (ISO 'h' Series)
| Nominal Size (mm) | h8 | h9 | h11 |
|---|---|---|---|
| >3 to ≤6 | +0.018/0 | +0.030/0 | +0.075/0 |
| >6 to ≤10 | +0.022/0 | +0.036/0 | +0.090/0 |
| >10 to ≤18 | +0.027/0 | +0.043/0 | +0.110/0 |
| >18 to ≤30 | +0.033/0 | +0.052/0 | +0.130/0 |
| >30 to ≤50 | +0.039/0 | +0.062/0 | +0.160/0 |
| >50 to ≤80 | +0.046/0 | +0.074/0 | +0.190/0 |
| >80 to ≤120 | +0.054/0 | +0.087/0 | +0.220/0 |
Fabrication & Machining Guidelines
Machining Alloy 625 work-hardens rapidly, requiring rigid machine setups, slow cutting speeds, and high feed rates. Use carbide tooling with positive rake angles, ample coolant, and avoid dwelling or rubbing. Recommended cutting speed: 15–25 m/min (turning), 8–12 m/min (drilling).
Welding Inconel 625 is considered highly weldable. Recommended processes: GTAW (TIG), GMAW (MIG), SMAW (with ERNiCrMo-3 / ENiCrMo-3 filler). Preheat is generally not required at ambient temperatures. Post-weld heat treatment (PWHT) is not mandatory but may be specified for stress relief in certain codes.
Heat Treatment
- Solution Annealing (Grade 1): 1093°C (2000°F), rapid quench — optimises corrosion resistance
- Solution Annealing (Grade 2): 1149–1204°C (2100–2200°F), rapid quench — optimises creep resistance
- Alloy 625 cannot be strengthened by age hardening (unlike Alloy 718)
Forming Due to high work-hardening rate, intermediate anneals may be required during cold forming. Hot forming should be carried out in the range 925–1175°C.
Applications of Inconel 625 Round Bars
- Aerospace & Defence Engine exhaust systems, thrust-reverser components, fuel nozzles, aircraft ducting, nacelle skins, and helicopter engine parts. The alloy’s fatigue resistance and thermal stability are critical in cyclic loading environments.
- Chemical & Petrochemical Processing Heat exchangers, reactor vessels, piping systems, and agitator shafts exposed to mixed acids, halide solutions, and oxidising-reducing process streams. Replaces titanium in many mixed-acid duty applications at lower cost.
- Oil & Gas / Subsea Wellhead components, Christmas tree hardware, subsea umbilicals, risers, flexible pipelines, and sour service (H₂S-bearing) equipment per NACE MR0175 / ISO 15156. Alloy 625 is extensively qualified for zone-3 and zone-4 sour environments.
- Marine & Naval Propeller shafts, seawater valves, submarine hulls and fittings, hydrofoil struts, and sonar domes. The alloy’s virtual immunity to seawater pitting and biofouling-accelerated corrosion makes it uniquely suited for long-life subsea structures.
- Nuclear Power Control rod drive mechanisms, reactor core internals, pressurised water reactor (PWR) steam generator tubing backing, and waste containment hardware where radiation resistance and dimensional stability are mandated.
- Pollution Control Flue gas desulphurisation (FGD) scrubbers, chimney liners, and ducting systems where concentrated sulphurous and halide acid condensates attack conventional alloys.
- Cryogenic Applications Due to its face-centred cubic (FCC) austenitic structure, Alloy 625 retains excellent toughness down to −196°C, making it suitable for LNG equipment, liquid nitrogen handling systems, and space vehicle propulsion components.
- Alloy 625 represents the optimal balance of corrosion performance, weldability, and cost for the majority of severe corrosion service applications.
Why Choose Jade Special Metals for Inconel 625 Round Bars?
- Certified Raw Material Traceability All heats sourced from approved mills with full EN 10204 3.1 certification. Heat number traceability maintained from ingot to finished bar.
- In-House Testing Capabilities Tensile, hardness, PMI (XRF), intergranular corrosion (ASTM A262 / G28), pitting corrosion (ASTM G48), and ultrasonic testing (UT) conducted in-house or at accredited third-party laboratories per customer specification.
- Extensive Inventory — Short Lead Times One of India’s largest stockholders of nickel alloy bar stock, enabling same-week despatch on standard sizes. Customised cut lengths processed within 24–48 hours.
- Global Export Capability Regular shipments to the UAE, UK, USA, Germany, Singapore, Australia, and the Middle East. Compliance with export documentation, ECNR requirements, and customer-specific QAP/ITP.
- Technical Application Support Our metallurgical team can advise on grade selection, heat treatment specifications, tolerance requirements, and alloy substitution — backed by decades of nickel alloy expertise.
