Tesco Steel & Engineering manufactures Inconel 625 flanges (UNS N06625 / W.Nr. 2.4856) — the niobium-molybdenum strengthened nickel-chromium superalloy with ~61% Ni, ~21.5% Cr, ~9% Mo and ~3.6% niobium. The Mo and Nb give very high strength by solid-solution strengthening (no heat treatment) plus outstanding resistance to pitting, crevice corrosion, chloride stress-corrosion cracking, seawater and a wide range of oxidizing and reducing acids — usable from cryogenic to ~1000°C. Available in weld neck, slip-on, blind, socket-weld, threaded, lap-joint, spectacle and orifice types to ASTM B564 / ASME B16.5. Class 150 to 2500, NPS 1/2″ to 24″, PN6 to PN400. ISO 9001:2015 certified. Made in India.
Inconel 625 (UNS N06625) Flanges
Inconel 625 Spectacle Blind (UNS N06625)
Tesco Steel & Engineering manufactures Inconel 625 flanges in all types from weld neck to orifice, Class 150 to 2500 — supplied with EN 10204 3.1 / 3.2 certification, PMI and third-party inspection on request. Explore the wider Inconel flange range, the general-purpose Inconel 600 flanges and high-temperature Inconel 601 flanges, and the flange dimension charts.
| Inconel 625 flanges are available in the following specifications: | |
|---|---|
| Material Grade | Inconel 625 / UNS N06625 / W.Nr. 2.4856 (NiCr22Mo9Nb) |
| Alloy Type | Nickel-chromium-molybdenum-niobium superalloy (solid-solution strengthened) |
| Size | 1/2″ NB to 24″ NB (DN 15 to DN 600); larger to ASME B16.47 |
| Class / Rating | 150#, 300#, 600#, 900#, 1500#, 2500# · 3000#, 6000#, 9000# (socket-weld / threaded) |
| Pressure Ratings | PN 6 – PN 400 (PN6, 10, 16, 25, 40, 64, 100, 160, 250, 320, 400) |
| Material Standards | ASTM B564, ASME SB564, AMS 5666; Grade 1 / Grade 2 tempers; EN designation 2.4856 |
| Dimensional Standards | ASME B16.5, ASME B16.47 (Series A & B), MSS SP-44, DIN EN 1092-1 |
| Flange Types | Weld Neck (WNRF), Slip-On (SORF), Blind, Socket Weld (SWRF), Lap Joint, Threaded / Screwed, Spectacle Blind, Long Weld Neck, Orifice, Plate |
| Flange Faces | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Tongue & Groove (T&G) |
| Weld Filler | ERNiCrMo-3 / ENiCrMo-3 (Inconel Filler Metal 625) |
| Testing | PMI, hydrostatic, UT, MT/PT per spec; EN 10204 3.1 / 3.2 |
Inconel 625 pairs a high nickel-chromium base with strong molybdenum and niobium additions. The Mo and Nb dissolve into the matrix to give solid-solution strengthening (the source of its high strength) and broad resistance to localized and acid corrosion.
| Element | Inconel 625 (UNS N06625) |
|---|---|
| Nickel (Ni) | 58.0% min (~61%) |
| Chromium (Cr) | 20.0 – 23.0% |
| Molybdenum (Mo) | 8.0 – 10.0% |
| Niobium + Tantalum (Nb+Ta) | 3.15 – 4.15% |
| Iron (Fe) | 5.0% max |
| Carbon (C) | 0.10% max |
| Titanium (Ti) | 0.40% max |
| Aluminium (Al) | 0.40% max |
| Mechanical Property (annealed, typical) | Inconel 625 |
|---|---|
| Tensile Strength | 830 – 1000 MPa (120–145 ksi) |
| Yield Strength 0.2% | 415 – 560 MPa (60–81 ksi) |
| Elongation | 30 – 45% |
| Service Temperature | Cryogenic to ~1000 °C |
| Density | 8.44 g/cm³ |
| Melting Range | 1290 – 1350 °C |
| Standard | Inconel 625 Designation |
|---|---|
| UNS (USA) | N06625 |
| Werkstoff (Germany) | 2.4856 |
| EN designation | NiCr22Mo9Nb |
| ASTM / ASME | B564 / SB564 (forgings); B443, B444, B446 (other forms) |
| AMS | 5666 / 5599 |
| Common names | Inconel 625, Alloy 625, Nickel Alloy 625 |
Inconel 625 Weld Neck Flange (WNRF)
Inconel 625 Slip-On Flange (SORF)
Inconel 625 Blind Flange
| Flange Type | Description & Inconel-625-Specific Use |
|---|---|
| Weld Neck (WNRF) | Tapered hub butt-welded to pipe for high-integrity, high-pressure seawater and sour-service lines; weld with ERNiCrMo-3 filler. |
| Slip-On (SORF) | Fillet-welded over the pipe; common in marine and chemical piping at moderate pressure. |
| Blind | Seals pipe ends and vessel nozzles in seawater, subsea and acid systems. |
| Socket Weld (SWRF) | Small-bore (1/2″–2″) instrument and branch connections in corrosive/marine service. |
| Lap Joint (LJRF) | Used with an Inconel 625 stub end where frequent dismantling is required; economizes on alloy in the backing ring. |
| Threaded (TRFF) | Internal NPT/BSP threads for non-welded low-pressure connections. |
| Spectacle Blind / Long Weld Neck | Isolation spades and nozzle/long-neck flanges in Inconel 625 for seawater and high-strength duty. |
| Property | 625 (N06625) | 600 (N06600) | 601 (N06601) |
|---|---|---|---|
| Type | Ni-Cr-Mo-Nb | Ni-Cr-Fe | Ni-Cr-Fe + Al |
| Molybdenum | ~9% | — | — |
| Strength | Very high | Moderate | Moderate |
| Aqueous / seawater corrosion | Excellent | Good (chloride SCC) | Good |
| Max temperature | ~1000°C | ~1095°C | ~1250°C |
| Typical role | Seawater, sour-service, high strength | General nickel alloy, chloride/HT | Furnace / cyclic-oxidation HT |
Solid-solution strengthening by Mo + Nb gives high tensile and fatigue strength in the annealed condition — no heat treatment needed.
Outstanding resistance to pitting, crevice corrosion and chloride stress-corrosion cracking in warm, flowing seawater.
Resists oxidizing and reducing acids, alkalis and sour (H2S) environments — one of the most versatile corrosion alloys.
Readily welded with ERNiCrMo-3 filler — 625 filler is also widely used to weld and overlay other alloys.
| Industry | Typical Application |
|---|---|
| Oil & Gas / Subsea | Sour-service, seawater, riser, manifold and wellhead flanged connections |
| Marine & Offshore | Seawater piping, bellows, expansion-joint and platform flanges |
| Chemical & Petrochemical | Acid, alkali and mixed-media reactor and piping flanges |
| Aerospace | Exhaust systems, ducting and high-strength flanged components |
| Power & FGD | Flue-gas desulphurization, scrubber and high-temperature flanges |
| Pollution Control | Aggressive chloride and acid-bearing flanged connections |
Made from certified Alloy 625 with PMI verification of Cr, Mo and Nb — full chemistry confirmed on the MTC.
Manufactured to ASTM B564 / ASME B16.5 in Grade 1 or Grade 2 temper for the required strength and corrosion performance.
WNRF, SORF, blind, socket-weld, threaded, lap-joint, spectacle, LWN, orifice and plate — in RF, FF, RTJ and T&G.
EN 10204 3.1 / 3.2 MTC, heat/lot traceability, hydrostatic and third-party inspection on request.
Inconel 625 flange prices reflect the high nickel, molybdenum and niobium content plus forging and machining — it is a premium high-strength superalloy for seawater, subsea and aggressive corrosion service. Tesco Steel & Engineering offers competitive ex-works pricing from Mumbai with full export documentation and material traceability. Click Ask for Quote or message us on WhatsApp at +91 92233 66922 with flange type, size (NB), pressure class, quantity and documentation requirements.
Q1. What is an Inconel 625 flange?
An Inconel 625 flange is a pipe flange made from the niobium-molybdenum strengthened nickel-chromium superalloy UNS N06625 (W.Nr. 2.4856) — about 61% nickel, 21.5% chromium, 9% molybdenum and 3.6% niobium plus tantalum. The molybdenum and niobium give high strength without heat treatment plus outstanding resistance to pitting, crevice corrosion, chloride stress-corrosion cracking, seawater and a wide range of acids, from cryogenic temperatures to about 1000 degrees C. Flanges are forged to ASTM B564 and machined to ASME B16.5 / B16.47 dimensions.
Q2. What is the chemical composition of Inconel 625?
Inconel 625 (UNS N06625) nominal composition: nickel 58% minimum (~61%), chromium 20–23%, molybdenum 8–10%, niobium plus tantalum 3.15–4.15%, iron 5% max, with carbon 0.10% max, manganese 0.5% max, titanium 0.4% max and aluminium 0.4% max. The molybdenum and niobium additions are what give the alloy its strength and broad corrosion resistance.
Q3. Why is Inconel 625 so strong without heat treatment?
Inconel 625 gains its high strength from solid-solution strengthening by molybdenum and niobium dissolved in the nickel-chromium matrix, so it does not rely on age-hardening. This gives it high tensile and fatigue strength in the annealed condition while keeping excellent ductility, toughness and weldability, and it retains strength from cryogenic temperatures up to about 1000 degrees C.
Q4. Is Inconel 625 good for seawater and marine service?
Yes. Inconel 625 has outstanding resistance to seawater and chloride environments — it strongly resists pitting, crevice corrosion and chloride stress-corrosion cracking even in warm, flowing seawater. This, combined with its high strength and fatigue resistance, makes it a leading choice for marine, offshore and subsea flanged connections, bellows, expansion joints and seawater piping.
Q5. What standards apply to Inconel 625 flanges?
Inconel 625 flanges are forged to ASTM B564 (UNS N06625) and machined to ASME B16.5 (1/2 inch to 24 inch) or ASME B16.47 / MSS SP-44 for larger sizes, with EN 1092-1 for PN-rated flanges. The European designation is W.Nr. 2.4856 / NiCr22Mo9Nb. Grade 1 (annealed) and Grade 2 (solution-annealed) tempers are available; material is supplied with EN 10204 3.1 / 3.2 certification.
Q6. What is the difference between Inconel 625 and 600?
Inconel 600 is a Ni-Cr-Fe alloy valued for chloride-SCC resistance and high-temperature use to ~1095 degrees C, but it has only moderate strength. Inconel 625 adds molybdenum and niobium, giving much higher strength and far broader aqueous corrosion resistance — including seawater, pitting, crevice and acid resistance — though its top oxidation temperature (~1000 degrees C) is a little lower. Choose 625 for strength plus aggressive aqueous/marine corrosion, and 600 for chloride-SCC and the hottest service.
Q7. Can Inconel 625 flanges be welded?
Yes. Inconel 625 has excellent weldability by GTAW (TIG), GMAW and SMAW using matching ERNiCrMo-3 / ENiCrMo-3 (Inconel Filler Metal 625). It is non-age-hardenable, so no post-weld heat treatment is generally required; in fact 625 filler is widely used to weld and clad other materials. Clean joints and controlled heat input give sound, corrosion-resistant welds.
Q8. What media does Inconel 625 resist?
Inconel 625 resists seawater and brine, oxidizing and reducing acids (nitric, phosphoric, sulphuric, hydrochloric at moderate levels), organic acids, alkalis, and chloride-bearing and sour (H2S) environments. It strongly resists pitting, crevice corrosion and chloride stress-corrosion cracking, making it one of the most versatile corrosion-resistant superalloys.
Q9. What are the mechanical properties of Inconel 625?
Typical Inconel 625 properties in the annealed condition: tensile strength about 830–1000 MPa (120–145 ksi), yield strength about 415–560 MPa (60–81 ksi), elongation about 30–45%, density 8.44 g/cm³. It offers among the highest strength of the corrosion-resistant nickel alloys while retaining excellent ductility and toughness.
Q10. Are Inconel 625 flanges supplied with material test certificates?
Yes. Every Inconel 625 flange is supplied with EN 10204 3.1 (or 3.2) mill test certificates confirming chemistry, mechanical properties and heat/lot traceability, with PMI, hydrostatic testing and third-party inspection on request. Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer and exporter from Mumbai, India.