Inconel 625 FastenersUNS N06625 · Manufacturer, trader & exporter, India
Also sold as Alloy 625 · UNS N06625 · W.Nr 2.4856 · Nicrofer 6020
Inconel 625 fasteners — stud bolts, hex bolts, nuts and washers — available in this alloy. ASTM F468 (N06625) where specified for applicable bolts, hex cap screws, socket-head cap screws and studs (0.250–1.500 in.), and ASTM F467 for applicable nuts (0.250–1.500 in.); for other types, material may be supplied to ASTM B446 bar where applicable, subject to the purchase specification. Dimensions to ASME B18 where applicable, or your drawing. State the finished fastener specification your project requires on the order. It is a nickel–chromium–molybdenum alloy with niobium, chosen for seawater, high strength and high temperature in one alloy. Kanak Steel & Engineering Co. manufactures, trades and exports it from Mumbai; EN 10204 3.1 or 3.2 certificates are available on request / as specified in the PO. Markets we have supplied to include Oman, UAE, Saudi Arabia, Brazil, Argentina, Spain and Chile (India is the home market).
- Stock & mill supply
- EN 10204 3.1 / 3.2
- PMI on request
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is Inconel 625 Fasteners?
Inconel 625 fasteners is a nickel–chromium–molybdenum alloy with niobium supplied as fasteners (UNS N06625). ASTM F468 (N06625) where specified for applicable bolts, hex cap screws, socket-head cap screws and studs (0.250–1.500 in.), and ASTM F467 for applicable nuts (0.250–1.500 in.); for other types, material may be supplied to ASTM B446 bar where applicable, subject to the purchase specification. Buyers specify it for seawater, high strength and high temperature in one alloy. It is also sold as Alloy 625, UNS N06625, W.Nr 2.4856.
- What it is
- Nickel–chromium–molybdenum alloy with niobium
- Material
- ASTM F468 (N06625) where specified for applicable bolts, hex cap screws, socket-head cap screws and studs (0.250–1.500 in.), and ASTM F467 for applicable nuts (0.250–1.500 in.); for other types, material may be supplied to ASTM B446 bar where applicable, subject to the purchase specification
- Feedstock (bar)
- ASTM B446, where applicable
- Dimensions
- ASME B18.2.1 · B18.2.2 · B18.31.2
- Threads
- UNC · UN-8 · metric
- Sizes
- M10 – M64 · ½" – 4"
- Best at
- Seawater, high strength and high temperature in one alloy
Inconel 625 Fasteners Specification & Sizes
| Material | ASTM F468 (N06625) where specified for applicable bolts, hex cap screws, socket-head cap screws and studs (0.250–1.500 in.), and ASTM F467 for applicable nuts (0.250–1.500 in.); for other types, material may be supplied to ASTM B446 bar where applicable, subject to the purchase specification |
|---|---|
| Material / feedstock | ASTM B446 — a bar specification, where applicable; it covers the bar, not the finished fastener |
| Manufacturing route | By type: bolts, studs, cap screws and nuts may be machined from bar, where applicable; threaded rod, U-bolts, eye bolts, anchor and foundation bolts are route-dependent; washers not asserted — all to the purchase specification or project drawing |
| Dimensional standards | ASME B18.2.1 (bolts) · B18.2.2 (nuts) · B18.31.2 (studs) · DIN 931 / 933 / 934 (legacy DIN) |
| Types | Stud bolt · Hex bolt · Heavy hex nut · Hex nut · Washer · Threaded rod · U-bolt · Eye bolt · Anchor bolt · Foundation bolt · Socket head cap screw · Machine screw |
| Threads | UNC, UN-8 and metric coarse |
| Coating | Plain · PTFE on request |
| Documents | EN 10204 3.1 |
Inconel 625 Stud Bolts: Grade & Nut Pairing
Inconel 625 studs and nuts may be machined from ASTM B446 bar, where applicable; the finished fastener specification is to the purchase specification or project drawing, and the nut is usually the same alloy.
Torque (T = K × F × d), stud length and coatings are covered in the fasteners guide.
| Galling | Stainless and nickel-alloy threads gall — always use anti-seize, and avoid high-speed tightening |
|---|---|
| Coatings | Usually supplied plain; PTFE coating on request to ease tightening |
| Marking | Grade symbol and maker's mark on each stud end and nut, as the standard requires |
| Certificates | EN 10204 3.1 for the bar heat; mechanical test reports on the finished bolts on request |
Inconel 625 Fasteners Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Nickel | As specified |
| Chromium | As specified |
| Molybdenum | As specified |
| Niobium + Tantalum | As specified |
| Iron | As specified |
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Titanium | As specified |
| Aluminium | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM B443 for UNS N06625.
Inconel 625 Fasteners Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification and condition to be verified: ASTM B443 for UNS N06625 — Grade 1 annealed plate.
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 8.44 g/cm³ |
| Melting range | 1290 – 1350 °C |
| Magnetic | Non-magnetic |
| PREN (approx.) | ≈ 51 |
Inconel 625 Equivalent Grades
Six-digit Harmonized System heading (nickel alloy, chapter 75). Your country adds its own digits — confirm with your customs broker. All HS codes.
How to Verify Inconel 625 Fasteners with PMI
Positive material identification with a handheld XRF gun confirms the alloy on the piece itself, in seconds, before it is cut or welded. Inconel 625 is most often mixed up with Hastelloy C276 — the table shows which elements tell them apart.
Handheld XRF does not measure carbon or nitrogen; those come from the mill certificate or optical emission (OES) testing. PMI can be arranged on request — state it on your enquiry.
Under technical review for TDS.
| Element | Inconel 625 | Hastelloy C276 |
|---|---|---|
| Nickel | As specified | As specified |
| Chromium | As specified | As specified |
| Molybdenum | As specified | As specified |
| Titanium | As specified | — |
| Niobium | As specified | — |
| Tungsten | — | As specified |
| Iron | As specified | As specified |
| Manganese | As specified | As specified |
Inconel 625 fasteners by type
Inconel 625 Fasteners Applications
Inconel 625 is specified when the cheaper grade will not survive the service but a higher alloy would be more than the job needs. These are the jobs our buyers use it for.
Inconel 625 Fasteners vs 825, 2507 and C276
| Grade | Fasteners standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| Inconel 825 | May be machined from ASTM B425 bar (UNS N08825), where applicable; finished fastener requirements are to the purchase specification or project drawing | ≈ 31 | Sulphuric and phosphoric acid service, chloride stress-corrosion cracking |
| Super Duplex 2507 | ASTM A1082 (S32750) where specified for applicable duplex bolts, studs, cap screws and nuts; for other types, material may be supplied to ASTM A276 / A479 bar where applicable, subject to the purchase specification | ≈ 42 | Seawater and high-chloride service where strength also matters |
| Inconel 625 | ASTM F468 (N06625) where specified for applicable bolts, hex cap screws, socket-head cap screws and studs (0.250–1.500 in.), and ASTM F467 for applicable nuts (0.250–1.500 in.); for other types, material may be supplied to ASTM B446 bar where applicable, subject to the purchase specification | ≈ 51 | Seawater, high strength and high temperature in one alloy |
| Hastelloy C276 | ASTM F468 (N10276) where specified for applicable bolts, hex cap screws, socket-head cap screws and studs (0.250–1.500 in.), and ASTM F467 for applicable nuts (0.250–1.500 in.); for other types, material may be supplied to ASTM B574 bar where applicable, subject to the purchase specification | ≈ 68 | The most aggressive mixed acids, wet chlorine and hypochlorite |
PREN = Cr + 3.3 Mo + 16 N, from mid-range chemistry. A screening guide, not a substitute for corrosion data on your medium.
Inconel 625 Corrosion Resistance — Element by Element
Each alloying addition has a job. Knowing which one protects against your medium is the quickest way to judge whether 625 fits.
About 9% molybdenum gives PREN above 50 — seawater pitting is rarely a concern.
Niobium strengthens the matrix without heat treatment.
High nickel makes it virtually immune to chloride stress-corrosion cracking.
Keeps useful strength and oxidation resistance at high temperature.
How your 625 fasteners order runs
- 01Enquiry review — we confirm size, standard edition and documents against your MR or drawing.
- 02Heat selection & PMI — the mill certificate is checked against your order; PMI can be arranged depending on product and requirements, as specified in the PO.
- 03Processing — cutting, machining or bevelling to your specification, with heat numbers marked as specified in the PO.
- 04Inspection — your third-party inspector witnesses, or we share photos and test reports.
- 05Packing & dispatch — seaworthy packing from Nhava Sheva (JNPT), Mumbai, FOB or CIF, documents sent before the vessel sails.
Standards on this page
Welding & Fabricating Inconel 625 Fasteners
Inconel 625 welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ERNiCrMo-3 (AWS A5.14) |
|---|---|
| Over-alloyed filler | ENiCrMo-3 electrode |
| Preheat | Not required; keep interpass temperature low |
| Cutting | Thermal or abrasive cutting; grind off heat-tinted edges before welding |
Follow your approved WPS; this is general guidance. See also 625 fittings and 625 flanges for the matching pipe-system parts.
How to Order Inconel 625 Fasteners: RFQ Checklist
Get an accurate quote the first time. Copy this list into your enquiry:
- Fastener type, size and length
- Thread form
- Material and marking
- Quantity in sets
- Certificate type
- Delivery port and date
Technical documentation
A Kanak Steel technical data sheet for this product is being prepared. It is released as a PDF only after the current standard text, each value and its evidence, and a named technical reviewer have been confirmed — so no draft or placeholder sheet is offered for download.
Need technical data now? Send your enquiry with the standard and edition you are ordering to.
| Document | Inconel 625 — Fasteners technical data sheet |
|---|---|
| Document ID | KS-TDS-N06625-FS |
| Grade | Inconel 625 |
| UNS | N06625 |
| Product form | Fasteners (bolts, cap screws, studs, nuts) |
| Standard | ASTM F468 (current edition F468-23(2026)) ASTM F467 (current edition F467-24(2026)) |
| Status | Under technical review for TDS |
- Technical Data Sheet — Under technical review
Inconel 625 fasteners — questions buyers ask
Is Inconel 625 the same as Alloy 625?
Alloy 625, UNS N06625, W.Nr 2.4856 are names used for Inconel 625 (W.Nr / EN numbers and older UNS variants are the closest designations; their limits can differ slightly, so specify the UNS number and ASTM grade on the order). Whichever name is on the enquiry, fasteners: ASTM F468 (N06625) where specified for applicable bolts, hex cap screws, socket-head cap screws and studs (0.250–1.500 in.), and ASTM F467 for applicable nuts (0.250–1.500 in.).
Why use Inconel 625 bolts instead of B7 carbon steel?
On Inconel 625 flanges in corrosive service, carbon-steel bolts corrode first. Matching-alloy bolting avoids galvanic corrosion and bolt failure.
What nut goes with Inconel 625 stud bolts?
Usually a heavy hex nut in the same Inconel 625 alloy — it may be machined from ASTM B446 bar, where applicable; finished requirements are to the purchase specification or project drawing.
How do I stop Inconel 625 bolts galling?
Use an anti-seize compound on threads and nut faces, tighten at moderate speed, and do not reuse galled nuts.
Inconel 625 or Hastelloy C276 — which should I choose?
Inconel 625 is chosen for seawater, high strength and high temperature in one alloy. Hastelloy C276 is the step up when you need more pitting resistance or strength. See the comparison table on this page, or ask us with your process conditions.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026