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Monel 400 Fasteners Supplier in Mumbai, India – ASTM F468 UNS N04400
Nicorex Alloys is an ISO 9001 and ISO 14001 certified supplier, importer, and stockist of Monel 400 fasteners in Mumbai, India. We supply these fasteners as per ASTM F468 (bolts/screws/studs) and ASTM F467 (nuts). Bar stocks are provided as per ASTM B164, and forgings as per B564.
Monel 400’s binary composition of 63-70% nickel and 28-34% copper gives Monel 400 bolted joints resistance to hydrofluoric acid at all concentrations up to boiling point, immunity to chloride stress corrosion cracking in seawater, and stable ductility down to −253°C (−423°F) for cryogenic flange service. This makes Nickel-Copper Alloy 400 (UNS N04400, Werkstoff 2.4360) the standard bolting material for HF alkylation units, marine flange assemblies, and chemical reactor closure studs. The Ni-Cu solid solution is thermodynamically stable and does not precipitate secondary phases during service, so mechanical properties remain consistent for long durations. Monel 400 is a solid-solution alloy strengthened only by cold working; it contains no age-hardening elements. Continuous service reaches 538°C (1000°F) in oxidising atmospheres, and the alloy maintains full toughness down to liquid hydrogen temperatures without a ductile-to-brittle transition.
The minimum tensile strength of Monel 400 fasteners is 550 MPa (80 ksi), the yield strength is 240 MPa (35 ksi), and the elongation is 35%. These fasteners are available in many types, including Monel 400 hex bolts, stud bolts, socket head cap screws (SHCS), Monel 400 nuts, lock nuts, flat washers, spring washers, threaded rods, U-bolts, anchor bolts, set screws, and eye bolts. Standard sizes range from M6 to M100 in metric and from 1/4 inch to 4 inches in imperial dimensions. Standard lengths range from 16 mm to over 500 mm. Thread forms are available in UNC, UNF, and metric. Monel 400 fasteners are listed to NACE MR0175 / ISO 15156 for sour service applications.
Monel 400 Fastener Specifications
Key Monel 400 fastener specifications like standards, and dimensions are covered in detail in the table below:
| Parameter | Details |
|---|---|
| Bolt / Screw / Stud Spec | ASTM F468 / F468M |
| Nut Spec | ASTM F467 / F467M |
| Bar Stock | ASTM B164 (Class A) |
| Forging Spec | ASTM B564 |
| Bolt Diameter | 1/4” – 1-1/2” (F468); M6 – M36 (F468M); larger from bar stock |
| Length | 16 – 500+ mm |
| Threads | UNC, UNF, Metric; Class 2A/2B or 6g/6H |
| Dimensional Standards | ASME B18.2.1, B18.2.2, B18.3, DIN 931/933/934/912, ISO 4014/4032 |
| Flange Bolting | ASME B16.5, Classes 150 to 2500 |
Monel 400 is listed in ASTM F468 (unlike Hastelloy C22, C2000, or Inconel 718). Always specify the fastener specification (F468 for bolts, F467 for nuts), not the bar stock specification (B164), to apply correct mechanical property requirements.
Chemical Composition of Monel 400 Fasteners
The chemical composition of Monel 400 fasteners and its key alloying elements as per ASTM F468 / ASTM F467 (UNS N04400) is provided in the table below:
| Element | Nickel (Ni) + Cobalt (Co) | Copper (Cu) | Iron (Fe) | Manganese (Mn) | Carbon (C) | Silicon (Si) | Sulfur (S) |
|---|---|---|---|---|---|---|---|
| Composition (%) | 63.0 min | 28.0–34.0 | 2.5 max | 2.0 max | 0.3 max | 0.5 max | 0.024 max |
The 28–34% copper gives Monel 400 bolting its exceptional HF acid and seawater resistance. The Ni-Cu solid solution is thermodynamically stable and does not precipitate secondary phases during service, so bolts retain full corrosion performance indefinitely without heat treatment concerns.
Mechanical Properties of Monel 400 Fasteners
Mechanical properties of Monel 400 fasteners, like tensile and yield strength, elongation, and hardness as per ASTM F468 (bolts/screws/studs) in the hot-formed condition, are covered below:
| Property | Tensile Strength (min) | Yield 0.2% (min) | Elongation (min, 4D) | Hardness | Condition |
|---|---|---|---|---|---|
| Value | 550 MPa (80 ksi) | 240 MPa (35 ksi) | 35% | 110–185 HB (62–90 HRB) | Hot Formed (HF) |
These are ASTM F468 fastener-spec values, not bar stock values from ASTM B164. The 240 MPa yield determines the achievable bolt preload in flange assemblies. Higher preload = better gasket sealing in HF acid service. ASTM F467 nuts: proof stress as per F467 table, hardness 110–185 HB.
Monel 400 Fastener Equivalent Grades
The standard equivalent designation of Monel 400 fastener is UNS N04400, and its Werkstoff Nr. is 2.4360. Some other global equivalents are covered in the table below:
| UNS | Werkstoff | DIN | JIS | GOST | ISO |
|---|---|---|---|---|---|
| N04400 | 2.4360 / 2.4361 | 17752 NiCu30Fe | NW 4400 | МНЖМц 28-2,5-1,5 | 15156 |
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Types of Monel 400 Fasteners Available
Monel 400 bolts, nuts, and studs are stocked in 10 forms as per ASME B18.2.1/B18.2.2/B18.3 and DIN/ISO:
Monel 400 Hex Bolts
UNS N04400 Stud Bolts
Alloy 400 Socket Head Cap Screws
WNR 2.4360 Hex Nuts
ASTM F468 UNS N04400 Lock Nuts
Monel 400 Flat Washers
Monel 400 Threaded Rods
WNR 2.4360 U-Bolts
UNS N04400 Set Screws
Alloy 400 Eye Bolts
Surface Finish and Coating Options for Monel 400 Fasteners
Monel 400 is inherently corrosion-resistant and rarely requires protective coatings. Surface treatments target anti-galling performance, not corrosion protection. The standard finish is plain, also referred to as self-colour. Fasteners can also be passivated using acid passivation to remove free surface iron introduced during machining. PTFE / Xylan coating is used for consistent torque-tension and reduced galling. Manganese phosphate can be applied for thread lubricity. Nickel-based anti-seize is mandatory for assembly (NOT copper-based, which causes galvanic issues with Monel). Hot-dip galvanising is NOT recommended as zinc coating is unnecessary and creates galvanic concerns.
Industries and Applications for Monel 400 Fasteners
- HF alkylation reactor flange studs and nuts, crude distillation column tray bolting, deaerator vessel closure studs, sour gas wellhead valve bonnet bolting (NACE MR0175).
- Hull fitting fasteners, seawater pump casing bolts, propeller shaft coupling studs, splash-zone platform bolting, and subsea valve assembly fasteners.
- Acid storage tank flange bolting (H₂SO₄, HCl, HF), caustic evaporator closure studs (NaOH service), reactor vessel head bolting for reducing-acid processes.
- Boiler feedwater heater tubesheet bolting, condenser waterbox fasteners (seawater-cooled). Bleach plant equipment bolting (ClO₂ service), digester vessel closure studs. RO system flange bolting, brine heater assembly studs, and chlorination system hardware.
How to Order Monel 400 Fasteners
- Fastener Type (hex bolt, stud bolt, nut, washer, SHCS, threaded rod, etc.)
- Material Grade (Monel 400 / UNS N04400 / Werkstoff 2.4360)
- Size / Diameter (e.g., M16, M20, 3/4", 1")
- Thread Type & Pitch (UNC, UNF, metric coarse, metric fine)
- Length (for bolts, studs, screws – specify mm or inches)
- Quantity (number of pieces or weight in kg)
- Applicable Standard (ASTM F468, F467, DIN, ISO)
- Dimensional Standard (ASME B18.2.1, DIN 931, etc.)
- Surface Finish (plain, passivated, PTFE coated, phosphate)
- Test Certificates Required (EN 10204 3.1 / 3.2, PMI report)
- Special Requirements (NACE compliance, impact testing, IGC testing)
- Packaging & Delivery (standard/export, delivery location)
Frequently Asked Questions
What ASTM Specifications Cover Monel 400 Fasteners?
How do you Prevent Galling in Monel 400 Bolt and Nut Assemblies?
Is Monel 400 Bolting Suitable for NACE Sour Service Applications?
Yes. UNS N04400 is listed under NACE MR0175 / ISO 15156 for H₂S environments. The alloy resists sulfide stress cracking and chloride SCC in sour gas conditions. Fasteners must ship in the annealed condition with documented hardness within NACE limits and EN 10204 3.1/3.2 MTCs.
What is the Maximum Service Temperature for Monel 400 Fasteners?
What is the Difference Between ASTM F468 and ASTM B164 for Monel 400 Bolting?
F468 is the finished fastener specification with mechanical property requirements for bolts, screws, and studs. B164 is the bar stock specification for the raw material from which fasteners are machined. Always specify F468 (bolts) or F467 (nuts) when ordering finished fasteners.
Can Monel 400 Bolts Be Paired with Stainless Steel 316 Nuts?
Pairing Monel 400 bolts with SS 316 nuts is not recommended. The galvanic potential difference in electrolytic environments can increase corrosion of the less noble material. Pair Monel 400 bolts with Monel 400 nuts or Monel K-500 nuts (same alloy family, higher hardness for anti-galling benefit). Mixed-material assemblies may be acceptable in dry environments, but need corrosion engineering review.