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Monel K500 Fasteners Supplier in Mumbai, India – Bolts, Nuts, Screws
Nicorex Alloys is ISO 9001 / ISO 14001 certified supplier, importer, and stockist of Monel K500 fasteners in Mumbai, India. We import and supply age-hardened UNS N05500 bolting solutions, providing superior yield strength and resistance to hydrogen embrittlement for critical subsea sour gas service.
Monel K500 is the age-hardened version of Monel 400. Same nickel-copper base, but 2.3–3.15% aluminium and 0.35–0.85% titanium trigger Ni₃(Ti,Al) gamma-prime precipitation hardening. Per ASTM F468: 130 ksi tensile (896 MPa) / 90 ksi yield (620 MPa) minimum, roughly 2.3–3× the strength of Monel 400 with no loss of seawater or HF acid corrosion resistance. K-Monel is unique in being the age-hardenable alloy that offers a combination of high strength, resistance to seawater, resistance to hydrogen embrittlement (HF resistance), and low magnetic permeability. This combination has made it the traditional high-strength bolting material of choice for marine use. At the same time, Monel K-500 offers outstanding age-hardened strength with the advantage of being non-magnetic.
UNS N05500, Werkstoff 2.4375. Supplied per ASTM F468 (bolts/screws/studs) and ASTM F467 (nuts). Bar stock per ASTM B865 / QQ-N-286. Types: Monel K500 hex bolts, stud bolts, SHCS, Monel K500 nuts, lock nuts, washers, threaded rods, U-bolts, set screws, and eye bolts. Sizes: 1/4” to 1-1/2” per F468; larger to M100 / 4” from B865 bar. Hardness: 24–37 HRC (aged). Elongation: 20%. NACE MR0175 / ISO 15156 listed (≤35 HRC).
Monel K500 Fastener Specifications
The following table shows the specifications of Monel K500 fasteners, including standards, dimensions, sizes, conditions, forms and other required information as per project needs:
| ASTM / ASME Standard | ASTM B865 / ASME SB-865 |
|---|---|
| Forms | Bolts, Nuts, Screws, Washers, Studs, Threaded Rods, Hex Bolts, Socket Head Cap Screws, Hex Nuts, Lock Nuts, Stud Bolts |
| Size | M6 – M100 (Metric); 1/4″ – 4″ (Imperial) |
| Length | 3 mm – 200 mm; Custom lengths available |
| Diameter | M6 – M100 (Metric); 1/4″ – 4″ (Imperial) |
| Thread Types | UNC, UNF, Metric Coarse, Metric Fine, BSW, BSF |
| Surface Finishes | Bright Finish, Pickled, Passivated, Hot-Dip Galvanised, Electropolished |
| Available Conditions | Hot Finished, Cold Drawn, Age Hardened |
Monel K500 IS listed in ASTM F468 (UNS N05500). F468 covers sizes 1/4” to 1-1/2”. Larger fasteners are machined from ASTM B865 bar. Always specify SA+A (aged) condition for high-strength applications.
Chemical Composition of Monel K500 Fasteners
The chemical composition of Monel K-500, as per ASTM F468, is given in the table below, with a focus on the most important components of aluminium and titanium in the hardening process.
| Nickel (Ni) | Copper (Cu) | Aluminium (Al) | Titanium (Ti) | Iron (Fe) | Carbon (C) | Manganese (Mn) | Silicon (Si) |
|---|---|---|---|---|---|---|---|
| 63.0 min | Balance (~27–33) | 2.30–3.15 | 0.35–0.85 | 2.00 max | 0.25 max | 1.50 max | 0.50 max |
Al (2.3–3.15%) and Ti (0.35–0.85%) are the key additions over Monel 400, which does not contain intentional Al or Ti. Together they form Ni₃(Ti,Al) gamma-prime precipitates during ageing heat treatment, transforming the soft Monel 400 matrix into a high-strength fastener material. Per F468: K500 yields 90 ksi vs 400 yields 30–40 ksi, a 2.3–3× strength increase with no loss of corrosion resistance.
Mechanical Properties of Monel K500 Fasteners
The mechanical properties of Monel K-500 are discussed below, with a focus on the high tensile and yield strength developed through solution annealing and ageing.
| Property (1/4”–7/8”) | Tensile Strength (min) | Yield 0.2% (min) | Elongation (min) | Hardness |
|---|---|---|---|---|
| Value | 896 MPa (130 ksi) | 620 MPa (90 ksi) | 20% | 24–37 HRC |
For 1”–1-1/2” diameter: yield minimum drops to 586 MPa (85 ksi). Per ASTM B865, typical aged bar values reach 965–1241 MPa (140–180 ksi) tensile / 690–930 MPa (100–135 ksi) yield. These are B865 typical aged values, not F468 minimums. K500 retains useful strength to 480°C (900°F) and maintains ductility to -196°C (liquid nitrogen).
Per F468: K500 yield (90 ksi) vs Monel 400 yield (30–40 ksi) = approximately 2.3–3× higher bolt preload per fastener. This directly reduces flange size and weight in marine equipment.
Monel K500 Fastener Equivalent Grades
The international designations of UNS N05500 are given below to ensure that the material meets the specifications for procurement and engineering purposes.
| UNS | Werkstoff | DIN | BS | Federal (US) | ASTM (Fasteners / Bar) | NACE / ISO |
|---|---|---|---|---|---|---|
| N05500 | 2.4375 | NiCu30Al | 3076 NA18 | QQ-N-286 | F468 / B865 | MR0175 / ISO 15156 (≤35 HRC) |
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Types of Monel K500 Fasteners Available
Alloy K500 bolts, nuts, and studs are stocked in 10 forms per ASME B18.2.1/B18.2.2/B18.3:
Monel K500 Hex Bolts
Monel K500 Stud Bolts
Monel K500 Socket Head Cap Screws
Monel K500 Hex Nuts
Monel K500 Lock Nuts
Monel K500 Flat Washers
Monel K500 Threaded Rods
Monel K500 U-Bolts
Monel K500 Set Screws
Monel K500 Eye Bolts
Surface Finish and Coating Options
Monel K500 is highly prone to galling when mated against itself or other nickel alloys. Always use anti-seize compound or thread treatment. Plain / self-colour (standard for marine service; inherent passivation in seawater). Passivated per ASTM A967. Silver plated for elevated-temperature anti-seize. PTFE coated for anti-galling with dissimilar metals. Nickel-based anti-seize recommended; copper-based acceptable for Monel-to-Monel assembly. Consider pairing a Monel 400 nut on K500 studs for a hardness differential that reduces galling.
Industries and Applications for Monel K500 Fasteners
High-strength marine bolting, seawater fatigue resistance, and low magnetic permeability drive K-Monel selection:
- Industries in which Monel K500 Fasteners are generally used are as follows:
- High-strength marine bolting, seawater fatigue resistance, and low magnetic permeability drive K-Monel selection:
- Propeller shaft coupling bolts, rudder stock studs, sea chest flange bolting, seawater pump fasteners, hull-mounted transducer housings, MCMV structural bolting, and non-magnetic sensor housing fasteners.
- HF acid alkylation unit flange bolting, sour gas wellhead studs (≤35 HRC), downhole tool joints, and production separator bolting in H₂S/CO₂ environments.
- HF handling equipment bolting, caustic soda plant studs, deaerated acid service fasteners. Pump shaft studs, impeller retaining bolts, valve stem fasteners. Non-magnetic fasteners for electronic warfare systems, submarine components, and torpedo hardware.
- Doctor blade clamping bolts, paper machine suction roll fasteners, bleach plant equipment in chloride-free zones.
How to Order Monel K500 Fasteners From Nicorex Alloys
Please provide following details to place an order for Monel K500 Fasteners
- Fastener Type (Hex Bolt, Stud Bolt, Socket Head Cap Screw, Nut, Washer, Threaded Rod, Anchor Bolt)
- Size (Diameter × Length in mm or inches)
- Thread Type (UNC, UNF, BSW, Metric Coarse/Fine)
- Material Grade (Monel K500 / UNS N05500)
- Standard (ASTM F468 / ASTM F467 / ASME SA193 B865)
- Finish (Bare, Passivated, Hot-Dip Galvanised)
- Hardness & Strength (Age-hardened condition per specification)
- Quantity (number of pieces or kg)
- Additional Requirements (NACE MR0175 compliance, subsea service, specific heat numbers)
- Documentation (MTC 3.1 per EN 10204, PMI report, third-party inspection certificate)
- Packaging (Standard wooden box / export-grade sea-worthy packing / ISPM 15 compliant)
- Delivery destination (domestic / international)
Frequently Asked Questions
What Is the Difference Between Monel K500 and Monel 400?
Same Ni-Cu base, but K500 adds 2.3–3.15% Al and 0.35–0.85% Ti for precipitation hardening. Per ASTM F468: K500 achieves 130 ksi min tensile / 90 ksi min yield vs 400’s 80 ksi / 35 ksi. B865 typical aged values reach 160 ksi / 115 ksi. Corrosion resistance is substantially equivalent, though K500 in aged condition has greater tendency toward stress-corrosion cracking. Choose 400 for general marine bolting at lower cost. Choose K500 when high preload, fatigue resistance, or low magnetic permeability are required.
Why Does Monel K500 Gall Severely During Assembly?
The Ni-Cu matrix is inherently soft at the thread surface, and K500’s high strength means greater clamping forces during tightening. Prevention: (1) always use anti-seize compound, (2) pair Monel 400 nuts on K500 studs for hardness differential, (3) PTFE-coated or manganese phosphate-treated threads, (4) slow, steady torque application with calibrated equipment.
Is Hydrogen Embrittlement a Risk for Monel K500 Bolting?
Yes, at hardness >35 HRC, K500 becomes susceptible to hydrogen-assisted cracking in cathodically protected marine environments. Limit hardness to ≤35 HRC for cathodically protected or subsea bolting. Avoid excessive cathodic protection potentials (<-1050 mV vs Ag/AgCl). Request hydrogen embrittlement testing per ASTM F1624 for critical applications.