Monel 400
UNS N04400 EN / W.Nr. 2.4360
The standard nickel-copper grade — seawater, hydrofluoric acid, sulphuric acid under reducing conditions, and salt production. Excellent mechanical properties from cryogenic to about 480 °C.
Monel — Nickel-Copper Alloys (400, K500, R405)
Nickel-copper alloys combining high strength with excellent corrosion resistance in seawater, hydrofluoric acid and a wide range of chemicals — plus a precipitation-hardening grade for shafts and fasteners.
Monel — Material Overview
Monel is the original nickel-copper alloy family (about 67% Ni, 30% Cu). The copper in solid solution gives Monel better resistance than pure nickel to flowing seawater, hydrofluoric acid and reducing chemicals, while retaining good strength from cryogenic to moderately high temperatures.
Monel 400 is the workhorse. Monel K500 adds aluminium and titanium for age-hardening — roughly three times the yield strength of 400 — which suits pump shafts, propeller shafts, oil-well tools and fasteners. Monel R405 is a free-machining version of 400 with controlled sulphur for high-speed automatic lathe work.
3grades listed
8,800 kg/m³typical density (Monel 400 ≈ 8.8; K500 ≈ 8.44 g/cm³)
6product forms
Available Grades
The grades below are the ones most often asked for. Each grade stays on this page — the material-first way to browse.
Monel K500
UNS N05500 EN / W.Nr. 2.4375
Age-hardening nickel-copper-aluminium alloy — same corrosion resistance as 400 with roughly triple the yield strength after heat treatment. Pump and propeller shafts, oil-industry tools, springs and fasteners.
Monel R405
UNS N04405
Free-machining Monel 400 with 0.025–0.060% sulphur for high-speed screw-machine parts — fittings, fasteners and instrument components.
Chemical Composition (indicative)
Nominal ranges as published in the common product standards. Values are indicative and for comparison only — always purchase against the current ASTM/EN specification and the mill test certificate.
Monel 400
| Element | Content |
|---|---|
| Nickel (Ni + Co) | ≥ 63.0 |
| Copper (Cu) | 28.0 – 34.0 |
| Iron (Fe) | ≤ 2.50 |
| Manganese (Mn) | ≤ 2.00 |
| Carbon (C) | ≤ 0.30 |
Monel K500
| Element | Content |
|---|---|
| Nickel (Ni + Co) | ≥ 63.0 |
| Copper (Cu) | 27.0 – 33.0 |
| Aluminium (Al) | 2.30 – 3.15 |
| Titanium (Ti) | 0.35 – 0.85 |
| Carbon (C) | ≤ 0.25 |
Monel R405
| Element | Content |
|---|---|
| Nickel (Ni + Co) | ≥ 63.0 |
| Copper (Cu) | 28.0 – 34.0 |
| Sulphur (S) | 0.025 – 0.060 |
Mechanical Properties (indicative)
Typical minimum values for the common product forms in the annealed / solution-treated condition. Actual properties depend on product form, specification revision and heat treatment.
Monel 400
| Property | Value |
|---|---|
| Tensile strength (min, annealed) | 480 MPa |
| Yield strength (min, annealed) | 170 MPa |
| Elongation (min) | 35 % |
Monel K500
| Property | Value |
|---|---|
| Tensile strength (aged, min) | 895 MPa |
| Yield strength (aged, min) | 585 MPa |
| Elongation (aged, min) | 15 % |
Monel R405
| Property | Value |
|---|---|
| Tensile strength (min) | 480 MPa |
| Yield strength (min) | 170 MPa |
Physical Properties
| Property | Value |
|---|---|
| Density (Monel 400) | 8.80 g/cm³ (8800 kg/m³) |
| Density (Monel K500) | 8.44 g/cm³ (8440 kg/m³) |
| Melting range | ≈ 1300 – 1350 °C |
| Thermal conductivity (20 °C, 400) | ≈ 22 W/m·K |
| Magnetic | Slightly magnetic; K500 becomes more magnetic when aged |
Available Product Forms
Monel is offered in the product forms below. Availability varies by grade and size — confirm the exact combination with our sales desk.
Pipes & Tubes
Seamless and welded pipes and tubes to ASTM/ASME, IS and BS specifications — including boiler, air-preheater and corten tubes.
Sheets, Plates & Coils
Hot-rolled and cold-rolled sheets, plates, coils, circles and flats in standard and cut sizes.
Pipe Fittings
Butt-weld, forged and socket-weld fittings — elbows, tees, reducers, caps, stub ends, olets and nipples.
Flanges
Weld neck, slip-on, blind, lap joint, socket weld, threaded, spectacle, ring joint, orifice and deck flanges to ASME B16.5, 150# – 2500#.
Bars, Rods & Wires
Bright and black round bars, square and hex bars, flats and wires in stainless, duplex, alloy, carbon and nickel-alloy grades.
Fasteners
Bolts, nuts, studs, washers and threaded rods in alloy and stainless grades.
Industrial Applications
- Seawater and brine piping, pump and valve internals
- Hydrofluoric acid and fluorine service
- Salt-production and evaporator equipment
- Propeller and pump shafts (K500)
- Oil-well drill collars and tools
- Fasteners, springs and instrument parts
Applicable Standards
| Standard | Scope |
|---|---|
| ASTM B165 / ASME SB165 | Seamless Monel 400 pipe |
| ASTM B127 / ASME SB127 | Monel 400 plate, sheet and strip |
| ASTM B564 / ASME SB564 | Nickel-alloy forgings (flanges, fittings) |
| ASTM B865 | Monel K500 rod, bar and wire (age-hardening) |
| ASTM B164 | Monel rod, bar and wire |
| ASME B16.5 / B16.47 | Flange dimensions (materials to the above specs) |
Quality & Documentation
Monel is supplied to ASTM/ASME specifications with EN 10204 Type 3.1 certification and heat-number traceability. For K500, the aged condition and hardness are reported. NDE, impact testing (Monel retains toughness to −196 °C) and third-party inspection can be arranged with the enquiry.
Related Engineering Calculators
Pipe Weight Calculator
Theoretical weight of pipe from outside diameter, wall thickness, length and material.
Round Bar Weight Calculator
Theoretical weight of round bars from diameter, length and material.
Sheet & Plate Weight Calculator
Theoretical weight of sheets and plates from length, width, thickness and material.
Technical Flange Calculator
ASME B16.5 dimensions, bolting pattern and weight estimates for 14 flange types.
Unit Conversion Calculator
mm ↔ in, m ↔ ft, kg ↔ t, kg/m ↔ lb/ft and MPa ↔ psi conversions.
Frequently Asked Questions
Is Monel better than stainless steel in seawater?
For full immersion and flowing seawater, Monel 400 generally outperforms 316L — it resists crevice and pitting attack and handles high-velocity seawater well. Super duplex and 625 are competitive alternatives where their strengths apply.
What is Monel K500 used for?
Wherever Monel 400's corrosion resistance is needed but the part is highly stressed: pump shafts, propeller shafts, oil-well tools, bolts and springs. Ageing (precipitation hardening) roughly triples its yield strength versus annealed 400.
Will Monel work in hydrofluoric acid?
Yes — Monel 400 is one of the few metals with good resistance to hydrofluoric acid across a wide range of concentrations, which is why it dominates HF-alkylation and fluorine-handling equipment.
Is Monel magnetic?
Monel 400 is slightly magnetic at room temperature; K500 is weakly magnetic when annealed and noticeably more magnetic after ageing — relevant for instruments and minesweeping applications.
Can Monel be welded?
Yes, with matching fillers (ERNiCu-7 / Monel 60) using standard processes. R405 with its sulphur is not recommended for welding — machine it instead.
Need Monel Priced?
Send the grade, product form, size and quantity — our sales desk replies with an offer and lead time within one business day.