Monel K-500 Flat Washers
ISO 7089 / ISO 7090ISO 6208
Age-hardened Monel K-500 washers suit loaded marine joints where a compact bearing face needs greater resistance to permanent deformation than annealed Monel 400 can provide. Their nickel-copper corrosion resistance is useful on pump, valve and deck-equipment hardware, with the seawater retained beneath the washer included in material selection.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Annealed / age hardened
EN 10204 3.1 MTC + heat-number traceability
Which standard is on your order?
Raw Material Specifications
Dimension Reference
Heat Treatment
Annealed or age hardenedAnnealing provides a workable starting condition, while controlled aging develops the higher strength specified for age-hardened K-500.
What we can make in Monel K-500
Normal series
Use under bolt heads and nuts on machined equipment faces with adequate surrounding seat area. The bore must clear the bolt shank and under-head radius so the washer lies flat.
Larger outside diameter
Use over slots, oversized holes and softer mounting surfaces to spread the bearing load. Washer thickness matters as well as diameter: a thin wide washer can dish over an unsupported opening.
Square & special profiles
Use on channel supports, slotted bases and special mounting pads where a round washer leaves insufficient support. Profile and hole position keep the bearing plate seated across the actual opening.
- Geometry
- Bore × outside diameter × thickness
- Forms
- Round · Square · Drawing profiles
- Function
- Bearing surface · Spacing
- Sizing
- Metric · Inch
- Final condition
- Annealed · age hardened
- Inspection
- Bore · Outside diameter · Thickness · Burrs
Manufacturing route
Small lots can be machined from suitable stock; repeat production uses cut or punched blanks with bore and outer edge finishing.
Heat treatment & final condition
Solution treatment and the specified aging condition are recorded against the production lot; final dimensions are checked after thermal processing.
Finished geometry
Final condition and hardness are chosen for bearing load, then flatness and parallel faces are checked after thermal processing.
Where K-500 fits — and what matters
Deck winches & topside equipment
Monel K-500 Flat WashersWinch bases and deck-mounted machinery transfer bolt loads through washers onto mounting plates. Age-hardened K-500 is useful when a compact washer must resist indentation under a highly loaded nut. Its marine corrosion resistance suits exposed hardware, while a wider outside diameter can accommodate the clearance holes in the baseplate.
Connection requirements
- Baseplate hole size and bearing area
- Installed bolt load
- Washer age-hardening condition
Seawater pumps
Monel K-500 Flat WashersA K-500 washer supports the nut on a heavily loaded seawater-pump cover. The hardened condition offers more resistance to permanent seating deformation than annealed Monel 400. Water retained beneath a washer is a crevice, however, so the pump flange exposure is more relevant than the alloy’s performance in freely flowing seawater.
Connection requirements
- Nut and spotface dimensions
- Washer hardness and thickness
- Drainage and retained seawater at the seat
Marine valve bonnets
Monel K-500 Flat WashersMarine valve bonnet nuts need a stable seat as the cover is removed and retightened during maintenance. K-500 washers pair a hard bearing surface with nickel-copper corrosion resistance. The washer’s inside chamfer or bore clearance must keep it off any stud fillet so the load bears on the full face.
Connection requirements
- Stud transition and inside-edge clearance
- Bonnet bearing-face diameter
- Matched washer condition and nut load
Same washer. Different material priorities.
Monel K-500 material dataMonel 400 Flat Washers
Monel 400 washers provide replaceable nickel-copper seats on marine flanges and pump covers. They suit bearing loads supported by the specified material condition and thickness. Water retained under the seat determines the local corrosion exposure, which can differ substantially from the flowing seawater inside the equipment.
Inconel 625 Flat Washers
Inconel 625 washers provide replaceable bearing faces on seawater-pump covers and chemical flange joints. Their nickel-chromium-molybdenum corrosion resistance is useful where liquid remains beneath the nut after exposed surfaces dry. Thickness and outside diameter let the washer support the nut pressure on a compact spotface or span a wider support opening.
Super Duplex 2507 Flat Washers
2507 washers combine high strength with super duplex chloride resistance for seawater covers, brackets and brine equipment. They are useful where the bearing face is highly loaded and 2205 offers insufficient corrosion margin. The underside is still a crevice, making temperature, deposits and chlorination relevant to the washer selection.
From drawing to documented delivery
- 01Drawing & BOMForm, dimensions and quantity
- 02Material & formingGrade, heat and manufacturing route
- 03Final inspectionGeometry, threads and ordered tests
- 04Documents & dispatchLot records and identified packing
Order documents
- Material identity
- UNS N05500 · heat number · ordered condition
- Final-part acceptance
- Lot-linked aging record and mechanical acceptance in the final condition.
- Dimensional record
- Bore · Outside diameter · Thickness · Burrs
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Build your K-500 washer enquiry
Questions about K-500 flat washers
Should the washer use the same alloy as the bolt?
The wetted assembly may need matching corrosion resistance, but the washer also needs sufficient bearing strength and thickness. The bolt grade does not by itself specify a hardened or load-rated washer.