A-286 Flat Washers
ISO 7089 / ISO 7090AMS 5525 / AMS 5858
A-286 flat washers provide an age-hardened bearing seat for turbine covers, hot valve hardware and exhaust supports. Elevated-temperature strength is useful beneath loaded nuts and bolt heads, with washer condition and dimensions selected for the seating pressure and heat cycle.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Solution treated and aged
EN 10204 3.1 MTC + heat-number traceability
Which standard is on your order?
Raw Material Specifications
Dimension Reference
Heat Treatment
Solution treated and agedSolution treatment prepares A-286 for precipitation aging, which develops strength for elevated-temperature loading.
What we can make in A-286
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
- Solution treated and aged
- 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 A-286 fits — and what matters
Gas & steam turbine casing joints
A-286 Flat WashersOn turbine casing and auxiliary cover joints, A-286 washers carry the nut pressure onto the machined seat. Age hardening provides bearing strength at elevated temperature. Matching thickness across a washer set also keeps the stud projection and tightening access consistent around the casing.
Connection requirements
- Operating metal temperature
- Nut bearing area and washer hardness
- Washer thickness and stud projection
Exhaust manifolds & expansion bellows
A-286 Flat WashersA-286 washers support bolt-head or nut pressure on exhaust brackets through heating and cooling cycles. Their aged hot strength is useful where a softer washer could deform at the operating temperature. On a slotted expansion support, washer thickness and the clamping arrangement must leave the designed thermal travel available.
Connection requirements
- Hot bracket temperature
- Slot width and required travel
- Washer span and thickness
High-pressure valve bonnets
A-286 Flat WashersHot valve bonnet joints can impose a high seating pressure beneath the nut. An age-hardened A-286 washer provides a replaceable bearing surface for that load and repeated overhaul tightening. Specifying the washer condition with the stud and nut avoids mixing a strengthened fastener with a soft seating component.
Connection requirements
- Bonnet stud preload
- Final heat-treatment condition
- Spotface diameter and washer flatness
Same washer. Different material priorities.
A-286 material dataInconel 718 Flat Washers
Age-hardened Inconel 718 washers are useful beneath high-preload turbine and valve fasteners, particularly where the seat diameter is restricted. Their strength helps resist permanent indentation at the bearing face. This is a different priority from choosing 625 washers mainly for wet corrosion resistance; the 718 heat-treatment condition belongs on the washer order.
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.
Monel K-500 Flat Washers
K-500 washers add bearing strength to marine bolted joints while retaining the nickel-copper alloy family used in seawater equipment. They are most useful where the loaded seat is compact. Age-hardened condition and mating fastener load matter more here than a generic seawater label; cathodically protected subsea assemblies require a separate hydrogen-susceptibility review.
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 S66286 · 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 A-286 washer enquiry
Questions about A-286 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.