304L Flat washers
ISO 7089 / ISO 7090
For 304L washers, low-carbon austenitic compatibility with fabricated stainless equipment is only useful with a bearing section that stays flat under load. Bore, outside diameter and thickness match the head or nut to the supported member.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Solution annealed
EN 10204 3.1 MTC + heat-number traceability
Which standard is on your order?
Raw Material Specifications
Dimension Reference
Heat Treatment
Solution annealed; cold worked for strengthened conditionsSolution annealing restores a ductile corrosion-resistant structure, while specified cold work raises strength without precipitation aging.
What we can make in 304L
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 annealed
- 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
The final annealed or specified strengthened condition is linked to the lot; an aging treatment is not assumed for a solid-solution alloy.
Finished geometry
Thickness, flatness and edge finish establish the bearing geometry; the washer is not labelled hardened solely because the alloy is corrosion resistant.
Where 304L fits — and what matters
Food & Beverage Equipment
Conveyor and washdown-equipment brackets304L flat washers spread bolt or nut bearing load across conveyor and washdown-equipment brackets, protecting the seating surface and bridging the specified hole clearance. Cleaning liquid can remain under the part; exposed finish and access for cleaning matter at the assembled joint.
Water Treatment & Desalination
Membrane-skid and pump supports304L flat washers spread bolt or nut bearing load across membrane-skid and pump supports, protecting the seating surface and bridging the specified hole clearance. The water stream, cleaning cycle and retained liquid define exposure at the installed part.
Pumps, Valves & OEM
Actuator mounts and pump baseplates304L flat washers spread bolt or nut bearing load across actuator mounts and pump baseplates, protecting the seating surface and bridging the specified hole clearance. Repeated maintenance makes fit, engagement and access part of the component specification.
Same washer. Different material priorities.
304L material data316L
Molybdenum-bearing stainless performance in wet equipment.
- Connection priority
- Bearing pressure and resistance to dishing
- Washdown and retained cleaner
- Cleaner concentration, rinse quality and deposits determine the exposure in covered joints. The low-carbon designation does not independently establish a fastener strength class. Include liquid retained at the two bearing faces and the bore around the shank in the exposure description.
17-4 PH
Aging-controlled strength and hardness.
- Connection priority
- Bearing pressure and resistance to dishing
- H900 versus H1150
- The aging condition changes the balance of strength, hardness and toughness. A replacement part needs the specified H condition, especially where contact wear and shock load occur together.
Inconel 625
Solid-solution strength and resistance to aggressive process liquids.
- Connection priority
- Bearing pressure and resistance to dishing
- Annealed or solution-annealed 625
- The delivery condition affects strength and high-temperature response. Keep the specified condition with the component’s mechanical acceptance; 718-style aging is not the strengthening route for 625. Include liquid retained at the two bearing faces and the bore around the shank in the exposure description.
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 S30403 · heat number · ordered condition
- Final-part acceptance
- Grade chemistry, supplied condition and ordered mechanical requirements.
- Dimensional record
- Bore · Outside diameter · Thickness · Burrs
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Build your 304L washer enquiry
Questions about 304L 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.