UNS S31603

316L Flat washers

ISO 7089 / ISO 7090ASTM A240

For 316L washers, molybdenum-bearing stainless performance in wet 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

Upload drawing

Which standard is on your order?

Raw Material Specifications

Dimension Reference

Heat Treatment

Solution annealed; cold worked for strengthened conditions

Solution annealing restores a ductile corrosion-resistant structure, while specified cold work raises strength without precipitation aging.

What we can make in 316L

normal flat washer, top view

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.

large flat washer, top view

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 flat washer, top view

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 · Cold worked
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 316L fits — and what matters

Stainless steel fermentation tanks with circular access doors and pipe fittings in a brewery

Food & Beverage Equipment

Conveyor and washdown-equipment brackets

316L 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.

Bore clearance · bearing diameter · thickness
Food & Beverage Equipment fasteners
Water-treatment machinery with parallel green pipes, gray pumps and yellow access platforms

Water Treatment & Desalination

Membrane-skid and pump supports

316L 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.

Bore clearance · bearing diameter · thickness
Water Treatment & Desalination fasteners
White centrifugal pump with a bolted casing, black inlet hose and worn paint

Pumps, Valves & OEM

Actuator mounts and pump baseplates

316L 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.

Bore clearance · bearing diameter · thickness
Pumps, Valves & OEM fasteners

Same washer. Different material priorities.

316L material data
UNS S17400

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.
17-4 PH flat washers
UNS N06625

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.
Inconel 625 flat washers
UNS S31803 / S32205

Duplex 2205

Duplex strength and chloride-corrosion resistance.

Connection priority
Bearing pressure and resistance to dishing
S31803 or S32205
The specified UNS fixes the chemistry. Solution treatment, section size and the ordered mechanical or corrosion tests establish the final duplex condition. Include liquid retained at the two bearing faces and the bore around the shank in the exposure description.
Duplex 2205 flat washers

From drawing to documented delivery

Heat treatment
Heat treatment
CNC machining
CNC machining
Rockwell hardness testing
Rockwell hardness testing
Wooden-crate packing
Wooden-crate packing
  1. 01Drawing & BOMForm, dimensions and quantity
  2. 02Material & formingGrade, heat and manufacturing route
  3. 03Final inspectionGeometry, threads and ordered tests
  4. 04Documents & dispatchLot records and identified packing

Order documents

Material identity
UNS S31603 · 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 316L washer enquiry

QUOTE LIST ITEM316L flat washers; UNS S31603; Plain washer

Questions about 316L 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.

Technical references & photo credits