Stainless Steel 310H Flat washers
ISO 7089 / ISO 7090ASTM A240
For Stainless Steel 310H washers, controlled-carbon stainless performance for sustained hot loading 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 annealedSolution annealing and rapid cooling retain alloying elements in solution and restore the specified corrosion-resistant condition.
What we can make in Stainless Steel 310H
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 ordered annealed or solution-treated state is retained in the lot record; forming and machining do not replace the specified thermal condition.
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 310H fits — and what matters
Furnaces & Heat Treatment
Heat-treatment fixturesStainless Steel 310H flat washers spread bolt or nut bearing load across heat-treatment fixtures, protecting the seating surface and bridging the specified hole clearance. Hot dwell, thermal expansion and repeated furnace cycles set the working load.
Power & Turbines
Boiler-duct supports and hot auxiliary bracketsStainless Steel 310H flat washers spread bolt or nut bearing load across boiler-duct supports and hot auxiliary brackets, protecting the seating surface and bridging the specified hole clearance. Hot dwell and start-stop expansion act on the supported or moving component.
Chemical Processing
Reformer tube-support and heater fixturesStainless Steel 310H flat washers spread bolt or nut bearing load across reformer tube-support and heater fixtures, protecting the seating surface and bridging the specified hole clearance. These parts work in the heated equipment zone, where sustained loading and thermal expansion govern their section and clearance.
Same washer. Different material priorities.
Stainless Steel 310H material dataIncoloy 800HT
Tightly controlled carbon and Al + Ti for creep duty.
- Connection priority
- Bearing pressure and resistance to dishing
- N08811 material control
- 800HT tightens the 800-family chemistry around creep performance. Its solution-treated, coarse-grain condition and N08811 identity should remain linked through forming and final acceptance. At the two bearing faces and the bore around the shank, the relevant metal temperature can differ from the process or furnace set point.
Inconel 718
Precipitation-hardened strength for compact, highly loaded connections.
- Connection priority
- Bearing pressure and resistance to dishing
- Strength after aging
- Machine-stock properties and final aged properties describe different states. The final heat-treatment lot and mechanical results establish the strength available in the installed part. At the two bearing faces and the bore around the shank, the relevant metal temperature can differ from the process or furnace set point.
A-286
Aged iron–nickel alloy strength for hot bolting.
- Connection priority
- Bearing pressure and resistance to dishing
- Grade 660 class
- An ASTM A453 Grade 660 order includes its class and corresponding processing requirements. The alloy name A-286 alone does not identify that acceptance condition. At the two bearing faces and the bore around the shank, the relevant metal temperature can differ from the process or furnace set point.
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 S31009 · 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 310H washer enquiry
Questions about 310H 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.