Stainless Flat Washers
| Standard | DIN 125 · ISO 7089 |
|---|---|
| Material | SS304 / SS316 |
| Strength Grade | — |
| Size Range | M3-M30 |
| Surface Treatment | Passivation |
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Product Description
Product Description & Key Specifications
ISO 7089 / DIN 125 stainless flat washers are supplied in SS304 / SS316 for corrosion-resistant bolted joints that need load distribution, surface protection and consistent bearing under bolt heads or nuts. Common supply range is M3-M30 with passivated finish and project packaging on request.
Flat washers are normally selected together with stainless hex bolts and stainless hex nuts to reduce local surface damage, improve bearing area and support more consistent assembly on slotted holes, painted surfaces, softer components or stainless frames. Washer size should match the bolt diameter, hole clearance, outside diameter and thickness required by the drawing or standard.
SS304 / A2 washers suit general outdoor stainless assemblies, while SS316 / A4 washers are preferred for marine, coastal, washdown and water-treatment environments. Passivation helps improve the stainless surface condition after stamping and supports long-term corrosion resistance in compatible stainless assemblies.
| Product type | Stainless flat washers |
|---|---|
| Standards | ISO 7089 / DIN 125 reference |
| Material | SS304 / SS316 |
| Strength grade | Project/OEM requirement, matched to stainless bolt assemblies |
| Size range | M3-M30, with washer dimensions confirmed by standard or drawing |
| Common models | M6, M8, M10, M12, M16, M20 stainless flat washers |
| Surface finish | Passivated stainless surface |
| Supply form | Washers only or matched bolt-nut-washer sets |
| Documentation | CoC, material certificate and dimensional report on request |
Dimensions & SpecificationsDIN 125A / ISO 7089
Technical Drawing
Dimensional Table
| Parameter | Φ1.6 | Φ1.7 | Φ2 | Φ2.3 | Φ2.5 | Φ2.6 | Φ3 | Φ3.5 | Φ4 | Φ5 | Φ6 | Φ7 | Φ8 | Φ10 | Φ12 | Φ14 | Φ16 | Φ18 | Φ20 | Φ22 | Φ24 | Φ26 | Φ27 | Φ28 | Φ30 | Φ32 | Φ33 | Φ35 | Φ36 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| d/min | 1.7 | 1.8 | 2.2 | 2.5 | 2.7 | 2.8 | 3.2 | 3.7 | 4.3 | 5.3 | 6.4 | 7.4 | 8.4 | 10.5 | 13 | 15 | 17 | 19 | 21 | 23 | 25 | 27 | 28 | 29 | 31 | 33 | 34 | 36 | 37 |
| d/max | 1.84 | 1.94 | 2.34 | 2.64 | 2.84 | 2.94 | 3.38 | 3.88 | 4.48 | 5.48 | 6.62 | 7.62 | 8.62 | 10.77 | 13.27 | 15.27 | 17.27 | 19.33 | 21.33 | 23.33 | 25.33 | 27.33 | 28.33 | 29.33 | 31.39 | 33.62 | 34.62 | 36.62 | 37.62 |
| dc/max | 4 | 4.5 | 5 | 6 | 6 | 7 | 7 | 8 | 9 | 10 | 12 | 14 | 16 | 20 | 24 | 28 | 30 | 34 | 37 | 39 | 44 | 50 | 50 | 50 | 56 | 60 | 60 | 66 | 66 |
| dc/min | 3.7 | 4.2 | 4.7 | 5.7 | 5.7 | 6.64 | 6.64 | 7.64 | 8.64 | 9.64 | 11.57 | 13.57 | 15.57 | 19.48 | 23.48 | 27.48 | 29.48 | 33.38 | 36.38 | 38.38 | 43.38 | 49.38 | 49.38 | 49.38 | 55.26 | 58.8 | 58.8 | 64.8 | 64.8 |
| h/max | 0.35 | 0.35 | 0.35 | 0.55 | 0.55 | 0.55 | 0.55 | 0.55 | 0.9 | 1.1 | 1.8 | 1.8 | 1.8 | 2.2 | 2.7 | 2.7 | 3.3 | 3.3 | 3.3 | 3.3 | 4.3 | 4.3 | 4.3 | 4.3 | 4.3 | 5.6 | 5.6 | 5.6 | 5.6 |
| h/min | 0.25 | 0.25 | 0.25 | 0.45 | 0.45 | 0.45 | 0.45 | 0.45 | 0.7 | 0.9 | 1.4 | 1.4 | 1.4 | 1.8 | 2.3 | 2.3 | 2.7 | 2.7 | 2.7 | 2.7 | 3.7 | 3.7 | 3.7 | 3.7 | 3.7 | 4.4 | 4.4 | 4.4 | 4.4 |
Engineering references
Technical resources
Review the applicable dimensions, drawing and standard relationship before confirming the ordered specification.02
Selection
Selection Advantages by Application
Solar PV Mounting Systems
M8, M10 and M12 stainless flat washers are commonly paired with PV rail bolts, clamps and bracket hardware. SS304 / A2 suits general outdoor projects; SS316 / A4 is preferred for coastal solar installations.
Renewable energy fastenersMarine & Coastal Hardware
SS316 / A4 passivated flat washers help reduce bearing damage under stainless nuts and bolt heads in salt spray or wet outdoor service. Common RFQ sizes include M8, M10, M12 and M16.
Marine fastenersConstruction & Outdoor Structures
M12, M16 and M20 stainless flat washers are used for railings, facade brackets, exposed frames and service platforms where washer bearing area and corrosion resistance both matter.
Construction fastenersRailway & Rolling Stock Equipment
M6, M8, M10 and M12 stainless flat washers support covers, brackets, access panels and maintenance hardware where surface protection and repeatable assembly are needed.
Railway fastenersWater Treatment / Hygienic Equipment
SS316 / A4 passivated washers are suitable for pumps, pipe supports, stainless skids and washdown equipment. Confirm washer diameter, crevice risk, cleanability and certificate requirements before ordering.
Hygienic equipment fasteners03
Assembly
Recommended Matching Products
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Manufacturing
Manufacturing & Quality Control
Manufacturing CapabilityQuality Control
Stamping or machining selected by washer size and quantityIncoming SS304 / SS316 material verification
Deburring and edge finishing after washer formingInner diameter, outer diameter and thickness inspection
Passivation and stainless surface finishingVisual inspection for burrs, deformation and surface defects
Standard, semi-standard and drawing-based washer supplyHardness or salt-spray tests arranged when specified
Bulk, small-box or bolt-nut-washer kit packagingCoC, MTC and inspection report prepared on request
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FAQ
Common Questions Before RFQ
What is the difference between ISO 7089 and DIN 125 washers?
ISO 7089 and DIN 125 are common references for standard flat washers. Many drawings still use DIN 125, while ISO 7089 is often used as the international reference. Confirm washer dimensions and tolerance before ordering.
Should I choose SS304 or SS316 flat washers?
SS304 / A2 is suitable for general corrosion-resistant assemblies. SS316 / A4 is preferred for marine, coastal, washdown, chemical or chloride-exposed environments.
What stainless flat washer sizes are commonly requested?
Common RFQ sizes include M6, M8, M10, M12, M16 and M20 stainless flat washers. Washer dimensions, thickness, material, finish and certificate requirements should be confirmed by standard or drawing.
Can flat washers be supplied with bolts and nuts?
Yes. Stainless flat washers can be supplied alone or as matched bolt-nut-washer sets with DIN 931, DIN 933, ISO 4014, ISO 4017 or drawing-based stainless bolts.
Are passivated stainless washers available?
Yes. Passivation is available for SS304 and SS316 flat washers to improve the stainless surface condition after stamping or machining.
When should I use a flat washer?
Flat washers are used to distribute load, protect the mating surface and support more consistent bearing under a bolt head or nut. Critical joints should follow the project drawing and assembly standard.
Need ISO 7089 / DIN 125 stainless flat washers?
Send your washer standard, size, material, quantity, surface finish, packaging and certificate requirements. Our team can match washers with stainless bolts and nuts for project procurement.
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