SS 904L WasherUNS N08904 · ASME B18.22.1 · Manufacturer, trader & exporter, India
Alloy 904L · UNS N08904
An SS 904L washer is a flat or spring ring that spreads bolt load. Finished fastener specification not asserted; material and manufacturing route not asserted — alloy (UNS N08904), dimensions and finished requirements are to the purchase specification. Flat washers protect the joint surface and spread load; spring and lock washers resist loosening. Match the washer material to the bolt to avoid galvanic corrosion.
See the SS 904L fasteners grade form page for standards and sizes.
- UNS N08904
- ASME B18.22.1
- EN 10204 3.1 / 3.2
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is an SS 904L Washer?
- What it is
- A flat or spring ring that spreads bolt load
- Finished spec
- Not asserted
- Material / feedstock
- Not asserted — alloy (UNS N08904), dimensions and finished requirements are to the purchase specification
- Dimensions
- ASME B18.22.1 · DIN 125 (legacy DIN)
- Grade
- SS 904L · UNS N08904
- Best at
- Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water
SS 904L Washer Specification
| Product | SS 904L Washer |
|---|---|
| Finished fastener specification | Not asserted |
| Material / feedstock specification | Not asserted — alloy (UNS N08904), dimensions and finished requirements are to the purchase specification |
| Dimensional standard | ASME B18.22.1 · DIN 125 (legacy DIN) |
| Manufacturing route | Not asserted |
| Project / purchase specification | Yes — finished fastener requirements are to the purchase specification or project drawing |
| Sizes | To suit M10 – M64 · ½" – 4" bolts (others on request) |
| Testing | PMI (as specified in the PO) · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 or 3.2 on request / as specified in the PO |
When to Choose a Washer
Flat washers protect the joint surface and spread load; spring and lock washers resist loosening. Match the washer material to the bolt to avoid galvanic corrosion.
- Flat, spring and lock
- ASME B18.21.1 · DIN 125 / 127 (legacy DIN)
- Material to match the bolt
More on choosing: Washer guide.
SS 904L Washer: Why 904L for washers
Flat washers protect the joint surface and spread load; spring and lock washers resist loosening. Match the washer material to the bolt to avoid galvanic corrosion. In SS 904L, the choice usually comes down to the medium and temperature — the rows here are the points buyers check for this exact combination.
| Why this grade | Stainless fasteners resist atmospheric and process corrosion. SS 904L is picked for dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water. |
|---|---|
| Typical service | Sulphuric acid plants — Coolers, piping and tanks for dilute sulphuric acid. |
| Bolting | as the project specifies |
SS 904L Washer Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Nickel | As specified |
| Chromium | As specified |
| Molybdenum | As specified |
| Copper | As specified |
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Nitrogen | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM A240 for UNS N08904.
SS 904L Washer Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
| Hardness | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification and condition to be verified: ASTM A240 for UNS N08904 — Annealed plate & sheet.
Full chemistry, properties and equivalents are on the SS 904L grade page.
Standards on this page
Other SS 904L fasteners
SS 904L Washer — questions buyers ask
Do I need washers on flange bolting?
Many specifications require through-hardened washers under nuts for controlled tightening; follow the project bolting spec.
What nut is used with SS 904L washers?
Usually a nut in the same alloy — it may be machined from ASTM A479 bar, where applicable; finished requirements are to the purchase specification or project drawing.
Which standard covers SS 904L washers?
Finished fastener specification: Not asserted. Material / feedstock: Not asserted — alloy (UNS N08904), dimensions and finished requirements are to the purchase specification. Dimensions: ASME B18.22.1 · DIN 125 (legacy DIN). State the finished specification, material and dimensions on your purchase order or project drawing.
What decides the price of a SS 904L washer?
The alloy price, the size and dimensions, quantity, and the testing and documents required. Send your list and we quote the same working day.
What documents do you supply?
EN 10204 3.1 or 3.2 certificates available on request / as specified in the PO; dimensional reports as required. PMI can be arranged depending on product and requirements, as specified in the PO.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026