SS 347 WasherUNS S34700 · ASME B18.22.1 · Manufacturer, trader & exporter, India
AISI 347 · UNS S34700
An SS 347 washer is a flat or spring ring that spreads bolt load. Finished fastener specification not asserted; material and manufacturing route not asserted — alloy (UNS S34700), 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.
- UNS S34700
- 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 347 Washer?
- What it is
- A flat or spring ring that spreads bolt load
- Finished spec
- Not asserted
- Material / feedstock
- Not asserted — alloy (UNS S34700), dimensions and finished requirements are to the purchase specification
- Dimensions
- ASME B18.22.1 · DIN 125 (legacy DIN)
- Grade
- SS 347 · UNS S34700
- Best at
- Welded high-temperature piping in refineries and power plants
SS 347 Washer Specification
| Product | SS 347 Washer |
|---|---|
| Finished fastener specification | Not asserted |
| Material / feedstock specification | Not asserted — alloy (UNS S34700), 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 347 Washer: Why 347 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 347, 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 347 is picked for welded high-temperature piping in refineries and power plants. |
|---|---|
| Typical service | Refinery hydroprocessing — Reactor effluent piping and exchangers. |
| Bolting | ASTM A193 B8C studs with A194 8C nuts |
SS 347 Washer Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Chromium | As specified |
| Nickel | As specified |
| Niobium | As specified |
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Phosphorus | As specified |
| Sulphur | 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 S34700.
SS 347 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 S34700 — Annealed plate & sheet.
Full chemistry, properties and equivalents are on the SS 347 grade page.
Standards on this page
Other SS 347 fasteners
SS 347 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 347 washers?
ASTM A194 8C heavy hex nuts.
Which standard covers SS 347 washers?
Finished fastener specification: Not asserted. Material / feedstock: Not asserted — alloy (UNS S34700), 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 347 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