SS 347 WasherASTM A193 · ASME B18.22.1 · Manufacturer, stockist & exporter, India
AISI 347 · UNS S34700
An SS 347 washer is a flat or spring ring that spreads bolt load, made from SS 347 to ASTM A193 B8C. 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.
- ASTM A193
- 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
- Material
- ASTM A193 B8C
- Dimensions
- ASME B18.22.1 · DIN 125
- Grade
- SS 347 · UNS S34700
- Best at
- Welded high-temperature piping in refineries and power plants
SS 347 Washer Specification
| Product | SS 347 Washer |
|---|---|
| Material standard | ASTM A193 B8C |
| Dimensional standard | ASME B18.22.1 · DIN 125 |
| Sizes | M10 – M64 · ½" – 4" (others on request) |
| Threads | UNC · UN-8 · metric coarse |
| Testing | PMI · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
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
- 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
| Element | Weight % |
|---|---|
| Chromium | 17.0 – 19.0 |
| Nickel | 9.0 – 13.0 |
| Niobium | 10 × C min, 1.00 max |
| Carbon | 0.08 max |
| Manganese | 2.00 max |
| Silicon | 0.75 max |
| Phosphorus | 0.045 max |
| Sulphur | 0.030 max |
SS 347 Washer Mechanical Properties
| Annealed plate & sheet | Value |
|---|---|
| Tensile strength | 515 MPa · 75 ksi |
| Yield strength 0.2% | 205 MPa · 30 ksi |
| Elongation | 40% |
| Hardness | 201 HB max |
Full chemistry, properties and equivalents are on the SS 347 grade page.
Other SS 347 fasteners
SS 347 Washers for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 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?
The material is ASTM A193 B8C; dimensions follow ASME B18.22.1 · DIN 125. Always state both on your purchase order, with the edition if your project specifies one.
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 mill certificates as standard, 3.2 with third-party inspection on request, plus dimensional and PMI reports.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026