SS 347 U-boltUNS S34700 · MSS SP-58 / manufacturer standard · Manufacturer, trader & exporter, India
AISI 347 · UNS S34700
An SS 347 u-bolt is a U-shaped bolt for clamping pipes to supports. Finished fastener specification not asserted; UNS S34700 material — requirements to the purchase specification or project drawing. U-bolts hold pipes to supports and structures. Sized by pipe NPS with a threaded length on each leg.
- UNS S34700
- MSS SP-58 / manufacturer standard
- 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 U-bolt?
- What it is
- A U-shaped bolt for clamping pipes to supports
- Finished spec
- Not asserted
- Material / feedstock
- UNS S34700 material; product form to the purchase specification
- Dimensions
- MSS SP-58 / manufacturer standard
- Grade
- SS 347 · UNS S34700
- Best at
- Welded high-temperature piping in refineries and power plants
SS 347 U-bolt Specification
| Product | SS 347 U-bolt |
|---|---|
| Finished fastener specification | Not asserted |
| Material / feedstock specification | UNS S34700 material; product form to the purchase specification |
| Dimensional standard | MSS SP-58 / manufacturer standard |
| Manufacturing route | Route dependent on product design and purchase specification |
| Project / purchase specification | Yes — finished fastener requirements are to the purchase specification or project drawing |
| Sizes | M10 – M64 · ½" – 4" (others on request) |
| Threads | UNC · UN-8 · metric coarse |
| 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 an U-bolt
U-bolts hold pipes to supports and structures. Sized by pipe NPS with a threaded length on each leg.
- Sized to pipe NPS
- With nuts and plates
- Matching or isolated material
More on choosing: U-bolt guide.
SS 347 U-bolt: Why 347 for u-bolts
U-bolts hold pipes to supports and structures. Sized by pipe NPS with a threaded length on each leg. 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 U-bolt 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 U-bolt 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 U-bolt — questions buyers ask
Should U-bolts match the pipe material?
Use the same alloy, or an isolating sleeve, to avoid galvanic corrosion between pipe and bolt.
What nut is used with SS 347 u-bolts?
ASTM A194 8C heavy hex nuts.
Which standard covers SS 347 u-bolts?
Finished fastener specification: Not asserted. Material / feedstock: UNS S34700 material; product form to the purchase specification. Dimensions: MSS SP-58 / manufacturer standard. State the finished specification, material and dimensions on your purchase order or project drawing.
What decides the price of a SS 347 u-bolt?
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