SS 347 UnionASTM A182 · MSS SP-83 · Manufacturer, stockist & exporter, India
AISI 347 · UNS S34700
An SS 347 union is a three-piece forged fitting that joins pipes and can be taken apart, made from SS 347 to ASTM A182 F347. Unions let a small-bore line be disconnected for maintenance without cutting. Made to MSS SP-83 in threaded or socket-weld ends.
- ASTM A182
- MSS SP-83
- 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 Union?
- What it is
- A three-piece forged fitting that joins pipes and can be taken apart
- Material
- ASTM A182 F347
- Dimensions
- MSS SP-83
- Grade
- SS 347 · UNS S34700
- Best at
- Welded high-temperature piping in refineries and power plants
SS 347 Union Specification
| Product | SS 347 Union |
|---|---|
| Material standard | ASTM A182 F347 |
| Dimensional standard | MSS SP-83 |
| Sizes | ⅛" – 4" (ASME B16.11) |
| Wall / class | Class 2000 / 3000 / 6000 / 9000 |
| Ends | Socket weld · NPT threaded |
| Testing | PMI · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
When to Choose an Union
Unions let a small-bore line be disconnected for maintenance without cutting. Made to MSS SP-83 in threaded or socket-weld ends.
- Three pieces: nut, male and female ends
- Threaded or socket weld
- Class 3000 / 6000
SS 347 Union 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 Union 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 pipe fittings
SS 347 Union — questions buyers ask
Can unions be used in high-pressure lines?
Class 3000 and 6000 unions are rated for high pressure on small bores, but many codes limit their use in hazardous service.
Which standard covers SS 347 unions?
The material is ASTM A182 F347; dimensions follow MSS SP-83. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a SS 347 union?
The alloy price, the size and schedule or class, 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