Stockist & supplier ASTM A240 · ASME SA-240 · ASTM A480
SS 347 Plates — ASTM A240 UNS S34700
SS 347 plate is niobium-stabilised austenitic stainless steel plate for elevated-temperature service. Teshi Group stocks and supplies ASTM A240 / ASME SA-240 347 (UNS S34700) plate and sheet, and 347H against order. Quotes are sent in 24–48 hours.
Also called: 347 plate, UNS S34700 plate, 1.4550 plate, niobium stabilised stainless plate, 347H plate
What is an SS 347 Plate?
Type 347 is an 18-8 austenitic stainless steel stabilised with niobium (columbium) at a minimum of ten times the carbon content. Niobium forms stable carbides, preventing chromium depletion at grain boundaries during welding or service in the sensitising range. 347 has good resistance to intergranular corrosion and good high-temperature properties, and is used in refinery hydro-processing equipment, high-temperature chemical plant, boiler and heater components, and aircraft exhaust parts. 347H has a controlled higher carbon range for creep strength.
Key features
- Stockist and supplier — sourced from stainless mills; Teshi does not manufacture plate
- ASTM A240 / ASME SA-240 Type 347 (UNS S34700)
- Niobium (columbium) stabilised against sensitisation
- 347H (UNS S34709) against order
- Plate and sheet; other sizes supplied against order
- Can be ordered together with flanges, fittings and fabrications manufactured by Teshi
Specification
| Supply | Stockist & supplier — Teshi Group, India, India |
|---|---|
| Standard | ASTM A240 / ASME SA-240; general requirements ASTM A480 |
| Grades | 347 (S34700); 347H (S34709) against order |
| Product forms | Plate (3/16 in / 4.76 mm and thicker per ASTM A480), sheet and coil; other sizes supplied against order |
| Condition | Solution annealed and descaled (pickled) |
| Finish | No.1 (hot rolled, annealed, pickled) for plate; 2B, BA or No. 4 for sheet |
| Testing | Chemical and tensile tests per A240; intergranular corrosion test (ASTM A262) when specified |
| Documents | Mill test certificate to EN 10204 3.1; EN 10204 3.2 / third-party inspection when the order specifies |
Applications
- Refinery hydro-processing reactors and piping parts
- High-temperature chemical plant
- Boiler and heater components
- Aircraft exhaust systems
- Expansion joints
Chemical composition — 347 (ASTM A240)
| UNS | C | Mn | P | S | Si | Cr | Ni | Nb (Cb) |
|---|---|---|---|---|---|---|---|---|
| S34700 (347) | 0.08 | 2.00 | 0.045 | 0.030 | 0.75 | 17.0–19.0 | 9.0–13.0 | 10×C min, 1.00 max |
Maximum unless a range is shown; % by weight. Per ASTM A240 Table 1.
Mechanical properties
| UNS | Tensile, min (MPa) | Yield 0.2%, min (MPa) | Elongation in 50 mm, min (%) | Hardness, max |
|---|---|---|---|---|
| S34700 | 515 | 205 | 40 | 201 HBW / 92 HRB |
Per ASTM A240 Table 2.
Technical data sheets
Dimensions & weights
FAQ
SS 347 Plate: common questions
What does stabilised mean for 347?
Niobium is added to combine with carbon so that chromium carbides do not form at grain boundaries. This keeps the steel resistant to intergranular corrosion after welding or high-temperature exposure.
What is the difference between 347 and 321?
347 is stabilised with niobium, 321 with titanium. Niobium carbides are more stable, and 347 is often preferred in refinery high-temperature service. Both have the same minimum strength under ASTM A240.
When is 347H specified?
When creep strength is needed at elevated temperatures. 347H has a controlled higher carbon content than standard 347. It is ordered against UNS S34709 and is common in refinery and boiler service.
Does Teshi manufacture stainless plate?
No. Teshi Group is a stockist and supplier of SS 347 Plate, sourced from established mills and supplied with the original mill test certificate. Teshi is an OEM manufacturer of flanges, fittings, fasteners, valves and custom fabrications, which can be ordered with it.
Need a size or grade not listed here?
We source against your specification from approved mills, with mill test certificates and inspection before dispatch.
Send us your specificationTraceability
From mill heat to your site
- 01
Approved mill material
Received against the mill certificate; heat number registered.
- 02
Forging & machining
Heat number carried through every stage in our Indian works.
- 03
PMI, dimensional & NDT
Every lot inspected to the governing standard; TPI witness on request.
- 04
Stamped & certified dispatch
Hard-stamped pieces with EN 10204 3.1 / 3.2 certificates.
Quick RFQ
Quote for SS 347 Plate in 24–48 hours
More steel plates
All steel platesSS 317L Plate
ASTM A240 · ASME SA-240
View productSteel Plates904L Plate
ASTM A240 · ASME SA-240
View productSteel PlatesDuplex 2205 Plate
ASTM A240 · ASME SA-240
View productSteel PlatesSuper Duplex 2507 Plate
ASTM A240 · ASME SA-240
View productSteel Plates254 SMO Plate
ASTM A240 · ASME SA-240
View productSteel PlatesHastelloy C276 & C22 Plate
ASTM B575 · ASME SB-575
View product