SS 347/347H Round Bars & Rods
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Get a QuoteStainless Steel 347 / 347H Explained
Stainless Steel 347 and 347H are niobium-stabilized austenitic stainless steels. To begin with, they are specifically engineered for excellent resistance to intergranular corrosion and high-temperature oxidation. Furthermore, the stabilization prevents chromium carbide precipitation during welding and prolonged thermal exposure — a common challenge in high-temperature service.
When selecting the right grade for your high-temperature application, consider the following: First, SS 347 offers superior corrosion resistance for general high-temperature service. In addition, SS 347H contains higher carbon content — providing enhanced creep and rupture strength for continuous high-temperature applications.
Consequently, these grades are commonly used in refinery systems, superheaters, and high-temperature pressure vessels. Moreover, they are trusted in petrochemical pipelines and power generation equipment. Equally important, SS 347/347H deliver exceptional structural stability under severe thermal and corrosive operating conditions.
Need expert guidance on selecting the right 347 grade for your application? Contact our technical team today — we’ll help you choose between 347 or 347H based on your operating temperature, creep strength requirements, and corrosion exposure, and provide a competitive quote tailored to your specifications.
Other Types of Stainless Steel 347 / 347H Bars
- Stainless Steel 347 / 347H square bars for precision machining
- UNS S34700 / S34709 stabilized austenitic grades
- Manufactured in accordance with ASTM A276 / ASME SA276
- DIN 1.4550 square bar dimensional standards
- ASME SA276 SS 347 / 347H hexagonal bar supply
- ASTM A276 certified stainless steel hex rods
- DIN 1.4961 / UNS S34700 material compliance
- Bright drawn and polished hex profiles available
- Stainless steel 347 rectangular bar profiles
- UNS S34700 / DIN 1.4550 grade specification
- ASTM A276 compliant rectangular sections
- Machined and polished rectangle bar finishes
- DIN 1.4961 stainless steel flat bar sections
- UNS S34700 flat bars for heavy-duty applications
- Produced as per ASTM A276 / ASME SA276 standards
- Hot rolled, ground and polished surface options
- ASTM A276 SS 347H stainless bright bars
- UNS S34700 / S34709 material grade availability
- Cold drawn, peeled and centerless ground finish
- High precision dimensional tolerance and smooth surface
- UNS S34700 stainless steel forged bar supply
- ASTM A276 compliant SS 347 / 347H forged rods
- Heat treated and rough machined forgings
- High strength forged bars for pressure and thermal service
347/347H STAINLESS STEEL ROUND BAR EQUIVALENT GRADES
| STANDARD | UNS | WNR. | JIS | EN |
|---|---|---|---|---|
| SS 347 | S34700 | 1.4550 | SUS 347 | X6CrNiNb18-10 |
| SS 347H | S34709 | 1.4961 | SUS 347H | X6CrNiNb18-12 |
SPECIFICATION OF STAINLESS STEEL 347/347H ROUND BAR
| Stainless Steel Round Bar Specification | ASTM A276 / A479, ASME SA276 / A479 |
|---|---|
| Dimension Standard | EN, DIN, JIS, ASTM, BS, ASME, AISI |
| Size | 14 mm – 300 mm |
| Thickness | 50 mm to 6000 mm Long |
| Length | 1 to 6 Meters, Custom Cut Length |
| Form | Round, Square, Hex (A/F), Rectangle, Billet, Ingot, Forging Etc. |
CHEMICAL COMPOSITION OF STAINLESS STEEL 347/347H ROUND BAR
| Grade | C% | Cr% | Mn% | Ni% | P% | S% | Si% | Nb + Ta% |
|---|---|---|---|---|---|---|---|---|
| 347 | 0.08 max | 17.0 – 20.0 | 2.0 max | 9.0 – 13.0 | 0.04 max | 0.03 max | 0.75 max | Min 10×C, Max 1.00 |
| 347H | 0.04 – 0.10 | 17.0 – 20.0 | 2.0 max | 9.0 – 13.0 | 0.03 max | 0.03 max | 0.75 max | Min 10×C, Max 1.00 |
MECHANICAL PROPERTIES OF STAINLESS STEEL 347/347H ROUND BAR
| Grade | Tensile Strength (ksi) | Yield Strength 0.2% (ksi) | Elongation (%) in 50 mm | Hardness (Brinell) MAX | Hardness (Rockwell B) MAX |
|---|---|---|---|---|---|
| 347 / 347H | 75 (515 MPa) | 30 (205 MPa) | 40 | 201 | 95 |
PHYSICAL PROPERTIES OF 347/347H STAINLESS STEEL ROUND BAR
| Density lb/in³ | Coefficient of Thermal Expansion (min/in)-°F | Thermal Conductivity BTU/hr-ft-°F | Specific Heat BTU/lb-°F | Modulus of Elasticity (psi) |
|---|---|---|---|---|
| 0.286 at 68°F | 9.2 at 68–212°F 20.5 at 68–1832°F |
9.3 at 200°F | 0.12 at 32–212°F | 28 × 10⁶ (annealed, E) |
Industries That Use Stainless Steel 347 / 347H Round Bars
These grades are preferred in industries where heat resistance, pressure strength, welding reliability, oxidation protection, and long operational service life are required.
Used in high-temperature and high-pressure mechanical systems.
Uses
Boiler parts, superheater components, turbine supports, heat exchangers.
Why SS 347 / 347H?
Excellent thermal stability and oxidation resistance under pressure.
Used in extreme operating conditions involving heat and pressure.
Uses
Refinery piping, pressure vessels, valves, fasteners, reactor supports.
Why SS 347H?
Superior creep strength and durability for continuous high-temperature service.
Used in corrosive and welded process environments.
Uses
Piping systems, shafts, structural frames, fabricated assemblies.
Why SS 347?
Niobium stabilization prevents intergranular corrosion after welding.
Used in heat-resistant structural and load-bearing components.
Uses
Engine supports, brackets, high-temperature fasteners.
Why SS 347H?
Maintains strength and stability at elevated temperatures.
Used in welded pressure and thermal equipment.
Uses
Pressure parts, frames, industrial assemblies.
Why SS 347?
Excellent weldability with resistance to carbide precipitation.
Used in continuous high-temperature operating environments.
Uses
Furnace fixtures, supports, thermal carriers.
Why SS 347H?
Enhanced creep resistance for prolonged thermal exposure.