Stainless Steel 347/347H Tubes Manufacturer & Supplier
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Midland Alloys, a leading 347H Tubing Manufacturer in India, produces premium quality tubes designed for high performance in demanding environments. These tubes are stabilized with niobium for enhanced resistance to intergranular corrosion, even after exposure to high temperatures. We produce them utilizing innovative procedures including cold drawing and seamless extrusion to achieve precise dimensional precision, flawless finish, and reliable strength. Our SS 347/347H Tubing meets ASTM A312 / ASME SA312 standards, making it suitable for critical applications worldwide. We provide UNS S34700/S34709 Tubing in sizes ranging from 6NB to 1200NB, outer diameters from 1/8″ NPS to 12″ NPS, and thicknesses from 0.6 mm to 12.7 mm. Our commitment to quality and timely delivery is consistent.
Benefits of UNS S34700 / S34709 Tubing
UNS S34700 and S34709 Tubing performs well in harsh environments, making it a popular choice in a variety of sectors.
- High Temperature Resistance – Performs reliably in continuous service up to 870°C.
- Corrosion Resistance – Resists oxidation and scaling in harsh environments.
- Intergranular Corrosion Resistance – Maintains strength after welding and exposure to high heat.
- Weldability – Can be welded using standard techniques without loss of corrosion resistance.
- Creep Strength – Holds structural integrity under prolonged stress at elevated temperatures.
Specification of 347/347H Stainless tube
Seamless Tube OD : 1 / 2" NB - 16" NB
Welded Tube OD : 1 / 2" NB - 24" NB
EFW Tube Size : 6.00 mm OD up to 914.4 mm OD
ASTM A213, A269, A249, A511, A554 / ASME SA213, SA269, SA249, SA511, SA554
Seamless / Welded / ERW / Fabricated / CDW / 100% X Ray Welded
Round, Square, Rectangular, Hydraulic Etc
Single Random, Double Random, Standard & Cut length
Plain Ends (PE), Threaded Ends (TE), Bevelled Ends (BW), Grooved Mechanical Joints or Grooved Ends, TBE (Treaded Both Ends)
SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXS, SCH XS
2B, No.4, No.1, No.8 Mirror Finish for Stainless Steel Tubes, Finish as per customer Requirements
Contact us today to discuss how Stainless Steel 347/347H Tubes can benefit your application. Whether you need guidance in selecting the right Tubes or have specific requirements, our team of experts is here to help you find the optimal solution.
Technical Details & Delivery Condition
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | |
| 347 | min. | – | – | – | – | – | 17.0 | 2.00 | 9.0 | – |
| max. | 0.08 | 2.0 | 1.00 | 0.045 | 0.030 | 20.0 | 3.00 | 13.0 | – | |
| 347H | min. | 0.04 | – | – | – | – | 17.0 | 3.00 | 9.0 | – |
| max. | 0.10 | 2.0 | 1.00 | 0.045 | 0.030 | 19.0 | 4.00 | 13.0 | – | |
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | |
| 347 | min. | – | – | – | – | – | 17.0 | 2.00 | 9.0 | – |
| max. | 0.08 | 2.0 | 1.00 | 0.045 | 0.030 | 20.0 | 3.00 | 13.0 | – | |
| 347H | min. | 0.04 | – | – | – | – | 17.0 | 3.00 | 9.0 | – |
| max. | 0.10 | 2.0 | 1.00 | 0.045 | 0.030 | 19.0 | 4.00 | 13.0 | – | |
| Grade | UNS No | Old British | Euronorm | Swedish SS | Japanese JIS | ||
| BS | En | No | Name | ||||
| 347 | S34700 | – | X6CrNiNb18-10 | 1.4550 | – | – | – |
| 347H | S34709 | – | – | 1.4961 | – | – | – |
Stainless Steel Tubes Grades We Offer
Difference Between Stainless Steel 347 Tubing and 321 Stainless Steel Tube
Stainless Steel 347 Tubing and 321 Stainless Steel Tube are both stabilized grades but the stabilizing ingredients differ. SS 347 is stabilized with niobium, whereas 321 is stabilized with titanium. This gives SS 347 better resistance to intergranular corrosion after welding and improved high-temperature strength compared to 321. ASTM A213 TP347 Tubes also handle slightly higher creep strength requirements than 321 Stainless Steel tubes, making them better for continuous service in extreme heat.
Round Bar
Analytic
Cut to Length
Centering
Heating
Perforation
Inspection of Size
Pickling
Inspection of Surface
Lubricating
Cold Drawing (Cold Rolling)
Degreasing
Annealing
Straightening
Cut
Pickling / Passivating
Inspection
Analytic
Marking
Packing & Shipping
Applications of DIN 1.4550 / 1.4961 SS Tubes
DIN: 1.4550 / 1.4961 SS Tubes are commonly used in the oil and gas industry for heat exchangers and pipes on offshore sites and refineries. In chemical processing plants, SS 347/347H Tubing is used for reactor vessels, transfer piping, and evaporators that handle aggressive chemicals. ASTM A213 TP347 Tubes are also used in power production facilities for boiler tubes and superheaters, where heat resistance is required. The aerospace industry uses them in exhaust manifolds, jet engine parts, and other high-temperature components.
Why Choose Midland Alloys Inc. for ASTM A213 TP347 Tubes
Midland Alloys Inc. is a trusted SS 347/347H Tube Supplier in Mumbai with years of experience. Our products meet the ISO 9001:2015, PED 2014/68/EU, and EN 10204 3.1/3.2 certification standards. We support third-party inspections by TÜV, BV, SGS, and DNV. We collaborate closely with engineering firms, EPC contractors, marine operators, and chemical facilities to deliver on time with complete export documents. Every tube undergoes strict in-house and independent testing, including Hydrostatic Testing for pressure resistance, Ultrasonic Testing for internal flaws, Radiographic Testing for weld seam quality, and PMI for grade verification. Mechanical tests like tensile, hardness, flattening, and bend tests are carried out as per order. With our commitment to quality and reliable supply, we make sure every ASTM A213 TP347 Tube meets the highest standards.
FAQs – SS 317/317H Tubes
Stainless Steel 347H Tubes can handle continuous service temperatures up to around 870°C (1600°F) and intermittent service up to 925°C (1700°F), making them suitable for high-heat applications.
Yes. SS 347 Tubes are safe for food-grade applications, especially in high-temperature cooking, sterilizing, or pasteurization processes.
No post-weld heat treatment is usually required, however cleaning and passivation are recommended to restore corrosion resistance.
