Stainless Steel 347/347H Pipes Manufacturer
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Midland Alloys Inc. is a reputable stainless steel pipe manufacturer and supplier from India that offers precisely engineered solutions for a range of demanding industries. Excellent resistance to intergranular corrosion is ensured by the austenitic stainless steel used to make our 347 and 347H pipes which are stabilized with tantalum and niobium. These pipes provide longer service life and structural integrity in applications requiring extended thermal exposure because they are made to function high temperature environments. The high carbon version 347H is ideal for thermal piping systems, chemical processing facilities and pressure vessels because it offers improved creep resistance.
Benefits of Stainless Steel 347 Seamless Pipes
- Excellent stabilization against chromium carbide precipitation
- Enhanced resistance to intergranular attack in oxidizing environments
- Performs well under continuous operation above 800°C
- Non-magnetic in annealed condition
- Superior weldability with low risk of sensitization
- Maintains tensile strength at elevated temperatures
- Composed of chromium-nickel with added niobium for enhanced stability
- Suitable for forming, bending, and deep-drawing processes
Difference Between Stainless Steel 347/347H Pipes and Stainless Steel 316 Pipes
Stainless Steel 347/347H Pipes differ from Stainless Steel 316 Pipes primarily in stabilization and thermal performance. While 316 pipes contain molybdenum for improved corrosion resistance in chloride-rich environments, 347/347H pipes are stabilized using niobium to prevent intergranular corrosion caused by carbide precipitation during high-temperature exposure. This makes 347/347H superior for continuous service in the 425–875°C range. 347H’s higher carbon content improves mechanical integrity and creep strength in thermal circuits and pressure vessels something that 316 might not be able to support as consistently under extended high-temperature service.
Technical Specifications of Stainless Steel 347 / 347H Pipes
Seamless Pipe OD : 1/8 -12" NPS
Welded Pipe OD : 6.35 to 114.3 mm
EFW Pipe Size : 6″ NB – 24″ NB
ASTM A312 / ASME SA312
Seamless, ERW, Welded, Fabricated
Round, Square, Rectangular, Hydraulic Etc
Single Random, Double Random & Cut Length.
Plain End, Beveled End, Treaded
SCH5, SCH10, SCH20, SCH30, SCH40, STD, SCH80, SCH 80S, SCH60, SCH80, SCH120, SCH140, SCH160, SCH XXS, SCH XS
No. 2B - Mill finish/ Matte finish, No.8 - Mirror finish, No. 4 - Brushed finish, Bright, Annealing, Polished, Mirror
Types of Stainless Steel 347 / 347H Pipes
Manufacturing Types
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Seamless PipeWeld-free, perfect for even strength and sizing precision.
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Welded PipeWelded from flat-rolled steel, widely used where economy and large sizes are required.
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ERW PipeElectric Resistance Welded (ERW) pipes provide neat, high quality weld seams and are ideal for medium-pressure applications.
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EFW PipeElectric Fusion Welded (EFW) pipes are welded by fusion welding, usually applied in larger diameters and high-demand processes.
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LSAWLongitudinal Submerged Arc Welded (LSAW) pipes provide straight seam welding which is favored for thick-wall pieces and structural requirements.
Pipe Forms
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Round PipeThe most common shape for fluid and gas transport.
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Square PipeUsed in architectural and structural applications requiring angular profiles.
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Rectangular PipeProvides greater strength in load-bearing regions and flat structures.
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Hydraulic PipeDesigned to provide precise dimensional control for fluid systems under pressure.
Contact us today to discuss how Stainless Steel 347/347H Pipes can benefit your application. Whether you need guidance in selecting the right pipes or have specific requirements, our team of experts is here to help you find the optimal solution.
Technical Details & Delivery Condition
| Grade | Ni | Mn | Si | S | C | Cr | P | Mo | N | |
| TP347 | min. | 9.0 | – | – | – | – | 17.0 | – | 2.00 | – |
| max. | 13.0 | 2.0 | 1.00 | 0.030 | 0.08 | 20.0 | 0.045 | 3.00 | – | |
| TP347H | min. | 9.0 | – | – | – | 0.04 | 17.0 | – | 3.00 | – |
| max. | 13.0 | 2.0 | 1.00 | 0.030 | 0.10 | 19.0 | 0.045 | 4.00 | – | |
| Grade | Tensile Strength minimum (MPa) | Yield Strength 0.2% Proof minimum (MPa) | Elongation minimum (% in 50mm) | Hardness | |
| Rockwell B (HR B) maximum | Brinell (HB) maximum | ||||
| 347 | 515 | 205 | 40 | 95 | 201 |
| 347H | 515 | 205 | 40 | 92 | 201 |
| GRADE / MATERIAL | UNS (USA) | WERKSTOFF NR. (Germany) |
| ASTM A312 347 | S34700 | 1.4550 |
| TP 347H | S34709 | 1.4961 |
Stainless Steel Pipe Grades We Also Offer
Stainless Steel 347/347H Pipe Dimensions
| Stainless Steel OD mm | Pipe WT mm | in. | Sch | Kg/m |
| 13.72 | 1.65 | 1/4 | 10S | 0.50 |
| 13.72 | 2.24 | 1/4 | 40S | 0.64 |
| 13.72 | 3.02 | 1/4 | 80S | 0.81 |
| 17.15 | 1.65 | 3/8 | 10S | 0.64 |
| 17.15 | 2.31 | 3/8 | 40S | 0.86 |
| 17.15 | 3.20 | 3/8 | 80S | 1.12 |
| 21.34 | 2.11 | 1/2 | 10S | 1.02 |
| 21.34 | 2.77 | 1/2 | 40S | 1.29 |
| 21.34 | 3.73 | 1/2 | 80S | 1.65 |
| 26.67 | 2.11 | 3/4 | 10S | 1.30 |
| 26.67 | 2.87 | 3/4 | 40S | 1.71 |
| 26.67 | 3.91 | 3/4 | 80S | 2.23 |
| 33.40 | 2.77 | 1 | 10S | 2.13 |
| 33.40 | 3.38 | 1 | 40S | 2.54 |
| 33.40 | 4.55 | 1 | 80S | 3.29 |
| 33.40 | 6.35 | 1 | 160 | 4.30 |
| 42.16 | 2.77 | 1¼ | 10S | 2.73 |
| 42.16 | 3.56 | 1¼ | 40S | 3.44 |
| 42.16 | 4.85 | 1¼ | 80S | 4.53 |
| 42.16 | 6.35 | 1¼ | 160 | 5.69 |
| 48.26 | 2.77 | 1½ | 10S | 3.16 |
| 48.26 | 3.68 | 1½ | 40S | 4.11 |
| 48.26 | 5.08 | 1½ | 80S | 5.49 |
| 60.33 | 2.77 | 2 | 10S | 3.99 |
| 60.33 | 3.91 | 2 | 40S | 5.52 |
| 60.33 | 5.54 | 2 | 80S | 7.60 |
| 60.33 | 8.74 | 2 | 160 | 11.29 |
| 73.03 | 3.05 | 2½ | 10S | 5.35 |
| 73.03 | 5.16 | 2½ | 40S | 8.77 |
| 73.03 | 7.01 | 2½ | 80S | 11.59 |
| 88.90 | 3.05 | 3 | 10S | 6.56 |
| 88.90 | 5.49 | 3 | 40S | 11.47 |
| 88.90 | 7.62 | 3 | 80S | 15.51 |
| 88.90 | 11.13 | 3 | 160 | 21.67 |
| 101.60 | 3.05 | 3½ | 10S | 7.53 |
| 101.60 | 5.74 | 3½ | 40S | 13.78 |
| 101.60 | 8.08 | 3½ | 80S | 18.92 |
| 114.30 | 3.05 | 4 | 10S | 8.50 |
| 114.30 | 6.02 | 4 | 40S | 16.32 |
| 114.30 | 8.56 | 4 | 80S | 22.67 |
| 114.30 | 13.49 | 4 | 160 | 34.05 |
| 141.30 | 6.55 | 5 | 40S | 22.10 |
| 141.30 | 9.53 | 5 | 80S | 31.44 |
| 141.30 | 15.88 | 5 | 160 | 49.87 |
| 168.28 | 3.40 | 6 | 10S | 14.04 |
| 168.28 | 7.11 | 6 | 40S | 28.69 |
| 168.28 | 10.97 | 6 | 80S | 43.21 |
| 168.28 | 14.27 | 6 | 120 | 54.75 |
| 168.28 | 18.26 | 6 | 160 | 68.59 |
| 219.08 | 8.18 | 8 | 40S | 43.20 |
| 219.08 | 12.70 | 8 | 80S | 65.63 |
| 219.08 | 18.23 | 8 | 120 | 91.30 |
| 219.08 | 23.01 | 8 | 160 | 112.97 |
Stainless Steel 347/347H Thickness Chart
| Nominal size [inches] | Outside diameter [inches] | Outside diameter [mm] | Wall thickness [inches] | Wall thickness [mm] | Weight [lb/ft] | Weight [kg/m] |
| 1/8 | 0.405 | 10.3 | 0.095 | 2.41 | 0.31 | 0.47 |
| 1/4 | 0.54 | 13.7 | 0.119 | 3.02 | 0.54 | 0.8 |
| 1/2 | 0.84 | 21.3 | 0.147 | 3.73 | 1.09 | 1.62 |
| 3/4 | 1.05 | 26.7 | 0.154 | 3.91 | 1.47 | 2.2 |
| 1 | 1.315 | 33.4 | 0.179 | 4.55 | 2.17 | 3.24 |
| 1 1/4 | 1.66 | 42.2 | 0.191 | 4.85 | 3 | 4.47 |
| 1 1/2 | 1.9 | 48.3 | 0.2 | 5.08 | 3.63 | 5.41 |
| 2 | 2.375 | 60.3 | 0.218 | 5.54 | 5.02 | 7.48 |
| 2 1/2 | 2.875 | 73 | 0.276 | 7.01 | 7.66 | 11.41 |
| 3 | 3.5 | 88.9 | 0.3 | 7.62 | 10.25 | 15.27 |
| 3 1/2 | 4 | 101.6 | 0.318 | 8.08 | 12.5 | 18.63 |
| 4 | 4.5 | 114.3 | 0.337 | 8.56 | 14.98 | 22.32 |
| 5 | 5.563 | 141.3 | 0.375 | 9.53 | 20.78 | 30.97 |
| 6 | 6.625 | 168.3 | 0.432 | 10.97 | 28.57 | 42.56 |
| 8 | 8.625 | 219.1 | 0.5 | 12.7 | 43.39 | 64.64 |
| 10 | 10.75 | 273 | 0.594 | 15.09 | 64.43 | 96.01 |
| 12 | 12.75 | 323.8 | 0.688 | 17.48 | 88.63 | 132.08 |
| 14 | 14 | 355.6 | 0.75 | 19.05 | 106.13 | 158.1 |
| 16 | 16 | 406.4 | 0.844 | 21.44 | 136.61 | 203.53 |
| 18 | 18 | 457 | 0.938 | 23.83 | 170.92 | 254.55 |
| 20 | 20 | 508 | 1.031 | 26.19 | 208.87 | 311.17 |
| 24 | 24 | 610 | 1.125 | 30.96 | 296.58 | 442.08 |
How SS 347 Pipes Are Manufactured
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 AISI 347 Stainless Steel Pipe
AISI 347 and 347H Stainless Steel Pipes are commonly used in industries requiring high heat resistance, mechanical strength, and corrosion protection. These pipes have high temperatures in aircraft exhaust systems without losing their structural integrity. They move aggressive gases and fluids in chemical processing facilities without experiencing corrosion fatigue. For high pressure and high-temperature cracking operations where material integrity is crucial petroleum refineries depend on 347H pipes. For long-term, safe operation under continuous heat exposure and pressure cycling, these pipes are also utilized in high-pressure boilers, superheaters and reheaters.
Why Choose Midland Alloys Inc. for ASTM A312 TP347H Stainless Steel Pipe
We are known for precise manufacturing in accordance with ASTM A312, EN, and ISO-certified standards. A well known manufacturer and exporter of high-quality 347/347H stainless steel pipes from India. Our facilities provide complete customization including non standard schedules, surface treatments, special end finishes and cut-to-length. We provide dependable logistics and compliance while meeting a variety of project needs in the Gulf, Europe, Africa, and Southeast Asia.
In addition to undergoing extensive internal testing, which includes hydrostatic pressure, PMI and flattening tests, each pipe is supplied with Mill Test Certificates (MTC) and, upon request, third-party inspections. We accommodate project-specific delivery schedules and are equally skilled in handling bulk and small-batch orders. Our commitment lies in building long-term partnerships, maintaining product integrity, and ensuring total client satisfaction. All pipes are clearly marked as per ASTM/ASME specifications (e.g., ASTM A312 / SA312) and are accompanied by Mill Test Certificates (MTCs) that verify full chemical and mechanical compliance.
Frequently Asked Questions (FAQs)
347 Pipes are commonly used in high-temperature applications like heat exchangers, boilers, and exhaust systems.
347H contains higher carbon content, improving creep resistance and strength at elevated temperatures.
No, in its annealed condition, 347 stainless steel remains non-magnetic.
