Chung Metal offers superior Stainless Steel 347H Hollow Bars, which are specifically engineered for applications demanding high creep resistance and long-term strength at high temperatures. SS 347H is a high-carbon variant of 347, possessing superior mechanical properties in harsh heat applications. Produced with close internal and external diameter tolerances, these hollow bars can be precision machined, welded, or applied in high-pressure systems. Perfect for heat-demanding industrial applications, Chung Metal’s 347H hollow bars are relied on in thermal processing, power generation, and oil refining processes. Their tubular structure provides minimal weight retention yet is capable of maintaining performance integrity under mechanical and thermal stresses.
SS 347H has 17–19% chromium, 9–13% nickel, and higher carbon (0.04–0.10%) than regular 347, with addition of niobium stabilization. It provides tensile strength of 550–750 MPa, yield strength of 200–300 MPa, and elongation of 30–40%. It can be used continuously up to 900°C temperature. The grade gives higher resistance towards stress rupture and creep deformation. The hollow bar design minimizes total material volume but is easily machinable and fabricable. It is not magnetic and is suitable in pressure-containing, welded, or high-heat applications.
| Standard | ASTM A276 / A479, ASME SA276 / A479 |
| Round Bar Size | 3mm~ 800mm |
| Square Bar Size | 4mm* 4mm ~100mm* 100mm |
| Flat Bar Size | 2mm ~ 100mm |
| Hex Bar Size | 2mm ~ 100mm |
| Angle Size | 3mm* 20mm* 20mm~ 12mm* 100mm* 100mm |
| 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 |
| Grade | C | Mn | Si | P | S | Cr | Co + Ta | Ni | Fe |
| SS 347H | 0.08 max | 2 max | 0.75 max | 0.045 max | 0.03 max | 17 – 20 | 10xC min 1.00 max | 9 – 13 | 62.74 |
| Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 8.0 g/cm3 | 1454 °C (2650 °F) | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 40 % |
| STANDARD | WERKSTOFF NR. | UNS | JIS | BS | GOST | AFNOR | EN |
| SS 347h | 1.4550 | S34700 | SUS 347 | – | 08Ch18N12B | – | X6CrNiNb18-10 |
| Stainless Steel 347h Hollow Bar Size | Chucked true to OD | Chucked true to ID | |||||||
| OD, mm | ID, mm | Max. OD, mm | Min. ID, mm | Max. OD, in. | Min. ID, in. | Max. OD, mm | Min. ID, mm | Max. OD, in. | Min. ID, in. |
| 32 | 20 | 31 | 21.9 | 1.220 | 0.862 | 30 | 21 | 1.185 | 0.827 |
| 32 | 16 | 31 | 18 | 1.220 | 0.709 | 30 | 17 | 1.181 | 0.669 |
| 36 | 25 | 35 | 26.9 | 1.378 | 1.059 | 34.1 | 26 | 1.343 | 1.024 |
| 36 | 20 | 35 | 22 | 1.378 | 0.866 | 34 | 21 | 1.339 | 0.827 |
| 36 | 16 | 35 | 18.1 | 1.378 | 0.713 | 33.9 | 17 | 1.335 | 0.669 |
| 40 | 28 | 39 | 29.9 | 1.535 | 1.177 | 38.1 | 29 | 1.500 | 1.142 |
| 40 | 25 | 39 | 27 | 1.535 | 1.063 | 38 | 26 | 1.496 | 1.024 |
| 40 | 20 | 39 | 22.1 | 1.535 | 0.870 | 37.9 | 21 | 1.492 | 0.827 |
| 45 | 32 | 44 | 33.9 | 1.732 | 1.335 | 43.1 | 33 | 1.697 | 1.299 |
| 45 | 28 | 44 | 30 | 1.732 | 1.181 | 43 | 29 | 1.693 | 1.142 |
| 45 | 20 | 44 | 22.2 | 1.732 | 0.874 | 42.8 | 21 | 1.685 | 0.827 |
| 50 | 36 | 49 | 38 | 1.929 | 1.496 | 48 | 37 | 1.890 | 1.457 |
| 50 | 32 | 49 | 34.1 | 1.929 | 1.343 | 47.9 | 33 | 1.886 | 1.299 |
| 50 | 25 | 49 | 27.2 | 1.929 | 1.071 | 47.8 | 26 | 1.882 | 1.024 |
| 56 | 40 | 55 | 42 | 2.165 | 1.654 | 54 | 41 | 2.126 | 1.614 |
| 56 | 36 | 55 | 38.1 | 2.165 | 1.500 | 53.9 | 37 | 2.122 | 1.457 |
| 56 | 28 | 55 | 30.3 | 2.165 | 1.193 | 53.7 | 29 | 2.114 | 1.142 |
| 63 | 50 | 62 | 51.9 | 2.441 | 2.043 | 61.1 | 51 | 2.406 | 2.008 |
| 63 | 45 | 62 | 47 | 2.441 | 1.850 | 61 | 46 | 2.402 | 1.811 |
| 63 | 40 | 62 | 42.2 | 2.441 | 1.661 | 60.8 | 41 | 2.394 | 1.614 |
| 63 | 36 | 62 | 38.3 | 2.441 | 1.508 | 60.7 | 37 | 2.390 | 1.457 |
| 63 | 32 | 62 | 34.4 | 2.441 | 1.354 | 60.6 | 33 | 2.386 | 1.299 |
| 71 | 56 | 69.9 | 58 | 2.752 | 2.283 | 68.9 | 57 | 2.713 | 2.244 |
| 71 | 45 | 69.9 | 47.3 | 2.752 | 1.862 | 68.6 | 46 | 2.701 | 1.811 |
| 71 | 40 | 69.9 | 42.4 | 2.752 | 1.669 | 68.5 | 41 | 2.697 | 1.614 |
| 71 | 36 | 69.9 | 38.5 | 2.752 | 1.516 | 68.4 | 37 | 2.693 | 1.457 |
| 75 | 60 | 73.8 | 62 | 2.906 | 2.441 | 72.8 | 61 | 2.866 | 2.402 |
| 75 | 50 | 73.8 | 52.2 | 2.906 | 2.055 | 72.6 | 51 | 2.858 | 2.008 |
| 75 | 40 | 73.8 | 42.5 | 2.906 | 1.673 | 72.3 | 41 | 2.846 | 1.614 |
| 80 | 63 | 78.8 | 65 | 3.102 | 2.559 | 77.8 | 64 | 3.063 | 2.520 |
| 80 | 50 | 78.8 | 52.4 | 3.102 | 2.053 | 77.4 | 51 | 3.047 | 2.008 |
| 80 | 45 | 78.8 | 47.5 | 3.102 | 1.870 | 77.3 | 46 | 3.043 | 1.811 |
| 80 | 40 | 78.8 | 42.6 | 3.102 | 1.677 | 77.2 | 41 | 3.039 | 1.614 |
| 85 | 67 | 83.7 | 69.1 | 3.295 | 2.720 | 82.6 | 68 | 3.252 | 2.677 |
| 85 | 55 | 83.7 | 57.4 | 3.295 | 2.260 | 82.3 | 56.0 | 3.240 | 2.205 |
| 85 | 45 | 83.7 | 47.6 | 3.295 | 1.874 | 82.1 | 46.0 | 3.232 | 1.811 |
| 90 | 71 | 88.6 | 73.1 | 3.488 | 2.878 | 87.6 | 72.1 | 3.449 | 2.839 |
| 90 | 63 | 88.6 | 65.3 | 3.488 | 2.571 | 87.3 | 64.0 | 3.437 | 2.520 |
| 90 | 56 | 88.6 | 58.5 | 3.488 | 2.303 | 87.1 | 57.0 | 3.429 | 2.244 |
| 90 | 50 | 88.6 | 52.6 | 3.488 | 2.071 | 87.0 | 51.0 | 3.425 | 2.008 |
| 95 | 75 | 93.5 | 77.3 | 3.681 | 3.041 | 92.4 | 76.2 | 3.641 | 2.997 |
| 95 | 67 | 93.5 | 69.3 | 3.681 | 2.728 | 92.2 | 68.0 | 3.630 | 2.677 |
| 95 | 50 | 93.5 | 52.7 | 3.681 | 2.075 | 91.8 | 51.0 | 3.614 | 2.008 |
| 100 | 80 | 98.5 | 82.3 | 3.878 | 3.240 | 97.4 | 81.2 | 3.835 | 3.197 |
| 100 | 71 | 98.5 | 73.4 | 3.878 | 2.890 | 97.2 | 72.1 | 3.827 | 2.839 |
| 100 | 63 | 98.5 | 65.5 | 3.878 | 2.579 | 97.0 | 64.0 | 3.819 | 2.520 |
| 100 | 56 | 98.5 | 58.7 | 3.878 | 2.311 | 96.8 | 57.0 | 3.811 | 2.244 |
| 106 | 80 | 104.4 | 82.5 | 4.110 | 3.248 | 103.1 | 81.2 | 4.059 | 3.197 |
| 106 | 71 | 104.4 | 73.5 | 4.110 | 2.894 | 103.0 | 72.1 | 4.055 | 2.839 |
| 106 | 63 | 104.4 | 65.7 | 4.110 | 2.587 | 102.7 | 64.0 | 4.043 | 2.520 |
| 106 | 56 | 104.4 | 58.9 | 4.110 | 2.319 | 102.5 | 57.0 | 4.035 | 2.244 |
| 112 | 90 | 110.3 | 92.5 | 4.343 | 3.642 | 109.2 | 91.4 | 4.299 | 3.598 |
| 112 | 80 | 110.3 | 82.6 | 4.343 | 3.252 | 108.9 | 81.2 | 4.287 | 3.197 |
| 112 | 71 | 110.3 | 73.7 | 4.343 | 2.902 | 108.7 | 72.1 | 4.280 | 2.839 |
| 112 | 63 | 110.3 | 65.8 | 4.343 | 2.591 | 108.5 | 64.0 | 4.272 | 2.520 |
| 118 | 90 | 116.2 | 92.7 | 4.575 | 3.650 | 114.9 | 91.4 | 4.524 | 3.598 |
| 118 | 80 | 116.2 | 82.8 | 4.575 | 3.260 | 114.6 | 81.2 | 4.512 | 3.197 |
| 118 | 71 | 116.2 | 73.8 | 4.575 | 2.906 | 114.5 | 72.1 | 4.508 | 2.839 |
| 118 | 63 | 116.2 | 66.0 | 4.575 | 2.598 | 114.2 | 64.0 | 4.496 | 2.520 |
| 125 | 100 | 123.1 | 102.7 | 4.846 | 4.043 | 121.9 | 101.5 | 4.799 | 3.996 |
| 125 | 90 | 123.1 | 92.8 | 4.846 | 3.654 | 121.7 | 91.4 | 4.791 | 3.598 |
| 125 | 80 | 123.1 | 82.9 | 4.846 | 3.264 | 121.4 | 81.2 | 4.780 | 3.197 |
| 125 | 71 | 123.1 | 74.0 | 4.846 | 2.913 | 121.3 | 72.1 | 4.772 | 2.839 |
| 132 | 106 | 130.0 | 108.8 | 5.118 | 4.283 | 128.8 | 107.6 | 5.071 | 4.236 |
| 132 | 90 | 130.0 | 93.0 | 5.118 | 3.661 | 128.4 | 91.4 | 5.055 | 3.598 |
| 132 | 80 | 130.0 | 83.1 | 5.118 | 3.272 | 128.1 | 81.2 | 5.043 | 3.197 |
| 132 | 71 | 130.0 | 74.2 | 5.118 | 2.921 | 121.2 | 72.1 | 5.035 | 2.839 |
| 140 | 112 | 137.9 | 115 | 5.429 | 4.528 | 136.6 | 113.7 | 5.378 | 4.476 |
| 140 | 100 | 137.9 | 103.1 | 5.429 | 4.059 | 136.3 | 101.5 | 5.366 | 3.996 |
| 140 | 90 | 137.9 | 93.2 | 5.429 | 3.669 | 136.1 | 91.4 | 5.358 | 3.598 |
| 140 | 80 | 137.9 | 83.3 | 5.429 | 3.280 | 135.8 | 81.2 | 5.346 | 3.197 |
| 150 | 125 | 147.7 | 128.1 | 5.815 | 5.043 | 146.5 | 126.9 | 5.768 | 4.996 |
| 150 | 106 | 147.7 | 109.3 | 5.815 | 4.303 | 146 | 107.6 | 5.748 | 4.236 |
| 150 | 95 | 147.7 | 98.4 | 5.815 | 3.874 | 145.7 | 96.4 | 5.736 | 3.795 |
| 150 | 80 | 147.7 | 83.6 | 5.815 | 3.291 | 145.3 | 81.2 | 5.720 | 3.197 |
| 160 | 132 | 157.6 | 135.3 | 6.205 | 5.327 | 156.3 | 134 | 6.154 | 5.276 |
| 160 | 122 | 157.6 | 125.4 | 6.205 | 4.937 | 156 | 123.8 | 6.142 | 4.874 |
| 160 | 112 | 157.6 | 115.5 | 6.205 | 4.547 | 155.8 | 113.7 | 6.134 | 4.476 |
| 160 | 90 | 157.6 | 94.0 | 6.205 | 3.701 | 155.2 | 91.4 | 6.110 | 3.598 |
| 170 | 140 | 167.4 | 143.5 | 6.591 | 5.650 | 166 | 142.1 | 6.535 | 5.594 |
| 170 | 130 | 167.4 | 133.6 | 6.591 | 5.260 | 165.8 | 132 | 6.528 | 5.197 |
| 170 | 128 | 167.4 | 131.6 | 6.591 | 5.181 | 165.7 | 130 | 6.524 | 5.118 |
SS 347H Hollow Bar offers excellent resistance to intergranular corrosion, high strength, and oxidation at elevated temperatures. Its high carbon content enhances creep resistance and mechanical properties, making it ideal for high-temperature applications like heat exchangers, reactors, and furnace parts, where durability and long-term performance are crucial.
The high carbon content in SS 347H improves its strength, particularly at elevated temperatures, by enhancing its resistance to creep and increasing tensile strength. This results in better durability, making it suitable for high-stress applications in extreme environments.
SS 347H Hollow Bar is commonly used in the chemical processing, aerospace, power generation, and petrochemical industries. Its excellent corrosion resistance makes it ideal for applications involving high temperatures, aggressive chemicals, and harsh environments, ensuring long-lasting performance.
347H hollow bars find application in furnace tubes, superheater tubes, high-pressure boilers, welded piping systems, and petrochemical reactors. Due to the high creep strength of the grade, it is well-suited for thermal processing plants, refineries, and power generation units. Its tubular structure makes it well-suited for heat exchanger tubes, shaft parts, and tubular structures in which strength as well as weight saving is a concern. SS 347H is very weldable and can withstand thermal stress. Chung Metal supplies these bars in varying internal diameters and special lengths for demanding sectors of structure and heat-intensive manufacturing.






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