Neil Metals is a reputable manufacturer and supplier of Stainless Steel 347 Hollow Bars, located in Kolkata, India. They specialize in delivering top-notch stabilized austenitic stainless steel products that are built to withstand tough conditions involving heat and corrosion. With a solid reputation for precision, durability, and compliance with international standards, Neil Metals supplies SS 347 hollow bars to various industries, including aerospace, chemical processing, power generation, and food processing. These hollow bars are particularly prized for their exceptional resistance to intergranular corrosion and their performance in high-temperature environments. Thanks to their advanced manufacturing capabilities and a strong focus on customer satisfaction, Neil Metals guarantees a reliable supply both throughout India and internationally.
Stainless Steel 347 Hollow Bars consist of 17–20% chromium and 9–13% nickel, with niobium (columbium) added to prevent carbide precipitation during welding and exposure to high temperatures. This stabilization significantly boosts resistance to intergranular corrosion, especially post-welding. The alloy boasts a tensile strength of about 515 MPa and a yield strength of around 205 MPa. SS 347 maintains impressive mechanical properties even at elevated temperatures and provides good oxidation resistance, formability, and weldability. Its hollow design not only reduces weight but also preserves strength, making it ideal for both structural and pressure-bearing 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 347 | 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 347 | 1.4550 | S34700 | SUS 347 | – | 08Ch18N12B | – | X6CrNiNb18-10 |
| Stainless Steel 347 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 |
The addition of columbium (niobium) in SS 347 improves its resistance to intergranular corrosion, particularly after welding. It stabilizes the steel's microstructure, preventing carbide precipitation at grain boundaries, and enhances overall corrosion resistance in aggressive, high-temperature environments.
SS 347 hollow bars are commonly used in the chemical processing, aerospace, power generation, and petrochemical industries. Typical applications include heat exchangers, reactor vessels, piping systems, and furnace components, where resistance to high temperatures and corrosion is essential.
These Stainless Steel 347 Hollow Bars are extensively utilized in high-temperature and corrosive settings where welding is necessary. They’re commonly found in heat exchangers, boiler tubes, exhaust manifolds, pressure vessels, and refinery equipment. In the chemical and petrochemical sectors, SS 347 is often used for piping and process equipment that face high heat and corrosive materials. Its stability during extended thermal exposure makes it a great choice for superheaters and radiant superheaters in power plants. Plus, the hollow design provides a cost-effective option for machining and fabrication.
We provide products that come with both mill test certificates and third-party test certificates, ensuring the highest standards of quality and compliance.
Neil Metals is a leading manufacturer, supplier, and exporter of high-quality bars, rods, and forgings, catering to various industries in Kolkata, India
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