Chuck Metals, based in Pulau Ujong, Singapore, is your go-to source for top-notch stainless steel products, including the highly regarded Stainless Steel 347 Hollow Bars. These bars are celebrated for their impressive performance under pressure and at high temperatures, making them a perfect fit for demanding industries like chemical processing, power generation, and marine engineering. With a strong focus on precision manufacturing, reliable availability, and attentive service, Chuck Metals is dedicated to providing customers throughout Singapore with stainless steel solutions that meet their specific needs for performance and durability.
The Stainless Steel 347 Hollow Bar is an austenitic stainless steel alloy that’s stabilized with columbium (niobium), which helps prevent intergranular corrosion after welding or when exposed to high temperatures. Its makeup features chromium (17–20%), nickel (9–13%), and carbon (up to 0.08%), along with small amounts of manganese, silicon, and phosphorus. This alloy boasts impressive mechanical properties, including a tensile strength of 75 ksi (515 MPa), yield strength of 30 ksi (205 MPa), and an elongation of 40%. It excels in high-temperature strength, oxidation resistance, and long-term stability in challenging thermal environments.
| 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 primary advantages of using SS 347 hollow bars in high-temperature applications include excellent resistance to intergranular corrosion, enhanced heat resistance, and stability in extreme conditions. These properties make it ideal for use in heat exchangers, reactors, and furnace components.
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.
You’ll find Stainless Steel 347 Hollow Bars in a variety of applications where high-temperature strength, corrosion resistance, and weldability are crucial. These bars are often used in components for heat exchangers, superheater tubes, furnace parts, and piping systems in chemical plants and refineries. The hollow design not only reduces material weight but also maintains mechanical integrity, making it an excellent choice for structural and fluid transport applications. Its stability and resistance to sensitization make it particularly valuable in scenarios involving repeated thermal cycling. Industries such as aerospace and oil and gas rely on this versatile material for their demanding applications.






We provide products that come with both mill test certificates and third-party test certificates, ensuring the highest standards of quality and compliance.
Chuck Metals is a leading manufacturer, supplier, and exporter of high-quality bars, rods, and forgings, catering to various industries in Singapore, Singapore
Copyright 2024 Chuck Metals. All rights reserved