

Duplex stainless steel tubes are a type of steel that is gaining popularity in various industries due to their unique properties. These steels are known for their excellent corrosion resistance, high strength, and good weldability.
Duplex steels are classified into two types: the standard duplex (austenitic-ferritic) and the super duplex (higher alloyed austenitic-ferritic). The most common grade of duplex stainless steel tubes is A790 Duplex, which is widely used in oil and gas applications.
The properties of duplex stainless steel tubes depend on their chemical composition. They typically contain elements such as chromium, nickel, molybdenum, and nitrogen. One key advantage of duplex stainless steel tubes is their excellent resistance to stress corrosion cracking (SCC). This makes them ideal for use in harsh environments where other materials may fail.
API 6D is a specification that covers pipeline valves made from duplex stainless steel. These valves must meet certain requirements for dimensions, chemical composition, and mechanical properties.
The phase balance of duplex stainless steel tubes plays an important role in determining their properties. The minimum amount of each element required to maintain the desired phase balance varies depending on the specific grade of steel.
Common Grades of Duplex Stainless Steel Tubes
Duplex 2205
Lean Duplex
Super Duplex
This grade has higher chromium and molybdenum content than other grades, making it highly resistant to corrosion in harsh environments such as seawater or chemical processing plants.
Duplex Stainless Steel Tubes
Specification
Size | 1/2″NB TO 12 “NB IN |
---|---|
Standards | ASTM A 790 ASME SA 790 |
Grades | (Duplex UNS S31803), UNS 2UNS S32205 (Duplex UNS S32205) |
Length | Single Random, Double Random & Cut Length |
Type | Seamless / ERW / Welded / Fabricated |
Form | Round, Hydraulic Etc |
Schedule | SCH20, SCH30, SCH40, STD, SCH80 |
Duplex Stainless Steel Tubes
Schedule Chart
3/4″ IPS(1.050″O. D.) | 8″ IPS(8.625″O. D.) |
---|---|
SCH 10, 40, 80, 160, XXH | SCH 5, 10, 40, 80, 120, 160, XXH |
1″ IPS(1.315″O. D.) | 10″ IPS(10.750″O. D.) |
1-1/4″ IPS(1.660″O. D.) | 12″ IPS(12.750″O. D.) |
SCH 10, 40, 80, 160, XXH | SCH 10, 20, 40(.375), TRUE40(.406), SCH80(.500) |
1-1/2″ IPS(1.900″O. D.) | 14″ IPS(14.000″O. D.) |
SCH 10, 40, 80, 160, XXH | SCH10 (.188), SCH40 (.375) |
SCH 10, 40, 80, 160, XXH | SCH10(.188), SCH40(.375) |
2 1/2″ IPS(2.875″O. D.) | 18″ IPS(18.000″O. D.) |
SCH 10, 40, 80, 160, XXH | SCH-40 (.375) |
2″ IPS(2.375″O. D.) | 16″ IPS(16.000″O. D.) |
3″ IPS(3.500″O. D.) | – |
SCH 5, 10, 40, 80, 160, XXH | – |
Duplex stainless steel tube
Weight Chart
NPS | Outside Diameter (in) | Outside Diameter (mm) | Wall Thickness (in) | Wall Thickness (mm) | Sched | Weight (kg/Mtr) | Weight (Lb/ft) |
---|---|---|---|---|---|---|---|
1/2″ | 0.84 | 21 | 0.109 | 2.769 | 40 STD | 1.268 | 0.851 |
1/2″ | – | – | 0.147 | 3.734 | 80 STD | 1.621 | 1.088 |
3/4″ | 1.05 | 27 | 0.113 | 2.87 | 40 STD | 1.684 | 1.131 |
3/4″ | – | – | 0.154 | 3.912 | 80 STD | 2.195 | 1.474 |
1″ | 1.315 | 33 | 0.133 | 3.378 | 40 STD | 2.501 | 1.679 |
1″ | – | – | 0.179 | 4.547 | 80 STD | 3.325 | 2.172 |
1 1/4″ | 1.66 | 42 | 0.14 | 3.556 | 40 STD | 3.385 | 2.273 |
1 1/4″ | – | – | 0.191 | 4.851 | 80 STD | 4.464 | 2.997 |
1 1/2″ | 1.9 | 48 | 0.145 | 3.683 | 40 STD | 4.048 | 2.718 |
1 1/2″ | – | – | 0.2 | 5.08 | 80 STD | 5.409 | 3.361 |
2″ | 2.375 | 60 | 0.154 | 3.912 | 40 STD | 5.441 | 3.653 |
2″ | – | – | 0.218 | 5.537 | 80 STD | 7.48 | 5.022 |
2 1/2″ | 2.875 | 73 | 0.203 | 5.516 | 40 STD | 8.629 | 5.793 |
2 1/2″ | – | – | 0.276 | 7.01 | 80 STD | 11.411 | 7.661 |
3″ | 3.5 | 89 | 0.216 | 5.486 | 40 STD | 11.284 | 7.576 |
3″ | – | – | 0.3 | 7.62 | 80 STD | 15.272 | 10.253 |
4″ | 4.5 | 114 | 0.237 | 6.02 | – | 16.073 | 10.79 |
4″ | – | – | 0.337 | 8.56 | – | 22.318 | 14.983 |
6″ | 6.625 | 168 | 0.188 | 4.775 | – | 19.252 | 12.924 |
6″ | – | – | 0.203 | 5.516 | – | 20.739 | 13.923 |
6″ | – | – | 0.219 | 5.563 | – | 22.318 | 14.983 |
6″ | – | – | 0.25 | 6.35 | – | 25.354 | 17.021 |
6″ | – | – | 0.28 | 7.112 | 40 STD | 58.263 | 18.974 |
6″ | – | – | 0.312 | 7.925 | – | 31.334 | 21.036 |
6″ | – | – | 0.375 | 9.525 | – | 37.285 | 25.031 |
6″ | – | – | 0.432 | 10.973 | 80 XHY | 42.561 | 28.573 |
6″ | – | – | 0.5 | 12.7 | – | 48.719 | 32.708 |
8″ | 8.625 | 219 | 0.188 | 4.775 | – | 25.233 | 16.94 |
8″ | – | – | 0.203 | 5.156 | – | 27.198 | 18.259 |
8″ | – | – | 0.219 | 5.563 | – | 29.286 | 19.661 |
8″ | – | – | 0.25 | 6.35 | 20 | 33.308 | 22.361 |
8″ | – | – | 0.277 | 7.036 | 30 | 36.786 | 24.696 |
8″ | – | – | 0.322 | 8.179 | 40 | 42.352 | 28.554 |
8″ | – | – | 0.375 | 9.525 | – | 49.216 | 33.041 |
8″ | – | – | 0.406 | 10.312 | 60 | 53.085 | 35.638 |
8″ | – | – | 0.5 | 12.7 | 80 XHY | 64.627 | 43.388 |
10″ | 10.75 | 273 | 0.188 | 4.775 | – | 31.588 | 21.207 |
10″ | – | – | 0.219 | 5.563 | – | 36.689 | 24.631 |
10″ | – | – | 0.25 | 6.35 | 20 | 41.759 | 28.035 |
10″ | – | – | 0.307 | 7.798 | 30 | 51.002 | 34.24 |
10″ | – | – | 0.344 | 8.738 | – | 56.946 | 38.231 |
10″ | – | – | 0.365 | 9.271 | 40 STD | 63.301 | 40.483 |
10″ | – | – | 0.438 | 11.125 | – | 71.852 | 48.238 |
10″ | – | – | 0.5 | 12.7 | 60 XHY | 81.53 | 54.735 |
10″ | – | – | 0.594 | 15.088 | 80 | 95.969 | 64.429 |
12″ | 12.75 | 324 | 0.188 | 4.775 | – | 37.57 | 25.222 |
12″ | – | – | 0.219 | 5.563 | – | 43.657 | 29.309 |
12″ | – | – | 0.25 | 6.35 | – | 49.713 | 33.375 |
12″ | – | – | 0.281 | 7.137 | – | 55.739 | 37.42 |
12″ | – | – | 0.312 | 7.925 | – | 61.735 | 41.445 |
12″ | – | – | 0.375 | 9.525 | – | 73.824 | 49.562 |
12″ | – | – | 0.406 | 10.312 | – | 79.727 | 53.525 |
12″ | – | – | 0.5 | 12.7 | – | 97.438 | 65.415 |
12″ | – | – | 0.562 | 14.275 | – | 108.966 | 73.154 |
14″ | 14 | 356 | 0.188 | 4.775 | – | 41.308 | 27.732 |
14″ | – | – | 0.219 | 5.563 | – | 48.012 | 32.233 |
14″ | – | – | 0.25 | 6.35 | 20 | 54.685 | 36.713 |
14″ | – | – | 0.281 | 7.137 | – | 61.327 | 41.172 |
14″ | – | – | 0.312 | 7.925 | – | 67.939 | 45.611 |
14″ | – | – | 0.375 | 9.525 | STD | 81.281 | 54.568 |
14″ | – | – | 0.438 | 11.125 | 40 | 94.498 | 63.441 |
14″ | – | – | 0.5 | 12.7 | XHY | 107.381 | 72.09 |
14″ | – | – | 0.625 | 15.875 | – | 132.983 | 89.278 |
16″ | 16 | 406 | 0.188 | 4.775 | – | 47.29 | 21.748 |
16″ | – | – | 0.219 | 5.563 | – | 54.98 | 36.91 |
16″ | – | – | 0.25 | 6.35 | 10 | 62.639 | 42.053 |
16″ | – | – | 0.281 | 7.137 | – | 70.268 | 47.174 |
16″ | – | – | 0.312 | 7.925 | 20 | 77.866 | 52.275 |
16″ | – | – | 0.344 | 8.738 | – | 85.677 | 57.519 |
16″ | – | – | 0.375 | 9.525 | 30 STD | 93.213 | 62.578 |
16″ | – | – | 0.438 | 11.125 | – | 108.433 | 72.797 |
16″ | – | – | 0.5 | 12.7 | 40 XHY | 123.289 | 82.77 |
18″ | 18 | 457 | 0.219 | 5.563 | – | 61.948 | 41.588 |
18″ | – | – | 0.25 | 6.35 | – | 70.593 | 47.393 |
18″ | – | – | 0.281 | 7.137 | – | 79.208 | 53.176 |
18″ | – | – | 0.312 | 7.925 | 20 | 87.792 | 58.939 |
18″ | – | – | 0.375 | 9.525 | STD | 105.144 | 70.588 |
18″ | – | – | 0.438 | 11.125 | 30 | 122.369 | 82.152 |
18″ | – | – | 0.5 | 12.7 | XHY | 139.198 | 93.45 |
18″ | – | – | 0.562 | 14.275 | 40 | 155.904 | 104.666 |
18″ | – | – | 0.625 | 15.875 | – | 172.754 | 115.978 |
20″ | 20 | 508 | 0.25 | 6.35 | – | 78.547 | 52.733 |
20″ | – | – | 0.282 | 7.163 | – | 88.458 | 59.386 |
20″ | – | – | 0.312 | 7.925 | – | 97.719 | 65.604 |
20″ | – | – | 0.375 | 9.525 | 20 STD | 117.075 | 78.598 |
20″ | – | – | 0.438 | 11.125 | – | 136.305 | 91.508 |
20″ | – | – | 0.5 | 12.7 | 30 XHY | 155.106 | 104.13 |
20″ | – | – | 0.594 | 15.088 | 40 | 183.378 | 123.11 |
20″ | – | – | 0.625 | 15.875 | – | 192.64 | 129.328 |
20″ | – | – | 0.688 | 17.475 | – | 211.368 | 141.901 |
24″ | 24 | 610 | 0.25 | 6.35 | – | 94.456 | 63.413 |
24″ | – | – | 0.281 | 7.137 | – | 106.029 | 71.183 |
24″ | – | – | 0.312 | 7.925 | – | 117.573 | 18.932 |
24″ | – | – | 0.375 | 9.525 | 20 STD | 140.938 | 64.618 |
24″ | – | – | 0.438 | 11.125 | – | 164.176 | 110.219 |
24″ | – | – | 0.5 | 12.7 | XHY | 186.923 | 125.49 |
24″ | – | – | 0.625 | 15.875 | – | 232.41 | 156.028 |
24″ | – | – | 0.688 | 17.475 | 40 | 255.148 | 171.293 |
24″ | – | – | 0.75 | 19.05 | – | 277.401 | 186.233 |
30″ | 30 | 762 | 0.25 | 6.35 | – | 118.318 | 79.433 |
30″ | – | – | 0.281 | 7.137 | – | 132.851 | 89.189 |
30″ | – | – | 0.312 | 7.925 | 10 | 147.353 | 98.925 |
30″ | – | – | 0.375 | 9.525 | STD | 176.731 | 118.648 |
30″ | – | – | 0.438 | 11.125 | – | 205.983 | 138.286 |
30″ | – | – | 0.5 | 12.7 | 20 XHY | 234.647 | 157.53 |
30″ | – | – | 0.625 | 15.875 | 30 | 292.066 | 196.078 |
30″ | – | – | 0.688 | 17.475 | – | 320.817 | 215.38 |
30″ | – | – | 0.75 | 19.05 | – | 348.988 | 234.293 |
36″ | 36 | 914 | 0.25 | 6.35 | – | 142.18 | 95.453 |
36″ | – | – | 0.281 | 7.137 | – | 159.672 | 107.196 |
36″ | – | – | 0.312 | 7.925 | 10 | 177.133 | 118.918 |
36″ | – | – | 0.375 | 9.525 | STD | 215.525 | 142.678 |
36″ | – | – | 0.438 | 11.125 | – | 247.79 | 166.353 |
36″ | – | – | 0.5 | 12.7 | 20 XHY | 282.372 | 198.57 |
36″ | – | – | 0.625 | 15.875 | – | 351.723 | 236.128 |
36″ | – | – | 0.688 | 17.475 | – | 386.487 | 259.467 |
36″ | – | – | 0.75 | 19.05 | – | 420.576 | 282.353 |
42″ | 42 | 1067 | 0.312 | 7.925 | – | 206.914 | 138.911 |
42″ | – | – | 0.375 | 9.525 | STD | 248.319 | 166.708 |
42″ | – | – | 0.5 | 12.7 | XHY | 330.97 | 221.61 |
42″ | – | – | 0.75 | 19.05 | – | 492.163 | 330.413 |
48″ | 48 | 1219 | 0.375 | 9.525 | STD | 284.112 | 190.738 |
48″ | – | – | 11.125 | 11.125 | – | 331.404 | 222.487 |
48″ | – | – | 0.5 | 12.7 | XHY | 377.822 | 253.65 |
48″ | – | – | 0.75 | 19.05 | – | 563.75 | 378.473 |
48″ | – | – | 0.875 | 22.225 | – | 655.969 | 440.383 |
Duplex stainless steel tubes
Pressure Rating
“Pipe O.D. (in.)” | Wall Thickness Of Pipe (Inches) | |||||||
---|---|---|---|---|---|---|---|---|
– | 0.028 | 0.035 | 0.049 | 0.065 | 0.083 | 0.095 | 0.109 | 0.12 |
– | Working Pressure (Psig) | |||||||
1/8 | 7900 | 10100 | – | – | – | – | – | – |
1/4 | 3700 | 4800 | 7000 | 9500 | – | – | – | – |
5/16 | – | 3700 | 5400 | 7300 | – | – | – | – |
3/8 | – | 3100 | 4400 | 6100 | – | – | – | – |
1/2 | – | 2300 | 3200 | 4400 | – | – | – | – |
3/4 | – | – | 2200 | 3000 | 4000 | 4600 | – | – |
1 | – | – | – | 2200 | 2900 | 3400 | 3900 | 4300 |
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