Seamless construction per ASTM A312 – no weld seam; uniform wall thickness; hydrotested & PMI verified
Multiple grades available – 304/304L, 316/316L, 321, 347, 310S, duplex 2205/2507, 904L
Wide size range – NPS 1/8″ to 24″; SCH 5S to 160S; custom lengths; AP, BA, MP, EP finishes
Stainless Steel Seamless Pipes are manufactured from solid billets through hot extrusion or cold drawing processes, resulting in a pipe with no longitudinal weld seam. This seamless construction provides superior pressure resistance, uniform wall thickness, and excellent mechanical properties for critical applications.
We supply seamless pipes in three of the most popular austenitic grades: 304, 316, and 321. Each grade offers unique advantages for different service environments, from general-purpose corrosion resistance to specialized high-temperature and chloride-resistant applications. All pipes comply with ASTM A312 / ASME SA312 and international equivalents
Technical Specifications
| Parameter | Details |
|---|---|
| Standards | ASTM A312 / ASME SA312, ASTM A269, EN 10216-5, JIS G3459 |
| Size Range (NPS) | 1/8″ to 24″ (DN 6 to DN 600) |
| Outside Diameter | 6.0 mm to 610 mm (0.236″ to 24″) |
| Wall Thickness | SCH 5S, 10S, 20S, 40S, 80S, 120S, 160S, XXS |
| Length | Single random (5-7m), double random (10-14m), or cut to exact length |
| End Finish | Plain end, beveled end, threaded, or grooved |
| Surface Finish | Annealed & pickled (standard), bright annealed (BA), mechanically polished |
Chemical Composition Comparison
| Grade | UNS | C (max) | Cr (%) | Ni (%) | Mo (%) | Other |
|---|---|---|---|---|---|---|
| 304 | S30400 | 0.08 | 18.0-20.0 | 8.0-11.0 | — | — |
| 304L | S30403 | 0.035 | 18.0-20.0 | 8.0-13.0 | — | — |
| 316 | S31600 | 0.08 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 | — |
| 316L | S31603 | 0.035 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 | — |
| 321 | S32100 | 0.08 | 17.0-19.0 | 9.0-12.0 | — | Ti ≥ 5×C% |
Key Differences Explained:
304 vs 304L: 304L has lower carbon (0.035% max), providing better weldability and resistance to sensitization (chromium carbide precipitation) after welding.
316/316L: Contains 2-3% molybdenum, which significantly improves resistance to pitting and crevice corrosion in chloride-rich environments like seawater.
321: Contains titanium (Ti ≥ 5×C%), which stabilizes the alloy and prevents chromium carbide precipitation during prolonged high-temperature exposure (550-850°C).
| ASTM/ASMEGrade | EN Grade | GB Unified Number | Chemical Component % | ||||||||||
| C | Cr | Ni | Mn | P | S | Mo | Si | Cu | N | Other | |||
| 201 | 1.4372 | 1Cr17Mn6Ni5N | ≤0.15 | 16.00-18.00 | 3.50-5.50 | 5.50－7.50 | ≤0.060 | ≤0.030 | – | ≤1.00 | – | ≤0.25 | – |
| 202 | 1.4373 | 1Cr18Mn8Ni5N | ≤0.15 | 17.00-19.00 | 4.00-6.00 | 7.50-10.00 | ≤0.060 | ≤0.030 | ≤1.00 | – | ≤0.25 | － | |
| 301 | 1.4310 | 1Cr17Ni7 | ≤0.15 | 16.00-18.00 | 6.00-8.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤1.00 | – | 0.1 | – |
| 302 | 1.4325 | 1Cr18Ni9 | ≤0.15 | 17.00-19.00 | 8.00-10.00 | ≤2.00 | ≤0.035 | ≤0.030 | – | ≤1.00 | – | – | – |
| 303 | 1.4305 | Y1Cr18Ni9 | ≤0.15 | 17.00-19.00 | 8.00-10.00 | ≤2.00 | ≤0.20 | ≥0.15 | – | ≤1.00 | – | – | – |
| 304 | 1.4301 | 0Cr18Ni9 | ≤0.08 | 18.00-20.00 | 8.00-10.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤0.75 | – | – | – |
| 304L | 1.4307 | 00Cr19Ni10 | ≤0.030 | 18.00-20.00 | 8.00-10.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤0.75 | – | – | – |
| 304H | 1.4948 | 0Cr18Ni9 | 0.04~0.10 | 18.00-20.00 | 8.00-10.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤0.75 | – | – | – |
| 309S | 1.4833 | 0Cr23Ni13 | ≤0.08 | 22.00-24.00 | 12.00-15.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤0.75 | – | – | – |
| 309 | 1.4828 | 0Cr23Ni13 | 0.04~0.10 | 22.00-24.00 | 12.00-15.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤0.75 | – | – | – |
| 310S | 1.4842 | 0Cr25Ni20 | ≤0.08 | 24.00-26.00 | 19.00-22.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤1.5 | – | – | – |
| 310H | 1.4821 | 0Cr25Ni20 | 0.04~0.10 | 24.00-26.00 | 19.00-22.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤1.5 | – | – | – |
| 314 | 1.4841 | 0Cr25Ni20Si | ≤0.25 | 23.00-26.00 | 19.00-22.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | 1.5-3.0 | – | – | – |
| 316 | 1.4401 | 0Cr17Ni12Mo2 | ≤0.08 | 16.00-18.50 | 10.00-14.00 | ≤2.00 | ≤0.045 | ≤0.030 | 2.00-3.00 | ≤0.75 | – | – | – |
| 316L | 1.4404 | 00Cr17Ni14Mo2 | ≤0.030 | 16.00-18.00 | 10.00-14.00 | ≤2.00 | ≤0.045 | ≤0.030 | 2.00-3.00 | ≤0.75 | – | – | – |
| 316H | 1.4436 | 0Cr17Ni12Mo2N | 0.04~0.10 | 16.00-18.00 | 10.00-14.00 | ≤2.00 | ≤0.045 | ≤0.030 | 2.00-3.00 | ≤0.75 | – | 0.10-0.22 | – |
| 316Ti | 1.4571 | 0Cr17Ni12Mo2Ti | ≤0.08 | 16.00-18.50 | 10.00-14.00 | ≤2.00 | ≤0.045 | ≤0.030 | 2.00-3.00 | ≤0.75 | – | – | Ti5(C+N)~0.7 |
| 317 | 1.4445 | 0Cr19Ni13Mo3 | ≤0.08 | 18.00-20.00 | 11.00-15.00 | ≤2.00 | ≤0.045 | ≤0.030 | 3.00-4.00 | ≤0.75 | – | 0.1 | – |
| 317L | 1.4438 | 00Cr19Ni13Mo3 | ≤0.03 | 18.00-20.00 | 11.00-15.00 | ≤2.00 | ≤0.045 | ≤0.030 | 3.00-4.00 | ≤0.75 | – | 0.1 | – |
| 321 | 1.4541 | 0Cr18Ni10Ti | ≤0.08 | 17.00-19.00 | 9.00-12.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤0.75 | – | 0.1 | Ti5(C+N)~0.7 |
| 321H | 1.4940 | 0Cr18Ni10Ti | 0.04~0.10 | 17.00-19.00 | 9.00-12.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤0.75 | – | 0.1 | Ti4(C+N)~0.7 |
| 329 | 1.4480 | 0Cr26Ni5Mo2 | ≤0.08 | 23.00-28.00 | 2.00-5.00 | ≤1.00 | ≤0.040 | ≤0.030 | 1.00-2.00 | ≤0.75 | – | – | – |
| 329J1 | 1.4480 | 0Cr26Ni5Mo2 | ≤0.08 | 23.00-28.00 | 2.00-5.00 | ≤1.00 | ≤0.045 | ≤0.030 | 1.00-2.00 | ≤0.75 | – | – | – |
| 330 | 1.4864 | N08330 | ≤0.15 | 14.00-17.00 | 33.00-37.00 | ≤2.00 | ≤0.045 | ≤0.040 | 1.00-2.00 | ≤1.5 | – | – | – |
| 347 | 1.4550 | 0Cr18Ni11Nb | ≤0.08 | 17.00-19.00 | 9.00-13.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤0.75 | – | – | Nb≥10*C%-1.0 |
| 347H | 1.4912 | 0Cr18Ni11Nb | 0.04~0.10 | 17.00-19.00 | 9.00-13.00 | ≤2.00 | ≤0.045 | ≤0.030 | – | ≤0.75 | – | – | Nb≥8*C%-1.0 |
| 409L | 1.4720 | S40900 | ≤0.03 | 10.50-11.70 | 0.5 | ≤1.00 | ≤0.040 | ≤0.020 | – | ≤1.00 | – | 0.03 | Ti6(C+N)-0.5 Nb0.17 |
| 430 | 1.4016 | S43000 | ≤0.12 | 16.00-18.00 | 0.75 | ≤1.00 | ≤0.040 | ≤0.030 | – | ≤1.00 | – | – | – |
| 436 | 1.4513 | S43600 | ≤0.025 | 16.00-19.00 | – | ≤1.00 | ≤0.040 | ≤0.030 | 0.75-1.0 | ≤1.00 | ≤0.025 | Nb+Ti:8(C+N)~0.80 | |
| 439 | 1.4510 | S43035 | ≤0.030 | 17.50-18.50 | – | ≤1.00 | ≤0.040 | ≤0.015 | – | ≤1.00 | – | ≤0.030 | Ti+Nb:0.2+4C~0.75 |
| 441 | 1.4509 | S44100 | ≤0.030 | 17.50-18.50 | – | ≤1.00 | ≤0.040 | ≤0.015 | – | ≤1.00 | – | ≤0.030 | Ti:0.1-0.6 Nb:3C+0.3~1.0 |
| 442 | 1.4741 | S44200 | ≤0.025 | 18.0-23.0 | – | ≤1.00 | ≤0.040 | ≤0.035 | – | ≤1.00 | – | ||
| 443 | S44300 | ≤0.025 | 19.5-22.0 | – | ≤1.00 | ≤0.035 | ≤0.015 | – | ≤1.00 | – | ≤0.025 | Nb+Ti:0.2+4(C+N)~0.75 | |
| 444 | 1.4521 | S44400 | ≤0.025 | 17.00-20.00 | – | ≤1.00 | ≤0.040 | ≤0.030 | 1.75-2.5 | ≤1.00 | ≤0.035 | Ti+Nb:0.2+4(C+N)~0.8 | |
| 446 | 1.4749 | S44600 | ≤0.2 | 23.0-27.0 | 0.75 | ≤1.50 | ≤0.040 | ≤0.030 | – | ≤1.00 | 0.25 | ||
| 410 | 1.4006 | 1Cr13 | 0.08~0.15 | 11.50-13.50 | – | ≤1.00 | ≤0.040 | ≤0.030 | – | ≤1.00 | – | – | – |
| 420 | 1.4031 | 2Cr13 | ≥0.15 | 12.00-14.00 | – | ≤1.00 | ≤0.040 | ≤0.030 | – | ≤1.00 | – | – | – |
| 420J2 | 1.4028 | 3Cr13 | 0.26-0.35 | 12.00-14.00 | – | ≤1.00 | ≤0.040 | ≤0.030 | – | ≤1.00 | – | – | – |
| S42040 | 1.4034 | 4Cr13 | 0.36-0.45 | 12.00-14.00 | – | ≤1.00 | ≤0.040 | ≤0.030 | – | ≤1.00 | – | – | – |
| 431 | 1.4057 | 1Cr17Ni2 | ≤0.2 | 15.00-17.00 | 1.25-2.50 | ≤1.00 | ≤0.040 | ≤0.030 | – | ≤1.00 | – | – | – |
| 440A | 1.4040 | 7Cr17 | 0.60-0.75 | 16.00-18.00 | – | ≤1.00 | ≤0.040 | ≤0.030 | 0.75 | ≤1.00 | – | – | – |
| 440B | 1.4041 | 8Cr17 | 0.75-0.95 | 16.00-18.00 | – | ≤1.00 | ≤0.040 | ≤0.030 | 0.75 | ≤1.00 | – | – | – |
| 440C | 1.4023 | 11Cr17 | 0.95-1.20 | 16.00-18.00 | – | ≤1.00 | ≤0.040 | ≤0.030 | 0.75 | ≤1.00 | – | – | – |
| 17-4PH | 1.4542 | 630 | ≤0.07 | 15.50-17.50 | 3.00-5.00 | ≤1.00 | ≤0.040 | ≤0.030 | – | ≤1.00 | 3.00-5.00 | – | Nb+Ta:0.15-0.45 |
| 17-7PH | 1.4568 | 631 | ≤0.09 | 16.00-18.00 | 6.50-7.50 | ≤1.00 | ≤0.040 | ≤0.030 | – | ≤1.00 | – | – | Al 0.75-1.50 |
| 15-5PH | 1.4545 | S15500 | ≤0.09 | 14.00-15.50 | 3.50-5.50 | ≤1.00 | ≤0.040 | ≤0.030 | 2.00-3.00 | ≤1.00 | 2.50-4.50 | – | |
| 416 | 1.4005 | Y1Cr13 | ≤0.15 | 12.00-14.00 | – | ≤1.25 | ≤0.06 | ≥0.15 | – | ≤1.00 | – | – | – |
| 420F | 1.4029 | Y3Cr13 | 0.3-0.40 | 12.00-14.00 | 0.5 | ≤1.25 | ≤0.06 | ≥0.15 | – | ≤1.00 | 0.6 | – | – |
| 430F | 1.4019,1.4104 | Y1Cr17 | ≤0.12 | 16.00-18.00 | – | ≤1.25 | ≤0.06 | ≥0.15 | – | ≤1.00 | – | – | – |
| 440F | 1.4025 | Y11Cr17 | 0.95-1.20 | 16.00-18.00 | – | ≤1.25 | ≤0.06 | ≥0.15 | – | ≤1.00 | – | – | – |
| 303 | 1.4305 | S30317 | ≤0.15 | 17.00-19.00 | 8.00-10.00 | ≤2.00 | ≤0.20 | ≥0.15 | – | ||||
