Gulf Union Ozone stocks ASTM A312 stainless steel seamless and welded pipes in TP304, TP304L, TP316, and TP316L from our Jeddah warehouse. Schedule 10S through 80S in half-inch to 12 NPS available ex-stock. EN 10204 3.1 material test certificates supplied with every order. Trusted by NEOM sub-contractors, Aramco EPC firms, and desalination project developers across Saudi Arabia.

ASTM A312 covers seamless, welded (ERW and EFW), and heavily cold-worked austenitic stainless steel pipes. The four grades most commonly specified for Saudi Arabia projects are:
18Cr-8Ni, no molybdenum. General purpose austenitic grade for non-chloride corrosive environments — chemical process, food and beverage, HVAC. Carbon ≤0.08%.
18Cr-8Ni, low carbon (≤0.03%). Prevents weld sensitization, allowing as-welded use without PWHT. The standard welded-construction choice wherever 304 grade is sufficient.
18Cr-10Ni-2Mo. The addition of 2–3% molybdenum raises the critical pitting resistance equivalent number (PREN) significantly above 304, providing resistance to chloride pitting and crevice corrosion — essential for coastal and offshore service.
18Cr-10Ni-2Mo, low carbon (≤0.03%). Combines 316's superior chloride resistance with 304L's immunity to weld sensitization. The dominant specification for NEOM coastal infrastructure, desalination project piping, and Aramco sour service where austenitic SS is specified.
| Property | TP304 | TP304L | TP316 | TP316L |
|---|---|---|---|---|
| Carbon max (%) | 0.08 | 0.03 | 0.08 | 0.03 |
| Chromium (%) | 18.0–20.0 | 18.0–20.0 | 16.0–18.0 | 16.0–18.0 |
| Nickel (%) | 8.0–10.5 | 8.0–12.0 | 10.0–14.0 | 10.0–14.0 |
| Molybdenum (%) | — | — | 2.0–3.0 | 2.0–3.0 |
| Tensile min (MPa) | 515 | 485 | 515 | 485 |
| Yield min (MPa) | 205 | 170 | 205 | 170 |
| Weld sensitization risk | Yes (PWHT recommended) | No (as-welded OK) | Yes (PWHT recommended) | No (as-welded OK) |
| Chloride pitting resistance | Moderate | Moderate | Good | Good |
| NACE MR0175 sour service | Yes (annealed, ≤22 HRC) | Yes (annealed, ≤22 HRC) | Yes (annealed, ≤22 HRC) | Yes (annealed, ≤22 HRC) |
Stainless steel pipes for Saudi Aramco process service are specified in grades 304L and 316L for corrosion resistance in chemical, utility water, and cooling-water systems. Gulf Union Ozone supplies ASTM A312 seamless and welded stainless steel pipe in grades 304/304L, 316/316L, 321, and 347 for petrochemical service. For produced-water and sour-gas applications at SAEP-347 Aramco facilities, duplex stainless steel pipe (UNS S31803 / S32205) is supplied to ASTM A790 with NACE MR0175 / ISO 15156 compliance documentation. Super duplex pipe (UNS S32750) for seawater injection and offshore riser service. All stainless steel pipe is supplied with EN 10204 3.1 MTCs, heat and batch number traceability, and spectroscopic material analysis (PMI test) certificates. Pipe sizes range from ½ inch NB to 24 inch NB; schedule selection (5S, 10S, 40S, 80S) per ASME B36.19 standard.
Manufactured without a weld seam by hot extrusion or cold drawing. The continuous, homogeneous wall has no potential weld defect sites — making seamless pipe the default choice for high-pressure process piping, offshore risers, and safety-critical service.
Formed from flat-rolled strip, seam-welded by Electric Resistance Welding (ERW) or Electric Fusion Welding (EFW), and solution-annealed. ASTM A312 requires full radiographic examination of the weld seam, making welded pipe structurally equivalent to seamless for many services. Typically 20–35% lower cost for large-diameter sizes.
Stainless steel pipe selection for Saudi Aramco seawater service requires careful attention to chloride stress corrosion cracking (CSCC) risk — austenitic grades 304L and 316L are susceptible above 60°C in chloride environments. Gulf Union Ozone advises on grade selection per SAES-A-007 Saudi Aramco corrosion control standard: 316L for ambient-temperature seawater cooling; duplex 2205 or super duplex 2507 for elevated temperature seawater service above 50°C; titanium Grade 2 as the ultimate solution for SWCC multi-stage flash evaporator heat rejection piping. PREN (Pitting Resistance Equivalent Number) calculations for each stainless grade in the specific Aramco or SWCC process environment are provided on request. Saudi Aramco Engineering Standard SAES-L-140 governs stainless steel piping material selection for all plant piping above ½-inch NB.
Stainless steel pipe dimensions are governed by ASME B36.19M (not B36.10, which covers carbon steel). The 'S' suffix schedule designations — 5S, 10S, 40S, 80S — apply to austenitic stainless steel pipe. For NPS 10 and below, Sch 40S wall = Sch 40 (B36.10) wall; for NPS 12 and above the schedules diverge.
| NPS (inches) | OD (mm) | Sch 5S — Wall (mm) | Sch 10S — Wall (mm) | Sch 40S — Wall (mm) | Sch 80S — Wall (mm) |
|---|---|---|---|---|---|
| ½" | 21.34 | 1.65 | 2.11 | 2.77 | 3.73 |
| ¾" | 26.67 | 1.65 | 2.11 | 2.87 | 3.91 |
| 1" | 33.40 | 1.65 | 2.77 | 3.38 | 4.55 |
| 1½" | 48.26 | 1.65 | 2.77 | 3.68 | 5.08 |
| 2" | 60.33 | 1.65 | 2.77 | 3.91 | 5.54 |
| 3" | 88.90 | 1.65 | 3.05 | 5.49 | 7.62 |
| 4" | 114.30 | 1.65 | 3.05 | 6.02 | 8.56 |
| 6" | 168.28 | 2.11 | 3.40 | 7.11 | 10.97 |
| 8" | 219.08 | 2.77 | 3.76 | 8.18 | 12.70 |
| 10" | 273.05 | 3.40 | 4.19 | 9.27 | 12.70 |
| 12" | 323.85 | 3.96 | 4.57 | 9.52 | 12.70 |
Source: ASME B36.19M. Tolerances apply: OD ±1%, wall thickness −12.5% / +no limit per ASTM A312. Request actual MTC for heat-number specific dimensions.
Stainless steel pipe for food-grade, pharmaceutical, and NEOM resort infrastructure supply requires electropolished bore and surface finish (Ra ≤ 0.8 µm) with 3-A Sanitary Standard or ASME BPE certification. Gulf Union Ozone sources hygienic-grade stainless steel pipe and fittings for the growing Saudi food processing and pharmaceutical manufacturing base in Riyadh, Jeddah, and KAEC (King Abdullah Economic City). For desalination and water treatment — SWCC multi-stage flash plants, brackish water reverse osmosis facilities, and SEC boiler feedwater systems — stainless steel pipe is supplied in Grade 904L (UNS N08904) for high-chloride, high-temperature seawater service where duplex may not be suitable. Pipe end connections for welded stainless service are supplied as plain bevel-end per ASME B16.25 ready for orbital TIG welding at the installation site.
The NEOM mega-project and The Line linear city require vast quantities of TP316L seamless pipe for saline water cooling systems, grey-water recycling infrastructure, and coastal utility distribution. NEOM EPC contractors are among the most active buyers of large-bore TP316L pipe in Saudi Arabia's Northern Red Sea corridor.
The Red Sea Project luxury island development requires corrosion-resistant piping for seawater intake, desalination distribution, and fire protection systems across the island clusters. TP316L is specified for all seawater contact systems. GUO's Jeddah location serves Red Sea Project logistics through the western coastal supply chain.
Aramco refinery and NGL projects specify TP316L for high-temperature, chloride-bearing process streams and TP304L for steam and condensate systems. ASTM A312 seamless pipe is specified in most Aramco piping material classes (PMCs) for stainless service above Class 150. NACE MR0175 sour service compliance required for certain gas plant applications.
Saudi Arabia operates the world's largest desalination capacity. SWCC (now National Water Company) and private operators specify TP316L for brine distribution, concentrate disposal, and heat exchanger headers. MSF and RO plants both require significant stainless piping in sizes from ½" to 12" NPS.
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Also useful: pressure class, service temperature, piping class reference, and whether NACE MR0175 compliance is required.
Gulf Union Ozone stainless steel pipe delivery covers Saudi Arabia from the Jeddah distribution centre: Jeddah same-day or next-day for stocked sizes in 304L and 316L; Jubail and Dammam 48–72 hours; Al Khobar 72 hours; Yanbu 72 hours; Riyadh 72–96 hours. EN 10204 3.1 mill test certificates with heat number traceability are issued for every stainless pipe delivery to Saudi Aramco facilities, supporting the SAEP-347 goods-receipt inspection requirement. Positive material identification (PMI) using X-ray fluorescence (XRF) analysers is available at the Jeddah warehouse for grade verification before despatch — critical for stainless and duplex pipe where grade substitution risk is higher than for carbon steel. Custom cut-to-length stainless pipe, orbital weld fitting, and electropolishing services are coordinated through approved Saudi fabricators within 2–5 working days lead time.
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