Stainless Steel Tube & Pipe

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Pipe / Tube 904L Stainless Steel Pipe
Super Austenitic Acid-Resistant Pipe, Provides Ultimate Corrosion Protection for Conveying Concentrated Sulfuric, Phosph

Seamless Stainless Steel Pipe — Grades, Sizes & Standards

Walmay supplies seamless stainless steel pipe produced by hot-piercing and cold-rolling/drawing, conforming to ASTM A312 / SA312, ASTM A213 (boiler and heat exchanger tubes), and ASTM A269 (general-service tubes). Seamless construction eliminates the longitudinal weld seam, making these pipes the standard choice for high-pressure systems, cyclic-load service, and corrosive media where weld-zone risk must be controlled.

Attribute	Seamless Specification
Grades	304, 304L, 316L, 321, 2205, 310S, 904L
Outside Diameter	6–219 mm standard; precision 3–25 mm; large bore to 630 mm on order
Wall Thickness	0.8–20 mm; Schedules 10S, 40S, 80S available
Length	6 m standard; 1–12 m cut-to-order; coil form ≤38 mm OD
Finish	2B, BA, AP (pickled-annealed), bright annealed
Standards	ASTM A312 / SA312 (austenitic); ASTM A790 (2205 duplex); ASTM A213 (boiler/HX tubes)
Testing	Hydrostatic, eddy-current, ultrasonic, PMI on request

Seamless stainless steel pipe is specified when operating pressure exceeds 10 MPa, when service involves thermal cycling, or when the medium is aggressive — chlorides, concentrated acids, or steam. For sanitary or architectural lines where surface finish is the primary requirement, TIG-welded pipe with a leveled inner weld is often the more cost-effective solution; Walmay supplies both.

Request a datasheet or quick quote for your specific OD, grade, and schedule.

Why Choose Walmay as Your Stainless Steel Pipe Exporter

Engineered for endurance

Pipes and tubes meet ASTM A312 / SA312 with high pressure resistance (up to 20 MPa for 304/316L ranges) and proven corrosion performance.

Tailored to your system

Certified quality, delivered on time

Collaborative project support

Pipe & Tube Dimensions for Corrosive Service

Item	Range / Options
Outside Diameter (OD)	3–630 mm (sanitary: 10–108 mm; precision: 3–25 mm)
Wall Thickness (WT)	0.5–20 mm (common: 0.8 / 1.2 / 1.5 / 2.0 / 3.0 / 4.5 / 6.0 mm)
Length	1–12 m (standard 6 m & 12 m), coil available ≤ 38 mm OD
Finishes	NO.1 / 2B / BA, brushed / HL, mechanical / electropolish
Processes	Seamless (piercing / rolling), TIG / ERW welded, leveling, passivation
Tests & Docs	Hydrostatic / helium leak (as specified), roughness report, MTC, ISO / SGS

Note: Actual pressure/temperature ratings vary by grade, OD/WT, weld vs seamless, and finish; consult Walmay for a verified datasheet per line class.

ASTM A312 / ASME SA312 Stainless Steel Pipe Schedule Chart

All Walmay stainless steel pipes are available per ASTM A312 / ASME SA312. Reference dimensions for seamless and welded austenitic stainless steel pipe:

NPS	OD (in)	OD (mm)	Sch 10S WT (in)	Sch 40S WT (in)	Sch 80S WT (in)
1/4	0.540	13.72	0.065	0.088	0.119
3/8	0.675	17.15	0.065	0.091	0.126
1/2	0.840	21.34	0.065	0.109	0.147
3/4	1.050	26.67	0.065	0.113	0.154
1	1.315	33.40	0.065	0.133	0.179
1-1/4	1.660	42.16	0.065	0.140	0.191
1-1/2	1.900	48.26	0.065	0.145	0.200
2	2.375	60.33	0.065	0.154	0.218
2-1/2	2.875	73.03	0.083	0.203	0.276
3	3.500	88.90	0.083	0.216	0.300
4	4.500	114.30	0.083	0.237	0.337
6	6.625	168.28	0.109	0.280	0.432
8	8.625	219.08	0.109	0.322	0.500
10	10.750	273.05	0.134	0.365	0.594
12	12.750	323.85	0.156	0.375	0.688

Custom OD (3–630 mm) and wall thickness outside standard schedules are available on request. Contact Walmay for a verified datasheet per line class.

Common Uses for Corrosion-Resistant Pipe & Tube

Process & Utilities

Chemical transfer, steam/condensate, CIP/SIP sanitary loops
Water & Marine

RO/desalination, seawater lines, potable water distribution, heat-exchange coils
Energy & Power

Superheaters, furnace tubes, balance-of-plant piping
Architecture & Fabrication

Handrails, frames, canopies, decorative profiles
Precision & Instrumentation

Sleeves, sensor housings, semiconductor gas lines

How to Select the Corrosion-Resistant Steel Pipe Tube

Medium & Corrosion Type

Chlorides/sea water → 316L / 2205 / 904L / 444
Non-oxidizing acids → 904L / 317L
Food contact & hygiene → 304 sanitary (Ra ≤ 0.6 μm), BA/electropolish

Pressure & Temperature

High pressure → seamless 316L / 2205
≥ 800 °C service → 310S / 321

Finish & Roughness (Ra)

Sanitary/precision → BA + electropolish
Architectural → HL/brush, mirror, or PVD color

Fabrication

Tight bends/forming → specify WT, grain direction, heat treatment
Welding → match filler metal; ensure post-weld cleaning/passivation

Quality & Compliance

ISO 9001 quality system; SGS material verification
MTC to ASTM/ASME/EN as ordered; optional 3.1/3.2 reports
Roughness (ISO 4288), hydro/helium leak, pressure hold, passivation records
Partner mills include POSCO and other qualified sources

FAQs

What is the difference between 304 and 316 stainless steel pipe?

304 is the most widely used stainless steel pipe grade, offering reliable corrosion resistance and weldability for water distribution, food processing, and general industrial service. 316 adds 2–3% molybdenum, which significantly improves resistance to chlorides, seawater, and acidic environments. For marine, coastal, chemical processing, or pharmaceutical pipelines, 316 or 316L (for welded assemblies) is the standard specification. For indoor, food-contact, or low-corrosion-risk systems, 304 is typically sufficient and more cost-effective. In highly aggressive environments — concentrated acids or high-chloride process media — grades such as 2205 duplex or 904L should be evaluated.

Is stainless steel good for pipes?

Yes — stainless steel is the preferred material for demanding piping applications because of its corrosion resistance, hygienic surface properties, mechanical strength, and long service life. Unlike carbon steel or galvanized pipe, stainless steel does not require protective coatings, is compatible with potable water and food-contact service (grade and finish dependent), and can withstand elevated pressure and temperature. Grades 304 and 316L are workhorses for water and sanitary service; 2205 and 904L address aggressive chemical and marine environments; 310S and 321 handle high-temperature service above 600 °C.

What's the difference between pipe and tube?

"Pipe" is typically specified by nominal size for pressure service, while "tube" focuses on precise OD/WT and tighter dimensional control. This page covers both sizing approaches for corrosion-resistant system purchasing.

Seamless vs welded — how to choose?

For higher pressure or severe cyclic loads, choose seamless; for sanitary/architectural with defined Ra or finish, welded with TIG and inner weld leveling is often ideal.

What Ra is recommended for sanitary media?

For dairy/beverage, Ra ≤ 0.6 μm (ID) is a common target; CIP/SIP systems often require passivation or electropolish.

Do you provide cut-to-length and surface treatments?

Yes. Options include cut-to-size, brushing/polishing, mirror-grade finishing as specified, passivation, marking for traceability, and supporting inspection documents per order.

Can you help with grade verification and testing?

Yes. PMI, hydrostatic testing, helium leak testing, pressure hold, roughness reports, and corrosion-related verification can be arranged based on project specifications.