Marine Seamless Stainless Steel Pipe

High-quality marine seamless stainless steel pipes made of 304L, 316L, and duplex stainless steel. Designed for shipbuilding and offshore applications, offering excellent corrosion resistance, high strength, and long service life. Available with ABS, DNV, and LR certifications.

Marine seamless steel pipes are specially designed for ship applications. As a professional supplier of seamless stainless steel pipes, we offer a wide product range and comprehensive specifications. Our products comply with ASTM, ASME, GB, RS, ABS, BV, CCS, RINA, and other standards.

We also support customization for various pipe dimensions, including large diameter, small diameter, thick wall, and thin wall pipes according to your requirements.

Marine seamless stainless steel tubes are manufactured using hot rolling piercing, cold drawing, or cold rolling processes. With a fully seamless structure, they provide excellent corrosion resistance, strong mechanical properties, and superior reliability.

In harsh marine environments, pipes are exposed to seawater corrosion, salt spray, and temperature fluctuations. Therefore, high-performance materials are required, and seamless stainless steel pipes are the ideal solution.

Common Grades

304 / 304L, 304H, 304N / 304LN
310
316 / 316L, 316H, 316Ti, 316N / 316LN
317 / 317L
321 / 321H
347 / 347H
S31803, S32205 (Duplex)
S32750 (Super Duplex)
904L, S31254

Standards

CCS (China Classification Society)

DNV (Det Norske Veritas)

LR (Lloyd's Register)

GL (Germanischer Lloyd)

ABS (American Bureau of Shipping)

BV (Bureau Veritas)

RINA (Registro Italiano Navale)

NK (Nippon Kaiji Kyokai)

GB/T 5312 (China National Standard)

ASTM A312 / A213 / A269

EN 10216-5

Product Specifications

Outer Diameter	6mm – 530mm
Wall Thickness	0.5mm – 30mm
Length	6m / 12m / Custom
Surface	Pickled, polished, sandblasted
Production Process	Hot rolled, cold drawn / cold rolled
Tolerance	According to ASTM / EN standards

Dimensional Tolerance

Cold Drawn Pipes	Steel Pipe OD (mm)		Steel Pipe WT (mm)
Cold Drawn Pipes	OD	Tolerance	WT	Tolerance
Cold Drawn Pipes	＞30–50	±0.3 mm	≤30	±10%
Cold Drawn Pipes	＞50–219	±0.8%	-	-
Hot Rolled Pipes	＞219	±1.0%	＞20	±10%

Key Advantages of Marine Seamless Stainless Steel Pipes and Tubes

1. Fully Seamless Structure – High Safety

No weld seams, uniform structure, excellent pressure resistance, impact resistance, and fatigue resistance. Ideal for critical systems such as engines, hydraulics, and fire protection.

2. Superior Marine Corrosion Resistance

Grades such as 316L and duplex stainless steel contain molybdenum, offering excellent resistance to chloride pitting, crevice corrosion, and stress corrosion cracking.

3. High Dimensional Accuracy

Cold drawing and cold rolling ensure excellent roundness, straightness, and uniform wall thickness, facilitating easy installation.

4. Certified for Marine Use

Complies with CCS, DNV, LR, ABS, and other classification societies. Full documentation including MTC, NDT reports, and heat treatment reports available.

5. Excellent Mechanical Properties

High strength and toughness, no brittle fracture at low temperatures, allowing thinner walls under the same pressure, reducing vessel weight.

6. Clean and Hygienic

Smooth inner surface prevents scaling and bacterial growth, suitable for potable water and food-grade systems.

7. Low Maintenance Cost

Corrosion-resistant, no need for frequent coating or replacement, reducing lifecycle costs.

Application Areas

Power system: Main engine/auxiliary engine cooling water pipes, fuel oil delivery pipes, steam pipelines, heat exchanger tube bundles;
Fluid system: Ballast water, seawater desalination, fire fighting, drinking water, sewage pipes;
Specialty vessels: Cryogenic pipelines for LNG carriers, corrosive media delivery pipelines for chemical tankers, high-pressure piping systems for offshore engineering platforms.

Marine Pipe Classification

According to standards, marine pipes are classified into Class I, II, and III based on design pressure and temperature.

Pipe Range	Class I	Class II	Class III
Pipe Range	Pressure (MPa)	Temp (°C)	Pressure (MPa)
Steam & Hot Oil	>1.6	≤300	0.7–1.6
Fuel Oil	>1.6	≤150	0.7–1.6
Other Media	>4.0	≤150	1.6–7.0

Note:

Pipes meeting Class I pressure and temperature fall under Class I

Those meeting Class II conditions are classified as Class II

Other media include air, water, lubricating oil, and hydraulic oil

Class III pipes can be manufactured according to approved national standards

Production Process

Raw Material Inspection
High-quality stainless steel billets with strict chemical composition control
Hot Piercing
Formation of hollow tubes at high temperature
Cold Drawing / Cold Rolling
Improved dimensional accuracy and surface quality
Solution Annealing
Relieves stress and enhances corrosion resistance
Pickling & Surface Treatment
Removes oxide scale and improves cleanliness
Non-Destructive Testing (NDT)
Includes UT, ET, etc., ensuring defect-free pipes

Stainless Steel Seamless Pipe Production Progress.jpg

Common Stock Sizes (mm)

25×4	42×5.5	76×5	168×12
27×3	42×6	76×5.5	168×14
27×4	48×3.5	76×6	219×11
28×4	48×4	76×7	219×13
30×5	48×5	83×7	273×9
32×4	48×5.5	89×4	325×8
34×3	50.8×3.65	89×5	377×16
34×3.5	57×3.5	89×12.5	377×20
34×4	60×4	114×6	426×20