Stainless Steel Pipes Power the Global Shipbuilding Industry in 2025
In 2025, the global shipbuilding industry continues to operate within a healthy growth cycle, maintaining steady momentum and supporting sustained demand for steel materials. Stainless steel pipes, in particular, are playing an increasingly critical role in modern ship construction, offshore engineering, and marine energy transportation.
According to market estimates, domestic demand for shipbuilding stainless steel pipes is expected to reach approximately 1.5 million tons in 2025. Material selection is becoming more diversified, with higher requirements placed on corrosion resistance, surface quality, and welding performance-areas where stainless steel pipe solutions clearly stand out.
From VLCCs to LNG Carriers: Stainless Steel Pipes at the Core of Marine Systems
With the expansion of global maritime transport, offshore oil and gas exploration, and LNG infrastructure, marine-grade stainless steel pipes for shipbuilding are now indispensable across a wide range of vessels.
A single VLCC (Very Large Crude Carrier) or VLGC typically requires hundreds of tons of stainless steel pipes for cargo heating systems, oil and gas transfer pipelines, and auxiliary process systems. LNG carriers further represent a flagship application, relying heavily on cryogenic stainless steel pipes for LNG ships to safely handle ultra-low temperatures down to −165°C.
Seamless and welded stainless steel pipe specifications by Ganyeah Group
Functional vs. Structural Pipe Applications
Shipboard steel pipes are generally divided into two categories:
- Functional system pipes
Used for fluid transport and processing, including ballast water, bilge, firefighting, fuel oil, hydraulic oil, inert gas, cargo oil, tank cleaning, heating, ventilation, and LNG/LPG cargo handling systems. These systems typically operate at pressures from 0.7 MPa to 40 MPa and temperatures between 60°C and 300°C. - Structural pipes
Applied in masts, railings, handrails, flagpoles, and various structural supports, where mechanical strength and durability are essential.
Across both categories, stainless steel pipes for marine fluid systems deliver reliable performance under complex operating conditions.
Stainless Steel Pipe Material Selection: Global Practices and Standards
Material selection for shipbuilding stainless steel pipes is primarily governed by classification society rules and long-term operational experience. Different countries and shipowners show varying preferences, but corrosion resistance remains the universal priority.
Commonly Used Grades in Marine Applications
Widely adopted materials include:
- Austenitic stainless steel pipes: 304L, 316L, 321, 347
- Duplex stainless steel pipes: S31803 (2205), 2507
- CRA-lined composite pipes for aggressive service environments
Key performance indicators include Pitting Resistance Equivalent (PRE), Critical Pitting Temperature (CPT), and Critical Crevice Corrosion Temperature (CCT).
Among these, 316L stainless steel pipes for shipbuilding remain the mainstream choice due to their balanced corrosion resistance, weldability, and availability.
Classification Society Requirements
- Germanischer Lloyd (GL) requires austenitic stainless steel pipes with low-temperature toughness to be fusion welded, supplied in heat-treated condition, and manufactured with a weld joint efficiency factor of 1.0. This has driven the widespread adoption of GTAW and PAW welding processes.
- Bureau Veritas (BV) allows grades such as 304/304L, 316/316L, 321, 347, and S31803 for liquefied gas carrier cargo piping. Notably, duplex S31803 is limited to −20°C, while austenitic grades are suitable for cryogenic LNG service.
In highly corrosive regions—such as the Gulf of Mexico or offshore West Africa—standard 316L may be insufficient, prompting upgrades to duplex or high-alloy corrosion-resistant stainless steel pipes.
Manufacturing Excellence: Surface Quality and Welding Make the Difference
Surface Treatment Determines Corrosion Resistance
The corrosion performance of stainless steel pipes is heavily influenced by surface condition. Processes such as pickling and passivation, precision finishing, and strict control of surface roughness are essential—especially for pipes exposed to chloride environments, stress corrosion cracking, or thermal fatigue.
High-quality cold-drawn or cold-sized welded stainless steel pipes can achieve surface finishes equal to or even better than seamless pipes, making them suitable for precision marine applications.
Welding Technology Is Critical
For wall thicknesses between 3 mm and 7 mm, GTAW and PAW welding of stainless steel pipes are the preferred methods for both austenitic and duplex grades. Thicker pipes may require combined welding processes, while GMAW/FCAW is now largely avoided for duplex stainless steel pipe manufacturing.
Special attention is also required for:
- Passivation of welded joints in 316L heating coils for crude oil tanks
- Dissimilar metal welding procedures between 9% Ni steel LNG tanks and TP316L stainless steel pipes
These details directly impact long-term safety and reliability.
Why Ganyeah Group for Shipbuilding Stainless Steel Pipes
Ganyeah Group provides high-performance stainless steel pipe solutions for shipbuilding and offshore engineering, covering material selection, precision manufacturing, and welding process control. With strict quality management and compliance with major classification society standards, we support customers across VLCC, LNG, LPG, and offshore vessel projects worldwide.
📩 Contact Ganyeah Group to discuss your requirements for marine stainless steel pipes and corrosion-resistant pipeline solutions.