Corrosion in Marine Applications? — Dual Internal & External Protection Extends Service Life

Marine and offshore environments present one of the harshest challenges for heat exchanger systems. High humidity, salt-laden air, and fluctuating temperatures accelerate corrosion, often leading to premature tube failure, leakage, and decreased thermal efficiency. Conventional carbon steel finned tubes tend to rust rapidly under these conditions, causing costly maintenance and unplanned shutdowns. To address this issue, Zhongyue Metallurgy has engineered a comprehensive dual-layer corrosion protection system specifically for its H-Type and L-Type Finned Tubes, ensuring long-term durability and stable performance in marine and coastal applications.

The first layer of protection is external coating. Each finned tube is coated with a red oxide zinc phosphate primer, a proven industrial-grade anti-corrosive material that provides excellent adhesion and chemical resistance. This coating effectively blocks moisture and salt penetration, preventing oxidation on the tube and fin surfaces. It also withstands high operating temperatures, making it ideal for marine boilers, desalination plants, and offshore power generation systems.

The second layer is internal protection, utilizing a volatile corrosion inhibitor (VCI) in tablet form. During storage or operation, VCI vapors form a molecular film inside the tube, preventing rust from forming on internal surfaces—even in high-humidity environments. This invisible barrier ensures that the internal walls remain dry and corrosion-free without affecting heat transfer efficiency or contaminating the process medium.

Zhongyue’s H Fin Tubes and L Fin Tubes (including wheel-type and perforated designs) are produced from premium materials such as A179, 20G, TP304, and 12Cr1MoVG, ensuring both mechanical strength and corrosion resistance. The fins, with thicknesses ranging from 1.5–3.5 mm and pitches as small as 10 mm, are welded using full-penetration technology to achieve strong metallurgical bonding. This not only enhances heat transfer performance but also reduces the likelihood of crevice corrosion between fins and base tubes.

Comprehensive hydrostatic, pneumatic, and eddy current tests are conducted to verify structural integrity and bonding strength. In marine trials, Zhongyue’s finned tubes demonstrated over five years of corrosion-free performance, even in continuous exposure to humid, saline environments.

By combining robust external coating and advanced internal anti-rust protection, Zhongyue’s dual-protected finned tubes deliver exceptional resistance to corrosion and oxidation. This innovation dramatically extends equipment lifespan, reduces maintenance costs, and ensures reliable, energy-efficient operation for marine heat exchangers, economizers, and coastal power systems operating under the most demanding environmental conditions.