Heat exchanger tubes used in petrochemical, refining, LNG, and seawater desalination industries face combined challenges including chloride corrosion, cyclic thermal loading, and high-temperature erosion. Industry technical experts emphasize that material selection must go beyond conventional corrosion resistance and comprehensively consider process media characteristics, shutdown maintenance conditions, and exposure to cleaning chemicals.
In terms of material selection practice, for seawater cooling systems, super austenitic grades (such as 904L and 6Mo alloys) and duplex stainless steels (2205, 2507) offer superior pitting and crevice corrosion resistance. In terms of manufacturing, bright annealing (BA) surfaces combined with passivation treatment can form a stable and dense chromium oxide film. For the most demanding applications, electro-polishing (EP) further reduces surface roughness and enhances oxide film stability.
Looking at recent project cases, a Southeast Asian petrochemical project custom-ordered ASTM A269 TP316L heat exchanger tubes with 25.4mm OD × 2.11mm wall thickness, requiring OD tolerance of ±0.05mm, wall thickness tolerance of ±5%, and surface roughness Ra ≤ 0.8μm. This reflects the industry trend toward high-precision customized heat exchanger tubes.
