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Quotes - Engineering - SalesMaterials and Surface Finishes
Most U-tube duty is served by 304L, 316L or carbon steel, and choosing between them is straightforward. The interesting decisions happen at the edges: chlorides at temperature, acids, seawater, sour service and anywhere the cleaning chemistry is more aggressive than the process. Bend radius interacts with all of it, because cold bending work-hardens the material and leaves residual stress exactly where corrosion likes to start.
Process Requirements
Thermal Solutions
Molybdenum. 316L contains it, 304L does not, and it substantially improves resistance to chlorides and to pitting. In hygienic and marine-adjacent service 316L is the default for that reason. In clean water and steam duty 304L is often entirely adequate and cheaper.
When chlorides are present at temperature, when the pH is aggressive, in seawater or brine, and in sour service. Chloride stress-corrosion cracking is the mechanism that most often ends a 300-series bundle's life, and it depends on chloride level, temperature and tensile stress together.
Yes. Duplex and high-strength alloys work-harden during bending and need a more generous minimum radius than austenitic stainless. Choosing the alloy and the bend radius together avoids a design that has to be revisited.
