304L and 316L Stainless
U-Tube Exchangers

U-Tube Heat Exchangers For

304L and 316L Stainless
U-Tube Duty

These two alloys cover most of the heat exchangers built. The difference between them is molybdenum, and the thing that eventually limits both is chloride stress-corrosion cracking.

304L and 316L are austenitic stainless steels with low carbon content, which reduces carbide precipitation at grain boundaries during welding and preserves corrosion resistance in the heat-affected zone. That is what the L means and it is why exchangers use the L grades.

Molybdenum. 316L contains roughly two to three percent, which markedly improves pitting and crevice corrosion resistance in chloride environments. That single addition is why 316L dominates hygienic, marine-adjacent and coastal service.

Where 304L Is Enough. Closed loops of treated water, clean steam and condensate, and general utility duty with no chloride source are all comfortably within 304L's range, and the cost difference against 316L is real.

Where 316L earns its premium is anywhere chlorides appear: coastal cooling water, brine, food streams carrying salt, and any plant using chlorinated sanitizers. On product-contact sanitary duty 316L is effectively the default regardless.