Engineers must choose from a variety of stainless steel types when configuring a package cooling tower. Type 301L stainless steel (SS), Type 304 SS, even Type 316 SS may be selectable options for tower structure and components, including cold water basins, when additional corrosion protection beyond galvanized steel is desired.
Understanding the different material attributes of stainless steel types can lead to more logical and reliable choices. Type 301L (the “L” designates the low carbon version of 301) has 0.03 percent maximum carbon content while Type 304 has 0.08 percent. This slight difference in carbon content greatly affects the corrosion resistance between the two materials in the welded regions.
While nearly identical in their chromium and nickel content and ability to resist chemical attack and corrosion in typical cooling tower environments, the low-carbon content of Type 301L offers superior corrosion resistance at welds compared with Type 304. Away from the weld, these two stainless steel types offer virtually the same corrosion protection in typical cooling tower environments.
Other advantages of some Type 301L grades include higher yield and tensile strength, and better fatigue resistance. They also cold-work faster, which reduces thinning and provides higher strength in the formed areas.
In extreme conditions, such as low pH environments, high chloride, extreme oxidizing or reducing environments, additional corrosion protection afforded by materials such as Type 316 stainless steel may be justified. Type 316 stainless steel contains molybdenum, which imparts even greater corrosion resistance.
Most cooling towers never experience these extreme environments. Choose wisely by selecting the materials best suited to your application. Avoid investing in costly materials your cooling tower will never need.