A number of materials can be used in heat exchanger tubes. The material is selected based on the characteristics of the fluids from the corrosion point of view. The material of the tubes is in contact with the tube-side and shell-side fluids and must be resistant to both.
Wall thickness is selected based on a mechanical calculation to resist the design pressures. The most commonly used materials are carbon steel, alloy steel, stainless steel, bronze, nickel, and their alloys (e.g., Monel, Inconel, and Hastelloy). For very corrosive fluids, more exotic materials such as titanium or even glass can be used.