Carbon Steel Heat Exchanger

Carbon steel heat exchangers are the most common type in petrochemical, power, and pharmaceutical industries. When the fluids are not highly corrosive, and when operating temperature and pressure fall within carbon steel's capability (shell design temperature typically -20℃ to 400℃, pressure up to 10 MPa or higher), carbon steel offers the best cost-to-performance balance.

The shell and tube bundle are made of Q345R, Q235B or similar pressure vessel steels. Tubesheets and baffles match the same material family. If the shell-side or tube-side medium contains mild corrosive components, a corrosion allowance (typically 1.5mm to 3.0mm) can be added during the mechanical design. For outdoor applications where rust prevention is needed, the external surface can be painted or hot-dip galvanized; internal surface cleaning or passivation is optional based on the medium.

Carbon steel has a higher thermal conductivity than stainless steel. For the same thermal duty, a carbon steel heat exchanger often requires slightly less heat transfer area. However, carbon steel is not suitable for chlorides, acids, alkalis, seawater cooling, or wet hydrogen sulfide service. If the equipment is to be installed in a high-humidity environment and will be idle for extended periods, internal corrosion may occur. In such cases, nitrogen blanketing or periodic ventilation is recommended.

We perform thermal calculations using HTRI/ASPEN and design to GB, ASME, or TEMA standards. Our shop capabilities include carbon steel plate rolling, automatic and manual welding, and non-destructive testing (RT/UT). Shell-side and tube-side pressure tests are conducted before delivery. ASME U Stamp, PED certification, and classification society certificates are available upon request. Our services cover the full process from thermal design, material procurement, to field installation guidance.