The short answer
Carbon steel is the workhorse for water, steam, oil and hydraulic lines and most fire mains; stainless is used where the process, the cleanliness or the temperature demands it, such as furnace cooling and hygienic lines. The specification decides. KBVI fabricates, welds and installs both, often on the same job.
Carbon steel
Most plant lines are carbon steel: cooling water, demin water, steam, oil, hydraulic and the fire mains. The BOS clarifier pump pipework at British Steel was 3 inch and 2.5 inch carbon steel schedule 40. It is fabricated to drawings, welded and installed in every size from small bore to large diameter.
Stainless steel
Where the process or the environment needs it: furnace cooling lines, hygienic process lines in food and pharmaceutical plant, and clean process areas. KBVI TIG welds stainless process and cooling lines, including the furnace pipework for Rolls-Royce in Sheffield.
Usually both
A plant is rarely one material. The specification sets the material for each line, and the contractor needs to fabricate, weld and install both to the same standard. That is the case on every job on KBVI's record.
Who decides the material?
The specification and the drawings. KBVI works to what is specified and raises it with the client if something on site does not match.
Do you weld both?
Yes. Carbon and stainless, with TIG on the stainless process and cooling lines.
