There are five types of carbon steel tubing that are used primarily for mechanical applications. Some examples of these are ready-to-use tubing with special ID finishes for hydraulic cylinder and fluid line applications, square and rectangular tubing for mechanical and structural applications, and carbon steel pipe.

Multiple processes are done to the metal before the finished product, two of those being hot rolled or cold-finished. In a previous blog, we explored the differences between hot rolled vs. cold-finished carbon bars. As a refresher, hot rolled products are brought to their finished size by rolling at elevated temperatures and considered first-stage metal with minimal finishing and processing as the tolerances are wider and the finish is not aesthetically ideal. 

If that hot-rolled product is then put through a series of additional processes, it becomes cold finished. Cold drawing gives a hot rolled bar a bright, clean, uniform surface that increases tensile and yield strength, turning and polishing removes surface imperfections and produces a finer, brighter, smoother finish, and grinding processes the bar to the closest tolerance while also giving it a high degree of straightness and a superior finish. 

Understanding the hot rolled and cold-finished processes can help you determine which carbon steel tubing is best when thinking in terms of mechanical applications. 

One exception is Buttweld mechanical tubing – the tubing that connects other tube and piping together – which is neither hot rolled nor cold formed. Buttweld carbon tubing is produced from continuous welded pipe and does not offer the inherent strength in the weld area of an electric resistance welded product. It is made from low carbon SRA steel with machinability and mechanical properties that are reduced as a result of lower carbon content. It is stocked at random lengths 17 to 24 feet.

Listed below are the five types of carbon steel tubing organized by hot and cold finishes.

Hot Finished Carbon


 Cold Finished Carbon


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