Although pipes and tubes may look similar, they are in fact quite different in nomenclature and sizing. Remember that pipes and tubes are rarely interchangeable. Here are some main differences between the two products:
Most of the pipes are round. Tubes are square, rectangular or round.
Tube is stronger than pipe.
Tube is steel in hot rolled and cold rolled. Typically, pipe is black steel in hot rolled. The galvanized appropriate to pipes and tubes.
Copper and brass tubes can shape relatively easy. Tubes are typically rigid. On the other hand, pipes are invariably rigid. Pipes cannot shape without special equipment.
Pipe is typically available in larger sizes than tube.