tube-drawing

from The Century Dictionary.

• noun The manufacture of tubes from a solid ingot by drawing out the metal over a mandrel and without a longitudinal seam or joint.
• noun The manufacture of tubes by forcing a semifluid material through a die, with a mandrel or triblet in place to form the bore.
• noun The removal of the tubes from a multitubular boiler for inspection and renewal.
• noun The forming of tubes by drawing them down from thick cylinders.