Composite metal tube and method of making the same

A method for manufacturing a lined metal tube comprising the steps of:

• inserting a length of polymeric tubing having a predetermined outer diameter into an inner diameter of metal tubing of essentially corresponding length, said metal tube having an unsealed side seam and an inner diameter at least 30% greater than said predetermined outer diameter of said polymeric tubing, said metal tube traveling at a first rate and said polymeric tubing being inserted at a second rate greater than said first rate yielding a rate differential essentially equal to a differential of said diameters;
• welding said unsealed side seam while maintaining said polymeric tubing at a location within said metal tubing opposed to said side seam during said welding;
• and
• reducing said metal tubing to an outer diameter essentially equal to said predetermined outer diameter of said polymeric tubing.

A method for manufacturing a metal tube having an interior surface resistant to interaction with materials to be conveyed therethrough, the method comprising:

• positioning a length of non-reactive tubing having a predetermined outer diameter within an inner diameter of metal tubing of essentially corresponding length having an unsealed side seam, wherein said inner diameter of said unsealed metal tube is at least 30% greater than said outer diameter of said non-reactive tubing;
• forming a suitable sealed side seam in said outer metal tube while maintaining said non-reactive tubing at a position opposed to said side seam during said formation step;
• and
• reducing said outer metal tubing to an outer diameter essentially equal to said predetermined outer diameter of said non-reactive interior tubing.