The process commences with the formation of welded Mother Tubes from tested prime quality Stainless Steel Strips on a continuous automtic Tube Mill. The latest multicathode TIG welding techique is employed for excellent weld quality with 100%fusion,alongwith Argon purging to prevent Oxidation of the weld. No filter metal is added.
These mother tubes are deoiled, cleaned, then solution annealed at 1050 C, in a continuous Solution Annealing Furnace followed by instant quenching to prevent chromium carbide precipitation. Solution Annealing ensures
• Recrystaillization of austenite grains for optimum corrosion resistance
• Removal of stresses during tube forming and welding.
• Impat, ductility and softness to, further cold drawing, if needed.
• Transfomation of weld zone and heat affected zone toAustenite structure.

Solution annealed tubes are straightened lightly on a Roller straightening machine to remove distrotions caused during annealing/ quenching.
Surface scales formed due to oxidation during annealing are removed by surface cleaning process. Surface cleaning process ensures full removal of' scales immersing the tubes in controlled strength acid bath viz. Hydrofluoric Acid, Nitric Acid etc. Cleaned tubes are then coated with special lubricants, and then tagged fore cold drawing.
Cold drawing results in a tube with much closer dimensional tolerances, provides smooth inner surface, improves the physical and metallurgical poperties for improved performance.
Cold drawing cycle is invariably followed by subsequent solution annealing, and pickling. Finally the tubes are passivated to impart extra corrosion resistance.
Marking : Finish tubes/pipes are etched with a special process with legible ink. Each pipe/tube is marked with material Grade, manufacturing standard, sice, Heat No. etc to co-relate with Mill Test Certificate.
Popular sizes of Stainless Steel pipes & tubes ae available Ex- stock or at a short notice. Welded pipes are supplied in as rolled condition (SA-312) and in cold drawing condition (SA-249).