When piercing bar come to our plant, we will track them by a production card named the Grade, Size, Furnace No.: and PO No. ( The red paper into the pipes)
In order to ensure the quality, we will do the inspection and grinding to get rid of the small crack caused during course of punching.
Because these small crack must be enlarged during course of next process ( Cold-drawing or cold-rolling) or hide into the body of pipe caused intergranular corrosion.
This is the first step, base step, also the most important step for us.