DIN 2559-3
DIN 2559-3 Preparation of welds - Part 3: Matching of inside diameters for circumferential welds on welded pipes
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 09/01/2007
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 09/01/2007