Qualify welder

View in ASME B36.10 Ed.2004 Item: 2 SIZEThe size of all pipe is the nominal IDENTIFIED BYpipe size.The manufacture of pipe NPS 1 / 8 (DN 6) to NPS 12(DN 300), inclusive, is based on a standardized outsidediameter (OD). This was OD Originally selected so thatwith the standard pipe OD and wall thickness Having aThat was typical of the period would Have an insidediameter (ID) Approximately equal to the nominal size.Although there's no such relation Between the existingstandard thickness - OD and nominal size - Thesenominal sizes and standard ODs continue in the useStandard''.''The manufacture of pipe NPS 14 (DN 350) and largerproceeds on the basis of an OD Corresponding to thenominal size. Answer: That is if a tube is 3 / 4 it will be considered 3 / 4 or 20mm round off because the asme + 0.5(Ie 3 / 4 is accurate: 19.05000, 20.00000 rounded)table as an ASME B31.10 Ed.2004Table 1 Weights and Dimensions of Welded and Seamless Wrought Steel PipeNPS = 3 / 4Outside Diameter = 1.05 inCalculation: 1.05 x 25.4 = 26.67mm (ie 26.67 mm is the external diameter of the tube)Welder qualification: According to ASME IX Ed.2010As in QW 416 Welding Variables (Performance welder)The diameter of the tube in the welding processes: SMAW, SAW, GMAW, FCAW, GTAW and PAW. It is an essential variable.See QW 403.16QW-403.16 A change in the pipe diameter Beyond therange qualified in QW-452, except the Permitted Otherwisein QW-303.1, QW-303.2, QW-381.1 (c), or QW-382 (c).If your case goes to joint top notch "V" You will use the QW 452.3QW 452.3If the welder Use your qualification in the real value of: 1 "in (25mm) or less your track will be qualified:diameter (external) = minimum size qualified soldier (an "in-25mm)diameter (external) = maximum qualified UnlimitedExample: In your case will be so. REAL VALUESDiameter (external) qualiicado least 3 / 4 (26.67) RANGE QUALIFIED Diameter = Min Size Max Diameter = welded UnlimitedYou must qualify your welder in tube 3 / 4 in.which can weld any diameter.