Qualify welder

[umi]

Hi everbody,
I have a question, I qualify welder follow to ASME IX, with pipe 2"inch, so I can use this welder do welding pipe 3/4 inch is not.
QW 452.3 ASME IX show that less than 25mm .
If we follow ASME B36.10 pipe schedules, 3/4 inch = 26.7 mm. So Can I do that right.

[Mr Welder]

View in ASME B36.10 Ed.2004


Item: 2 SIZE

The size of all pipe is the nominal IDENTIFIED BY
pipe size.
The manufacture of pipe NPS 1 / 8 (DN 6) to NPS 12
(DN 300), inclusive, is based on a standardized outside
diameter (OD). This was OD Originally selected so that
with the standard pipe OD and wall thickness Having a
That was typical of the period would Have an inside
diameter (ID) Approximately equal to the nominal size.
Although there's no such relation Between the existing
standard thickness - OD and nominal size - These
nominal sizes and standard ODs continue in the use
Standard''.''
The manufacture of pipe NPS 14 (DN 350) and larger
proceeds on the basis of an OD Corresponding to the
nominal 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.2004

Table 1 Weights and Dimensions of Welded and Seamless Wrought Steel Pipe

NPS = 3 / 4
Outside Diameter = 1.05 in

Calculation: 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.2010

As 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 403.16

QW-403.16 A change in the pipe diameter Beyond the
range qualified in QW-452, except the Permitted Otherwise
in 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 452.3


QW 452.3

If 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 Unlimited


Example: In your case will be so.


REAL VALUES
Diameter (external) qualiicado least 3 / 4 (26.67)


RANGE QUALIFIED
Diameter = Min Size Max Diameter = welded Unlimited


You must qualify your welder in tube 3 / 4 in.
which can weld any diameter.