With this part, we will know GENERAL about Welder qualification follow ASME IX.

1)  Main purpose for Welder qualification:

– To verify the skill of an individual to preform a qualified welding procedure specification ( WPS ) to produce a good weld.

– Welders qualify to specific welding process NOT welding procedures ( need note this one: welding process & welding procedure )

– Welding process:
            • Welder: have SMAW / GTAW / FCAW / GMAW …
            • Welding operators : SAW…

– Welding types:
               • MANUAL / SEMI-AUTOMATIC – Welders
               • MACHINE- welding operators
               • AUTOMATIC- welding operators

2)  Welders can be qualified by /  Acceptability Criteria For  Welder Tests:

• visual inspection and
• destructive testing / radiographic inspection

• For Visual examination: refer QW-302.4 & QW-194:

• For  Bend test: refer QW 163 ( note:  No open discontinuities in the weld or HAZ greater than 1/8-in )

•  For Radiographic acceptance criteria: refer QW-191. 

Pls take note that: Ultrasonic examination can replace RT in some case as below mention:

3) Essential Variables: these are variables what when they are changed, the welder have to re-qualify.

• For welder:

• For Welding operator:

– Welder performance essential variables: for each Welding Process, it has some difference as below, example:

For next part we will go detail for each essential Variable & know How to qualify a Welder.