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.