Welder qualification follow ASME IX- Part 2: Essential Variable for Welder Qualification!

Following the discussion in Part 1: Welder qualification follow ASME IX- Part 1: Genenral

Now we continue with the concerns on Essential Variable for Welder qualification status in Certification and Welding limitation at the site.

1) Essential variable ( QW-351 ) – for welder:

– A welder shall be requalified whenever a change is made in one or more of the essential variables listed for each welding process.

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– Take an example for GTAW process: ( for other welding process, we do same thing, check each variable to know what happen on it when we change them ).

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+ Joints: QW-402.4 states the deletion of backing is essential

Welders were qualified with backing so they are only allowed to weld on backing.

To be see more in ASME IX:

weld 27

+ Base metal: 

– QW-403.16 states a change in the pipe diameter qualified is essential. 

  • Welders were qualified on plate so they can only weld on plate.

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  • A change in the pipe diameter:

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  • Thickness limit:

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–  QW-403.18 states a change in the P-No. material qualified is essential. 

  • Welders were qualified on P-No. 1 material so they are qualified to weld P-No. 1 through P-No. 15F, P-No. 34, and P-No. 41 through P-No. 49.

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weld 32.PNG

weld 33

  • QW-420:

weld 34.PNG

  • QW-423:

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+ Filler metal:

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  • QW-404.14states a change between using filler metal or not using filler metal is essential. Welders were qualified with filler metal so they are only allowed to
    weld with filler metal.
  • QW-404.15 states a change in F-No. is essential. Ex: Welders were qualified with F-No. 6 so they are only allowed to weld with F-No. 6.

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  •  QW-404-22 states a change between using a consumable insert or not using consumable insert is essential. Welders were qualified without a consumable insert so they are only allowed to weld without a consumable insert.
  • QW-404.23 states a change in the type of filler metal is essential. Welders were qualified using a solid wire so they can only weld with a solid wire.
  • QW-404-30:  states a change in the weld metal thickness qualified is essential. Ex: Welders deposited 1/4-in. GTA weld and 1/2-in. of GMA weld so they are qualified to deposit an 1/2-in. GTA weld and unlimited GMA weld.

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+ Position: QW-405

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  • QW-405.1 states a change in the position qualified is essential. Ex: Welders were qualified in the flat (1F) position so they can only weld in the 1F position.

weld 41

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  • QW-405.3 states a change in the weld direction for vertical weld is essential. 

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+ Gas: QW-408.8 states the omission of inert gas backing is essential. Ex: Welders were qualified with backing so the variable does not apply.

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+ Electrical: QW-409.4:  states a change in the current and polarity is essential. Welders were qualified using DCEP so they can only weld using DCEP. 

WELD 47.PNG

Pls read ASME IX to know more information. We just show how we check essential variable follow ASME IX.

Pls see next part: How to  carry out a Welder qualification!!!

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