Essential Variable Change Checker Calculator

Check if a welding parameter change requires a new PQR per ASME Section IX essential variable rules (QW-400)

Input Parameters

Results

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Thickness Qualification
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Max Qualified Thickness
in
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P-Number Change
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Requalification Required
Note: This checks the two most common essential variable changes per ASME IX. A complete evaluation should also include process (QW-402), filler metal F-number (QW-404), and positions (QW-405).

Reference

ASME IX Essential Variables (QW-400): QW-403 Thickness: PQR <1.5" qualifies to 2T max; >=1.5" qualifies unlimited QW-403.5 P-Number: Change requires requalification Min qualified thickness: max(T/2, 1/16") These are the two most commonly checked essential variables.