B16.34, para. 8.4, addresses welding if a defect removal results in a thickness below an acceptable value.Question: If we require a 1.75" BW wall for a valve, but the valve is supplied in 1" wall thickness, can we add weld filler and machine to 1.75" wall (with NDE per 16.34). Or does this paragraph just address a minor local repair (not a major weld build up and machining)?It's unclear if 16.34 allows or addresses a major weld build up and the machining for the required (thick) bore. In my opinion this would be no repair, but part of a 'fabrication methode', and the repair instructions are not intended for this use, wher you normally would have solid materials, casted or other 'normal' methodes.You can argue that welded overlay on surfaces are used (in some small extent) for ball valvelves to cut material cost down, for instance inconel or other on casted or fabricated steel balls.This is however an exception, and not used for critical parts of pressure containing construction details.

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