Clarification QW-409.4

[Yael Nieto]

I have a misgiving wiht QW-409.4

ASME Section IX Ed 2021 describes: 

QW-409.4 A change from AC to DC, or vice versa; and in DC welding, a change from electrode negative (straight polarity) to electrode positive (reverse polarity), or vice versa. This variable does not apply to a WPS qualified for welding base metals that are assigned to P-No. 8, P-Nos. 21 through 26, and P-Nos. 41 through 49.

I have a base metal P8-P8 WPS, so I know if the construction code requires impact testing for base metal(s) or weld metal, then the for the WPS the variable is supplementary essential but my base metal is P8, also aply ?

[Mohd Siraj]

dear,

P8 material can be used up to -195C without any impact testing...lests know why you conduct impact testing?

[Rameshbabu B]

Though for base material it is exempted up to -196 deg C the weld metal is restricted for -104 deg .

Hence it is mandatory when you qualifies PQR it is recommended to have impact testing.

If you have existing qualification without notch toughness you can supplement the impact testing followed by establishing test with parameters of existing PQR and support it.

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[Kannayeram Gnanapandithan]

QW 409.4 for supplementary essentials on change in Current/Polarity, when referring code call impact testing. This is  exempted for ASS, Al, Ni base alloys for change in Current/Polarity. 

This essential variable are applicable other than exempted material. This Exemption is not for other base materials due to  metallurgical changes taking place while welding.  

So not necessary to do toughness if referring code does not calls, and, temp also

 

THANKS & BEST REGARDS,

KG.PANDITHAN, BE, IWE,  CSWIP 3.1,

ISO 9712 Level 2 in VT,

ASNT-Level II in PT,MT,RT & UT,

LA ISO 9001-2015,

International Welding Engineer. 

CONSULTANT-WELDING & QUALITY

Mobile no: +919940739349

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