Partial Penetration Overlay Base Metal Thickness - ASME Section IX 1

[MrGezus]

Good afternoon, everyone. I have done a PQR using this:

Originally I used the PQR base metal thickness as 1/2" but the customer is saying it should be 1" on both the PQR and the WPS. This is for a 625 overlay with mechanicals to meet "as part of the design criteria" in API 6A. I am unclear as to why it would be 1" over 1/2" or visa versa. To me Table QW-453 states it should be T qualified which would be 1/2".

 

[CWEng]

This PQR is done like an inlay of corrosion resistant material, similar to is done with flange grooves. I would agree with your customer, in that the original, and restored base metal thickness is 1" thick. It would be similar to a partial penetration groove weld. In those cases, you don't use the base metal thickness left at the bottom of the groove, but the entire plate thickness is your "T".

 

[metengr]

If you review Table QW-453, the thickness T qualified of the coupon, is the thickness T qualified for the base material. So, if you select 1/2" thickness for the coupon, the WPS for CRO is qualified for 1/2" thickness and not 1".

However, are you taking credit for the strength of the overlay in the design of the flange? If so, this is no longer considered a CRO WPS and instead would be a groove weld procedure qualification.

 

[MrGezus]

If you review Table QW-453, the thickness T qualified of the coupon, is the thickness T qualified for the base material. So, if you select 1/2" thickness for the coupon, the WPS for CRO is qualified for 1/2" thickness and not 1".

However, are you taking credit for the strength of the overlay in the design of the flange? If so, this is no longer considered a CRO WPS and instead would be a groove weld procedure qualification.

Okay, I understand this because it's not only acting as a corrosion resistance barrier. Would I still use the same table for CRO procedure qualification or use the gtaw groove table? I ended up writing it up using the CRO essential variables and the customer accepted it. I did end up changing it to 1" as per their request.

 

[metengr]

If you are taking credit for the weld metal strength equal to or greater than the base metal and not simply a corrosion barrier coating, yes, you would qualify your joint design as a groove weld procedure. The filler metal would be 625.

 

[MrGezus]

If you are taking credit for the weld metal strength equal to or greater than the base metal and not simply a corrosion barrier coating, yes, you would qualify your joint design as a groove weld procedure. The filler metal would be 625.

Okay, great. Thank you. Is there a place in Section IX that states something like what you are saying? While I agree with you, I am just curious if I had missed a section about this besides the partial pen ~= groove weld.

 

[DVWE]

Did you take a chemical analysis of the overlay on the test coupon?

 

[metengr]

Okay, great. Thank you. Is there a place in Section IX that states something like what you are saying? While I agree with you, I am just curious if I had missed a section about this besides the partial pen ~= groove weld.

Please see below in the 2013 Edition of ASME Section IX;

QW-202.3 Weld Repair and Buildup. WPS qualified
on groove welds shall be applicable for weld repairs to
groove and fillet welds and for weld buildup under the following
provisions:
(a) There is no limitation on the thickness of base metal
or deposited weld metal for fillet welds.
(b) For other than fillet welds, the thickness range for
base metal and deposited weld metal for each welding
process shall be in accordance with QW-451, except there
need be no upper limit on the base metal thickness provided
qualification was made on base metal having a thickness
of 11/2 in. (38 mm) or more.

 

[david339933]

If you review Table QW-453, the thickness T qualified of the coupon, is the thickness T qualified for the base material. So, if you select 1/2" thickness for the coupon, the WPS for CRO is qualified for 1/2" thickness and not 1"

Is not a CRO WPS qualified on T less than 1" good for T qualified to unlimited? That's how I read QW-453

Ignoring PP and Strength as stated above.

 

[metengr]

Yes, you are correct, my mistake during review. It would 1/2" to unlimited.