Qualification of dissimilar base metal welding

[mariocalvo]

Dear all,

I have a dissimilar welding between P5A and P1. To carried out this joint, a buttering will be used. Our supplier has sent to us a PQR with the following steps:

1-P5A is buttered with E7018-A1 (up to 7mm after machining) and PWHT at 710ºC.
2-Weld the buttering to the P1 and PWHT at 620ºC.

The problem is that, the welding between P1 and the buttering, was done with 3 pass with GTAW (filler metal ER70S-6) and 1 pass with SMAW with E7018-A1. On the WPS the last pass will not be carried out.

Is that change allow by the code?
And on the other hand, the CS filler metal is alloyed with some Mo of E7018-A1 upgrading the mechanical properties of the weld, and this situation will not be done on production. I´am not sure if this PQR qualifies this joint and the WPS.

Thanks in advance.

 

[stanweld]

A change between A-1 analysis welding filler material to A-2 analysis weld filler metal or vice versa is permitted per QW-404.5 "Qualification with A-No.1 shall qualify for A No.2 and vice versa." It is noted that the ER70S-6 may or may not meet A-No.1 classification; your supplier would have to prove it.

What does his WPS state?

 

[metengr]

mariocalvo;
Sorry but I am confused with your post. The way I understand your question is this;

1. The P-No. 5A base material was buttered using E 7018 A1 and was subsequently PWHT at 710 deg C.

2. After this activity, the weld joint was completed using the GTAW process with ER70S-6 filler metal and the coupon was subjected to a final PWHT at 610 deg C correct?

Now in production welding, what do you intend to do? Do you intend to butter, PWHT, complete the weld and PWHT using what process and filler metals?

 

[mariocalvo]

Thanks for your repair,

Stanweld:

Filler metal for GTAW is ER70S-6 SFA 5.18 number A 1.

Metengr:

The secuence is as you posted, but on the PQR a final pass was done with SMAW filler metal E7018-A1.

The question is that this final pass will not be carried out in producction, and i´m not sure if it is allow and if this final pass will upgrade the mechanical properties of the joint.

 

[metengr]

The question is that this final pass will not be carried out in producction, and i´m not sure if it is allow

The WPS is still valid for production welding.

...and if this final pass will upgrade the mechanical properties of the joint.

No.