welding procedure for P1 to P4 material acc. asme IX 5

[batenburgjvb]

I have the following question,
When I have a welding procedure according ASME IX for SMAW and GTAW-SMAW for a P4 to P4 material.
Do I need a additional procedure for a P1 to P4 material?
QW-403,11 says no, but my client says yes I do? Who is right

JvB

 

[welding1]

Following the ASME code through logically
Welding Procedures requirements are defined in QW 200
Qw253 and QW256 list the variables for SMAW and GTAW respectively.
Both refer to QW403.11 for base materials as an essential variable.
QW 403.11 refers to QW 424.1 which states:-

Base Metal(s) Used for Procedure Qualification Coupon
One metal from P-No. 4 to any metal from P-No. 4

Base Metals Qualified
Any P-No. 4 metal to any metal from P-Nos. 4, 3, or 1

You are correct! Unless someone knows some hidden clause in this code that I am not aware of. I am using the 1999 addenda but I don’t think this will have changed in the latest issue?


For information on the ASME 9 and more

http://www.gowelding.com

 

[lalaith]

Your client is right. You will have to qualify a P1-P4 procedure. A change in P number is an essential variable.

The base metal that you test on doesn't negate the need for a qualified welding procedure.

However, if you have welders that are qualified to weld the P4-P4 procedure they should be able to weld the P1-P4 procedure without requalifying as long as the the F number of the filler metal doesn't change.

 

[MURZ]

Welding1 is correct. Qw-424.1 is very clear. If you have a WPS that has been qualified using P4 to P4 you can use the procedure to weld P4 to P4, P4 to P3, and P4 to P1 materials. I would write another WPS for the welding of P4 to P1 and support this WPS with the PQR for the P4 to P4 material. The catch here is that all other essential variables must remain the same. For example, you can not change the filler metal.

ASME Section IX interpretation IX-89-58 deals with this subject.

Question (1): “A WPS is qualified for P5 to P5 base metals. Will the PQR for this procedure also support a new WPS for P5 to P4 base metals if all other welding variables remain the same?

Reply (1): “YES”

Although the P numbers are different, the concept is the same. I would however caution you as to your application. I do not know what code you are fabricating to (section I, B31.1). In ASME Section I the PWHT for P4 is 1100 F this also happens to be the PWHT for P1 material (no problem here). However, in ASME B31.1, the PWHT for P4 material is 1300 to 1375 F. Since the lower critical temperature for P1 material is ~1340 F I would be very hesitant to use the procedure to weld P4 to P1. If your current WPS shows a PWHT temperature in this range, I would suggest you qualify another WPS using P4 to P1 material.

You have to keep in mind that the ASME codes are primarily safety codes and not necessarily operational codes. The do not consider all of the different metallurgical combinations that may be possible for fabrication. It is up to the user of the code to make sure that the materials they are welding are metallurgically compatible with respect to PWHT, weld design, service requirements, and mechanical properties.

Hope this helps.

 

[ElderX]

I'm not looking at the code right now, but based on my rather limited memory I think you are correct.

 

In my experience with the welding of boilers You can use metal filler for PROCESS GTAW SFA 5.18 and low hydrogen as per specification AWS 5.1 prefer E-7018-1 for Process SMAW.

It is more Economic procedure and in accordance with CODE requirements.

Regards

Jorge