ASME Std IX understanding

[saipemsmspetti]

Please, kindly ask for your help.

1. In ASME Sec IX,QW -452.1(b) is stated "Maximum to be welded". Does it mean "Unlimited" or something else? Why isn’t it written "Unlimited"?

2. Why ASME Sec IX doesn't have P-Number 2. What happened with this P-2.

Thanks in advance

Darko

 

[metengr]

1). The maximum to be welded for the welder performance qualification (QW-452.1b) is based on the WPS used to qualify the welder. For example, if the WPS is qualified for a max weld deposit thickness of 2" for SMAW, and the welder qualifies on a coupon that is 1/2" or greater in thickness using this WPS, they would be qualified to a 2" max weld deposit thickness using SMAW.


2). P-2 materials are no longer used and were replaced by P-No 3 materials. I remember seeing P-No 2 materials in the 1952 Edition of the ASME Boiler and Pressure Vessel Code.

 

[saipemsmspetti]

Thank you very much 'metengr'
I have some other problem with understanding of ASME IX Code.
In 407.1 for PWHT it confuses me (1)No PWHT.Why it is statet so.
For me it seems like only one direction of qualification.
If we qualified WPS with PWHT it is mandatory to do it in production. But if we qualified WPS without PWHT we can apply PWHT for stress relieving without new qualification.
It means that PWHT (stres relieving - below the lower transformation) will not deteriorate weld mechanical characteristics in any way.

Am I right or wrong. Desperate for answer.

 

[metengr]

saipemsmspetti;

In 407.1 for PWHT it confuses me (1)No PWHT.Why it is statet so.
For me it seems like only one direction of qualification.
If we qualified WPS with PWHT it is mandatory to do it in production. But if we qualified WPS without PWHT we can apply PWHT for stress relieving without new qualification.
It means that PWHT (stres relieving - below the lower transformation) will not deteriorate weld mechanical characteristics in any way.

QW-407.1 states that a separate procedure qualification is required if any of the following conditions occurs;

Now you must understand that paragraph (a) relates to those base materials where conditions 1 through 5 would specifically apply. If any of those conditions occurs, a procedure must be re-qualified.

Example, lets say you qualified a procedure with PWHT, if you intend to use this same procedure without (or No) PWHT, it must be requalified with NO PWHT.

Upper transformation temperature is the temperature where you have 100% austenite for ferrous materials and you cool or quench (normalize heat treatment). This heat treatment changes the original mechanical properties of the base metal.

The lower transformation temperature is the lower critical transformation temperature and is typically never exceeded for a subcritical PWHT. Exceeding the lower transformation temperature during PWHT will also change the original mechanical properties of the base metal.

A PWHT that is qualified below the lower critical transformation temperature is called a subcritical PWHT and yes, it will not change the original mechanical properties of the base metal.

Once you have understood these definitions of PWHT, review conditions 1-5, again.

 

[saipemsmspetti]

Thanks 'metengr'. Seems to be my angel on haven.

But, let me ask once again. I understood you and 407.1 demands concerning transition temperatures. But let me ask directly:
If I have qualified WPS without PWHT, can I apply stress relieving PWHT (below lower transformation) in production without new qualification. This 'No PWHT' is for me comrehensive that only in case of 'qualified with PWHT' is not allowed to do it in production without PWHT, but in opposite direction 'qualified without PWHT' doesn't ask for new qualification if we apply stress relieving PWHT in production. Am I wrong.

 

[saipemsmspetti]

Thanks 'metengr'. Seems to be my angel on haven.

But, let me ask once again. I understood you and 407.1 demands concerning transition temperatures. But let me ask directly:
If I have qualified WPS without PWHT, can I apply stress relieving PWHT (below lower transformation) in production without new qualification. This 'No PWHT' is for me comrehensive that only in case of 'qualified with PWHT' is not allowed to do it in production without PWHT, but in opposite direction 'qualified without PWHT' doesn't ask for new qualification if we apply stress relieving PWHT in production. Am I wrong.

 

[metengr]

Question;

If I have qualified WPS without PWHT, can I apply stress relieving PWHT (below lower transformation) in production without new qualification.

Reply; No. A PWHT that is subcritical, meaning below the lower critical transformation temperature is still considered a PWHT and must follow the temperature and time requirements per ASME B&PV Code.

Stress relief versus PWHT are sometimes confusing terms. However, PWHT implies that welding was performed on the pressure retaining item and PWHT refers to reduction of residual stress AND tempering of the weld base metal HAZ hardness and weld deposit (if applicable).

 

[saipemsmspetti]

I agree with you 'metengr'. It is also logical to me, in the light of welding technology, but I realised that ASME sentences and statements sometime are clumsy expresed. So I should wright gor 407.1 a(1) No/Yes PWHT or with/without PWHT and it would be much clearer and in correlation with our technicaly bacgrounded opinion. Am I right.

 

[metengr]

saipemsmspetti;
Yes. As much as I deal with Code language, it does get frustrating. Our predecessors started Code language and to this day one has to follow the practice (A-Always, S-Shall, M-Maybe, E-Except).

With/Without PWHT is the most common expression for WPS.