ASME Std IX understanding
ASME Std IX understanding
(OP)
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
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





RE: ASME Std IX understanding
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.
RE: ASME Std IX understanding
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.
RE: ASME Std IX understanding
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.
RE: ASME Std IX understanding
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.
RE: ASME Std IX understanding
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.
RE: ASME Std IX understanding
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).
RE: ASME Std IX understanding
RE: ASME Std IX understanding
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.