metalseng
Materials
- May 23, 2008
- 17
I have some questions regarding the P No grouping used in ASME B & PV Code (IX). I am going to use specific examples to explain my question. Please note that my questions are not about qualifying welding procedure for certain alloys but I am using them as examples.
First a simple hypothetical situation:
(P No 4 and Group 1 materials)
I want to a WPS for welding A387 Type 12 Class 1 plate to the same. The minimum tempering temperature for this is 1150F and the minimum tensile strength is 55 ksi.
Now I want to a WPS for welding A182 Type 11 Class 3 to the same. The minimum tempering temperature is 1150F (as above) but the minimum tensile strength is 75 ksi (as opposed to 55 ksi for A387 Type 12 class 1). The question is can I use a WPS qualified for A182 Type 11 Class 3 to weld A387 Type 12 Class 1.
The general question -Do I have to qualify the alloy (within a certain P no and Group) with maximum strength in order to use the qualified WPS for any alloy within the same Group?
Now let’s make this bit more complicated.
I want to weld A202 Class B to the same. The minimum tensile strength specified is 85 ksi and this is an as-rolled plate. However, ASME B & PV code IX lists this under Pno 4 and Group No 1 (same as the above-mentioned two alloys). Does that mean I can use the WPS qualified above (which may have a PWHT) to weld this (as- rolled)?
Though ASTM A202 has been superseded and I used it as an example,my general question is how to deal when alloys within a certain P no and Group no combination have different tempering temperatures.
Summing everything, do we have to have several PQRs (different strength levels and PWHT) for alloys even though they fall under same P No and group no? I tried to find how the code addresses this, but I could not find anything. I would appreciate if anyone could clarify this and specify the section of the code that deals with this.
Thank You.
First a simple hypothetical situation:
(P No 4 and Group 1 materials)
I want to a WPS for welding A387 Type 12 Class 1 plate to the same. The minimum tempering temperature for this is 1150F and the minimum tensile strength is 55 ksi.
Now I want to a WPS for welding A182 Type 11 Class 3 to the same. The minimum tempering temperature is 1150F (as above) but the minimum tensile strength is 75 ksi (as opposed to 55 ksi for A387 Type 12 class 1). The question is can I use a WPS qualified for A182 Type 11 Class 3 to weld A387 Type 12 Class 1.
The general question -Do I have to qualify the alloy (within a certain P no and Group) with maximum strength in order to use the qualified WPS for any alloy within the same Group?
Now let’s make this bit more complicated.
I want to weld A202 Class B to the same. The minimum tensile strength specified is 85 ksi and this is an as-rolled plate. However, ASME B & PV code IX lists this under Pno 4 and Group No 1 (same as the above-mentioned two alloys). Does that mean I can use the WPS qualified above (which may have a PWHT) to weld this (as- rolled)?
Though ASTM A202 has been superseded and I used it as an example,my general question is how to deal when alloys within a certain P no and Group no combination have different tempering temperatures.
Summing everything, do we have to have several PQRs (different strength levels and PWHT) for alloys even though they fall under same P No and group no? I tried to find how the code addresses this, but I could not find anything. I would appreciate if anyone could clarify this and specify the section of the code that deals with this.
Thank You.
