Table-3 shows a brief summary of ‘F’ and filler metals (according to ASME BPVC, Table: QW-432). Hence it is assumed if a welder can make a satisfactory weld with a particular filler metal, he will be able to weld with all the filler metals belonging to that particular ‘F’ number. The usability characteristics fundamentally determine the ability of a welder to produce sound welds with a given filler metal. The basis for F number grouping is usability characteristics. The F Number: F number grouping (for filler metals) is done to reduce the number of welding procedure specifications (WPS) and welder performance qualifications. FILLER METAL (ELECTRODE/WELDING ROD) GROUPING: Base metals that were previously assigned ‘S’ Numbers were reassigned the corresponding P Numbers or P Numbers and Group Numbers.
ASME BPVC SECTION IX CODE
S Numbers were assigned to those materials which were acceptable for use by the ASME B31 Code for Pressure Piping, or by selected Boiler and Pressure Vessel Code Cases, but were not included in section II of ASME Boiler and Pressure Vessel (BPVC). Tensile strength (min.) – 65 Ksi (or 450 Mpa)Īnother grouping of base metals was the ‘S’ numbers, but the ‘S’ number is not used nowadays.We will take an example of SA516 Gr 65 from table QW/QB-422 (Page – 118 of ASME Section IX, 2017 edition), we can find out the following values Group numbers are assigned only to those materials which require toughness testing for the qualification of its WPS. Group numbers are subsets of ‘P’ numbers and assigned to ferrous-based metals. Now that we have understood ‘P’ numbers let’s move on to the group numbers. Table–2 shows the assignment groups for various metals and their alloys (according to ASME BPVC). Whenever there is a change in the base material from existing WPS, the compatibility shall be considered with regards to the following factors Suppose, if we change the base metal from an existing qualified WPS and if the new base metal falls in the same ‘P’ number then the requalification of the existing WPS is not required, it means no need for a new PQR.īut this doesn’t mean that one can easily substitute the base material, from existing WPS, of same ‘P’ number at any time. Though all materials of the same ‘P’ number don’t exhibit the same properties, but after considering the above-mentioned parameters, ASME has done this logical grouping. This grouping of base metals has been done on the basis of the following parameters Hence, to reduce these costly and time-consuming activities, ASME has done groupings of base metals and has assigned certain P numbers to each group of metals. sending it to a lab for destructive test.Conducting a procedure qualification requires a lot of time and money due to the following procedural requirements The main purpose of assigning this number system is to reduce the number of procedure qualification records (PQR). These numbers can be found in ASME BPVC Section IX, please see Table–1 for details Table – 1 ASME Boiler and pressure vessel code (BPVC) has assigned certain numbers to base metals (to be welded) as well as to filler metals (electrodes).įor base metals, ASME has assigned two number system, these are įor filler metals, the number system which is assigned, are as follows
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