F-numbers and A-numbers in ASME indicate respectively what aspects of filler metals?

F-numbers and A-numbers in ASME indicate respectively what aspects of filler metals?

• A. F-numbers indicate usability, A-numbers indicate chemical composition
• B. F-numbers indicate chemical composition, A-numbers indicate usability
• C. F-numbers indicate welding speed, A-numbers indicate amperage
• D. F-numbers indicate base metal group, A-numbers indicate heat treatment

Answer: (A)

The essential idea is that filler-metal classification in ASME uses two identifiers to capture separate ideas: where the filler metal can be used, and what its chemistry is. The F-number tells you which base-metal families the filler metal is approved for—that is, its usability with those base metals in welding applications. The A-number, on the other hand, encodes the filler metal’s chemical composition—its alloying elements and overall alloy group—which determines the weld metal chemistry and how it will behave in service. So, the F-number is about compatibility with base metals (usability), while the A-number is about the filler metal’s chemistry (composition). The other statements mix up those roles or bring in unrelated factors like welding speed, amperage, or heat treatment, which aren’t what these numbers indicate.

The essential idea is that filler-metal classification in ASME uses two identifiers to capture separate ideas: where the filler metal can be used, and what its chemistry is. The F-number tells you which base-metal families the filler metal is approved for—that is, its usability with those base metals in welding applications. The A-number, on the other hand, encodes the filler metal’s chemical composition—its alloying elements and overall alloy group—which determines the weld metal chemistry and how it will behave in service.

So, the F-number is about compatibility with base metals (usability), while the A-number is about the filler metal’s chemistry (composition). The other statements mix up those roles or bring in unrelated factors like welding speed, amperage, or heat treatment, which aren’t what these numbers indicate.