NAVSEA requires the use of electrodes that comply with the military standards when they are listed in Table II. AWS filler metals are not automatically "permitted" when the table lists a military standard that is applicable. If the contractor elects to use AWS filler metals instead of a military filler metal that is listed, permission must be obtained and a system instituted to ensure compliance (paragraph 5.2.1).
Even when an AWS filler metal specification is listed by NAVSEA TP278, the purchase order has to include additional testing that is typically above and beyond what is normally required to meet AWS or ASME quality control requirements. Refer to footnote 6 of Table II. The quality control testing typically required by AWS or ASME is not as stringent as similar military filler metal specification.
As I mentioned before, I assumed the electrodes prohibited by TP278 are those that are known to introduce hydrogen into the molten weld puddle. However, if that was the only consideration there would be other covered electrodes that would be prohibited such as the 6011 and 7024. I don’t know what other considerations are factors in NAVSEA’s decision to prohibit certain filler metals.
The low hydrogen type electrodes manufactured to a military specification must undergo more stringent quality control testing than similar electrodes manufactured to AWS and ASME standards. You would have to compare the testing requirements of AWS A5.01 to the applicable military filler metal specification to note the differences between the "standard" testing regiment for AWS versus the minimum testing requirements of the appropriate military standard. AWS A5.01 has various levels of testing that can be imposed by the customer for various reasons, i.e., nuclear or military applications, etc. These additional levels of tests (schedules) must be stated in the purchase order when the filler metals are ordered. Even packaging requirements can be added to the purchase order, i.e., hermetically seal cans instead of cardboard packaging for low hydrogen covered electrodes.
Best regards - Al