ASTM doesn't have Code Cases (or anything similar to my knowledge). It will make changes to standards, such as additional alloys covered, based upon ASME Code Cases.
For pending changes by the ASTM work committee for a particular standard, go to
enter the standard such as A182 & search, then click on 'Active Standard.' Click 'Related work' and for A182/A182M-05a you can find pending actions, e.g.:
WK9353 -- "Addition of UNS S32906 (F XX) to A182. The grade is already covered in ASTM A789, A790, A479, A240, A480, and ASME Code Case 2295-2."
Also, before clicking on 'Active Standard,' you can find changes to previous standards, e.g.,
WK6338 -- "ASME has requested the addition of UNS S32615 to A182. The grade is already covered by A213 and ASME Code Case 2029-3."
This was a proposed change to A182/A182M-04a which is no longer listed as pending, so I presume it's in A182/A182M-05a.