From when it first came out as a stock item in the Valenite catalog till I retired in 1997, we always used the 1/2 IC on edge, triangle carbide like the TPMC-32NV. This was used in 304, 316, 316L, 319, Hastalloy, 17-4, hard SAE 4140, and a few other forgiving materials. We used a C5 grade with TiN coating. I still use that same geometry today to thread barrel tenons.
This insert is an on-edge design of 3 cutting tips. Being an on edge insert it can stand considerable abuse. A single tip will cut 20-30 or better barrels before going to the next tip. The 32NV size will work from the smallest threads to a 8 TPI pitch.