MS-342 is a Northrop Grumman specification for 6Al-4V calling for “TITANIUM 6AI-4V, ELI, RA FORGINGS”
Northrop Grumman is an Aerospace and Defense company famous for the B-2 Spirit Bomber, and more recently its unmanned aircraft RQ-4.
Like other Major Tier 1 Aerospace companies, Northrop Grumman has special quality approvals for the procurement of Titanium. MS-342 is a quality specification for TITANIUM 6AI-4V, ELI, RA FORGINGS.
The ELI stands for Extra Low Interstitial, while the RA stands for Recrystallization Annealed.