SAE AMS 6551A:2018-06-03

Steel Bars, Forgings and Tubing 1.75Cr - 4.0Ni - 0.5Mo - (0.35 - 0.40C) Premium Aircraft Quality Consumable Electrode Vacuum Remelted

This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.