Jeff Calcaterra September 2017 Savannah, GO AMS 6454 Revision Status Steel, Strip and Plate 4340 Vacuum Consumable Electrode Remelted Jeff Calcaterra September 2017 Savannah, GO

Overview Two primary issues Composition does not align with SAE J404 for Manganese, Phosphorous and Sulfur. No minimum magnification required for decarburization examination.

Composition Element AMS6454 SAE J404 (E4340) Mn 0.065 – 0.90 0.065 – 0.85 P 0.010 max 0.025 max S AMS6454 is remelted material, J404 is not limited to remelt. P,S changes make sense? Why would remelted material have larger compositional range than single melt? Align Mn with J404? Also affects AMS6414 (bar, forging, tubing)

Decarburization AMS6454 section 3.4.5.1 states metallographic inspection for decarb “…at a magnification not to exceed 100x.” No minimum established Section 3.4.5.2 for microhardness traverse states testing IAW ASTM E384 “…at a magnification not exceeding 100x.” E384 controls magnification based on size of indent. SAE J419 “Methods of Measuring Decarburization” recommends 100x magnification be used for metallographic methods. No magnification called out for microhardness SAE J419 is not cited by AMS6454

Recommendation Align Mn composition in AMS6454 and AMS6414 with SAE J404 – 0.65-0.85. No changes to P or S. Revise wording in AMS 6454 section 3.4.5.1 from: “A cross section of the surface shall be visually examined metallographically at a magnification not to exceed 100X.” To: “A cross section taken perpendicular to the surface shall be prepared, etched and visually examined in accordance with SAE J419 and at a magnification of 100x unless otherwise agreed on between the purchaser and producer.” Eliminate magnification requirement in hardness traverse method, section 3.4.5.2 “The total depth of decarburization shall be determined by a traverse method using microindentation hardness testing in accordance with ASTM E384, at a magnification not exceeding 100X, conducted on a hardened but untampered specimen protected during heat treatment to prevent changes in surface carbon content.” Wording changes should be made to AMS6414, 6415