AMS6409F Steel, Bars, Forgings, Mechanical Tubing and Forging Stock 0.80Cr - 1.8Ni - 0.25Mo (0.38 - 0.43C) (SAE 4340) Special Aircraft Quality Cleanliness Normalized and Tempered

AMS6409F results from a Five-Year Review and update of this specification that updates the title, revises composition (3.1), condition (3.2.2), updates note on Table 2, updates macrostructure (3.3.1.1, 3.3.1.2, 8.9), adds specimen heat treatment (3.3.3), updates decarburization (3.3.4.1, 3.3.4.5), adds strain rate to tensile testing (3.3.5.1), prohibits unauthorized exceptions (3.6, 4.4.5, 5.2.1, 8.8), acknowledges periodic testing (4.2.1, 4.4.4), allows prior revisions (8.7) and is the result of a Five-Year Review and update of the specification.