Cursory Examination of a Parachute Bag Knife, P/N 71172

摘要

A parachute bag knife was received for a quick-look analysis to determine the reason for edge deformation after normal use. The U.S. Army Research Laboratory performed hardness testing, chemical analysis, and metallography. Hardness testing in conjunction with metallography showed a layer of decarburization around the periphery of the knife (not on the blade edge, however). Chemical analysis verified alloy AISI 4130 was used. Metallography also revealed a less than optimal microstructure for this alloy. It was recommended that future parts be quenched and tempered to produce a tougher knife edge.