Patent ID: 8899094

Claim:
A method for investigating ballistic resistance of steel, the method comprising: measuring a ballistic limit V 50 of a steel object, the measuring including firing a projectile so that it strikes the steel object and results in a ballistic crater in the steel object; micro-imaging the steel object before the ballistic limit V 50 is measured so that austenite contained in the steel object is shown in the micro-imaging; measuring an austenitic volume fraction of the steel object at least once before and at least once after the ballistic limit V 50 is measured, a first said austenitic volume fraction measurement being said measuring of the austenitic volume fraction at least once before the ballistic limit V 50 is measured, a second said austenitic volume fraction measurement being said measuring of the austenitic volume fraction at least once after the ballistic limit V 50 is measured, the first said austenitic volume fraction measurement being performed using a vibrating sample magnetometer on a non-deformed portion of the steel object, the second said austenitic volume fraction measurement being performed using the vibrating sample magnetometer on a ballistically deformed portion of the steel object; microhardness-mapping the steel object after the ballistic limit V 50 is measured so that the ballistic crater is shown in the microhardness-mapping; and considering indication by said ballistic limit V 50 measurement, said micro-imaging, the first said austenitic volume fraction measurement, the second said austenitic volume fraction measurement, and said microhardness-mapping, with respect to an enhancement of ballistic resistance of the steel object in association with ballistically induced plasticity in the steel object, the ballistically induced plasticity involving transformation of austenite to martensite in the steel object.