Behavior of Metals Under Dynamic Conditions (NS-109): Application of Pure Strain Rate Tests to an Investigation of Two 76 mm Gun Tubes
CALIFORNIA INST OF TECH PASADENA
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This report presents the results of a study of two 76 MM gun tubes supplied by Watervliet Arsenal, and which had been ruptured by detonation of a high explosive shell in the bore. One tube fragmented badly while the other exhibited a ductile fracture. Specimens taken from each tube consisted of thin wall tubular cylinders which were tested both statically and dynamically under uniaxial stress conditions. The dynamic tests were made at strain rates as high as 190 in.in.sec. Rupture of some of the specimens occurred with very low maximum uniform strain. Static tensile tests and Izod impact tests failed to reveal any difference in the two gun tubes. The tests on the uniaxial thin wall specimens show that the gun tube while the gun tube that failed in a ductile manner has a much higher maximum uniform strain. These results are discussed in relation to the influence of strain rate on the properties of each material and the effect of metallographic structure on the results. The conclusions of this investigation cannot be applied to all gun tubes until other guns are investigated.