Metallurgical Examination of a Cast Turret Manufactured by the American Steel Foundries

摘要

Metallurgical examination of two specimens representing the thinnest and thickest sections (1 in. to 1-1/4 in. and 3 in. to 3-1/2 in. respectively) of an M4 Cast Turret, No. B171, produced by the American Steel Foundries, indicated that the properties of the two sections were a function of the ease with which they could be hardened by quenching. The thin section has been fully quenched out and has good impact strength at both room temperature and at -40 F. The thick section has not been completely hardened through the section, as evidenced by the decreased impact strength at the center of the section when tested at -40F. These results were corroborated by fracture tests. The impact properties of the heavy section are, however, deemed adequate to insure ductile behavior upon ballistic impact. (Author)