Heavy Tank T26E1 Metallurgical Examination of Components which Failed Under Ballistic Tests
WATERTOWN ARSENAL LABS MA
Pagination or Media Count:
A trunnion shaft supporting the gun carriage was submitted which shattered during the ballistic tests. It was found that the shaft failed because it possessed extremely low impact strength as a result of improper heat treatment of a steel SAE 6150 having insufficient hardenability for the section 3 14 in. involved. It is recommended that the trunnion shaft be made from a steel having sufficient hardenability for a 3 14 in. round and that it be heat treated to a hardness of 34 to 38 Rockwell C. Bolts attaching the turret to the upper race ring were sheared during the ballistic tests. The bolts were made from SAE 4140 steel satisfactory heat treated to a hardness of 31-33 Rockwell C, and it was concluded that the bolts must be made larger if it is expected that they should withstand the stresses resulting from this type of attack. Bolts attaching the commanders cupola to the turret were fractured during the ballistic attack. The bolts were made from SAE 3140 steel satisfactorily heat treated to a hardness of 33 Rockwell C. It was concluded that they should be redesigned if they are expected to withstand the stresses resulting from the ballistic attack to which they were subjected. Additional keywords UA Reports.
- Metallurgy and Metallography
- Combat Vehicles