Metal strip coil and method for manufacturing the same

A metal strip coil comprising a metal strip wound around a winding core,

• wherein the metal strip is wound from one end side toward the other end side of the winding core at a winding angle which is tilted with respect to an axial direction of the winding core, turns back at the other end portion, is wound from the other end side toward the one end side of the winding core at a winding angle which is tilted with respect to the axial direction of the winding core, turns back at the one end portion, and is repeatedly wound in such a manner,
• wherein in the turnback, the metal strip has a turnback portion at which the metal strip is wound in a direction perpendicular to the axial direction of the winding core,
• wherein turnback portions are formed in a multistage manner from an inner circumference toward an outer circumference, each turnback portion being arcuate in a side view of the metal strip coil, and a line connecting a midpoint of the arcuate arc with a center of the arc is formed so as to rotate stepwise in one direction, in an order of the arcuate turnback portions which are formed in the multistage manner from the inner circumference to the outer circumference.