Overlapped blank and molding method thereof

A molding method of an overlapped blank comprising:

• preparing an overlapped blank comprising
• a first metal plate including a bulged excess portion, a first flat portion provided adjacent to the excess portion, and a second flat portion provided adjacent to the excess portion on an opposite side to the first flat portion,
• a flat second metal plate overlapped on the first flat portion and the second flat portion,
• a first joint portion where the first flat portion and the second metal plate are joined to each other, and
• a second joint portion where the second flat portion and the second metal plate are joined to each other;
• and
• bending the overlapped blank with the first metal plate being directed to an outer side of the bending of the overlapped blank, wherein
• in the preparing of the overlapped blank,
• the excess portion has a cross-sectional length in a cross section and a linear length which is a distance between opposite ends of the excess portion in the cross section;
• and
• the cross-sectional length of the excess portion satisfies the following relationship
• L0+0.65(t1+t2)≤L1≤L0+1.35(t1+t2)
• L0:
• the linear length of the excess portion,
• L1:
• the cross-sectional length of the excess portion,
• t1:
• a plate thickness of the first metal plate, and
• t2:
• a plate thickness of the second metal plate.