Overlapped blank for hot stamping, method of manufacturing overlapped hot stamp molded body, and overlapped hot stamp molded body

A method of manufacturing an overlapped hot stamp molded body, the method comprising:

• heating an overlapped blank for hot stamping, the overlapped blank for hot stamping comprising:
• a first steel sheet;
• and
• at least one second steel sheet connected to a surface of the first steel sheet via a welding point and smaller in area than the first steel sheet, wherein:
• the first steel sheet is a plated steel sheet having an aluminum-based plated layer on both faces of the first steel sheet, and the second steel sheet is a plated steel sheet having an aluminum-based plated layer on both faces of the second steel sheet;
• a coating weight of the aluminum-based plated layer on the first steel sheet is W1 (g/m2) in terms of an average coating weight on both the faces;
• a coating weight of the aluminum-based plated layer on a surface on a side not in contact with the first steel sheet in the second steel sheet is W2 (g/m2);
• and
• each of the W1 and the W2 is within a range of 20 g/m2 or more and 120 g/m2 or less, and satisfies relationships of following Expression (1) and Expression (2);
• and
• in hot stamp molding of molding after the heating, providing a bent part subjected to bending at least a part of an overlapped part of the first steel sheet and the second steel sheet,
• 30≤(W1−W2)≤100 Expression (1)
• (W1/W2)2×(t1/t2)≥1.5 Expression (2)
• where t1 (mm) is a sheet thickness of the first steel sheet and t2 (mm) is a sheet thickness of the second steel sheet in the Expression (2).

An overlapped hot stamp molded body comprising:

• a first steel sheet having a sheet thickness of T1 (mm);
• and
• at least one second steel sheet connected to a surface of the first steel sheet via a welding point, smaller in area than the first steel sheet, and having a sheet thickness of T2 (mm), wherein:
• the first steel sheet is a plated steel sheet having an aluminum-based plated layer having an average plating thickness of K1 (μm) on both faces on both the faces of the first steel sheet;
• the second steel sheet is a plated steel sheet having an aluminum-based plated layer having a plating thickness of K2 (μm) on a surface on a side not in contact with the first steel sheet;
• and
• relationships of following Expression (11) and Expression (12) are satisfied
• 10≤(K1−K2)≤33 Expression (11)
• (K1/K2)2×(T1/T2)≥1.5 Expression (12).