Automotive-body layered structural member and production method thereof

A production method of an automotive-body layered structural member including a first part that has been cold press-formed from a first blank of metal sheet and a second part that has been cold press-formed together with the first part from a second blank of metal sheet that has been partially joined to the first blank in a layered state, the first part and the second part being further joined together in a layered state,

• characterized in that:
• a combination of a strength grade and a sheet thickness of the first blank and a strength grade and a sheet thickness of the second blank is selected such that portions of the first part and the second part in the layered state that have sprung back after the cold press forming adhere to each other in a free state;
• the first blank and the second blank of the selected combination of the strength grades and the sheet thicknesses are layered and partially joined together;
• from the first blank and the second blank having been layered and partially joined together, the first part and the second part in a state of being layered and partially joined together are formed together by the cold press forming such that portions of these parts that have sprung back adhere to each other in a free state;
• and
• at least the portions adhering to each other of the first part and the second part are further joined together.