LAP WELDING MEMBER OF HIGH-STRENGTH STEEL SHEET AND MANUFACTURING METHOD OF THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a lap welding member of a high-strength steel sheet which prevents a formed article from being fractured at a low strain on an HAZ most softened part of a spot welding part upon collision even when the spot welding is performed for the formed article of the high-strength steel sheet having a tensile strength of 1,180 MPa or more.SOLUTION: A lap welding member includes a first constituent member 1 as a steel sheet or a formed body thereof of which the tensile strength is at least 1,180 MPa and a second constituent member 7 as another steel sheet or a formed body thereof which is overlapped on the first constituent member and is spot-welded. The lap welding member includes a nugget 2 formed by spot welding and a softened region 3 disposed adjacently to the nugget 2 in the longitudinal direction of the lap welding member and at least on the first constituent member side and the softened region 3 is disposed so as not to reach an HAZ most softened part formed on a circumference of the nugget.