Patent ID: 11772147

Abstract:
A strength flanging method which improves the method of stretch flanging by press forming so as to disperse strain generated during a forming operation in a blank and in turn prevent the formation of cracks at the center of an arc part, which strength flanging method performs stretch flanging using a stretch flanging tool provided with a top surface part having a protruding part in a top view, straight wall parts, a main slanted wall part between the top surface part and the straight wall parts positioned forming an angle with the top surface part of more than 0° and less than 90° and with the straight wall parts of 10° or more and less than 90° and having two intersecting ridgelines at the straight wall part sides, a first sub slanted wall part sharing one ridgeline among the two ridgelines with the main slanted wall part and positioned forming angles with the top surface part and a straight wall part of more than 0° and less than 90°, and a second sub slanted wall part sharing the other ridgeline among the two ridgelines with the main slanted wall part and positioned forming angles with the top surface part and a straight wall part of more than 0° and less than 90°.