Abstract: A front stay member is inserted into a through-hole in a bumper reinforcement. A first end of a middle stay member is fitted onto a portion of the front stay member that protrudes from the through-hole until the first end of the middle stay member comes into contact with the bumper reinforcement. A rear stay member is inserted into a second end of the middle stay member until the second end of the middle stay member comes into contact with the step on the rear stay member. A magnetic field shaper is disposed so as to face portions of an outer peripheral surface of the middle stay member that respectively overlap the front stay member and the rear stay member, and the middle stay member is clinched onto the front and rear stay members by applying an electromagnetic force to the magnetic field shaper.

Abstract: A target tubular member with flange, such as a bumper stay, has a flange having an outer diameter larger than the diameter of an axial section and is formed by electromagnetic forming without excessive expansion. The tubular member with flange includes an axial member made of a tubular aluminum alloy extrudate and a flange member joined to an end of the axial member. The axial member has an end flange being integrated at its end and having an area smaller than that of the flange member. The flange member has a hole, and a cylindrical hole flange at the edge of the hole. The axial member fits in the hole of the flange member, the end flange is in intimate contact with the flange member, and the outer periphery of a small-diameter portion of the axial member is in intimate contact with the inner periphery of the hole flange. The hole flange is held between the end flange and a protrusion.

Abstract: A target tubular member with flange, such as a bumper stay, has a flange having an outer diameter larger than the diameter of an axial section and is formed by electromagnetic forming without excessive expansion. The tubular member with flange includes an axial member made of a tubular aluminum alloy extrudate and a flange member joined to an end of the axial member. The axial member has an end flange being integrated at its end and having an area smaller than that of the flange member. The flange member has a hole, and a cylindrical hole flange at the edge of the hole. The axial member fits in the hole of the flange member, the end flange is in intimate contact with the flange member, and the outer periphery of a small-diameter portion of the axial member is in intimate contact with the inner periphery of the hole flange. The hole flange is held between the end flange and a protrusion.

Abstract: A target tubular member with flange, such as a bumper stay, has a flange having an outer diameter larger than the diameter of an axial section and is formed by electromagnetic forming without excessive expansion. The tubular member with flange includes an axial member made of a tubular aluminum alloy extrudate and a flange member joined to an end of the axial member. The axial member has an end flange being integrated at its end and having an area smaller than that of the flange member. The flange member has a hole, and a cylindrical hole flange at the edge of the hole. The axial member fits in the hole of the flange member, the end flange is in intimate contact with the flange member, and the outer periphery of a small-diameter portion of the axial member is in intimate contact with the inner periphery of the hole flange. The hole flange is held between the end flange and a protrusion.

Abstract: A target tubular member with flange, such as a bumper stay, has a flange having an outer diameter larger than the diameter of an axial section and is formed by electromagnetic forming without excessive expansion. The tubular member with flange includes an axial member made of a tubular aluminum alloy extrudate and a flange member joined to an end of the axial member. The axial member has an end flange being integrated at its end and having an area smaller than that of the flange member. The flange member has a hole, and a cylindrical hole flange at the edge of the hole. The axial member fits in the hole of the flange member, the end flange is in intimate contact with the flange member, and the outer periphery of a small-diameter portion of the axial member is in intimate contact with the inner periphery of the hole flange. The hole flange is held between the end flange and a protrusion.