Abstract: A spinning forming method includes: preparing a plate including a back surface at which a ring-shaped projection is formed along an outer peripheral edge of the plate, a ratio of a thickness at a reference position of the plate to a thickness at a tip end of the projection being 0.7 or less, the reference position being a position where an inclination of a portion of the back surface which portion extends toward the tip end of the projection is 45° or more; rotating the plate; moving a processing tool outward in a radial direction from an inner side of the projection to a position above the projection while pressing the processing tool against a front surface of the plate that is rotating; and locally heating a portion of the plate against which portion the processing tool is pressed.

Abstract: A spinning forming method includes: preparing a plate including a back surface at which a ring-shaped projection is formed along an outer peripheral edge of the plate, a ratio of a thickness at a reference position of the plate to a thickness at a tip end of the projection being 0.7 or less, the reference position being a position where an inclination of a portion of the back surface which portion extends toward the tip end of the projection is 45° or more; rotating the plate; moving a processing tool outward in a radial direction from an inner side of the projection to a position above the projection while pressing the processing tool against a front surface of the plate that is rotating; and locally heating a portion of the plate against which portion the processing tool is pressed.

Abstract: A tube diameter expanding method includes: rotating a tube having one end fixed to a turntable about a center axis of the tube; inserting a rod-like roller which extends in an axial direction of the tube into the tube from another end of the tube, and bringing the rod-like roller into contact with a forming region extending from the other end to a predetermined position of the tube; heating the forming region of the tube; cooling at least a section located near the forming region and within a non-forming region extending from the predetermined position to the one end of the tube; and moving the rod-like roller in a state of contacting the forming region of the tube, in a direction from the one end of the tube toward the other end of the tube and outward in a radial direction of the tube.