The invention provides a hole
flanging and in-mold tapping process for a high-strength plate, and relates to the technical field of automobile part
machining. The hole
flanging and in-die tapping process for the high-strength plate comprises the steps that firstly, a convex
hull is punched and drawn, a female die is of a through hole structure, the hole
diameter is 0.1 mm smaller than the target outer
diameter of a flanged hole on one side, the top of a punch is designed to be an inverted-cone smooth arc-shaped protrusion, the
diameter of the protrusion is 0.25 mm larger than the
maximum diameter of a chamfer of an inner hole of the flanged hole on one side, the curvature
radius R of the arc is 0.5-1 mm, and the height of the convex
hull is accurately controlled to be 30% + / -0.05 mm of the thickness of a material; it is ensured that the plastic flow allowance of 30% of the material thickness exists in the follow-up pressure returning procedure; secondly, convex
hull forming is conducted, and a 90-degree + / -1-degree inverted-cone-shaped knot is adopted as a punch. Materials needed by hole
flanging are drawn into a convex hull through convex hull
punching and drawing, the shape of a flanged hole is formed through back upsetting, meanwhile, burrs are reversely patted after
punching is conducted, broken burrs generated after
punching are extruded to be smooth again, and it is guaranteed that in the subsequent hole flanging procedure, the end face of the flanged hole cannot have serious cracks and sawtooth shapes.