PIERCER MANDREL Russian patent published in 2015 - IPC B21B25/00 

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly, to piercer mandrel. Mandrel length equals that of pierced blank. Mandrel features variable cross-section with two through bores. First bore has rotational axis aligned with that of the mandrel. Bore diameter varies over its length equal to cylindrical part diameter counting from the mandrel front part makes 2/3 of the mandrel maximum OD to increase by 2 mm and to stay invariable at the mandrel remained length. Second bore rotational axis crosses that of the mandrel. Bore diameter equals 5 mm and does not vary over the entire length. Second bore rotational axis belongs in the plane perpendicular thereto and is located some 4/5 of mandrel length from mandrel front end.

EFFECT: decreased load to the mandrel and difference between article wall depth, ruled out defects of continuously cast billets.

2 dwg