PIERCING APPARATUS, MANDREL USED FOR PIERCING APPARATUS AND METHOD OF PRODUCING SEAMLESS STEEL PIPE

摘要

FIELD: machine building.SUBSTANCE: invention relates to piercing of blanks. Prevention of defects such as slivers inner surface of hollow sleeve is provided by fact that firing installation comprises a mandrel having a through hole which extends along central axis of mandrel adapted to central portion transmittance sewn workpiece through said through hole, wherein installation has a plurality of rollers placed around mandrel in axial direction, or container for placing workpiece and mandrel with its piercing pressing workpiece in its axial direction.EFFECT: reducing probability of occurrence of defects.16 cl, 19 dwg