| 摘要 |
FIELD: tube production, namely processes for piercing in helical rolling mills. ^ SUBSTANCE: method for piercing ingot-blanks in helical rolling mills comprises steps of biting ingot-blank by means of rolls; intensively deforming wall on mandrel and rolling out hollow body having no inner rigid support; again rolling out hollow body of sleeve in deformation zone restricted by means of cantilever portions of rolling rolls. ^ EFFECT: elimination of sleeve curvature, lowered wall thickness difference of sleeve. |
