METHOD OF PRODUCING LONG-AXIS ARTICLES Russian patent published in 2019 - IPC B21K21/06 

FIELD: technological processes.

SUBSTANCE: invention relates to metal forming and can be used in making long-axis hollow articles of high accuracy from initial billet with diameter not exceeding inner diameter of article. Container is used, in the bottom part of which there is a drawing matrix having the possibility of movement and fixation, and a fixed mandrel. Matrix and mandrel have conical working surfaces arranged with clearance. Impact punch on a workpiece mounted on a mandrel in a container with a fixed drawing matrix. Method comprises extruding a workpiece metal into said gap to produce a cup. Then, the matrix is released from fixation and drawing of the extruded part of the workpiece on the mandrel under action of the matrix at the fixed puncheon. Gap between conical surfaces of matrix and mandrel is set equal to sum of wall thickness of hollow article and metal layer of workpiece, which is required to increase its length during broaching.

EFFECT: reduced deformation force, increased article length and fine-grained structure.

1 cl, 1 dwg