METHOD FOR RESTORING OUTER SURFACE OF PIERCING MILL MANDRELS AND STAMP FOR ITS IMPLEMENTATION Russian patent published in 2023 - IPC B23P6/00 B21J5/02 B21J13/02 

FIELD: pipe rolling production.

SUBSTANCE: tools for piercing and rolling mills used in the restoration of hollow products, for example, mandrels of piercing and rolling mills. When restoring the outer surface of a piercing mill mandrel containing a toe, a working cone, a reverse cone, an internal axial cavity, after wear of the mandrel during its operation, the worn outer layer is removed, a new outer mandrel body is made to replace the worn one without forming a reverse cone from the workpiece, material which corresponds to the material of the removed outer layer, and the volume of the workpiece is equal to the volume of the restored layer, then the inner body remaining after removing the worn layer is inserted into the resulting new outer body and the rear conical section of the mandrel is formed by joint crimping by hot stamping of the inner body and the outer body. The new outer mandrel body is made by hot stamping.

EFFECT: increasing the durability of piercing mill mandrels and simplifying the production process.

6 cl, 4 dwg