SU956079A1 - Method of helical mandrel free rolling - Google Patents

Description

(B) METHOD OF TRANSFER AND SCREW ROOFING

I

The invention relates to the field of metal forming and relates to the production of tubular solid billet on cross-screw rolling mills.

There is a method of cross-helical rolling, containing the deformation of a solid billet with compression of 2S SOZ without a mandrel by two rollers mounted on the feed angle.

In this technological mode, at the site before the workpiece meets the guiding tool, dangerous tensile stresses arise, which can lead to metal destruction. In the case of rolling under the same conditions, ring fracture is observed at the three-roll mill, and at the same time, the cast structure is not sufficiently explored due to the peculiarities of the stress-strain state.

The known method of cross-helical rolling continuous heated billet

without mandrel with rollers, providing preliminary compression of the workpiece before the next firmware. This method can work only on the periphery-irile layers, which is not enough when using ingots.

In order to improve the structure over the entire cross section of the proposed method, the solid heated billet is first deformed with three rollers in 2-5 passes with a stretch of 2-3, and then two rolls and guide discs with a stretch of 2-5.

Extracts, tools, and number of passes allow cast to work.

“5 The structure of both the peripheral and central layers of the ingot.

The rolling mode in a two-roll mill with guide discs is determined by the requirement for thorough development of the metal structure and its compaction.

Claims (1)

The rolling mode in a three-roll mill is determined mainly by the dimensions of the ingot and the final profile, as well as the requirement for a fairly thorough study of the cast structure, which excludes the possibility of destruction in a two-roll mill. On the basis of experimental data, it was found that it is advisable to carry out rolling in 2-5 passes with a stretch of 2-3 and compression in each pass 10-20. The use of a three-roll helical rolling mill as a draft is also caused by the possibility of deforming large-sized ingots than on a two-roll mill with much smaller equipment mass and energy intensity of the process. Screw rolling of a solid billet on a three-roll mill is characterized by a smooth increase in reduction along the deformation zone. In the central layers, a scheme with two compressive stresses is carried out, which excludes the possibility of axial fracture. However, severe plastic deformation is localized mainly in the peripheral layers, this causes an insufficiently complete study of the cast structure of the central layers of the workpiece and does not ensure the healing of all defects. 95 4 A billet, crimped on a three-roll stack and possessing higher plasticity compared to ingot, is deformed on a two-roll screw rolling mill with guide discs at large feed angles (3-20-40) and an ovalization ratio close to one. With this setting of the mill, the rolls and discs form an almost closed gauge, and the discs play an actively deforming role, with maximum compressive deformation observed in the central layers of the workpiece. Claims method of cross-helix rolling without rolling deformations of heated solid billet, characterized in that, in order to improve the structure throughout the section, the deformation is carried out sequentially by three rollers in 2-5 passes with a stretch of 2-3, and then two rollers and guide discs with a 2-5 draw