SU534260A1 - The method of setting the helical rolling mill - Google Patents

Description

(54) METHOD OF SETTING MILL SCREW

ROLLING

The invention relates to the field of pressure treatment of metals and can be used in the manufacture of pipes or other rotation gel on helical rolling mills,

A known method of setting piercing mills; including turning workers, rolls at a certain feed angle and ensuring the process of deformation of a solid heated billet into the sleeve. To intensify the firmware process, additional support is applied to the end of the workpiece in the axial direction fl. The use of special devices for creating a stable backwater limits its use within wide limits. It should be noted that the impact of external overpressure outside the source of deformation only partially solves the problem of semi-eHi products of the required quality.

Improving the conditions of deformation, which determine:;. The irrigation quality of the rolled tubes, is achieved by the use of a multi-roll stand. However, an increase in the number of wafers located in one plane without displacement during rolling does not allow rolling a wide assortment of pipes due to the limited size of the caliber.

The most well-known method of setting the G2D helical rolling mill is when the workpiece is deformed by two pairs of work rolls displaced along the rolling axis, turned at feed angles, and the feed angle of the last pair sets the feed angle of the previous pair.

With such a setting, a tensile stress scheme directed along the pipe axis acts, conditions are created to break the continuity of the metal and to reveal defects of metallurgical origin, especially when rolling pipes from alloyed steel grades. Small values of tension do not give the effect of achieving the required wall deformation. These circumstances limit the use of a known mill setting method.

Claims (2)

The aim of the invention is to improve the quality of liners sewn from alloyed steels and alloys by creating rolling conditions with back pressure. To do this, in the proposed method of setting the helical rolling mill, which includes a turn at the feed angles of two successively displaced pairs of rolls, forming a single deformation zone, rolls the first pair at the feed angle, a larger feed angle of the second pair. directly within the hearth itself. This provides a favorable scheme of action of forces along the axis of the pipe and the walls of the pipe and eliminates the ruptures of the latter, especially in the manufacture of pipes from low-plastic steels and alloys. The stability of the rolling process is achieved by improving the gripping conditions of the workpiece (reducing the reduction in front of the toe of the mandrel) and increasing the area of the contact surface, which forms the required dimensions of the resulting sleeve or tube. The head created by the proposed setting is constantly operating in the caliber zone and is adjusted by changing the ratio of the absolute values of the angles of feeding of the rolls, the entry of the bits into each pair. The proposed adjustment mode can be carried out in a mill of any design, having two or more pairs of rolls with the possibility of a turn after THEM at the feed angle. The proposed method can also be carried out in the rolling process by varying the shodach angles in the indicated manner by the required values for a ratio of the feed angles of the preceding and subsequent pairs of rolls exceeding one. This ratio may vary from unit at the beginning and at the end of the process to a value greater than one in the established process. FIG. Figures 1 and 2 depict a scheme for a helical rolling mill with two pairs of rolls, designed on a horizontal and vertical plane. Example. Heated to the rolling temperature, the billet is set into a deformation zone formed by two pairs of rolls 1 and 2 displaced relative to each other during rolling. During rolling, the billet is simultaneously subjected to deformation in different directions, while setting the feed angle of the preceding pair 15, and the subsequent 12 ° creates a backpressure force in the rolling direction, which is 1.006-1.015, which allows the billets to be rolled into a sleeve of chrome-molybdenum steels and hard steels. The use of the proposed method of setting up a helical rolling mill as compared with the known method of w rolling provides the following advantages: - the possibility of obtaining a product of high surface quality without reducing the accuracy of geometric dimensions; - creation of the possibility of flashing continuous cast billets with a favorable stress-state scheme, which eliminates the destruction of the integrity of the material; -improving the conditions for removing the mandrel from the tube when rolling hollow articles on a movable long mandrel by creating a backwater directly at the deformation zone; -expansion of the range of rolled steel grades; -improving the conditions of capture while reducing crimping before the toe of the mandrel All these advantages significantly improve product quality and increase mill productivity. Claims The method of setting up a helical rolling mill, which includes a turn at the feed angles of two successively displaced pairs of work rolls, forming a single continuous deformation zone, characterized in that, in order to improve the quality of the sleeves by creating rolling conditions with a head, , a larger feed angle of the second pair. Sources of information taken into account in the examination; 1. USSR author's certificate No. 142268, cl. B 21 B 19 / O4, 1961. 2. USSR Author's Certificate No. 330891, cl. B 21 B 19/00, 1972. .one