RU2293615C1 - Method for rolling asymmetrical rail shapes in rough roll grooved passes - Google Patents

Abstract

FIELD: rolled stock production, possibly rolling asymmetrical rail shapes, mainly tongue rails featured by large length difference of flange beads at different sides of shape.

SUBSTANCE: method comprises steps of multiple reduction of blank in roll grooved passes, namely in symmetrical trapezoidal passes used as rough ones and in skew rail type passes used as intermediate and final passes. Different length beads of flange of tongue rail are rolled in first trapezoidal pass at shifting ridge of lower groove of pass relative to upper groove of pass to side of future short bead of rail flange by value k = 3 - 5 mm. Rolling in symmetrical trapezoidal passes is realized at filling grooves at side of future short bead of flange with less amount of metal in comparison with other side of passes corresponding to long bead of rail flange.

EFFECT: improved quality of shapes due to high accuracy of shape members geometry, enhanced efficiency of process.

3 dwg

Description

The invention relates to rolling production and can be used when rolling asymmetric rail profiles, mainly witty rails, characterized by a large difference in the length of the flanges of the sole on different sides of the profile.

A known method of rolling asymmetric rail profiles such as witty rails on a beam mill [1. p. 49, fig. 2, fig. 3]; which is the closest in its technical essence and the achieved results to the alleged invention and is taken as a prototype.

The disadvantages of the method of rolling asymmetric rail profiles according to the prototype include the fact that for rolling asymmetrical in the area of the flanges of the sole of the wedge rail, a roll is applied in the form of a symmetric trapezoid. As a result, one flange has to be intensively shortened in the shaped rail gauges, which is formed into a short flange on the finished profile, and due to a lack of metal, the long flange often turns out to be unfilled and does not meet the requirements for the profile geometry. Thus, non-uniform deformation of the metal in the region of the profile flanges in rail gauges does not contribute to the quality design of the profile, it requires settings during rolling, which leads to a decrease in quality indicators and productivity.

The technical problem solved by the invention is to improve the quality of the rolled profile by accurately performing its geometry and increasing productivity.

The technical result is achieved by the fact that in the known method of rolling asymmetric rail profiles of the type witty rail, including multi-pass compression of the workpiece in rolls with calibers, the initial formation of different lengths of the flanges of the sole of the witty rail is carried out in the first asymmetric trapezoidal gauge in a duoreversive stand 900 lower, relative to the upper stream towards the future short flange of the sole of the witty rail by k = 3-5 mm, and the subsequent rolling is carried out yayut in symmetric trapezoidal calibers line 800 with a considerably smaller filling them with metal future side flange short sole compared with the other side gages that goes into the long flange sole Ostryakova rail.

The known and proposed technical solutions have the following common features: both of them are methods of rolling asymmetric rail profiles such as a sharp rail, both include multi-pass crimping of the workpiece in rolls with calibers, providing for the use of trapezoidal calibers as rough, gauges of the rail type skid-mounted as intermediate and finishing caliber .

The proposed method differs from the prototype in that the initial formation of different lengths of the flanges of the sole of the wedge rail is carried out in the first trapezoidal gauge in the duoreversive stand 900, displacing the crest relative to the upper brook toward the future short sole flange when the bore rolls in the lower groove of the caliber by k = 3-5 mm, and the subsequent rolling is carried out in symmetrical trapezoidal gauges of line 800 with significantly less metal filling from the side of the future short sole flange on the right eniyu on the other side of the caliber that goes into the long flange soles Ostryakova rail.

These distinctive features exhibit in the aggregate new properties that are not inherent in them in the known sets of features and consist in increasing the accuracy of the profile geometry, reducing the profile tuning time during rolling and increasing productivity. This indicates that the proposed technical solution meets the criteria of the invention of "novelty."

When studying other well-known technical solutions in this technical field, the features that distinguish the claimed solution from the prototype were not identified and therefore they provide the claimed technical solution with the criterion of "inventive step".

Figure 1-2 presents the proposed method of rolling asymmetric rail profiles such as rails witty OP-50 and OP-65 (figure 3) in draft calibers.

Figure 1 shows the rolls of the duoreversive stand 900 with calibers 1-2-3-4 and the rolling pattern of the original workpiece in them (the movement of the workpiece is shown by arrows). The alternate double rolling of the roll without tipping in calibers 2 and 3 is explained by the desire to improve the surface quality of the roll faces going to the formation of the sole, head and massive neck of the profile due to their preliminary cutting with subsequent settlement. In caliber 4, which is the first trapezoidal gauge in the general scheme for rolling the profile, when the rolls are bored, the crest of the lower stream is offset from the upper by an amount k = 3-5 mm towards the future small profile flange.

Figure 2 shows the metal filling of the flanges of the trapezoidal gauges during rolling by the proposed method. Figure 3 shows the profile shape witty rails type OR-50 and OR-65.

An example of the implementation of the method is shown when rolling the rail profile witty OP-65 in the rail and beam shop of OJSC "NKMK".

An initial billet with a section of 300 × 330 mm is rolled in rolls of stand 900 according to the following scheme: 2 passes in the 1st gauge to a section of 210 × 350 mm, after tilting 90 ° in calibers 2-3, to a section of 210 × 260 mm, after the next turning 90 ° in the same calibers 2-3 to a cross section of 155 × 255 and after the next tilting of 90 ° the roll is rolled in a trapezoidal vertical gauge to a height of 165/210 mm and a sole width of 190 mm. In the trapezoidal caliber, the ridge of the lower stream is displaced relative to the upper streams by k = 5 mm (Fig. 2) towards the future small sole flange. Such a shift made it possible in subsequent symmetrical trapezoidal gauges on line 800 during rolling of the roll to increase the length of the flange oriented to form a large flange of the base of the profile and to reduce the length of the flange of the roll going to the formation of a small flange of the base of the profile.

A decrease in the offset of the ridge in the lower stream of the first trapezoidal caliber k <3 mm does not have the desired effect, and with an increase in the offset k> 5 mm, the stability of rolling of the roll in this gauge deteriorates, which negatively affects the accuracy of the elements of the finished profile and the stability of rolling.

Using the proposed method for rolling asymmetric rail profiles in draft calibers provides the following advantages over the existing one:

1. improves the accuracy of the implementation of the profile elements;

2. Increases rolling performance.

Information sources

1. The journal "Steel", 1990, No. 12, p. 47-50.

Claims (1)

The method of rolling asymmetric rail profiles in rough gauges, mainly witty rails, characterized by a large difference in the length of the flanges of the sole on different sides of the profile, including multi-pass compression of the workpiece in rolls with calibers, involving the use of symmetrical trapezoidal gauges as rough, skid-mounted intermediate gauges of rail type and as fine caliber, characterized in that the initial formation of the sole with different lengths of the flanges is carried out in the first rape-shaped gauge, with the offset of the crest of the lower stream of the caliber relative to the upper stream towards the future short flange by k = 3-5 mm, and subsequent rolling in symmetrical trapezoid calibers is carried out with much less metal filling from the side of the future short flange of the sole compared to another side gauges corresponding to the long flange of the sole.

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