SU1014601A1 - Sheet rolling method - Google Patents

Abstract

METHOD FOR ROLLING OF SHEETS LINES1 of a mill with a reversible vertical stand in a roughing group, in which a regulated compression of narrow faces along the length of the workpiece is carried out, characterized in that, in order to reduce metal loss in the form of lateral hey sheets by eliminating wedging pcKatoB in rough passes, the amount of compression of narrow faces of the workpiece. After each reversal of the vertical stand, a & 0.45-0.55 of the amount of compression of the previous pass is set. L

Description

The invention relates to rolling production and can be used in the production of thick sheets in the hot-strip line of a hot rolling mill, in the draft group of which a reversing stand with vertical rolls is installed. There is a known method of rolling sheets, consisting in alternate compression of the workpiece in cages with vertical and horizontal rollers, in which rolling is completed by compression in vertical rollers, compression in which is first increased and then reduced to the desired final width of the sheets so that compression in the last but one pass is less than the required final width by 1-2% fl. The disadvantage of this method is that the constant direction of rolling in the vertical and alternate; The reduction of the workpiece in horizontal rollers leads to a wedge shape of its shape, which ultimately leads to an increase in lateral trimming on sheets of finite size. The closest to the proposed technical essence and the achieved result is a method of rolling slabs with side crimping narrow faces in the mill line with a reversing vertical stand in the roughing group, in which the front end of the slab is rolled with side crimping to half its length, then reverse the cage and roll the rear end to the middle with the same side crimping, after which it is set in a horizontal cage G21, However, with the known method, the butt cut is mainly reduced. which can be reduced: to, 0.36%. The purpose of the invention is to reduce metal losses in the form of side trimming of sheets by eliminating the wedge shape of rolls in roughing gaps. This goal is achieved by the fact that according to the method of rolling sheets in a mill line with a reversible vertical stand, in the rough group, in which sequential scheduled reduction of narrow faces along the length of the workpiece is carried out, the size of the narrow faces of the workpiece after each reverse of the vertical stand is set to 0 , 45-0.55 of the amount of reduction of the previous pass. t In FIG. 1-3 depicts the sequence of compression of the workpiece in a vertical cage; in fig. 4 is a diagram of the measurement of the dimensions of the workpiece after rolling in the vertical stand of FIG. 5, a graph of the dependence and change of the wedge visibility of the workpiece as a function of the reduction in the vertical stand. When rolling in vertical rolls 1, the front end of the workpiece 2, due to non-contact deformation, receives an additional narrowing, i.e. its width (when crimping narrow edges, there is less gap between the rollers, i.e. the width of the rest. The rear end is narrowed or not significant, since its non-contact deformation precedes the rolling of this part in vertical rolls. The subsequent compression of the rear end of the workpiece when passing through the gap between the vertical rollers eliminates all or part of its non-contact deformation. Due to this, there is almost no narrowing of the rear end. If several passes are made in the vertical rolls (roar When the rolling passes, the former rear and front ends of the slab are reversed in the even passages (the former front end becomes the back and vice versa) i Since the reduction in vertical rolls in all gaps is, as a rule, the same and more non-contact deformation, in odd In the case of passes, the narrowing of the former front end is completely removed, but the workpiece receives the narrowing of the former rear (now front in relation to the rolls) end - shaped wedge shaped. But since the vertical cage is located on the front side of the rough horizontal frame, the total number of passes is odd during reverse rolling, and ultimately, the workpiece gets a narrowing of the front end. Appeared in the vertical rolls. the clinoid shape is maintained when rolled in horizontal rolls, which results in a wedge shape of the unedged sheets and an increase in the amount of side trimming. For example, the experimental rolling on the 3600 mill showed that the width of the rear ends of the unedged sheets is on average 35-45 mm greater than the width of the front ones. Measurements of the workpiece after rolling was made according to the above scheme. After measurements, the relative constrictions were determined, respectively, by the ne of the average f, and the posterior end of the 3 VTz J, then the wedge shape of the workpiece d. According to the data obtained, the graphs of the MV2 function were constructed, where –5 is the amount of reduction of narrow faces. The intersection of the x-axis corresponds to the condition O. the absence of a wedge shape of the workpiece. After processing the experimental results, a generalized dependence was obtained, which can be written in the form of a formula or a graph (Fig. 5). (1, From (1) it follows that the condition for the absence of a wedge shape of rolls corresponds to 45., From (1) in particular. L. In that with f2. 0.55 wedge follows, the visibility of rolls will be - 2 number, which is significantly less After the first pass in vertical rolls with a reduction in B, the forward end of the tapered x (wedge-shaped) is narrowed. Then the rolls are brought together by the value of ДВ2 0.55 liters, reversed and the second pass is made. the second pass narrowing of the former front end of the workpiece is reduced by the amount of compression LV, ie, mills It is equal to x lvp, but the former rear end gets a narrowing, roughly equal to avalanche x-Bg. In general, we obtain an equal width of the front and rear ends. In the third stage, the rollers are diluted by an amount greater than the width of the workpiece, reversed and the third blank the pass for transferring the roll to the horizontal stand. The presence of a blank pass in the vertical rolls does not affect the performance of the plate mill, since the above operations are carried out when rolling the previous slab of the rough stand. The time of rolling in the roughing stand is much longer than the time of rolling in; vertical (longer roll length and number of skips). The method is carried out as follows. . A billet with a size of 250x1400x X2260 mm is set into vertical rolls and is crimped. In the first pass, the reduction value is 40 mm. Then set the rear end and compressed by the amount of 20 mm, i.e. 0.6 of the first pass reduction. The choice of the amount of compression is selected on the basis of the following considerations; If the second compression is less than 0.45 from the first, the rear end narrows less than the front, and if the second compression is more than 0.55, on the contrary, as a result of the compression, the workpiece still retains the wedge-shaped shape. .. Alternate compression with the task of the workpiece after reversing with the rear end is carried out to a certain size, until the widths of the front and rear ends are equal, and then directed to 1k-Lrizrvatalnymi rolls {see tab. 1 and 2).

Parameters of rolling slab 250x1400x2260 mm in vertical rolls (end compression). Note: d T T b l i c a 1

absolute compression in vertical rolls, mm;

H initial thickness, mm;

|: front end width, mm; rear end width, mm; width of the central part, mm;

Bn and l is the length of the section of roll, on which a wedge-shaped form is formed, respectively for the front and rear ends of the workpiece, mm.

.The results of measuring the wedge shape of the sheets when rolling according to the proposed mode on the 3600 mill Use ttp JViar eMot bpb 25 yoby slyb in tikalyyy yalyyah obespech vae tto (fune i o,

Table 2 is a known increase in the yield of aqueous No. of 6–7 kg / t due to the improved shape of the sheets.

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Claims (1)

METHOD OF SHEET ROLLING I am in Linchestan with a reversible vertical stand in a roughing group, in which regulated compression of narrow faces along the length of the workpiece is carried out, characterized in that, in order to reduce metal losses in the form of a side: sheet trimming by eliminating the wedge-shaped peaks and rough passes, the value narrowing the narrow edges of the workpiece. ' after each reverse of the vertical crib is set equal to 0.45-0.55 of the compression value of the previous pass.