SU1378961A1 - Method of producing thin bands - Google Patents

Abstract

The invention relates to the field of ferrous metallurgy, in particular to sheet rolling. The purpose of the invention is to reduce the end cut after cold rolling by stabilizing the transverse thickness variation along the length of the rolled stock after pickling. According to the invention, in the production of thin strips by hot rolling, pickling and cold rolling coils in the cells of the finishing group of a wide strip hot rolling mill, rolled up is formed with increased bulge compared to the middle part of the front and rear sections of a certain length of strip. The reduction in end trimming after cold rolling is formed by compensating for uneven scale formation over the width of the end sections and the middle of hot rolled coils by increased convexity of the end sections of the rolled strip, which results in a uniform transverse thickness difference along the hot rolled rolled strip after the etching, which contributes to the shape of the end of the skin, which is no longer enough. stripes. 1 tab. F (L with 00 with O5

Description

This invention relates to ferrous metallurgy, in particular to sheet rolling.

The purpose of the invention is to reduce the end cut-off after cold rolling by stabilizing the transverse difference thickness along the length of the crucible after etching,

In the process of producing thin strips according to the invention, in the finishing group of the hot-strip wide-strip mill, roll-up rolls are formed with an increase in the convexity of the front and rear sections of the strip, respectively, at a length of 2-8 and 3-15% of its total length towards the ends of the strip at 10-40% compared with the size of the convexity of the middle part. After hot rolling, the strip is etched and its subsequent cold rolling.

The reduction of the end trim after cold rolling in the implementation of the proposed method is formed by compensating for the uneven formation of dross over the width of the end sections and the middle of hot rolled rolls by increased convexity of the end sections of the rolled strip, which results in a uniform transverse thickness variation along the length of the hot rolled rolled edge after pickling. helps to improve the shape of the end sections of the cold rolled strip. An increase in the convexity of the front section of the roll for a length of up to 2% of the total length of the strip is advisable to assign thin strips of up to 1.2 mm. A lower value may increase the end edge due to the difference in thickness in the subsequent strip. Up to 8% of the entire length of the strip with an increased convexity of the front section should be assigned when rolling relatively thick sheets (12 mm), since the coil reeled out of the thick sheet is looser and has a greater formation of scale over a longer length. An increase in the convexity over a length of more than 8% of the total length of the strip may increase the overall level of thickness variation and it will not be reduced when it is further processed in the NTA. The extent to which an increased bulge is assigned at the rear end of the strip is characterized by large values, since the end sections

five

0

five

0

five

0

five

The strips of the strip are outer turns of the coil.

On thick strips, it is advisable to designate an increase in the convexity at the ends of the strip up to 40% compared with the middle part. Larger values than 40% may have the opposite effect and are impractical. An increase in convexity up to 10% rationally on thin strips, a further decrease does not have an effect in the total decrease in thickness variation due to the removal of scale from the strip. The additional increase in convexity is maximum at the ends of the strip and decreases to the level of convexity in its middle section.

Example. Getting a tackle (2.4x910 mm bands) at PShS 1700 hot rolling. From the analysis of the results of the experimental comparison rolls according to the proposed (numerator) and well-known (denominator) methods (see table), it follows that the proposed method ensures a reduction in the expenditure ratio of the metal due to an additional increase in the end convexity compared to the middle part of the strip by 0.01- 0.03 mm or 18-32% relative to the middle part, which, together with the etching of the strip in the NTA, stabilized the thickness variation along the strip length to 0.01 mm, while by a known method the thickness variation at the ends minutes and a middle portion of the strip reached

0.03 mm.

The main technical and economic advantages of the proposed method are to reduce the expenditure ratio of the metal by reducing the end trim and improving product quality by reducing the thickness variation.

Claims (1)

Invention Formula A method of producing thin strips, which includes obtaining a coiled hot rolled strip in the finishing group of a wide-strip mill with the formation of a variable section along the length, pickling and subsequent cold rolling of the strip, characterized in that, in order to reduce the end trim after cold rolling by stabilizing the transverse differences in thickness along the length of the rolled after etching, the magnitude of the convexity of the front and rear sections of the hot rolled strip, respectively, at a length of 2–8% and 3–15% of its total length increase towards the ends of the strip by 10-40% compared with the size of the convexity of its middle part. Note: Experiments 1 and 5 are beyond the limits; 2-4 - according to the proposed method.