RU2350408C1 - Method of channel bars rolling - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method includes multipass straining of bloom in horizontal and vertical rollers with gauges, with forming of developed profile and following leg bend in. Infusion uniformity of separate elements of profile, reduction of probability raised local wear of pass contour is provided ensured by that deformation in the first one or two passes are implemented in rollers with flat body, and in following passages excluding leader, - in roll opening with elongation ratio in each, not exceeding 1.56. After straining in rollers with flat body strip is strained in vertical rolls with elongation ratio 1.01-1.26. After straining in vertical rolls strip is strained in two passes in rollers with slitting pass, then - in vertical rolls, then - in two gauges with developed flanges with elongation ratio 1.20-1.46 in each, and rolling is finished by strip drafting in straight-flange gauges with flanges inclination, uniformly increasing from 30-45° till 90°. Furthermore, straining in last but one and in last passages is implemented with elongation ratio 1.10-1.30 and 1.10-1.16 agreeably.

EFFECT: improving of channel bars, efficiency of rolling process and reduction of rollers consumption.

4 cl, 1 dwg, 1 tbl

Description

The invention relates to the field of metallurgy, specifically to rolling production, and can be used to obtain steel equal-channel channels.

A known method of rolling channels, including multi-pass hot deformation of the profile strip in the rolls with calibers with the formation in the finishing stand of the profile with a curved wall, and when forming the profile in the finishing stand on the surface areas of its wall adjacent to the corners of the profile, form thickenings of trapezoidal shape with regulated sizes , which are then rolled out in the process of cold dressing [1].

The disadvantages of this method are the low quality of the channels, since during cold plastic deformation of the thickened wall there is a longitudinal curvature and distortion of the cross-sectional shape of the channels, which reduces their quality and yield. In addition, deep streams are made to form the strip profile on the rolls. This increases the consumption of rolls.

There is also known a method of rolling channels, comprising sequential compression of the workpiece in closed gauges, according to which the strip after the control gauge is centered by both the lower and upper rolls, maintaining a constant wall width [2].

The disadvantages of this method are that the rolls with closed gauges have a large depth of cuts (streams). This leads to an increase in contact slip due to the difference in peripheral speeds along the depth of the stream, increased wear of the streams and a deterioration in the quality of the rolled channels.

The closest analogue to the present invention is a method of rolling channels, including multi-pass deformation of a square billet in horizontal and vertical rolls with calibers with the formation of a detailed profile and subsequent folding of the shelves, and before the penultimate pass, the shelves of the profile strip are bent in vertical rolls at an angle of 22-26 °, in the penultimate pass, rolling is carried out in horizontal rolls with a hood of 1.10-1.30, and in the final pass, the profile strip is rolled with a hood of 1.19-1.25 and dnovremennym shelves podgibaniem an angle 10-14 ° [3].

The disadvantages of this method are that in the process of rolling the profile strip there is increased wear of calibers, especially with a large depth of streams. This reduces the quality of channels, increases the consumption of rolls and mill downtime associated with transshipment, which reduces the productivity of the rolling process.

The technical problem solved by the invention is to improve the quality of channels, the productivity of the rolling process and reduce the consumption of rolls.

The stated technical problem is solved by the fact that in the known method of rolling channel channels, including multi-pass deformation of a square billet in horizontal and vertical rolls with calibers with the formation of a detailed profile and subsequent folding of the shelves, according to the invention, the deformation in the first one or two passes is carried out in rolls with a smooth barrel, and in subsequent passes, excluding the precursor, in open gauges with an extraction coefficient in each of them not exceeding 1.56. After deformation in rolls with a smooth barrel, the strip is deformed in vertical rolls with a drawing coefficient of 1.01-1.26, and after deformation in vertical rolls, the strip is deformed in two passes in rolls with split gauges, in vertical rolls, then in two passes in calibers with unfolded shelves with an extraction coefficient of 1.20-1.46 in each and complete rolling by deformation of the strip in straight-line calibers with an angle of inclination of the shelves uniformly increasing from 30-45 ° to 90 °. In addition, deformation in the penultimate and last passes is carried out with the drawing coefficients of 1.10-1.30 and 1.10-1.16, respectively.

The invention is illustrated in the drawing diagram of the deformation along the passages of a square billet in the channel.

Multipass deformation of a square billet in horizontal and vertical rolls with gauges with the formation of a detailed profile and subsequent folding of the shelves eliminates the need for a banding of the strip, reduces the necessary depth of cuts (depth of streams), which increases the permissible number of regrinding of rolls.

Deformation in the first one or two passes in the rolls with a smooth barrel provides effective stretching of the strip. The absence of cuts on the rolls reduces their consumption, increases the uniformity of deformation over the cross section, improves the quality of the finished channels. Deformation in open calibers with a draw ratio not exceeding 1.56, and other conditions being equal, ensures uniform drawing of individual strip elements, reduces the likelihood of increased local wear of streams, which increases the resistance of calibers and the quality of the strip.

The deformation of the strip in vertical rolls with a draw ratio of 1.01-1.26 after deformation in the rolls with a smooth barrel provides the strip calibration in width and study of its sides. Subsequent deformation of the strip in open split gauges forms on the expanded profile a pair of thickened sections in the corners of the future channel. In this case, split gauges are formed by streams on rolls with a shallow depth of cut, which increases the permissible number of regrinding of rolls, reduces the unevenness of wear of streams, and improves the quality of finished profiles and rolling productivity. Subsequent deformation in vertical rolls reduces the width of the strip.

The deformation of the strip in series in two calibers with unfolded shelves with a draw ratio of 1.20-1.46 in each also eliminates the need to increase the depth of streams, stabilizes the rolling process, improves the quality of channels and the resistance of rolls. Subsequent deformation in straight-flange calibers improves the accuracy of rolled channels. Simultaneously with the compression in the straight-flange calibers, the flanges are uniformly folded with a gradual increase in the depth of the streams evenly distributed over the straight-flange calibers. Moreover, in the penultimate and last straight shelving calibers, the brooks of which have the greatest depth of cuts, the drawing coefficient is reduced to the values of 1.10-1.30 and 1.10-1.16, which ensures a decrease in the contact slip of the metal in the centers of deformation and wear of the streams. In this case, the pre-caliber is closed, which allows to increase the accuracy of the finished channel. Simultaneously with rolling, the caliber shelves in the last two passes are finally bent to an angle of 90 °. This ensures high accuracy of the cross section of the finished channels and increase their quality.

It was experimentally established that the deformation of the strip in open gauges proceeds stably at stretching coefficients not exceeding 1.56. An increase in the drawing coefficient of more than 1.56 leads to an increase in the unevenness of deformation, bending of the strip at the exit of the caliber, overflow of the caliber, a decrease in the resistance of the rolls and the quality of the channels.

When deforming in vertical rolls with a drawing coefficient less than 1.01, the lateral sides of the strip and the complete elimination of the width are not worked out. An increase in the drawing ratio of more than 1.26, firstly, leads to increased wear of the streams and, secondly, does not exclude the loss of stability of the strip in caliber, the distortion of its shape, which affects the quality of the channels.

Deformation of the strip in two calibers with unfolded shelves with an extraction coefficient of less than 1.20 requires an increase in the required number of passes, which is irrational. An increase in the drawing ratio of more than 1.46 increases the unevenness of deformation along the strip section, the unevenness of the wear of the rolls, their consumption, and also leads to a decrease in productivity due to frequent transshipments.

When the angles of inclination of the shelves in the first straight-shelf caliber are less than 30 °, an increase in the total number of passes is required, which is irrational. An increase in the angle of more than 45 ° requires an increase in the depth of streams of this and subsequent calibers. This increases the consumption of rolls, reduces the productivity of rolling due to more frequent transshipment of rolls. Deviation of the angle in both directions from the value of 90 ° reduces the quality of the channels.

Deformation in the penultimate (pre-finishing) and last (finishing) passes with drawing coefficients less than 1.10 does not allow to provide the required dimensional accuracy of the finished channels, which reduces their quality. An increase in the coefficient of extraction in the penultimate pass more than 1.30 and in the last more than 1.16 increases the unevenness of deformation over the cross section, bending of the strip at the exit of the rolls, and the formation of defects.

Method implementation examples

Continuously cast billets of square section 100 × 100 mm, 6 m long, are heated in a methodical furnace of a section rolling mill 350 to a temperature of 1280 ° C for rolling channel No. 8 and dispensed onto a furnace rolling table. The heated billet is deformed in the first pass in horizontal rolls with a smooth barrel with a drawing coefficient λ ₁ = 1.16 (see drawing, profile 1). In the second pass, the strip is repeatedly deformed in horizontal rolls with a smooth barrel with a drawing coefficient λ ₂ = 1.20 (profile 2).

The resulting flat strip is set into vertical rolls with an open box caliber (3rd pass) and crimped in width with a drawing coefficient λ ₃ = 1.10 (profile 3). The strip emerging from the rolls is set into horizontal rolls with split gauges, in which the strip is crimped in two passes. In the fourth pass with a drawing coefficient λ ₄ = 1.16, a pair of thickened sections is formed in the strip at the corners of the future channel (profile 4). In the fifth pass, in horizontal rolls with an open split gauge, the strip is crimped with a drawing coefficient λ ₅ = 1.56.

The sixth pass is carried out in vertical rolls with an open caliber, with a drawing coefficient λ ₆ = 1.10 (profile 6).

Two subsequent passes are carried out in horizontal rolls with open gauges and unfolded strip shelves, with hood coefficients λ ₇ = 1.25 and λ ₈ = 1.35 (profiles 7 and 8).

Further deformation of the strip is carried out sequentially in straight-line calibers with hood coefficients λ ₉ -λ ₁₂ and with tilt angles φ ₉ -φ ₁₂ , uniformly increasing from 30 ° to 90 °:

λ ₉ = 1.36; φ ₉ = 30 °; horizontal rolls, open gauge (profile 9);

λ ₁₀ = 1.01; φ ₁₀ = 50 °; vertical rolls, open gauge (profile 10);

λ ₁₁ = 1.20; φ ₁₁ = 70 °; horizontal rolls, closed pre-finishing gauge (profile 11);

λ ₁₂ = 1.13; φ ₁₂ = 90 °; horizontal rolls, open finishing caliber (profile 12).

Due to the fact that the deformation is carried out with the formation of a detailed profile in open horizontal and vertical calibers with a drawing coefficient λ in any of the passages not exceeding 1.56, the rolled channels are of high quality: the yield of grade 1 is Q = 98.7%. At the same time, by reducing wear, an increase in roll resistance and the duration of each campaign is achieved: roll consumption is reduced to c = 1.32 kg / t of rolled metal. This, in turn, reduces the required number of transshipment rolls and increases the productivity of the rolling process by ΔP = 3.5%.

Implementation options of the proposed method and indicators of their effectiveness are shown in the table.

Table. Channel rolling modes and indicators of their effectiveness No. p / p λ λ ₃ λ ₇ λ ₈ φ ₉ , deg. λ ₁₁ λ ₁₂ Q% s, kg / t ΔP,% one. 1.009 1.009 1.19 1.19 29th 1.09 1.09 78.5 1,54 - 2. 1.01 1.01 1.20 1.20 thirty 1.10 1.10 99.6 1.35 3.2 3. 1.28 1.10 1.25 1.35 37 1.20 1.13 99.8 1.32 3,5 four. 1,56 1.26 1.46 1.46 45 1.30 1.16 99.6 1.33 3.4 5. 1,57 1.27 1.47 1.47 46 1.40 1.17 79.9 1,59 - 6. not regl. not regl. not regl. not regl. 10-26 (Δφ) 1,2 (λ ₁₂ ) 1.22 (λ ₁₃ ) 75,4 1,62 - Note: in option 6, Δφ is the change in the angle of the hem of the shelves.

From the data presented in the table, it follows that when implementing the proposed method (options No. 2-4), improving the quality of channels, productivity of the rolling process and reducing the consumption of rolls is achieved. In cases of transcendental values of the declared parameters (options No. 1 and No. 5), as well as the use of the prototype method (option 6), there is an increase in the wear of the roll calibers, which leads to an increase in their consumption, a decrease in the quality of channels and the performance of the rolling process.

As a basic object in determining the effectiveness of the proposed method adopted the prototype method. Using the proposed method will increase the profitability of the production of channels on the section rolling mill 350 by 5-7%.

Literature used in the preparation of the description of the invention

1. Auth. testimonial. USSR No. 1678469, IPC B21B 1/08, 1991

2. Patent of the Russian Federation No. 2272683, IPC B21B 1/08, 2006

3. Patent of the Russian Federation No. 2111803, IPC B21B 1/08, 1998 - Prototype.

Claims (4)

1. A method of rolling channels, including multi-pass deformation of a square billet in horizontal and vertical rolls with calibers, with the formation of a detailed profile and subsequent folding of the shelves, characterized in that the deformation in the first one or two passes is carried out in rolls with a smooth barrel, and in subsequent, with the exception of the preflight, aisles - in open gauges with an extraction coefficient in each of them not exceeding 1.56. 2. The method according to claim 1, characterized in that after deformation in the rolls with a smooth barrel, the strip is deformed in vertical rolls with a draw ratio of 1.01-1.26. 3. The method according to claim 2, characterized in that after deformation in vertical rolls, the strip is deformed in two passes in rolls with split gauges, followed by deformation in vertical rolls, then in two passes in calibers with deployed shelves with a draw ratio of 1.20 -1.46 in each, and complete rolling by crimping strips in straight-line calibers with an angle of inclination of shelves uniformly increasing from 30-45 ° to 90 °. 4. The method according to claim 1, characterized in that the deformation in the penultimate and last passages is carried out with drawing coefficients of 1.10-1.30 and 1.10-1.16, respectively.

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