RU2356656C1 - Rolling method of channels - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method includes successive clamping of work material in gauges. Stable height of shelves and qualitative edge machining of shelves along the full length of rolled channel is provided ensured by blank after rough group of gauges is rolled with constant width of wall and constant height of profile between control gauges, herewith shelf height changing Δh in control gages of finishing group is regulated by mathematical dependence.

EFFECT: reduction of discard, subquality products and improvement of marketable appearance of products, and also production increasing ensured by reduction of adjusting time.

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Description

The invention relates to ferrous metallurgy, in particular to rolling production, and can be used in the rolling of channels.

A known method of rolling channels in two-roll calibers, which consists in sequentially compressing the workpiece in shaped calibers in 9 passes (A.P. Chekmarev and others. "Calibration of rolling rolls." M., "Metallurgy", 1971, p. 388, V.K. . Smirnov and others. "Calibration of rolling rolls." M., Metallurgy, 1987, S. 323).

The disadvantages of this method of rolling channels is the ability to obtain shelves of channels of different heights, which leads to an increase in the percentage of marriage and substandard metal. This is because an increase in the width of the channel wall of the upper roll during the rolling process by 2–3 mm makes it necessary to have a “reserve” of metal in the shelves in order to provide an increase in the width of the wall, since the natural broadening of the wall does not provide such an increase, and since the roll in the stream the upper roll has some freedom, this leads to unequal channeling. In addition, to ensure the required shelf height, a workpiece is required that is 2-2.5 times higher than the shelf of the finished channel, and therefore when rolling, large loads are applied to the drive and rolls, which leads to breakage of the rolls and a decrease in production.

The closest analogue is the method of rolling in two-roll calibers (see patent No. 2272683, authors A.A. Morozov and others), which consists in sequentially compressing the workpiece in shaped gauges for 9 passes with a constant wall width in the last five passes. This method is used in the manufacture of channel number 16U.

The disadvantages of this method of rolling the channels is the possibility of obtaining different heights of the shelves along the length of the channel and poor-quality processing of the edges of the shelves, which leads to an increase in the yield of marriage and worsening the presentation of the product. This is because, due to the excessive height of the shelves of the intermediate sections of the channel in the control gauges, thickenings are formed at the lower ends of the shelves, which upon further rolling form the wavy edge of the shelves. In addition, a decrease in the height of the shelves in the control calibers is determined without taking into account the specific dimensions of the caliber.

The technical problem solved by the invention is to ensure a stable height of the shelves and high-quality processing of the edges of the shelves along the entire length of the rolled channel, which leads to a decrease in rejects, substandard products and an improvement in the presentation of the products, as well as an increase in production by reducing the setup time.

The problem is solved in that in the method of rolling the channels, which consists in sequentially compressing the workpiece, in contrast to the closest analogue, the workpiece after the rough gauge group is rolled with a constant wall width and constant profile height between control calibers, and the change in shelf height Δh in the control calibers is fine groups are determined by

where D is the depth of the groove;

C is the gap in caliber;

R is the blunting radius;

y is the angle of inclination of the wall of the caliber (release caliber);

λ is the relative decrease in the channel wall thickness in this passage.

This dependence is obtained empirically and is empirical.

The same extraction of the wall and shelves, the absence of an increase in the width of the wall, as well as a decrease in the height of the shelves in the control calibers, taking into account the specific dimensions of the caliber and the relative decrease in the wall thickness in this passage, ensures a stable height of the shelves and high-quality processing of the edges of the shelves along the entire length of the rolled channel, which leads to to reduce marriage, substandard products and improve the presentation of products.

Figure 1 shows a part of the caliber.

Figure 2 shows the calibration scheme, which implements the proposed method, starting with the fourth caliber, which is the control, the width of the wall In the subsequent passes remains constant, and in the last gauge due to the straightening of the wall we obtain the required size. The height of the profile between the fourth, sixth and ninth calibers, which are the control, remains constant, and the change in shelf height Δh in the control calibers of the finishing group is determined by the dependence

where D is the depth of the groove;

C is the gap in caliber;

R is the blunting radius;

y is the angle of inclination of the wall of the caliber (release caliber);

λ is the relative decrease in the channel wall thickness in this passage.

The height of the shelves after the control calibers K ₁ and K _g will be equal to H ₁ = H ₂ -Δh ₁ and H _g = H ₁ -Δh _g .

The numbering of control calibers is given in the order of calculation - against the course of rolling.

Figure 3 shows a calibration diagram for an example of a specific implementation.

The proposed method was carried out as follows.

At the Magnitogorsk Iron and Steel Works, a billet with a section of 152 × 170 mm was rolled in a mill of 450 varietal shop in ten passes to obtain channel No. 18U.

From the first to the third gauge there is an increase in the width of the wall after each pass. Starting from the fourth gauge, which is the control, the workpiece is centered by keeping the wall width constant in the remaining gauges B = 178 mm. In the last tenth gauge, the wall width is 180 mm due to its straightening.

From the first to the fourth gauge there is a decrease in the height of the channel shelf. Between the fourth and sixth, as well as between the sixth and ninth control calibers, the height of the channel shelf remains constant, equal to 84 and 74.9 mm, respectively. The height of the shelf in the tenth gauge remains constant and equal to the height of the shelf of the channel in the ninth control gauge and is 71.3 mm. The change in shelf height Δh in the sixth and ninth control calibers is determined by the dependence

where D is the depth of the groove;

C is the gap in caliber;

R is the blunting radius;

y is the angle of inclination of the wall of the caliber (release caliber);

λ is the relative decrease in the channel wall thickness in this passage.

So, in the sixth control gauge when rolling the channel No. 18U, the dimensions of the caliber elements have the following meanings:

y = 11.3 °; D = 12 mm; C = 6 mm; R = 12 mm; λ = 1.272,

So, in the ninth control gauge during the rolling of channel # 18U, the dimensions of the gauge elements have the following values: y = 11.3 °; D = 14 mm; C = 6 mm; R = 10 mm; λ = 1.13,

The height of the shelves after the control calibers K ₁ - VI and K _G - IX will be equal to

H ₁ = H ₂ -Δh ₁ = 84-9.1 = 74.9;

H _G = H ₁ -Δh _g = 74.9-3.6 = 71.3 mm.

The proposed rolling method made it possible to master the production of channel No. 18U on the 450 mill with a constant shelf height and high-quality edge processing, as a result, the number of defective products and substandard products decreased, the setup time also decreased, which led to an increase in production by 8%.

Claims (1)

The method of rolling channels, including sequential compression of the workpiece in gauges, characterized in that the workpiece after the draft group of calibers is rolled with a constant wall width and constant shelf height between control calibers, and the change in shelf height Δh in the control calibers of the finishing group is determined by the dependence

where D is the depth of the groove of the caliber, mm;
C is the gap in caliber, mm;
R is the blunting radius, mm;
y is the angle of inclination of the wall of the caliber - release of the caliber, deg .;
λ is the relative decrease in the channel wall thickness in this passage,%.

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