RU2362643C2 - Method for profiling of equal channel - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention is related to rolling production, in particular to technology of cold-bent section bars. Flat work is bent serially as per passes to produce shelves and walls of channel bar. At that in the first three passes, flanges are bent inside profile according to the mode given in invention formula. Concave wall is produced, starting from the second pass by upward bending of wall with creation of bent edge sections, after achievement of a certain angle between wall and shelves, flanges are created in shelves, which are bent to a certain angle with simultaneous downward bending of wall edge sections by a certain angle and with creation of the right angle between these sections and shelves. In the last but one pass the shelves are bent to a certain angle with preservation of the right angle between them and mentioned edge sections. In the last pass the shelves are bent inside at a certain angle.

EFFECT: improved geometry of special-purpose channel bars.

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Description

The invention relates to rolling production and can be used for the manufacture of cold-formed profiles for special purposes.

Such profiles (for example, equal-channel channels) are made by sequentially bending the strip blank elements in the rolls of a roll-forming mill. The technology for profiling equal-channel channels is described in sufficient detail in the book, under the editorship of I.S. Trishevsky "Production of bent profiles (equipment and technology)", M., "Metallurgy", 1982, S. 243-246.

To increase the rigidity of channel profiles (especially from a workpiece of relatively small thickness - up to 3 ... 5 mm), their walls are often made either with corrugations of various configurations or with a curved cross section (convex or concave), and flanges are made on the shelves.

There is a method of continuous production of channels, in which the profiling in the last two (finishing) stands is carried out with bending radii coming from one point, and in all other stands with radii of constant magnitude but offset to the profiling axis, and the value of these radii is 1, 5 ... 2.0 times more than the value of the radii in the finishing stands (see AS USSR No. 1296259, class B21D 5/06, published in BI No. 10, 1987).

However, this method is not suitable for the manufacture of a channel with a concave wall and flanges on the shelves.

The closest analogue to the claimed object is a method for profiling equal-channel channels by a.s. USSR No. 1296258, cl. B21D 5/06, publ. in BI No. 10, 1987

This method consists in sequentially bending the strip billet along the aisles with the formation of shelves and the channel wall and is characterized by the fact that the bending places in the last two passages are formed with radii less than in draft passages, 2 ... 2.5 times, and the total angles of the bending of the shelves in intermediate passages, the values of the final bending angle with the radii of the bending places having an intermediate value between the said radii are taken equal to 0.65 ... 0.9.

The known method does not allow to obtain high-quality channels with a concave wall and flanges on the shelves.

An object of the present invention is to improve the geometry of special-purpose channels.

To solve this problem, in a method for profiling an equal-hollow channel with a concave wall and flanging on the shelves, including sequentially bending the strip billet with the formation of shelves and the channel wall, the first three passes are bending flanging into the profile according to the mode: 0 ° → 45 ° → 75 ° → 91 °, a concave wall is obtained, starting from the second pass, upward deflection of the wall with the formation of curved edge sections, when reaching an angle of 78 ° between the wall and the shelves, they form flanges on the shelves, why the latter are bent to an angle of 80 ° with simultaneous bending downward of the edge sections of the wall by an angle of 10 ° and with 80 ° forming an angle of 90 ° between these sections and shelves, in the penultimate passage, the shelves are bent to 87 ° while maintaining a right angle between them and the said edge sections, and in the last pass, the shelves are bent inward by 3 °.

The above process parameters are obtained empirically and are empirical.

The essence of the proposed technical solution is to find the sequence and bending angles of the individual elements of the channel for special purposes, as a result of which the required profile geometry is obtained.

A diagram of the implementation of the proposed method is shown in the drawing (Roman numerals — numbers of forming passes).

The bending of flanges 1 into the profile (ie, in the direction to the y-axis, begins on the formed strip 2 in the first pass and ends in III when they reach an angle α = 91 °. Bending of the flanges 3 of the channel to angles β with a deflection of its wall 4 up and with the formation of curved edge sections 5, it is carried out starting from passage 2. When β = 78 ° (in the VII passage), the shelves are bent to an angle β = 80 ° in the VIII passage with simultaneous bending down of the edge sections 5 of the wall downwards the angle γ = 10 ° with the formation of the angle δ = 90 ° between these sections and the shelves.

In the penultimate IX pass, the shelves 3 are bent to an angle β = 87 ° with maintaining the value of δ = 90 °, and in the last X pass, the shelves are bent inward at an angle γ = 3 ° to obtain a finished profile having dimensions: N = 80 mm, β = 40 mm, S = 1.2 mm, a = 8 mm, β = 90 °, α = 91 ° and γ = 3 °.

Experimental verification of the proposed method was carried out on a roll forming unit 1 ÷ 4 × 50 ÷ 300 OJSC "Magnitogorsk Iron and Steel Works".

For this purpose, when profiling the channel 80 × 40 × 1.2 mm (see drawing), the method parameters were varied, evaluating the results for the output of channels that fully met the requirements of the technical conditions.

The best results (yield of quality profiles within 99.2 ... 99.8%) were obtained using the proposed technology. Deviations from the recommended profiling parameters worsened the achieved indicators.

So, when folding flanges, starting from II ... IV passes, part of the finished profiles had increased longitudinal (helical) twisting, which was not corrected when dressing on the mill. A reduction in aisles with bending of flanges to two led to a similar result. An increase in the number of such passes did not improve the geometry of the channels, but complicated (and made it more expensive) the manufacture of rolls.

When the channel bends upward in the first pass (i.e., simultaneously with the bending of the flanges), the centering of the formed strip worsened to produce unequal flanges. The beginning of wall deflection in III or IV passes required an additional passage to achieve a given flanging angle - α = 91 °. The bending of the shelves to the angle δ = 80 ° in the 7th passage (at β = 68 °) caused their great “springing” (unbending) and the failure to fulfill the required corners of the finished profiles. The bending of the edge sections of the channel wall to an angle γ = 10 ° in the VIII pass was also recognized as the best option, since in other cases a 90 ° angle between these sections and the shelves was not provided, which worsened the geometry of the finished profiles. The bending of the shelves in the IX (penultimate) passage through an angle β ≠ 87 ° also led to a deterioration in geometry. To obtain an angle β = 90 ° on the finished profile, it was necessary to bend the shelves inward by only 3 °.

The method chosen as the closest analogue (see above) has not been tested due to its obviously unsuitability for obtaining the required channel. Thus, the experiments confirmed the acceptability of the technical solution found to achieve the goal and its advantage over the known object.

Technical and economic studies conducted at OJSC MMK showed that the use of the described technology to produce bent channel channels for special purposes will increase the yield of high-quality rolled products by at least 3% with a corresponding increase in profit from sales.

Concrete example

Channel, 80 × 40 × 1.2 mm, shown in the drawing, is molded in ten passes. Bending of flanges in I ... III passes according to the regime: 0 ° → 45 ° → 75 → 91 °. The deflection of the channel wall up - in the II passage. Upon reaching the angle β = 78 °, the shelves are bent to an angle of 80 °, while at the same time bending down the edge sections of the wall by 10 °. In the IX aisle - bending of the shelves of an angle of 87 ° while maintaining a right angle between them and the edge sections of the channel wall; in the X passage - bending the shelves into the profile by 3 °.

Claims (1)

A method for producing a profiled equal-channel channel with a concave wall and flanges on the shelves, comprising sequentially bending the strip billet along the aisles with the formation of shelves and the channel wall, while in the first three passes bending the flanges inside the profile according to the mode: 0 ° → 45 ° → 75 ° → 91 °, a concave wall is obtained, starting from the second pass, upward deflection of the wall with the formation of curved edge sections, when reaching an angle of 78 ° between the wall and the shelves, flanges are formed on the shelves, for which the last bend They are bent to an angle of 80 ° with simultaneous bending downward of the edge sections of the wall by an angle of 10 ° and with the formation of an angle of 90 ° between these sections and the shelves, in the penultimate passage, the shelves are bent to 87 ° while maintaining a right angle between them and the mentioned edge sections, and in the last the aisle is bent inward by 3 °.

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