RU2388564C1 - Profile-iron bending mill - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly specialised roll mills to produce 4 mm-thick roll-formed shapes. Proposed mill comprises roughing and finishing stands with stand space behind which vertical rolls are mounted to move through preset vertical distances and across mill crosswise axis. Five vertical rolls are fitted behind every roughing stand, roll cylindrical part length making at least the forming height in this stand and having a certain diametre. Rolls are staggered with respect to mill lengthwise axis and can additionally move parallel to said axis to vary lengthwise distance between them to maximum value. At least two rolls arranged on opposite sides of aforesaid axis are drive rolls. Taper elements are fitted on roll end faces with taper surface facing each other, said rollers having maximum diametres.

EFFECT: improved geometry of cold roll-formed shapes to due reduced lengthwise curvature.

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Description

The invention relates to the processing of metals by pressure and can be used on specialized mills for the production of high-quality bent profiles.

Multi-stand roll-forming mills contain two groups of stands: roughing and finishing. For each mill stand, vertical rollers are installed (one pair), the purpose of which is to transfer a strip from one stand to another. Continuous mills are often used for profiling (especially for long sections with a thickness of up to 4 mm), which are described in sufficient detail, for example, in the book of AP Chekmarev and VB Kaluzhsky “Bent profiles of hire”. M., "Metallurgy", 1974, p.30-32.

A roll forming mill is known, comprising a series of sequentially installed forming stands with rolls forming gauges, and at least one of the forming stands is rotatable around a vertical axis and equipped with a drive for its rotation (see AS USSR No. 988407, class B21D 5 / 06, published in BI No. 2, 1983). However, on this mill, it is impossible to obtain high-quality profiles with high-quality geometry from a strip blank bent in the horizontal plane (i.e., crescent) in excess of the permissible values.

The closest analogue to the claimed object is a continuous bending mill 1 ÷ 4 × 50 ÷ 300, given in the book of I. S. Trishevsky and others. "Production of bent profiles (equipment and technology)." M., "Metallurgy", pp. 75-76 and 105.

This mill for forming high-quality bent profiles contains roughing and finishing groups of stands with an inter-clearance distance L, behind which pairs of vertical rollers are installed, and is characterized by the fact that the rollers are mounted on special tables with the possibility of vertical and transverse, relative longitudinal axis of the mill, moving at specified distances . The design of the known mill also does not provide profiles with high-quality geometry from a sickle-shaped strip blank.

An object of the present invention is to improve the geometry of cold-formed profiles by reducing their longitudinal curvature.

To solve this problem, in a roll-forming mill for forming high-quality bent profiles up to 4 mm thick, containing roughing and finishing groups of stands with an inter-clenched distance L, behind which vertical rollers are installed, made with the possibility of moving along given distances vertically and across the longitudinal axis of the mill, in unlike the closest analogue, five vertical rollers with a length of their cylindrical part not less than the molding height in this stand and with its diameter d = (0,060 ... 0,065) are installed behind each forming stand of the draft group ) · L, staggered relative to the longitudinal axis of the mill, with the possibility of additional movement parallel to this axis and changing the longitudinal distance between them to a maximum value equal to (0,180 ... 0,185) · L, with at least two rollers located on different the sides from the aforementioned axis of the mill are driven, and conical elements are installed at the ends of the rollers, facing conical surfaces facing each other, with a maximum diameter of these elements D = (1.23 ... 1.25) · d.

The given parameters of the mill were obtained experimentally and are empirical.

The essence of the proposed technical solution lies in the possibility of eliminating the curvature of the moldable strip emerging from each roughing stand of the mill by appropriate installation of vertical rollers that work similarly to rollers of a plate straightening machine. On existing roll forming mills, molding from a sickle-shaped workpiece usually leads to a distortion of the cross section of the finished profile (for example, an equal-shelf profile is obtained with shelves of different widths, often beyond tolerances).

The inventive roll-forming mill is schematically shown in figure 1 (the section between two adjacent stands is shown), figure 2 shows a top view, and figure 3 is a view of a vertical roller (arrow - rolling direction).

Between the forming stands 1 and 2 there is a roller table 3 (Figs. 1, 2), on which vertical rollers 4 ... 8 are installed, two of which (4 and 5) are driven (the drive of the rollers and rolls of the stands is not shown). The rollers are mounted on the axes 9, moved both across the longitudinal axis xx of the mill, and along it; in addition, the rollers can be moved along the vertical axis 9. Three rollers (4, 6 and 8) are installed to the left of the xx axis, and two (5 and 7) to the right. The maximum distance “c” between the rollers is equal to the maximum width of the profile leaving the stand 1, and the maximum distance between the rollers along the xx-ℓ axis = (0.180 ... 0.185) · L.

Each roller (figure 3) is made with a cylindrical part 10 with a diameter d = (0,060 ... 0,065) · L and with two conical elements 11 at the ends of the roller, the maximum diameter of which D = (1,23 ... 1,25) · d. The height of the cylindrical part 10 of the roller h is equal to the maximum molding height in stand 1.

The mill works as follows. Formed by the rolls 12 of the stand 1, the strip 13 extends between the vertical rollers and, if necessary, is straightened by them by means of the respective installation of the rollers. The drive rollers 4 and 5 contribute to the advancement of the strip into the rolls 14 of the stand 2. The conical surfaces of the roller elements 11 keep the moldable strip from vertical displacement.

After correcting the crescent portion of the strip, the rollers are freed from contact with the strip or moved apart by a distance “c” equal to its width.

An experimental verification of the proposed mill was carried out on a roll forming unit 1 ÷ 4 × 50 ÷ 300 of OJSC Magnitogorsk Iron and Steel Works. For this purpose, the parameters of the five-roller installation were varied in the draft group of stands of this mill, and we also tested the installation with three rollers, profiling strips with a thickness of 4.5 ... 5.0 mm (on this mill it is allowed to produce angle and channel profiles of this thickness) and a variant of the mill, taken as the closest analogue. The maximum crescent shape of the strip blank was 12 mm per 3 m of its length.

The best results (yield profiles with high-quality geometry) in the range of 99.0 ... 99.8% were obtained using the inventive object. Deviations from its recommended parameters worsened the achieved indicators.

Thus, the use of only three rollers of the recommended parameters did not lead to the correction of the longitudinal curvature of the profiles formed from strips with a crescent of more than 10 mm per 3 m in length. The curvature of the profiles formed from strips with a thickness of 4.5 ... 5.0 mm was not corrected when using five rollers installed between all the stands of the draft group of the mill (unacceptable bending of the side elements of the profiles occurred). Performing four or all of the non-driven rollers caused injury (risks, scratches) to part of the profiles.

The curvature of the profiles was not corrected when using rollers with d 0,0 (0,060 ... 0,065) · L, as well as when 0,1 <0,18L (installation of rollers with 0,1> 0,185L was prevented by the presence in the stands of the upper rolls with a rolling diameter of 478 adopted on this mill) mm). The yield of profiles with the required geometry was reduced when using rollers without conical elements at their ends and at D <1.23 d, and for D> 1.25d and d = 0.065L, the rollers did not fit in the intercellular spaces.

The use of a well-known object, selected as the closest analogue (see above), gave the output of high-quality profiles from the workpiece with increased sickle shape of not more than 12%. Thus, an experimental verification confirmed the acceptability of the technical solution found to achieve the goal and its advantage over a known object.

Feasibility studies have shown that the implementation of the present invention on mills similar to the 1 ÷ 4 × 50 ÷ 300 roll forming mill of OJSC MMK will increase the yield of cold-formed profiles with the required geometry by approximately 15% and will allow the use of a strip billet with a sickle shape of up to 12 mm / 3 m, which will reduce the metal consumption during profiling (due to currently cut sections of bands with the specified crescent shape) by at least 1% with a corresponding increase in profits from the sale of rolled products.

Concrete example

In the draft group of stands (I ... VI) roll forming mill 1 ÷ 4 × 50 ÷ 300 installed vertical rollers according to figure 1 and 2.

Mill parameters:

L = 1000 mm; the diameters of the upper and lower rolls, respectively, 478 and 165 mm; d = 0,063 · L = 0,063 · 1000 = 63 mm; ℓ _max = 0.183 · L = 0.183 · 100 = 183 mm.

The rollers are made with conical end elements having D = 1.24 · 63≈78 mm; maximum height h = 104 mm.

Claims (1)

Roll forming mill for forming high-quality bent profiles up to 4 mm thick, containing draft and finishing groups of forming stands with inter-stand distance L, behind which there are vertical rollers made with the possibility of moving at specified distances vertically and across the longitudinal axis of the mill, characterized in that for five vertical rollers with a length of their cylindrical part not less than the molding height in this stand and with its diameter d = (0,060 ... 0,065) · L, located in chess ohm order relative to the longitudinal axis of the mill, with the possibility of additional movement parallel to this axis and changing the longitudinal distance between them to a maximum value equal to (0,180 ... 0,185) · L, with at least two rollers located on opposite sides of the said axis of the mill, are driven, and conical elements are installed at the ends of the rollers, facing conical surfaces facing each other, with a maximum diameter of these elements D = (1.23 ... 1.25) · d.

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