RU2343032C2 - Profile-bending machine - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: bent section bars are produced simultaneously from two cold rolled strip blanks of different width, from which the narrower strip is imposed on wider strip. Profiling is done is serially installed setting and molding stands. Upstream setting stand centering vertical rollers are installed for alignment of bottom strip and pair of cylindrical rollers for alignment of top strip. Upstream the first molding stand at a certain distance from it two centering rollers are installed, having cylindrical section of preset diameter and cylinder-taper section installed above also with preset diameter. At that generatrix of tapered surface intended for contact with upper profiled strip is inclined to horizontal line at preset angle.

EFFECT: higher quality of double-layer bent profiles.

2 cl, 2 dwg, 1 ex

Description

The invention relates to equipment for metal forming and can be used for the production of two-layer high-quality bent profiles.

Such profiles of a relatively simple cross-sectional configuration (for example, channels and angles) are formed simultaneously from two strip blanks of different widths superimposed on each other, and the blanks can be from different grades of steel and with different properties. For forming two-layer sections made of cold-rolled strip steel (i.e. the thickness of these profiles does not exceed 8 mm), existing roll forming mills are acceptable (they are described, for example, in the book under the editorship of I. S. Trishevsky “Production of bent profiles (equipment and technology) ”, Moscow: Metallurgy, 1982, p. 71-78 and 83-90), but subject to changes in the design of their individual nodes.

Known continuous roll forming mill for forming profiles with vertical shelves, containing drive and non-drive stands, one of which contains rolls with an angle of inclination of the side forming elements 65 ° ... 75 ° (see AS USSR No. 1362538, class B21D 5/06 , published in BI No. 48, 1987). However, this mill is unacceptable for the manufacture of high-quality two-layer profiles.

The closest analogue to the claimed object is a bending mill according to US Pat. RF №2243841, cl. B21D 5/06, publ. in BI No. 1, 2005

This mill contains sequentially installed master and forming stands with vertical centering rollers in front of them and is characterized by the fact that the forming stands are combined in blocks of 3 ... 5 in each and installed on a common base plate of the block, and one or two pulling devices are installed between the blocks. Such a mill is also unsuitable for the production of high-quality high-quality two-layer profiles.

Indeed, one of the most important problems in the manufacture of such profiles is the exact centering (especially in the initial stage of the molding process) of two strip blanks at the same time - upper and lower. Since two-layer high-quality bent profiles are made with “locks” on the edges of the shelves, the width of the upper strip located inside the profile is always less than that of the lower (external) strip, the edges of which are folded 180 °, forming lock joints. Therefore, both strips must be set in caliber (and in smooth rolls of the setting stand) strictly symmetric to their axis average in width.

The technical task of the present invention is to improve the quality (geometry improvement) of double-layer bent profiles, mainly channels and corners (both equal and unequal).

To solve this problem, the proposed roll forming mill for profiling channels and angles simultaneously from two cold-rolled strip billets of different widths, of which a narrower one with a width b is superimposed on a strip with a width B> b, includes centering and forming stands installed in front of the setting stand vertical rollers for centering the lower strip and a pair of cylindrical rollers for centering the upper strip installed in front of the first forming stand at a distance from it For more than half of the span, two centering rollers having a cylindrical section with a diameter d and located above it are cylindrical with a diameter D> d, while the generatrix of the conical surface intended for contact with the upper profiled strip is inclined to the horizontal at an angle α = arctg (1, 7 ... 2.0) S _b / Δb, where S _b is the thickness of this strip, Δb = B-b; the diameter difference Dd = (1.3 ... 1.5) · Δb.

The given relation for determining the value of h was obtained experimentally and is empirical.

The essence of the technical solution found is to determine the optimal location of the centering rollers, their configuration and dimensions, ensuring the proper position of the upper of the two strips in terms of obtaining high-quality geometry of two-layer profiles.

Since when bending the edge elements of a strip blank, its edges rise at a certain distance from the axial plane of the forming rolls (the so-called smooth transition section of a certain length is formed - see, for example, the guide edited by I.S.Trishevsky “Production and use of bent profiles rolled ”, M .: Metallurgy, 1975, p. 82-83), then the centering rollers in front of the forming (second) mill stand should be located at a distance of not more than half of the inter-stand space and not less than the length of the specified section. Otherwise, the edges of the upper strip (and its proper centering) are not contacted with the lower surface of the cylindrical roller sections.

The proposed roll forming mill (its first two stands) is shown schematically in figure 1, and figure 2 is a view of the centering roller in front of the second mill stand (arrows - the direction of movement of the formed strip).

The first (master) 1 and second (first forming) 2 mill stands are located at a distance L between them (figure 1). The upper 3 and lower 4 strip blanks after the auxiliary rollers 5, which bend the strips, are directed to the master stand 1. In this case, the lower strip 4 is centered by vertical rollers 6, and the upper one - by rollers 7 installed in the immediate vicinity of this stand, in which the overlay upper strip to lower. Before entering the forming stand 2, the double strip 8 is additionally centered by the rollers 9 installed at a distance l≤0.5L from it, and after leaving this stand is sent to the subsequent forming stands of the mill.

The vertical centering roller 9 of height h and height H (Fig. 2) contains a cylindrical section 10 with a diameter d and a cylindrical 11 with a diameter D, and the difference D-d can be in the range (1.3 ... 1.5) Δb. The lower strip 4 is in contact with its edge 12 with the surface of the cylindrical portion 10 of the roller, and the upper 3 with its lateral edge 13 is in contact with the conical surface 14 of this roller, as a result of which both strips are centered with respect to the midline yy of the workpiece and caliber.

When the mill is operating, the strips coming from two uncoilers move at different levels, which is ensured by the appropriate separation device installed after the uncoilers.

An experimental verification of the inventive mill was carried out on a high-quality roll-forming unit 2 ÷ 8 × 100 ÷ 600 OJSC "Magnitogorsk Iron and Steel Works".

For this purpose, for profiling double cold rolled strip billets with a total thickness of 3 ... 8 mm from different steel grades, two additional rollers were installed in front of the mill stand, centering the upper strip, and centering rollers of the proposed design in front of its second stand. The parameters of the rollers in front of the second stand were different (by replacing the rollers) depending on different thicknesses and widths of the strips, and the angle of the bending of the shelves remained constant (8 °).

In the experiments, the distance l of the rollers from the second stand was varied, as well as the Δb value of the workpiece. The best results (yield of high-quality channels and angles within 99.1 ... 99.8%) were obtained using the inventive object. Deviations from its recommended parameters worsened the achieved indicators.

So, when centering rollers were removed in front of the second stand beyond the specified distance (i.e., to a distance of more than 0.5L), the shift of the upper strip relative to the lower was observed with a deterioration in the geometry of the profiles; A similar result was observed in the absence of upper centering rollers in front of the first stand, and in some cases, a lock connection was not made at one of the profile edges.

When the angle α is greater or less than the recommended one (see above), the centering of the upper strip worsened (for large α), or the wear of the conical surface of one of the rollers was significantly accelerated (for small α). The value of the difference Dd of the sections of the rollers, equal to (1.3 ... 1.5) Δb (recommended), was recognized as optimal: with a small value, the centering of the upper strip worsened (even with its exit above the roller), and with a large one, the dimensions of the rollers unreasonably increased and the cost of their manufacture.

It was also revealed that installing the recommended centering rollers in front of the third stand does not make sense: in the second stand along with the folding of the profile shelves, the edges of these shelves also bend (to form “locks”), i.e. the upper strip is fixed on the lower.

The mill, chosen as the closest analogue (see above), was not tested in the experiments because of its obviously unsuitability for the production of two-layer varietal profiles. Thus, an experimental verification confirmed the acceptability of the technical solution found to achieve the goal and its advantage over a known object.

According to technical and economic studies at OJSC MMK, the use of the present invention in the production of two-layer high-quality bent profiles will make it possible to obtain rolled products with the required geometry and increased strength characteristics.

Concrete example

Roll forming mill (see figure 1) is designed for the manufacture of two-layer channels and corners of cold-rolled strips up to 4 mm thick (S _max = 8 mm).

The interstand distance of the mill L = 1.4 m; the rollers in front of II stand are installed at a distance l = 600 mm and have the form shown in figure 2. At a maximum value of b = 50 mm, the angle α = arctan1.85 S _b / Δb = arctan 1.85 · 4 / 50≈8.5 °.

Other parameters of the rollers (see figure 2):

D-d = 1.4 Δb = 1.4 · 50 = 70 mm; d = 120 mm;

D = d + 70 = 120 + 70 = 190 mm; h = 60 mm;

H = 75 mm.

Claims (2)

1. Roll forming mill for profiling channels and angles simultaneously from two cold-rolled strip billets of different widths, of which a narrower one with a width of “b” is superimposed on a strip with a width of B> b, including sequentially installed setting and forming stands installed in front of the setting stand, centering vertical rollers for centering the lower strip and a pair of cylindrical rollers for centering the upper strip, installed in front of the first forming stand at a distance from it no more than half of the inter there are also two centering rollers, each of which has a cylindrical section with a diameter d and a cylindrical section located above it with a diameter D> d, while forming a conical surface intended for contact with the upper profiled strip, inclined to the horizontal at an angle α = arctg (1.7 ... 2.0) S _b / Δb, where S _b is the thickness of this strip, Δb = B-b. 2. The mill according to claim 1, in which each centering roller is made with a diameter difference D-d of (1.3 ... 1.5) · Δb.

Images