RU2158642C2 - Method for profiling cut-through angle - Google Patents

Abstract

FIELD: plastic metal working, namely manufacture of cold bent angular cut-through shapes. SUBSTANCE: method comprises steps of successive bending of flanges and shaping bent portions between said flanges in rough, intermediate and final passes, limiting crosswise motion of shaped piece only in rough pass; setting bending up angle values equal respectively to 20, 40 and 46 degrees; at final pass cutting-through angular shape according to predetermined configuration and size in place of bending shape while maintaining constant angle between bent up flanges. EFFECT: lowered cost for making angular shapes with cut-through bent portions, enhanced quality of angular shapes.

Description

 The invention relates to rolling production and can be used in the manufacture of cold-formed corner profiles with notches.

 Perforated bent profiles having holes on their elements (for example, shelves), obtained without removing metal, are produced on roll forming units equipped with special additional equipment, and, most often, stripping of a strip billet is carried out before its profiling. The technology for manufacturing profiles with notches is described, for example, in a book under the editorship of I.S. Trishevsky Production of bent profiles (equipment and technology). M.: Metallurgy, 1982, p. 289-295. When performing a notch operation on finished bent profiles, the technology of their preliminary molding is similar to the production of bent profiles without notches.

 A known method for the production of perforated sheets, which provides for the deformation of sheets with pre-punched holes or a joint process for forming holes and their deformation on a mill having rolls with streams located against the holes on the sheets (see US Pat. Cl. 29-6.1, N 3293725 dated December 27, 66). The disadvantage of this method is its inapplicability for the production of grooved corners.

The closest analogue to the claimed method is the technology (calibration) of the manufacture of perforated equilateral corners of 45 x 2 mm, given in the book of I. O. Trishevsky and others. Perforated profiles. M .: Metallurgy, 1972, p. 133, fig. 52b. This technology includes sequential bending of the corner shelves with the formation of bending points between them in the rough and intermediate passages and is characterized by the fact that in the first three passes the lateral displacement of the formed strip is limited, and in the finishing (last) pass the corner shelves are unbent by 1 ^o .

 A disadvantage of the known technology is the relatively large (six) number of moldable passes, which increases the consumption of rolls and production costs, as well as the inability to obtain a high-quality corner with grooves (or perforations) at its top (i.e., the bend between the profile shelves).

 Indeed, since the portion of the bend during profiling of the corner takes up a very small part of the width of its sweep (more precisely, πR / 2, where R is the radius of the bend), when bending the strip blank with notches, they can shift in the transverse direction away from the future vertex of the corner, in particular, when using a sickle-shaped (i.e. curved in the horizontal plane) billet, which will lead to rejection of profiles due to crushing of notches.

 An object of the invention is to reduce the cost of manufacturing bent grooved corners and improve their quality when the location of the grooves in the bend of the formed strip.

To solve this problem, in a method comprising sequentially bending the corner shelves and forming bending places between them in the rough and intermediate passages with limiting the lateral displacement of the formed strip, the mentioned limitation is carried out only in the rough pass, and the bending angles along the passages are taken equal to 20, 40 and 46 ^o , while in the finishing passage, punches are made of cutouts of a given shape and size at the bend of the profile, keeping the angle between its folded shelves unchanged.

The essence of the technical solution found is that at first an equal-angle corner is formed from the strip, and then, on its bending section, notches of a given configuration and size are performed. This allows you to reduce the number of closed gauges that center the moldable strip, from three (in the known method) to one, as well as the total number of stands and the simultaneous use of the maximum bending angles per pass (20 ^o ).

In addition, the final total bending angle is taken equal to 46 ^o in order to compensate for the "springing" (unbending) of the shelves of the finished profile, leaving this angle unchanged in the stand where the profile is cut. The absence of folding of shelves in the last aisle reduces the residual stresses in the profile, which is especially important for preserving the specified parameters of arched slots.

 The presence of grooves at the corner bend allows you to use it, first of all, as an element of packaging of rolled strip steel, since such an arrangement of the grooves virtually eliminates their wrinkling and contributes to the maximum removal of moisture from the roll, preventing metal corrosion.

 An experimental verification of the found technical solution was carried out on a roll-forming unit 1-4x50-300 of ZAO Rolled-Bent Profile of Magnitogorsk Iron and Steel Works. For this purpose, equal-angle corners 100 x 1.2 mm and 120 x 1.5 mm from art. 3kp, at the places of bending of which arch arches were made with a height of 8 ... 10 mm, a width of 10 ... 12 mm every 150 .... 200 mm.

It was found that in order to obtain high-quality profiles, it is necessary and sufficient to use only one caliber, the first draft stand, to cover the lower roll with the flanges, and take the total number of forming stands to be three with the maximum value of the bending angle ( ^o pass) of 20 ^° .

The use of a softer profiling scheme (0 ^o ---> 15 ^o ---> 32 ^o ---> 44 ^o ---> 46 ^o ) in some cases led to a decrease in the final angle between the shelves of the corners, which made them difficult the use in subsequent manufacture of arcuate elements for packaging rolls and caused cracks around individual cuts.

 The profiling of the corners was also carried out using the technology selected as the closest analogue (see above). In this case, cuts in the middle of the width of the initial billet were made in the first stand, closed (like the next two) by the flanges of the lower rolls, and the total number of stands was six. To ensure the free passage of cuts through all calibers, their lower rolls had circular grooves in the middle of the length of the barrels, which complicated their manufacture. After profiling, up to 12% of the corners were deformed (partially wrinkled) notches, which did not allow to use them for their intended purpose.

 Thus, the experiments confirmed the acceptability of the proposed method for solving the problem and its advantages over the known technology.

 According to the data from the Complex of New Technologies CJSC of the Magnitogorsk Iron and Steel Works, the use of the proposed technical solution for the manufacture of bent grooved corners reduces the labor costs for their production by at least two times, by reducing the consumption of rolls and making their manufacture cheaper, and also increases the yield of profiles of the required quality, which increases the profit from their sale.

Concrete example
Equal-shelf corner 100 x 1.2 mm (width of shelves 100 mm, thickness 1.2 mm) from st. 3kp is profiled in three stands with bending angles (along the aisles) of 20, 40 and 46 ^o ; bending radii in all passes - 2 mm.

 In the fourth finishing stand, punching is carried out at the points of bending of the profile of arched notches with a height of 8 mm and a width of 10 mm every 158 mm of length, and bending of the corner shelves is not performed.

 The first mill stand, rough, is made with the closing of the caliber by the flanges of the lower roll.

Claims (1)

A method for profiling a cut-through corner, including sequentially bending its shelves and forming bending places between them in the rough, intermediate and finishing passes, limiting the lateral displacement of the formed strip, as well as punching the notches, characterized in that the said restriction is carried out in the rough pass, and the bending angles are the passages are taken equal to 20, 40 and 46 ^o , respectively, while the notches are punched with a given shape and size at the bend of the profile in the finishing passage with a constant angle between its bent floors kami.