SU1169774A1 - Method of manufacturing formed sections with portions of double thickness - Google Patents

Abstract

THE METHOD OF MANUFACTURING OF PUMPED PROFILES WITH ELEMENTS OF DOUBLE THICKNESSES, AIR PIECES APPLICATIONS WITH CENTRAL CIRCUITS AND WITH AN ENVELOPE LAYER, FRIED CURVES, MULTI-TRANSFORMABLE BENDING IN ROLLS, INCLUDING A BETWEEN CURVE WITH SEQUENCED ONE-ROUND BY A MULTI-TRANSFORMABLE BENDING IN ROLLS, INCLUDING A BETWEEN CURVE, BEARING WITH A SINGLE CURVE, BEARING MULTI-TRANSFORMABLE BENDING IN ROLLS, INCLUDING A BETWEEN CURVE WITH SPACIOUSING ONE ROLLS the double thickness element of the bulge from the envelope layer, characterized in that, in order to increase the quality of the profiles, by improving the density of contact between the layers double thickness, at the first transitions, the extreme parts of the blank are given a curved cross-sectional shape to form an envelope layer, and the alignment of the layers is carried out simultaneously with the beginning of the formation of the double-S element of thickness due to the curvature of the envelope to the convexity of the element, while increasing the curvature of the envelope layer, at the same time, the envelope layer is bent to a greater extent than the envelope, by an amount equal to the curvature of the envelope layer at the precursor of the transition.

Description

 si The invention relates to the processing of metals by pressure, in particular to the production of curved rolled sections with double thickness elements from coiled or strip blanks in rolls of a roll forming mill, and can be used in metallurgy, mechanical engineering and other areas of the metalworking industry,. The purpose of the invention is to improve the quality of curved profiles with double thickness elements, mainly with a semicircular cross section, due to the improved density of contact between the corrugation layers. FIG. 1 shows a flat element of double thickness; in fig. 2 - bent at an angle a / element of double thickness and force, acting in the implementation of such bending in the rolls; in fig. 3 - stratification of a curvilinear element of double thickness; in fig. 4 shows a cross-sectional shape of the workpiece with separated curvilinear envelopes and flat envelopes of the moldable member; in fig. 5 - curvilinear element of double thickness with combined envelope and envelope layers; in fig. 6, - transitions of forming the element by thickness thickness according to the proposed method. In FIG. 1-6 - the following notation is accepted: 1 - place of bend through 180 °; 2 - section of the envelope layer of the element of double thickness; 3 - edge; 4 - section of the envelope layer of the element of double thickness. In accordance with the theory of plastic bending, in the process of bending in the rollers of a double thickness element at an angle d of the contact surface undergo deformations of different signs: the surface relative to the bending layer is compressed; the contact surface of the envelope layer is stretched. As a result, stresses arise on the contact surfaces, the effects of which are manifested in the mutual slippage of the contact surfaces and the work of friction forces on the path (thickness of the blank). This work will interfere with the shaping, reducing the given value of the hem angle oL by a certain angle f. The external manifestation of this is the formation of a gap along the edge, determined by the angle of under-shaping H ci - -, and stratification of the curvilinear element of double thickness. According to the proposed method, it is advisable to make the production of curved profiles with double thickness elements by means of a multi-transition bending of a flat initial piece, during which first At the first technological transitions, the extreme areas of the workpiece are bent, giving them a curved cross-sectional shape, until the edges of these areas touch the non-deformed ovannoy part blank. Then the flat parts of the workpiece, conjugated with curved sections by the bending method, are combined with the latter by bending in the direction of the convexity of the element, at the same time increasing the curvature of these curved sections. As a result, a billet with curvilinear elements of double thickness, in which the envelope and curvature of the layers are conjugated at the place of bending by 180 °, is obtained. At the subsequent transitions, increasing the curvature of elements of double thickness, these elements of the required shape and size are obtained. The proposed method can be implemented in rolls of a roll forming mill having at least 12 working stands, each of which has a pair of calibrated rolls, in calibrations of which a rolled or strip metal billet is subsequently formalized to obtain a profile of the required configuration. The designs of such roll forming mills are well known. So, when the most simple flat bent profile with a semicircular element of double thickness along the edges is manufactured on the pilot mill (the sweep width of the element is 100 mm, the thickness of the original billet is 3 mm, the profile material is Stz steel, the inside radius of the element is 31 mm) the billet rolls of the first stand are assigned to a profile mill (Fig. 6, pos. I). In the rolls of the subsequent stands (Fig. 6, pos. TS-U ||), on the workpiece, the edge sections are bent, giving them a curved cross-sectional shape, and they are bent in succession until they come into contact with the flat part of the workpiece. 4 (the same in Fig. 6, pos.USH). The curvilinearity of the folded portion is determined by the bending radius Rjj 4.5 - 18 li- (the particular selected value was .5,143 mm), which corresponds to 3.14 - А 160-175 (the bend angle 180 2 mm corresponded to the value 180 - . -y- 160 °). This interval of hem angles is limited on the one hand (angle 175 °) by the condition for plastic (and not elastic) bending of the circumflex layer 2, on the other (angle 160 by the condition of unimpeded entry of the resulting profile shape into the subsequent roll gauge. The second limitation is determined by bending angle / 3 and associated deflection h. At the same time, the straightness of the bend 3 and the curvature of the envelope of the 2 layers of the element should be considered when entering the profile into this gauge, their alignment and bending at an angle -ft of the bend t at an angle greater than the envelope layer and this elevation is equal to the angle ft, at which the envelope layer is preliminarily bent when entering this gauge Based on the maximum bending angle used in practice when forming elements and Vie exceeding usually 60 per pass and the nominal value of the angle of bending over the passage of 20%, the angle of the preliminary bending of the envelope layer should not exceed 40, which corresponds to the selected limiting value of the angle of inclination of the envelope layer to the envelope equal to 160. The one shown in FIG. 5, the profile form is obtained from the form shown in FIG. 4, by bending the circumscribed layer to the side of the element’s curvature along the radius R and simultaneously increasing the curvature from R to R of the curving layer while bending it in the same angle transition (fl - / 3). Thus, the combination of the layers of the element into a single element of double thickness is carried out while simultaneously increasing its curvature. On subsequent transitions, this curvature is increased to obtain an element with the required geometrical parameters (Fig. 6, pos. X-XI). As shown by the data obtained. in the manufacture of the above profile with a double thickness element along the edges as a result of using the proposed method, the clearance in the edge zone was reduced from 3-3.5 to 0.20, 25 mm, i.e. an almost gapless connection of two thicknesses was obtained over the entire contact surface. The invention, in comparison with the known method, allows significantly (from 3-3.5 to 0.2-0.25 mm) to reduce the gap in the edge zone of a double-thickness element, which provides almost no shameful connection between the thickness of the element; In addition, there is no need to use additional onepaivffl seam roller welding for tightly connecting two thicknesses of the element, which simplifies and cheapens the production of such profiles, eliminates the welding operations that adversely affect the environment from the production process; From the multi-transition technological process, bending in the rolls eliminates the transition, in which, using known methods, a flat element of double thickness is formed, as a result of which the metal is saved and the weight of the set of work rolls is reduced. The proposed method of making double-cut corrugated profiles allows mastering the production of a new type of curved profiles with double-thickness elements.

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Claims (1)

METHOD FOR MANUFACTURING BENT PROFILES WITH DOUBLE THICKNESS ELEMENTS, mainly with a semicircular cross-sectional shape and with an envelope layer located on the convex side by multi-transitional bending in rolls, including preparation of workpieces with separated one-thickness envelopes from them and the envelope envelopes from them and element double thickness convexity from the envelope layer, characterized in that, in order to improve the quality of the profiles, by improving the density · contact of the layers of the element double thickness, at the first transitions, the cross sections are curved to the extreme sections of the workpiece, forming an envelope layer, and the layers are combined simultaneously with the beginning of forming a double thickness element by bending the envelope layer towards the convexity of the element while increasing the curvature of the envelope layer, while the layer is bent to a greater extent than the envelope, by an amount equal to the curvature of the envelope layer at the previous transition. > 1169774.