SU1140851A1 - Method of manufacturing bent sections - Google Patents

Abstract

A METHOD FOR MAKING PUSHED PROFILES containing small width areas, preferably less than six billet thicknesses, enclosed between two bending places, by means of 9/1 through the bending transitions in rolls of profile elements, characterized in that, in order to improve the quality of the profiles by ensuring accuracy and geometrical dimensions, on the last transitions, the sections of the profile that are placed between two places of bending are subjected to alternating bending simultaneously with the hem of the extreme elements, while the curvature of the first the deflection is chosen to be of the opposite sign with respect to the curvature of adjacent bending points, and the amount of deflection in each transition is determined from the dependence f-4.-lo, .t). g (ll-K -SinJl2n, where P and p are the radii of curvature along the middle layer of the bend points adjacent to the deflected flat area in the pressure transition; S is the thickness of the workpiece; the current distance X is neither from the middle of the deflected flat element to the point for which se the amount of deflection is determined; b the width of alternating deflections of a flat element in transitions, 5, 5, respectively, the yield, strength and strength of the workpiece material, the total number of transitions from n 4., the number of alternations, the number of transitions in which there is a program value f, including the first passage, wherein the first deflection is carried out,

Description

- The invention relates to the processing of metals by pressure, in particular, to methods for producing bent sheet profiles in rolls of a roll forming mill. A known method of manufacturing curved sheet profiles by successively bending in rolls of profile elements in transitions, containing flat elements placed between two bend points, in which deflection profile elements are deflected. 1 The disadvantage of the known method is that the deflection of the walls outwards during the manufacture of profiles with a width the horizontal wall bd S will lead to an unrecoverable defect - obtaining a non-planar horizontal wall,. The purpose of the invention is to improve the quality of the profiles by ensuring the accuracy of the geometric dimensions. The goal is achieved by the fact that the method of manufacturing curved sheet profiles containing flat areas of small width, preferably less than six billet thicknesses, enclosed between two places of bending, by successively bending in rolls of profile elements, on the last transitions of the profile placed between two places of bending, alternating bending simultaneously with the hem of the extreme elements, while the curvature of the first deflection is chosen to be opposite to the curvature adjacent bending places, and bending were rank in each passage was determined from the dependence). where P and J) are the radii of curvature along the middle layer of the bend points adjacent to the deflected flat area in this transition; S is the thickness of the workpiece; X is the current value of the distance NIN from the middle of the deflection of a flat element at the point for which the amount of deflection is determined; b is the width of alternating deflections of the flat element along transitions; 5 and dg are respectively the limits of strength and yield strength of the material of the workpiece, n is the total number of transitions with the alternating deflection K is the number of the transition in which the deflection is the value of f, considering the first transition in which the first deflection is made. Fig, 1 shows a molding scheme. a profile with the implementation of alternating deflections of a flat element in the last three transitions; in fig. 2 diagrams of changes in alternating bending along the width (b) of a planar element and along transitions. According to the proposed method of making curved profiles, the following sequence of its implementation is expedient. In accordance with the profile configuration, a molding scheme is developed and the hem angles of the elements along transitions are established. The shape and size of the profile and its elements are determined by transitions. The position of the rectilinear element 1, whose width is less than six thicknesses, enclosed between two bending points 2 and 3 is determined. The radii (p and f) of the middle layer of these bending points along transitions are determined. By the experimentally established formula, the number of alternating deflections is determined. R. + R. Where R and Rj are the internal radii on the 1-profile profile of the bend places, between which a flat element with a width of less than six masses is enclosed. Moreover, the fractional part of the first term of formula (2) is rounded to one. Assuming from the last transition, the number of n determines the transition of the first deflection f and the direction of curvature of this deflection. Yes, using formula (1), plot plots (f, ..., f,.,., F) of all alternating probes across the width (b) of the glossy element by transitions. Then, using the diagrams, calculations are made of the gauges of the rolls of the last transistors, in which the alternating signs should be carried out. The proposed method can be implemented on a profile bending mill having the appropriate technical characteristics for forming this profile. For example, when forming a special profile 75 to 60 X 60 X 6 mm of a header from St, 3, at a mill of 1-5 x 30-500, roll calibration is applied with bending of elements in nine cages according to the mode, degrees: 8, 6, 8; 18, 12, 18; 30, 20, 30; 45, 30, 45; 53, 35, 53; 63, 39, 63; 75, 43, 75, 83, 44, 83 and 90, 45, 90. The width of the flat element of the horizontal wall of this profile, enclosed between two bend points with internal radii R R 9 m, is 23 mm, i.e. less than 6-S 36 mm. Therefore, to ensure the straightness of the horizontal wall, its flat element was subjected to alternating deflections in the last passages, the number of which was determined by the formula (2): 3S 3-6 RR + The direction of the first deflection of the flat element of the horizontal wall in the seventh transition was selected inside profile, which corresponded to the opposite sign of its curvature relative to the curvature of adjacent bending points. The calculated radii on the middle layer of bending points adjacent to the horizontal wall are in these transitions, mm: 10.8; 9.4; 9.8; 9.2; 9 and 9. When the ratio; -L ...., H. B (for Art. 3) according to formula (1) were proi. .. four. . calculations were made and diagrams were constructed for alternating sign deflections along the wall width in these transitions. The maximum calculated values of the deflections (in the middle of the straight-line section) of the walls at the transitions were: -1.08 mm; +0.88 mm; 0.48 mm. As the measurements of the profiles of the pilot batch made by the proposed method showed, the controlled dimensions fully corresponded to TU 14-2-341-78 .. There was no deflection of the flat wall section. When using the proposed method, the occurrence of flatness in the form of deflections of non-deformable flat portions with a width of less than six thicknesses is prevented. In the manufacture of special profiles 75 X 60 X 60 X 6 mm according to the proposed method, the deflection of the rectilinear element of the horizontal wall is absent, and the width of this element on the finished profiles x is equal to the calculated (23 mm), and in the production according to a known method, the deflection of the horizontal wall is 1.7- 2.2 mm, the rectilinear element of the wall is absent - the curvature of the adjacent bending places passes (matches) into the curvature of the curved rectilinear element, which is a rejection sign. Comparative data show a significant improvement in the quality of the finished product when applying the proposed method, which reduces the laboriousness of using profiles in products by eliminating editing operations, reducing the consumption of metal and tools by expanding the range of iTbix profiles, such as flat elements less than six thicknesses that were not produced before the application of the proposed method.

1 iper move

2nd junction

3rd junction

th re; one

 transition

6 and transition

7th junction

8th junction

Home Profile / 2m npoiuf., 1st Prague

FIG. 3 deflection

Claims (2)

METHOD FOR MANUFACTURING BENT PROFILES containing flat sections of small width, mainly less than six thicknesses of the workpiece, enclosed between two bending points, by following the bending transitions in the rolls of the profile elements, characterized in that, in order to improve the quality of the profiles by ensuring their accuracy geometrical dimensions, at the last transitions, sections of the profile located between two places of bending are subjected to alternating bending simultaneously with bending of the extreme elements, while curvature of the deflection, the opposite sign is chosen with respect to the curvature of adjacent bending places, and the magnitude of the deflection in each transition is determined by 2p where and p are the radii of curvature along the middle layer of the bending points adjacent to the deflectable flat section in the given transition; workpiece thickness; the current value of the distance from the middle of the deflection of the flat element to the point for which the amount of deflection is determined; the width of the alternating deflections of the flat element for transitions, respectively the limits of the "yield strength and strength of the workpiece material," the total number of transitions with alternating deflection, the number of the transition in which the deflection is carried out by f, considering the first 'transition in which the first deflection is carried out.