SU603181A1 - Method of making bent box-like rolled profiles - Google Patents

Description

one

. The invention relates to the processing of metals by pressure, and more specifically to the field of the production of box-shaped curved profiles on roll forming units.

In the process of making curved box-shaped profiles of rolling in a number of cases, especially in the manufacture of profiles with relatively narrow walls, there is no quality molding of the bending points to the required radius of curvature, a loss of straight linear walls and their curvature occurs, the constancy of the gap between the edges due to metal spring and lateral curvature of flat areas.

Methods are known for the production of curved profiles, according to which the billet is successively changed into a finished profile in the rolls of mill IJ.

However, the use of these methods in a number of cases, for example, when forming profiles with relatively narrow walls (L | 5do 10-20, where b and 5 are the width and thickness of the wall) and small relative radii of curvature in places of bend R | 5 to 1- 1.5 does not allow to make profiles of the required quality and to ensure the straightness of the walls of their transverse deflection, a given curvature at the places of bending, and a stable gap between the closing floors.

The closest to the proposed method to the technical essence is a method in which, with the aim of qualitative forming of the places of bending with their curvature into minimum radii at the edges of cis shelves, c. In the profiling process, the side walls and the shelves are hemmed at the same time, and at the free bending stage, when the upper roller. does not contact with the inner surface of the bend points, the side walls of the profile bend outwards, and the deflection is chosen so that the deformation of the side walls from the deflection does not go beyond the limits of elastic deformations.

The disadvantage of this method is that the profile edges are crushed under the action of the roll elements, the loss of stability of the elements being bent, which does not allow to create the necessary efforts for the high-quality shaping of the bending places and giving them the required curvature.

Claims (2)

In a number of cases, especially for making profiles with relatively small overall dimensions b / 5-20, this method is unacceptable, since the deforming forces applied to bending the curvature of the bend and the wall, and the curvature of the bend is less than the required. The aim of the invention is to form high-quality bending places, prevent loss of stability of the straight sections of the profile and ensure a stable gap between the shelves. To this end, in the last transitions of forming the profile, it is compressed along the outer contour, straighten temporarily bent sections and simultaneously compress in the transverse the direction of the edge-guiding element of the roll, additionally twisted the places of bending and metal moving from them adjacent. recalculated land plots. When making a time profile, the initial plastic distortion of the rectilinear sections of the box-shaped profile and its compression along the outer contour in the caliber of the rolls in the last transitions allows to increase the bending moment at the bend points and to distort these areas to smaller ones. relative radii, at the same time warning of loss of stability - straight profile elements, the use of transverse compression of the formable profile (along the cross section contour) of the edge of the roll element by applying force to the interlocking flanges allows better shaping of the bend points for greater curvature and stabilization along the length the profile is the size of the gaps between the closing shelves by preventing the metal from curving the curved sections and distorting the shape of the cross section cheni profile At the same time, the cross compression created in combination with the displacement of 1 1 ggall to the places of bend from adjacent rectifiable areas ensures the bending of the places of bend to the minimum radii of curvature without thinning. Fig. 1 shows a scheme of technological transitions in the G-V / shaping of the box-shaped profile; Fig. 2 shows a diagram of the effect of the forming forces from the rolls on the profile with previously curved straight sections in the last transitions. A box-shaped profile is formed from flat workpiece 1 in rolls with an initial curvature (transitions I and of its straight sections; in the last transitions (V transition), the profile plastically compresses the outer contour in the caliber of the Vschkov and simultaneously compresses the edge roll element and temporarily curved flat areas are straightened, additionally bending the bend points and moving metal onto them from adjacent straightened areas. For example, in accordance with the proposed The manufacture of a box profile of 44x28x19x2 mm from steel StZ is produced in rolls of a roll-forming mill 2-6x50-500 with a forming speed of up to 3 m / s - in a hard bending mode (bending angles, per pass up to 45). At the same time, in the first four transitions from slabs with a cross-sectional size of 2x142 MMI shape the transition section of the profile by simultaneously bending the side walls, shelves and flanging, with the profile wall, side walls and the flanges being curved outward. In this case, the curvature of the transitions increases. Upon reaching the shape of the profile close to the end, it is plastically compressed, along the outer insulator in the wash caliber (transition v) by the forming forces PJ, p2 / Pi, the roll guide element (force P) is pressed in the transverse tangential direction and straightened temporarily curved flat plots. At the same time, the metal from adjacent straightened and transversely compressible areas during compression is mixed in months of bending. Temporal curvature of the straight profile sections at the first transitions, and then the simultaneous lateral compression of the profile by the edge-guiding element of the roll and compression along the outer contour allows to increase the bending moment at the places of the bend and to distort these areas to smaller radii. profile linear elements due to their preliminary bending and reduction of metal springback due to tangential compression of the places of bending. At the same time, when bending is molded by known methods, when sequential bending of profile sections by transitions is performed, it is not possible to create the required bending moment due to relatively rigid and narrow straight line sections of the profile and their curvature under the action of forces. rolls. At the same time, after the profile leaves the gauge, its shape is disturbed due to a considerable metal springback not only in the places of the bend, ba, but also in the rectilineated straight line sections. The use of lateral compression of the workpiece of the moldable profile by the edge-guiding roll element ensures the constancy of the width of the gap between the closing shelves. The application of the proposed method allows to improve the quality of box-shaped curved rolled profiles by reducing the minimum permissible radii of curvature at the bend points, ensuring the straightness of the shelves and profile walls, making the length of Eaz.ora stable between the closing edges of the shelves, reducing the shape distortion of the profile due to spring. metal, the claims of the method of manufacture of bent box-shaped rolled profiles, including the subsequent forming of the profile from a flat billet into a roll with a a con-guiding element and a temporary curvature of the rectilinear members of the profile, characterized in that, in order to qualitatively shape the bend places, prevent the loss of stability of the rectilinear sections of the profile and ensure a stable gap between the shelves, in the last transitions of forming the profile it is compressed by an external contour , straighten the temporarily bent sections and simultaneously compress in the transverse direction the edge-guiding element of the roll, additionally bend the bend points and cross the metal on them from adjacent rectifiable areas. Sources of information taken into account in the examination 1. I. Trishevsky and ftj “Production and use of curved rolled sections. Directory. M., Metallurgists, 1975, p. 203-216. 2. USSR Author's Certificate No. 294406, Cl, B 21 O 5/06, 1970, S