SU837466A1 - Method of producing closed cross section and semiclosed cross section shaped parts - Google Patents

Description

t

The invention relates to the processing of metals by pressure, specifically to the field of the production of profiles of closed and semi-closed sections, and is intended for use in the production of such profiles on section bending units.

The difference in the shape of the lower and upper curvilinear elements (places of bend) of closed and semi-closed profiles, when they are formed by multi-transition bending from a flat billet in rolls of roll forming units, does not allow obtaining the same radius of curvature for these elements.

The closest to the invention to the technical essence is a method of producing closed and G-shaped profiles, according to which, with the multi-transition bending of strip material in the mill rolls during one technological process, two methods of forming curvilinear elements are successively used: in the first stage with internal fixation zones of places of a bend (a stage of constrained are flexible), on the second - without fixing of an internal and external zones of places of a bend by a roll Gstadi free are flexible) 1. At the same time one of the workers (forming) rolls has contact with the inner surface of at least one place of bending of the molded profile; in the second stage, the work rolls do not have contact with either the outer or the inner surface of the places of the bend. To reduce the radii of curvilinear elements in the second stage, the profile is compressed in rolls.

The disadvantage of the prototype is the impossibility of precisely fulfilling curved profile elements at the free flexible stage. For example, in the manufacture of a closed profile of 230x100x8 mm according to the existing method, the curvilinear elements at the shelves and walls of the finished profile have outer radii of 18 and 26 mm, respectively, with the required radius of these elements of 22 mm. Thus, the deviation from the nominal is about t 19%.

These disadvantages are explained as follows. At the stage of free bending rolls, they have contacts only with flat profile elements along their outer contour, and, therefore, do not limit the movement of metal of curvilinear profile elements into corner cavities of the caliber rolls. With an increase in profile compression in the rolls, the curvilinear elements, under the influence of compression, bend to a smaller radius and, as it were, are pressed into the free space of the angular cavities of the caliber. In this case, all curvilinear elements are deformed approximately to the same degree. Consequently, their radii of curvature decrease to the same extent, therefore, after the end of the reduction, the previously existing difference in the values of the radii of curvature of the places of bending remains on the finished profile.

Thus, the use of profile reduction in rolls at the free-bending stage with the methods described provides a reduction in the radii of curvilinear elements, but does not eliminate the differences in their size. This defect remains on the finished profile, leading to a decrease in its quality and a decrease in the carrying capacity (the resistance moment decreases).

The aim of the invention is to improve the quality of the profiles. For this purpose, simultaneously with the compression of the linear sections at the transitions of the free bending, the curvilinear Elements are crimped.

FIG. given a closed profile before compression in the rolls; in fig. 2 semi-closed profile, before compression in rolls; on fig.Z- closed profile at the final moment of reduction in rolls according to the existing method; figure 4 - semi-closed profile at the final moment Compress the rolls according to the existing method; in Fig.5 a closed profile at the final moment of reduction in rolls according to the proposed method; figure 6 - semi-closed profile at the final moment of reduction in the rolls on the proposed method.

When making profiles of closed or semi-closed sections by multi-transition bending of strip metal in rolls of a roll-forming mill, it is advisable in the process of free bending of curvilinear profile elements in the last transition to attach to these curvilinear elements and adjacent flat elements of force distributed along the outer contour of these elements.

Practically, the proposed method, for example, for the production of a closed profile of 230x100x8 mm, is implemented as follows.

The forming of a strip (sheet) metal profile is carried out in 14 working cells of a roll forming unit of the type 2-8x100-600.

Molding mode or numerical value of gradual hem angles

elements of the profile of transitions (cells) are given in the table.

The mode of forming a closed profile .230x100y.

10 24 38 46 46 46 46 52 57 66 74 81 89 90

20 34 48 56 63 71 79 87 90 90

.

The sequence of actions in the manufacture of the 230x100x8 mm profile is as follows.

The profile flange in three transitions (stands 1-3) is folded over by a total angle P) 38. A wall (side) profile in these transitions is not formed. In the fourth transition, the flange is hemmed to p walls per dL 6 °. In transitions i 5-7, the shelf is not folded, and the wall is folded to the angle ai 48 within the same limits. Starting from transition 8 until the end of the process, the shelves and walls are simultaneously bending.

The constrained bending, i.e., with the fixation of the inner zone of the places of bending by the work roll, in this case is carried out: shelves - in transitions 1-4, walls - in transitions 4-7. Free bending (without fixing the places of bending with a roll) is carried out in transitions. The transition 8, in which the bending of the shelves is carried out without fixing the places of bending with the roller, and the walls with fixing, is an intermediate (transitional) stage between the constrained and free bending stages.

Gauges, stands 13-14 are constructively made with concave areas on work rolls covering the bend points. The radius of curvature of these sections is equal to 22 mm, which

provides application to curvilinear elements and adjacent flat elements of forces distributed over the entire outer contour of these elements.

At that moment, when the moldable profile (its front end) enters the caliber of stand 33, it has a cross section formula as indicated in FIG. The mill stops and adjusts this stand by settling (lowering) the upper roll until the rolls come into contact with the profile throughout the outer contour, i.e. before the pressing force is distributed around the outer perimeter of the flat and curvilinear elements (Fig. 5). stand 14 adjustment. The further process with continuous (or single-piece) profiling is carried out with the adjustment obtained.

Thus, the proposed method allows;

- to increase the accuracy of curvilinear elements and the whole profile of closed and semi-closed sections; - to increase by 3-5% the carrying capacity of such profiles without changing their weight characteristics;

- produce products that are certified to be of the highest quality category.

Claims (1)

1. Production and use 5 curved rolled profiles. Reference to. Ed. I.S. Trishchevsky. M., Metallurgists; 1975, p. 203-216. FIG L FIG. 2 niUllllli + TTHfttn j / jj CHSJJAI /  ifffffffffiK fflffftfllf fui.B