RU2564798C2 - Production of bent channel from sheet blank with longitudinal banding in truing and device to this end - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to bending-rolling of sheets and can be used for fabrication of aircraft engines from bent channels. Sheet blank passes through banding-rolling machine stands with upsetting of pre-bent walls and/or channel flanges at the last forming stand to produce a resilient swivel. Bending force is applied to said channel at inlet and outlet of said stand to produce preset lengthwise curvature of said channel. Note here that extra guide forces at channel flanges and walls at the exit of the last forming stand preserve the cross-section shape of the channel. Point of application of bending forces at exit of the last forming stand is changed to change the radius of lengthwise curvature of the channel. Note here that the last forming stand bending module and bending-rolling stand are shifted from said last stand in direction of lengthwise bending. Guide elements of bending module interact with channel wall surfaces located in lengthwise bending plane.

EFFECT: higher quality and efficiency.

3 cl, 3 dwg, 1 tbl

Description

The invention relates to pressure treatment of sheet material in a roller device and is intended for use in the manufacture of parts from bent profiles by bending.

Known methods and devices for bending profiles by methods of rotational-local deformation in rollers using contact compressive forces to increase ductility and reduce forces for longitudinal bending of the profile (RF patents N2259250, 2429928, etc.), however, there is a decrease in wall thickness, which unacceptable in the process of bending thin-walled bent profiles, especially with coatings.

The closest technical solution is the method and device described in US patent No. 7337642, in which the longitudinal bending of the profile is carried out in the process of profiling in a special bending device, placed after rolling stands profiling a bent profile. The bending device carries out a longitudinal bending of the profile, creating a bending moment by moving the rollers of the bending device relative to each other. For thin-walled bent profiles by this technology, multiple passage through a bending device is assumed to obtain small radii of longitudinal curvature, which leads to a downtime of the rolling mill stands. In addition, the longitudinal bending of the thin-walled profile in a bending device with moving rollers leads to loss of stability and distortion of the cross-sectional shape of the thin-walled profile.

The present invention is the provision of longitudinal bending of thin-walled bent profiles by combining the processes of profiling and longitudinal bending. The technical result that provides a solution to the problem is to increase the productivity and quality of longitudinal bending of thin-walled bent profiles by eliminating corrugation of the walls and shelves of the profile and distortion of the cross section of the profile.

The problem is solved as follows.

According to the proposed method, the longitudinal bending of a thin-walled bent profile is carried out in the process of passing a sheet billet through the stands of a profile bending machine with a draft of pre-bent walls and (or) shelves of the profile in the last forming stand and creating, when the rollers rotate in the deformation zone, a volumetric compressed-stress deformed state in the form of a plastic a hinge with a bending force applied to the profile in the last forming stand at the inlet and at the outlet to give the profile a predetermined longitudinal curvature with simultaneous additional guiding forces on the shelves and walls of the profile at the exit of the last forming stand to maintain the shape of the cross section of the profile.

If it is necessary to obtain longitudinal curvature of the profile with a variable radius, the place of application of bending forces at the exit from the last forming stand is changed to change the radius of the longitudinal curvature of the profile.

To implement the claimed method of longitudinal bending, a device is proposed, the prototype of which is selected roller bending and rolling line (see US patent No. 7337642).

The proposed device for longitudinally bending a thin-walled bent profile during profiling comprises sequentially installed bending rolls in which stepwise profiling of the cross section of a thin-walled bent profile with draft in the last forming stand is carried out, a bending module at the outlet of the last forming stand with guide elements interacting with walls and shelves of the profile, with the bending module and the rolling mill stand from which the profile moves last a forming stand, are offset from the latter in the direction of longitudinal bending, and the bending modulus guide elements interact with the surface profile of each wall arranged in the longitudinal plane of bending.

The essence of the proposed method for longitudinal bending of a thin-walled bent profile during profiling is illustrated by drawings on the example of profiling schemes and longitudinal bending of a Z-shaped bent profile of high-strength hard to deform aluminum alloy B 95och AM for aircraft frames:

figure 1 shows a longitudinal section of the profiling stands and bending module;

figure 2 is a cross section of the last forming stands;

figure 3 is a cross section of a bending module.

Thin-walled sheet stock, the width of which exceeds the profile sweep length by 2-8%, enters the sequentially installed bending and rolling stands. In each stand during rolling, the sheet blank is profiled with a roller tool, i.e. plastic bending is performed with the formation of a section of the profile. The final profile section is obtained in the last forming stand 2 (FIGS. 1 and 2), while profile 4 leaves the bending mill 1 with a height H1 greater than the height Hp of the finished profile 5 after the last forming stand 2. Created in the process of profiling the excess in height (Н1> Нп) and the initial margin along the profile sweep length make it possible to implement the constrained bending method in the last forming stand 2, in which, due to the precipitation of the profile shelves on Δh1 and Δh2 under tight conditions (see Fig. 2), a small morning radius bending points (up to 1.5 of the original slab thickness) using thin blanks of hard deformable materials. In the process of upsetting the pre-bent profile shelves by rotating rollers 6 and 7 (see Fig. 2), under constrained conditions, plastic flow of material occurs in the section of the profile with an increase of 5-10% of the wall thicknesses of the profile in the places of bending, in the last forming stand 2 in the focus deformation creates a volumetric compressed deformed state in the form of a plastic hinge, which leads to a displacement of the profile at the exit of the last forming stand 2 and the need for additional technological operations - editing (Markovce Shaping VA constrained to bend straightening rollers and thin bent sections / VL Markovtsev, VI Filimonov - Ufa:. UlSTU, 2006. S.25-32). This plastic hinge is proposed to be used for longitudinal bending of the profile during profiling during the manufacture of “stringer” or “frame” parts from thin-walled sheet blanks. To this end, it is proposed to create bending forces on the profile by shifting the bending mill 1 relative to the last forming stand 2 by Δun and the bending module 3 relative to the last forming stand 2 by Δur. In this case, the bending and rolling machine for the manufacture of bent profiles begins to function as a roll forming device in which both profiling and longitudinal bending of the profile are carried out. The last forming stand 2 simultaneously performs the role of the forming stand of the bending machine and the pressure roller of the roll forming device. The bending mill 1, from which the profile moves to the last forming stand 2, also participates in the shaping of the profile and acts as a load support roller of the roll forming device. And the bending module 3 is an unloading support roller of the roll forming device.

In the process of manufacturing a bent profile by tight bending, as well as with simultaneous upsetting and longitudinal bending, deforming forces arise in the profile at the exit from the last forming stand 2 in the profile, which can lead to distortion of the cross-sectional shape of the profile. To eliminate this phenomenon, the bending module 3 provides guide elements 8, 9, 10 and 11 (see figure 3), which provide additional guiding forces transmitted through the profile to the deformation zone in the last forming stand 2 and due to plastic deformation in the zone plastic hinge eliminates corrugation on shelves and profile walls.

The proposed method was implemented in LLC “Research Institute“ MITOM ”and OJSC“ Ulyanovsk NIAT ”, Ulyanovsk in the manufacture of Z-shaped aviation bent profiles from sheet blanks with a thickness of 1.5, 1.8 and 2 mm of aluminum alloys B 95, 1163 and In 1469 in freshly quenched and annealed conditions on a bending and rolling machine GPS 350M6 for frames and stringers of an airplane. Table 1 presents the result of pilot work on the longitudinal bending of Z-shaped profiles while maintaining the cross-section of the profile with an accuracy of ± 0.2 mm.

Table 1 Experimental data on the manufacture and longitudinal bending of aircraft profiles Profile section dimensions, mm Profile material Bend radius Minimum radius of longitudinal curvature Np height wall thickness 27 1,5 V95och 2.0 300 1.8 In 1469 3.0 350 63 1.8 1163AM 3.0 400 68 1,5 V95och1163AM 3.0 500 78 2.0 1163AM 6.0 600

Claims (3)

1. A method of manufacturing a bent profile from a sheet blank with its longitudinal flexible during profiling, including the sequential formation of the profile in the bending mill and obtaining its final shape of the walls and shelves by upsetting pre-bent walls and shelves of the profile by creating a rotation of the rollers in the deformation zone of the volumetric a compressed-stressed deformed state in the form of a plastic hinge and with simultaneous longitudinal flexible bending forces in the last molding stand to impart rofilyu predetermined longitudinal curvature, characterized in that the bending force for the longitudinal profile bending pose on the inlet of the latter molding crate and the output therefrom simultaneously with the application of additional forces on the guide wall and the flange profile in a plane buckling to maintain the shape of the cross-sectional profile. 2. The method according to 1, characterized in that they change the place of application of bending and guiding forces at the exit of the last molding stand to change the radius of the longitudinal curvature of the profile. 3. A device for manufacturing a bent profile from a sheet blank with longitudinal bending during its profiling, comprising sequentially installed bending rolls, in which the cross-sectional profiling of the bent profile with the draft in the last forming stand is carried out sequentially, a bending module at the exit from the last forming stand with guiding elements interacting with the walls and shelves of the profile, characterized in that the bending module and the rolling mill stand, from which the profile l moves to the last molding stand, located offset from the latter in the direction of longitudinal bending, and the guiding elements of the bending profile are configured to interact with the walls and shelves of the profile located in the plane of longitudinal bending.

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