RU2492015C1 - Method of making frames - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly, to making the frames from rolled sections and tee-beams welded from separate sheets. Bending is carried out at the die by consecutive pressures between which workpiece is displaced to allow maximum tolerable wall necking nearby bending radius. Constraint is applied over the workpiece wall length between die supports while over wall height it is applied from workpiece center of gravity to wall free edge. Note here that said constraint depends on bending force.

EFFECT: higher quality.

3 cl, 2 dwg, 1 tbl

Description

The invention relates to the processing of metals by pressure, and in particular to methods of manufacturing frames from rolled sections, as well as from T-beams obtained by welding from individual sheet elements.

Known are traditional methods of forming parts of frames from profiled steel and welded T-beams using transverse elastoplastic bending on presses (see Kuklin OS, Shabarshin VP Means of technological equipment for case-processing workshops. Part I. L., Central Research Institute "Rumb" , 1985, Part II. L., Central Research Institute "Rumb", 1989). With these bending and straightening methods, a bending force is applied in the direction of greatest stiffness of the profile in the direction of its walls. For this shaping, high forces are required up to 15,000 kN (1,500 tf), while significant inflections at the ends of the profile up to 3-4 profile heights may remain. With a significant loss of profile, the walls lose their stability, which reduces the quality and bending capabilities. To eliminate this drawback, special constraining devices are used (see O. Kuklin. Improving the manufacture of bent parts of the ship's hull. "Shipbuilding", 1980, No. 1; Moshnin EN. Bending and editing on rotary machines. "Mechanical Engineering", 1967 .); A.S. No. 740342, patents No. 1503930, 1542660, 1563806, No. 2336135, etc.

Closest to the claimed technical solution is a method of bending steel profiles according to Europatent (EP No. 0093685), which is taken as the closest analogue. In this method, to reduce the loss of stability of the profile wall, bending forces are applied acting in a direction parallel to the profile wall and compressive forces acting in a direction perpendicular to its shelves. In this case, fixed supports are used, located on both sides of the movable heads of the press, moving perpendicular to the profile, and bending and compressive forces are applied only to the shelf defining the external radius of the bending of the profile, and thus cause only compressive forces in the profile wall. Due to this, the loss of profile stability is reduced.

The disadvantage of this method is the very high values of bending forces, which contribute to the occurrence of stresses tending to tear the shelf off the wall both when applying forces and when removing them due to different degrees of springing of the shelf and wall, which increases the capital, material and energy consumption of bending processes profiles with limited length and height of bending profiles.

The objective of the present invention is the expansion of the use of cold bending in the manufacture of frames using wall tightness for a variety of sizes of profiles on universal bending equipment using deforming equipment.

Using the present invention will provide a technical result, which consists in increasing resource saving in the processes of forming (bending and straightening) frames from profiles and welded T-beams by increasing the utilization rate of sheet metal from which the stiffening ribs are cut.

The specified technical result is achieved as follows.

In the proposed method for the manufacture of frames, bending is carried out in the stamp by successive pressing between which the workpiece is moved and with the greatest allowable thinning of the wall at the external bending radius, while constraint is applied along the length of the workpiece wall - between the supports of the stamp, and along the height of the wall - from the center of gravity of the workpiece section to the free edge of the wall, and the wall tightening force is chosen equal to P _CT = P (0.13 ÷ 0.30) ≈ 0.25P, where P is the bending force.

In the particular case of the proposed method, the distance between the supports is taken to be five heights of the workpiece, and the step of pressing is selected in the range of one or two of its heights.

In another particular case of the proposed method, the bending force at the end of each pressing is removed at a minimum speed in accordance with the capabilities of the used bending equipment.

In the third particular case of the proposed method for billets with a wall height of more than 300 mm, bending is performed with bending of the end of the billet in two passes. In this case, the first pressing is carried out in the position of the workpiece extended beyond the support of the stamp by an amount equal to 1-2 steps of pressing, and the bending of the end of the workpiece in the first pass is carried out by more than half the specified radius, moving the workpiece in the direction opposite to the main movement, and in the second pass - to the specified radius of the part. Then, from the bends made, bending is continued along the main movement to half the length of the workpiece, after which they are transferred to the other end of the workpiece and similar bending is performed from the other end in the opposite direction to the end of bending in its middle part.

Compared with the known solutions, it is flexible on presses, including the closest analogue, in the proposed method, constraining forces are applied to the wall of the workpiece profile or welded beam over the entire area between the bending supports and from the free edge of the wall to the center of gravity of the cross section, the distance between the supports is taken equal to five heights, which is optimal for the profile hire used in shipbuilding, the start of bending is carried out in the position of the workpiece, extended beyond the support of the stamp by an amount equal to 1-2 steps of pressing, and for the workpiece to with a wall height of more than 300 mm, the end section is bent in two stages, moving the workpiece in the direction opposite to the main movement, while in the first pass, bending is performed by more than half the specified radius, and in the second pass, by the specified part radius, step and the sequence of clicks on the bent workpiece is selected in the optimal range of 1-2 of its height.

The invention is illustrated by the following schemes:

Figure 1 - sequence of bending of the workpiece along its length.

Figure 2 - diagram of the application of efforts.

Figure 1 shows a diagram of the flexible billet of the frame, consisting of a wall 1 with a wall height of more than 300 mm and a shelf 2 with the end section 4 extended beyond the support 3. In this case, the bending of the end of the workpiece is performed in two passes: on the first pass, P ₁ is bent on value is more than half a predetermined radius, and then moving the workpiece in a direction opposite to the main movements, operate the second pressure P _2, then the second pass - by a predetermined radius bends parts then produced by bending bends continue R ₃ toward the middle portion of otovki to half its length F _k. After moving to the other end of the workpiece 5, a similar bend P _n +1, P _n +2, P _n +3 is performed from the other end in the opposite direction until the end of bending in its middle part. The tightness zone of the wall is indicated by 6. The constraint of the wall 6 is chosen equal to PCT = P (0.13 ± 0.30) ≈ 0.25P, where P is the bending force, and constraint is applied along the length of the workpiece wall between the die supports, and in height wall of figure 2 - from the center of gravity of the cross section of the workpiece to the free edge of the wall. The distance between the supports is taken equal to l≈5h, where h is the height of the profile, and the step of applying the force P is t = (1 ÷ 2) h.

Compared with the known methods of bending profiles, the proposed method can be used for bending profiles with a wall inward and wall outward, which expands the scope of its application.

и $$\perp \frac{18\times 185}{31\times 90}$$

в производственных условиях ОАО «Адмиралтейские верфи» применительно к шпангоутам основных заказов предприятия. Получены положительные результаты без какого-либо заметного повреждения сварных швов, выполняемых даже без обычных усилений.As an example of using the proposed method, the bending of welded T-beams made of high-strength steels with cross-sectional dimensions was tested $$\perp \frac{\mathrm{one}2\times \mathrm{one}50}{2\mathrm{one}\times 60}$$

and $$\perp \frac{\mathrm{one}8\times \mathrm{one}85}{3\mathrm{one}\times 90}$$

in the production conditions of Admiralty Shipyards, as applied to the frames of the main orders of the enterprise. Positive results were obtained without any noticeable damage to the welds, performed even without the usual reinforcements.

The application of the proposed method allows to reduce the cost of manufacturing one meter of a frame from a welded beam by 2.4 times compared with the methods of cutting a curved wall from a sheet, welding it with a bent shelf and subsequent bending in a stamp with tightness of the wall, which follows from the calculation of technical and economic efficiency process, the results of which are given in the table.

Table The cost of materials in the manufacture of 1 m frame Name Curved welded tee with carved wall Straight welded brand followed by bending Material utilization 0.531 0.9 Metal consumption 1 m of beam, t 0.128 0,052 The cost of 1 ton of metal, rubles. 15,000 15,000 The cost of the metal necessary for the manufacture of 1 m of beam, rub. 1920 780

At the same time, the capital intensity of the process was also significantly reduced due to the use of the flexible bending presses for bending profiles instead of purchasing expensive specialized bending machines (up to € 1.5 million per unit), as well as eliminating the heat treatment of curved profiles and blanks.

Another example is the bending of "heavy profiles" Nos. 1968 and 1979 with a wall height of 615 mm at OJSC "PO" Sevmash "at the SKMZ-TVCh installation and the NZTSG machine. At the same time, bending at the SKMZ-TVCh installation was carried out using high-frequency currents, and at the NZTSG machine, it was done in the cold one with tightness of the wall. In this case, the bending of the end sections of the profile on the NZTSG machine was carried out according to the claimed method in two stages, satisfactory results were obtained on the quality of bending, due to which the process energy consumption was reduced by 1.5 times.

Claims (3)

1. A method of manufacturing a frame, including bending a T-shaped workpiece in the plane of the wall with its constriction in the axial direction to the bending plane, characterized in that the bending is carried out in the stamp by successive pressing between which the workpiece is moved, with the greatest allowable thinning of the wall at the external bending radius , while constraint is applied along the length of the wall of the workpiece - between the supports of the stamp, and along the height of the wall - from the center of gravity of the cross section of the workpiece to the free edge of the wall, while the force of tightness of the wall is chosen t equal to P _article = P (0,13-0,30), where P is the bending force. 2. The method according to claim 1, characterized in that the distance between the supports is taken to be five heights of the workpiece, and the step of pressing is selected in the range of one or two of its heights. 3. The method according to claim 1, characterized in that the bending force at the end of each pressing is removed at a minimum speed in accordance with the capabilities of the equipment used.

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