RU2056188C1 - Method of making special bent non-symmetrical sections - Google Patents

Abstract

FIELD: metal pressure forming. SUBSTANCE: method comprises steps of applying a bending effort to flat members of a section upon multitransition bending of members of the section in rolls, applying to remaining portions bending moments, balancing the bending moments and shape changing moments, being created at bending up of the flat members of different width by different angles, by applying at least in one technological transition a cross compressing effort to one member of the section; applying the cross compressing effort to a terminal bent portion of a flange normally relative to its end surface, and holding a flat portion of the flange, including the terminal bent member, in a formation plane over all technological transitions. EFFECT: enhanced quality of special non-symmetrical bent sections. 1 cl, 4 dwg, 2 tbl

Description

 The invention relates to pressure machining of sheet material using rolls of a special shape and is intended for use mainly in ferrous metallurgy, as well as in transport, tractor and agricultural machinery and shipbuilding.

 A known method of manufacturing asymmetric bent profiles (ed. St. N 654085, class B 21 D 5/06, publ. 09/15/83), according to which, in order to ensure high-quality molding of profiles due to the increased accuracy of their geometric dimensions, in each rough technological at the same time, the shelves of the profile are bent in opposite directions by angles that ensure equal horizontal displacements of the edges of the shelves; ayut profile relative to the top wall of the bending space for greater shelf accumbens, in the finishing process of forming the transitions return wall molding profile plane, and then doformovyvayut profile to a predetermined configuration.

 A significant drawback of this analogue is the obtaining in some cases of low quality profiles due to the lack of mutual balancing of the form-changing moments of all profile elements for all technological forming transitions.

 There is also a known method of manufacturing bent zeta profiles (Chekmareva A.P. and Kaluzhsky V.B. Bent profiles for hire. M. Metallurgy, 1974, p. 121. Fig. 65, c) according to which, in order to improve the quality of bent zeta profiles due to reducing their helical twisting relative to the longitudinal axis during multi-jib bending of flat profile elements in the rolls in the first transitions form an unequal corner, then both bending points are formed, while bending the wall in the opposite direction, the wall bending intensively it than the shelves, and in the last passages only the wall is bent.

 The main disadvantage of the second analogue (as well as the first one) is the obtaining in some cases of low quality profiles due to helical twisting that goes beyond the permissible limits due to the lack of mutual balancing of the form-changing moments applied to all flat elements of the formed strip in all technological forming transitions. Concrete mode recommendations are needed.

 The closest in technical essence to the invention is the method of manufacturing asymmetric trough profiles with one shelf, selected as a prototype, according to which, in order to improve the quality of bent profiles by reducing their helical twisting relative to the longitudinal axis, with multi-junction of one of the walls and multi-junction of the rest flat elements in the rolls simultaneously form all three places of bending with the axis of profiling in the center of the middle place of bending, and the smaller section The stripes were bent more intensively.

 The disadvantage of the prototype and analogues is that in the manufacture of special bent asymmetric profiles of the zeta type, in which the extreme part of one shelf is bent along an arc of a circle in the direction coinciding with the direction of the bending of the shelves of the profile, in some cases they receive low quality profiles due to their helical twisting out of range.

 To obtain profiles with helical twisting within the permissible limits, it is necessary to apply a transverse compressive force to the extreme curved part of the profile flange perpendicular to its end, based on the condition of mutual balancing of the total (along the cross-section of the formable strip) shaping moments for all technological forming transitions.

So, for example, the profiling mode in the manufacture of a special bent asymmetric profile of 81 x 44 x 30 x 4 mm zeta type of low-alloy steel 09Г2 (with the widths of flat and reamers of curved elements b ₀ 44.0 mm, b ₁ 46.0 mm, b ₂ 26.0 mm, b ₃ b ₅ 17.0 mm, b ₄ 18.0 mm, inner radius of the bending places r 9.0 mm, inner radius of the curved part of the shelf R 26.0 mm, end angles of bending of the places of bending α _to = β _to ^about 90, the end bent portion bending angle δ _{to the} shelves ^90, the initial preform S 4 mm thickness and width of the metal blank in the initial _zag 167.9 mm) defined th method according to the prototype is shown in Table. 1, where α is _the final bending angle of the bending profile, located between the wall and the shelf having a curved part;
β _{to the} final bending angle of the second bending profile;
δ _{to the} final bending angle of the curved part of the profile shelf;
b ₀ the sweep width of the curved part of the profile shelf,
b _{1 is the} width of the flat part of the profile shelf having a curved part,
b _{2 the} width of the other profile shelf,
b ₃ , b _{5 the} widths of the reamers of the bending points of the profile with finite bending angles, respectively, α _k , β _k ,
b _{4 the} width of the profile wall.

 The profile was formed in a continuous manner on a roll forming mill 1.4 x x50.300.

 Due to the lack of information on the number of technological transitions and the values of the bending angles of the bending places in all technological transitions (except the last) in the manufacture of the profile according to the prototype method, they were determined by expert estimates and taken equal to the values of the corresponding parameters in the manufacture of the trough profile prototype method with one shelf 50 x 50 x x17 x 43 x 3 mm.

 In the first technological defining transition, the initial workpiece is moved along the roll forming mill.

In the second forming process twelfth passages formed by the profile wall profile multijunction rotation until reaching the last twelfth molds transition finite rotation angle γ ^about 57 _to multi-hop and other flat hem profile elements. The bending angles of the bending places and the bent part of the flange in the last twelfth technological molding transition were equal to the final bending angles of the bending places α _к = β _to 90 ^о and the curved part of the flange δ _to 90 ^о .

To obtain a finished special bent asymmetric profile of 81 x 44 x x 30 x 4 mm zeta type according to the prototype method, 12 technological transitions were required. The helical twisting of the finished profile was 2 ^about -2 ^about 30 'per 1 m of length, which goes beyond the requirements of GOST 8281-80 Cold-bent steel. Channel bars are unequal. Assortment '' (permissible helical twisting of 1 ^about 1 m length).

 The technical task is to improve the quality of special bent asymmetric profiles of the zeta profile by reducing their helical twisting relative to the longitudinal axis.

 This is achieved by the fact that during multi-jib bending of profile elements in rolls, when bending forces are applied to flat profile elements and bending moments are applied to other elements, and these bending moments and shape-changing moments are balanced when bending flat elements of different widths to different angles by applying in at least one of the technological forming transitions of the transverse compressive force to one of the profile elements, the transverse compressive force is applied to the extreme curved part profile shelves, to which the extreme curved element belongs, are kept in the molding plane in all technological forming transitions.

 To ensure helical twisting of the finished profile within acceptable values, it is necessary and sufficient that the system of total (cross-sectional) shape-changing moments applied to the forming strip in all technological transitions be balanced, which ensures an increase in the quality of the profiles by reducing their helical twisting relative to the longitudinal axis.

In order to apply a transverse compressive force P _t to the extreme curved part of the profile flange perpendicular to its end, it is necessary and sufficient when designing the technology to provide for closing gauges and the presence of restrictive collars of the upper rolls from the side on which the curved part of the flange is formed.

 The analysis of the method of manufacturing special bent asymmetric profiles of the zeta type, in which the extreme part of one shelf is bent along an arc of a circle in the direction coinciding with the direction of the folding of the profile shelves, indicates that the method is industrially applicable and a positive effect when implementing the invention will be obtained by balancing the total cross sections of the moldable strip) of the forming moments applied to the moldable strip in all technological forming transitions, by a system of transverse compressive forces applied to the bent portion of the shelf at the profile perpendicular to its end.

Figure 1 shows a diagram of the molding of a special bent asymmetric profile of a zeta type, in which the extreme part of one shelf is curved along an arc of a circle in the direction coinciding with the direction of folding of the shelves of the profile, according to the claimed method; figure 2 is a cross section of a finished special bent asymmetric profile of a zeta type, in which the extreme part of one shelf is curved along an arc of a circle in the direction coinciding with the direction of folding of the shelves of the profile; figure 3 auxiliary scheme for determining the angle of rotation for the passage Δγ _{t, 1} of the profile wall when forming only one bending point with a finite bending angle α _to in the t-th technological forming transition; in Fig. 4, an auxiliary circuit for determining the angle of rotation for the passage Δγ _{t, 2} of the profile wall when forming only one bending point with a final bending angle β _k in the t-th technological molding transition.

 In the manufacture of special bent asymmetric profiles of the zeta type, in which the extreme part of one shelf is bent along an arc of a circle in the direction coinciding with the direction of the folding of the profile shelves, according to the claimed method by multi-transition folding of the profile elements in the rolls when the folding forces are applied to the flat elements, and to the remaining elements are bending moments, and balance these bending moments and shape-changing moments that occur when bending flat elements of different widths to different angles , by applying at least one of the technological forming transitions of the transverse compressive force to one of the profile elements, the transverse compressive force is applied to the extreme curved part of the profile flange perpendicular to its end, and the flat part of the profile flange, which belongs to the extreme curved element, in all technological forming transitions withstand in the plane of molding.

 In the master technological transition I, the blank of profile 1 is moved along the mill.

In the technological forming transitions II, III, IV, V, the curved part of the shelf 2 and the bending points of the profile 3 and 4 are simultaneously formed. In all technological forming transitions II, III, IV, V, the flat part of the shelf 5 is held in the molding plane. In the process of forming the transitions II, III, IV bent portion flange 2 is bent at an angle δ _t until the last mold transition V final bending angle δ _k. The place of bend 3 in the technological forming transitions II, III, IV is bent at an angle α _t . bending the wall 6 until the final bending angle α _{k is} reached in the last technological forming transition V. The place of bend 4 in the technological forming transitions II, III, IV is bent at an angle β _t , bending the shelf 7, until the final bending angle β _{k is} reached in the last technological forming transition V. In at least one intermediate technological forming transition III, a transverse compressive force P _{t is} applied to the end face 8 of the curved part of the shelf 2.

In order to apply a transverse compressive force P _t to the extreme curved part of the profile flange perpendicular to its end, it is necessary and sufficient when designing the technology to provide for closing gauges and the presence of restrictive collars of the upper rolls from the side on which the curved part of the flange is formed. The value of the transverse compressive force P _t is determined when setting up the mill.

 This method can be carried out using a device containing a set of rolls for the manufacture of special bent asymmetric profiles of the zeta type, in which the extreme part of one shelf is curved along an arc of a circle in the direction coinciding with the direction of folding of the profile shelves.

For example, the profiling mode in the manufacture of a special bent asymmetric profile of 81 x 44 x 30 x 4 mm zeta type of low-alloy steel O9G2 (with the widths of flat and reamers of curved elements b ₀ 44.0 mm, b ₁ 46.0 mm, b ₂ 26.0 mm, b ₃ b ₅ 17.0 mm, b ₄ 18.0 mm, inner radius of the bending places r 9.0 mm, inner radius of the curved part of the shelf R 26.0 mm, end angles of bending of the places of bending α _to = β _to 90 ^about , the final bending angle of the curved part of the shelf δ _to 90 ^about , the metal thickness of the original billet S 4 mm and the width of the original billet B _zag 167.9 mm), determined according to the method shown in the table. 2.

 The profile was formed in a continuous way on a roll forming mill 1.4 x x 50.300.

In the first master technological transition I, the blank of profile 1 was moved along the mill. In the second ninth technological forming transitions II, III, IV, V, the curved part of the flange 2 and the bending points of the profile 3 and 4 were simultaneously molded. In the second ninth technological forming transitions II, III, IV, V, the flat part of the flange 5 was held in the molding plane MM. In the second eighth technological forming transitions II, III, IV, the curved part of the shelf 2 was bent at an angle δ _t until the final ninth technological forming transition V reached the final bending angle δ _to 90 ^about . The place of bend 3 in the second eighth technological forming transitions II, III, IV was bent at an angle α _t , bending the wall 6, until the final ninth technological forming transition V reached the final bending angle α _to 90 ^about . The place of bend 4 in the second eighth technological forming transitions II, III, IV was bent at an angle β _t , bending the shelf 7, until the final ninth technological forming transition V reached the final bending angle β _to 90 ^about . In the fifth seventh technological forming transitions III applied transverse compressive forces P _t to the end 8 of the curved part of the shelf 2.

To obtain a ready-made special bent asymmetric profile of 81 x 44 x x 30 x 4 mm zeta type, in which the extreme part of one shelf is bent along an arc of a circle in the direction coinciding with the direction of folding of the profile shelves from low-alloy steel 0972, according to the claimed method, 9 technological transitions. Helical twisting of the finished profile was ^about 0 ^o 0 20'-50 'and 1 m length, which is within the requirements of GOST 8281-80 "cold-formed steel. Channel bars unequally. Range" (permissible helical twisting ^about 1 per 1 m length).

According to the test data on the roll forming mill 1.4 x 50.300, the manufacturing method allows, in comparison with the prototype:
to improve the quality of special bent asymmetric profiles of the zeta type, in which the extreme part of one shelf is bent along an arc of a circle in the direction coinciding with the direction of the bending of the shelves of the profile, by reducing their helical twisting relative to the longitudinal axis (for example, in the manufacture of a bent profile 81 x 44 x 30 x 4 mm of the described type according to the claimed method, helical twisting relative to the longitudinal axis was 0 ^about 20'-0 ^o 50 'per 1 m of length, in the manufacture of the prototype method 2 ^about -2 ^about 30' per 1 m of length);
expand the assortment of complex asymmetric bent profiles (due to profiles whose production has not been mastered earlier due to technological difficulties);
reduce mill downtime by reducing the time to adjust and adjust the mill by 10-15% (due to a decrease in the number of technological transitions);
reduce the number of technological transitions by 10-20% (for example, in the manufacture of a special profile of 81 x 44 x 30 x x 4 mm of the described type, 9 technological transitions were required by this method, and 12 by the prototype method).

 The method does not adversely affect the state of the environment.

 The economic effect will be obtained by improving the quality of special bent asymmetric profiles of the zeta type, in which the extreme part of one shelf is bent along an arc of a circle in the direction coinciding with the direction of the bending of the profile shelves, expanding the assortment of the produced profiles, reducing the number of technological transitions and downtimes of the roll forming mill due to reduce time for adjustment and adjustment.

Claims (1)

 METHOD FOR PRODUCING SPECIAL BENDED ASYMMETRIC PROFILES of the zeta type, in which the extreme part of one shelf is curved along an arc of a circle in the direction coinciding with the direction of the folding of the profile shelves, by multi-jib folding of the profile elements in the rolls, according to which the folding forces are applied to the flat elements a - bending moments and balance these bending moments and shape-changing moments that occur when bending flat elements of different widths to different angles, by application in at least one of the technological forming transitions of the transverse compressive force to one of the profile elements, characterized in that the transverse compressive force is applied to the extreme curved part of the profile flange perpendicularly to its end, and the flat part of the profile flange to which the extreme curved element belongs all technological forming transitions are kept in the molding plane.

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