RU2071848C1 - Method of making roll-formed different-flange angles - Google Patents

Abstract

FIELD: plastic metal working, namely, production of roll-formed different-flange angles in ferrous metallurgy, transport, tractor and agricultural machine engineering and ship-building. SUBSTANCE: object of the invention accomplished by arranging initial blank at guiding technological transition non-symmetrically relative to shaping axis in such a way that difference between distances of edges of initial blank from said axis is equal to width difference of shape flanges; at technological shaping transitions keeping apex of bending zone in shaping plane; bending up flanges of shape by angles inversely proportional to their width values until achieving at last technological shaping transition final angle value of smaller flange whose value is calculated according to given formula and finally shaping bending zone of shape. Cross compression effort and cross motion of shape are realized at prefinal and final technological shaping transitions. At prefinal technological shaping transition the above mentioned procedures are performed at side of convex edge of initial blank towards side of concave edge of said blank up to position in which projections of flanges with adjacent portions of bending zone until lengthwise plane, normal relative to shaping plane and passing through centers of bending zone, are determined by given expressions. At final technological shaping transition - at side of concave edge of initial blank towards side of convex edge of blank up to position in which projections of flanges with adjacent portions of bending zone are determined by other given expressions. EFFECT: enhanced quality of roll-formed difference-flange angles due to lowered helical torque and reduced width difference of flanges of shape made of crescent-like initial blank. 3 dwg, 3 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.

 In the production of bent sections of rolled products, a roll stock is used; according to the standards GOST 19903-74 "Hot-rolled sheet steel" and GOST 19904-74 "Cold-rolled sheet steel" the crescent shape of steel supplied in coils should not exceed 10 mm over a length of 3 meters. When forming high-quality bent unequal profiles from the sickle-shaped initial billet, defects may occur on the finished profile in the form of the width of the extreme flat elements and twisting relative to the longitudinal axis.

 A known method for the production of bent profiles of rolled products (see ed. St. USSR N374906, class B21D 5/06, 1981), according to which, in order to prevent distortion of the dimensions of the finished profile due to uneven deformation during bending, the original billet is extended in places the greatest longitudinal deformations by compression in the rolls of the master stand.

 The disadvantage of the first analogue is that its use in the manufacture of bent unequal corners from a sickle-shaped initial billet does not provide the proper quality of the profiles due to the excessively large widths of the profile shelves and its helical twisting that go beyond the permissible limits.

 Also known is a method of manufacturing unequal bent bent profiles (see article by I. Trishevsky and V. I. Miroshnichenko. Study of the process and development of a mode for profiling asymmetrical bent profiles. In the book "Theory and technology for the production of economical bent profiles". UkrNIImeta, issue 15, Kharkov: published by UkrNIImeta, 1970, p. 170), according to which, in order to prevent helical twisting of bent unequal corners, unequal shelves are bent by the total angles in the technological forming transitions, inversely proportional to their widths.

 The disadvantage of the second analogue is that in the manufacture of bent unequal corners from sickle-shaped initial blanks, low-quality profiles are obtained due to the different widths of the shelves and helical twisting of the profiles that are outside the permissible limits. To obtain profiles without these defects, it is necessary to apply transverse compressive forces to compensate for the shortcomings in the distribution of the material of the initial workpiece.

 Closest to the claimed method according to the technical essence is the method of manufacturing equal-length high-quality bent sections of rolled products selected as a prototype (see the article by V. Stukalov, V.P. Miroshnichenko, V.I. Dakhnovsky, E.S., The main causes of defects on bent profiles and measures for their In the collection "Bent profiles of hire. Kharkov: ed. UkrNIImeta, issue 8, 1980, p.109 112), according to which, in order to improve the quality of equal-shelf bent profiles by reducing the width of their shelves, in the process of preparing the strip to profile They use an inclined gauge composed of two conical rolls, which should ensure the elongation of the concave edge of the sickle-shaped initial workpiece with a subsequent decrease in the width of the shelves of the finished profile.

 A significant disadvantage of the prototype method is that its use reduces the shelf width of the finished profile to acceptable values only in the manufacture of bent profiles from the initial workpiece of small thickness (S≅2 mm) with a small specific crescent shape (g 1.1.5 mm / m) ; in all other cases, the positive effect of the application of the prototype method is completely insufficient. This disadvantage is due to the lack of due regard for the peculiarities of strip forming in the manufacture of a high-quality profile from a sickle-shaped initial blank.

 In addition, the disadvantage of the prototype method is that when forming bent unequal corners, low-quality profiles are obtained due to their helical twisting that goes beyond acceptable limits. To obtain profiles with helical twisting within acceptable limits, it is necessary to determine the profiling mode from the condition of mutual balancing of the total (over the cross-section of the formed strip) form-changing moments for all technological forming transitions.

So, for example, the profiling mode in the manufacture of a bent unequal angle of 50 • 34 • 3 mm (with the widths of flat elements and the sweep of the bend located between them b ₁ 44.0 mm, b ₂ 28.0 mm, b ₃ 6.6 mm, with a finite bending angle of the bending point A _z 90 ^o , a finite external radius of the bending place R _to 6.0 mm, the metal thickness of the initial billet S 3.0 mm, the width of the initial billet B _zag 78.6 mm), from the sickle-shaped initial billet with specific crescent g 3.5 mm / m with an interstand distance of l 1 m, determined according to the prototype method, are given in table 1.

 The profile was formed in a continuous manner on a 1.4 • 50 roll forming mill. 300 from a roll stock.

In the first and second preparatory technological transitions, the initial billet was turned in opposite directions by 10 ^o .

 In the third master technological transition, the initial billet was directed along the roll forming mill.

 In the fourth and eighth technological forming transitions, the profile shelves were bent in opposite directions. The values of the bending angle of the profile shelves were determined by the method of expert estimates.

To obtain the finished profile according to the prototype method, 8 technological transitions were required. The helical twisting of the finished profile was 1 ^o 20 '1 ^o 50' per 1 meter of length, which goes beyond the requirements of GOST 19772-74 "Steel bent unequal corners. Assortment" (permissible helical twisting of 1 ^o per 1 meter of length). The maximum deviations of the width of the shelves of the finished profile amounted to ± 2.0 mm when manufacturing it from a sickle-shaped initial workpiece with a specific crescent of g 3.5 mm / m, which goes beyond the requirements of the above GOST (permissible maximum deviations of the width of the shelf not more than ± 1.0 mm for shelves up to 50 mm wide with continuous profiling).

 The aim of the invention is to improve the quality of bent unequal corners by reducing their helical twisting and raznosirinennost shelves profiles.

и отформовки места изгиба профиля, прикладывание поперечного сжимающего усилия и поперечное перемещение профиля осуществляют в предпоследнем и последнем технологических формующих переходах: в первом из них со стороны выпуклой кромки исходной заготовки в сторону ее вогнутой кромки до положения, при котором проекции полок профиля с прилежащими частями места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, определяются выражениями: для большей полки профиля

для меньшей полки профиля

а во втором из них со стороны вогнутой кромки исходной заготовки в сторону ее выпуклой кромки до положения, при котором проекции полок профиля с прилежащими частями места изгиба определяются выражениями:
для большей полки

для меньшей полки

где: n номер последнего технологического формующего перехода;
b₁ и b₂ ширины соответственно большей и меньшей полок профиля;
a_x,n и a_x,n-1 проекции большей полки профиля с прилежащей частью места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, на плоскость формовки соответственно в последнем и предпоследнем технологических формующих переходах;
a_y,n и a_y,n-1 проекции большей полки профиля с прилежащей частью места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, на нормаль к плоскости формовки соответственно в последнем и предпоследнем технологических формующих переходах;
b_x,n и b_x,n-1 проекции меньшей полки профиля с прилегающей частью места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, на плоскость формовки соответственно в последнем и предпоследнем технологических формующих переходах;
b_y,n и b_y,n-1 проекции меньшей полки профиля с прилежащей частью места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, на нормаль к плоскости формовки соответственно в последнем и предпоследнем технологических формующих переходах;
β_n и β_n-1- углы подгибки меньшей полки соответственно в последнем и предпоследнем технологических формующих переходах;
R_n-1 наружный радиус места изгиба профиля в предпоследнем технологическом формующем переходе;
R_к наружный радиус места изгиба на готовом профиле;
S толщина металла исходной заготовки.The claimed objective is achieved by the fact that in the manufacture of profiles from sickle-shaped blanks having convex and concave edges, by sequentially bending the bends in the rolls of the shelves of the profile of different widths to different angles in opposite directions, transversely moving the profile simultaneously with its molding in two intermediate technological forming transitions under the influence of a transverse compressive force applied to the end of the profile shelf from the side of the convex edge of the initial workpiece in the first of these transitions and with the sides of the concave edge in the subsequent, in the defining technological transition, the initial workpiece is positioned asymmetrically relative to the molding axis, and the difference in the distances of the edges of the original workpiece from the molding axis is equal to the difference in the width of the profile shelves, in the technological forming transitions the top of the bending point is held in the molding plane, the profile shelves are bent at the corners , inversely proportional to their widths, until the final bending angle reaches the final bending angle of a smaller profile shelf, the value of orogo calculated as follows:

and molding the bending of the profile, applying transverse compressive forces and lateral movement of the profile is carried out in the penultimate and last technological forming transitions: in the first of them from the convex edge of the original workpiece towards its concave edge to the position at which the projection of the profile shelves with adjacent parts of the place bending to the longitudinal plane, the normal molding plane and passing through the centers of the bending place, are determined by the expressions: for a larger profile shelf

for a smaller profile shelf

and in the second of them from the side of the concave edge of the original billet to the side of its convex edge to the position at which the projections of the profile shelves with adjacent parts of the bending point are determined by the expressions:
for a larger shelf

for a smaller shelf

where: n is the number of the last technological forming transition;
b ₁ and b ₂ widths respectively of the larger and smaller shelves of the profile;
a _{x, n} and a _{x, n-1} projections of a larger profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal plane of the molding and passing through the centers of the bend, onto the molding plane, respectively, in the last and penultimate technological molding transitions;
a _{y, n} and a _{y, n-1} projections of a larger profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal molding plane and passing through the centers of the bend, to the normal to the molding plane, respectively, in the last and penultimate technological forming transitions;
b _{x, n} and b _{x, n-1} projections of the smaller profile flange with the adjacent part of the bend to the longitudinal plane, the normal plane of the molding and passing through the centers of the bend, onto the molding plane, respectively, in the last and penultimate technological forming transitions;
b _{y, n} and b _{y, n-1} projections of a smaller profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal molding plane and passing through the centers of the bend, to the normal to the molding plane, respectively, in the last and penultimate technological forming transitions;
β _n and β _n-1 are the bending angles of the smaller flange, respectively, in the last and penultimate technological forming transitions;
R _{n-1 is the} outer radius of the bend of the profile in the penultimate technological forming transition;
R _{to the} outer radius of the bend on the finished profile;
S is the thickness of the metal of the original billet.

 The profiling mode of symmetrical bent profiles of rolled products is developed under the assumption of a symmetry of the distribution of the metal of the initial billet relative to its axis, which is combined with the axis of molding, all parameters of the stress-strain state of the metal of the strip being molded and kinetostatic conditions of molding, which is ensured by the equality of the bending angles of shelves of the same width; As a result, in the manufacture of a symmetrical high-quality profile from a high-quality initial workpiece, the wideness of the profile shelves and its helical twisting are practically absent.

In the manufacture of equal-bent bent profiles with a nominal width of shelves b from the initial workpiece with specific crescent g, the widths of the shelves of the finished profile turn out to be variable along the length of the profile and varying in magnitude, and the maximum deviations along the width of the shelves in most cases go beyond the permissible limits: in the cross section with the maximum the widths of the shelves with their widths are equal to the following values: B ₃ = b + gl, B ₄ = b-gl (l spacing). To obtain equal-quality high-quality bent profiles of proper quality from the sickle-shaped initial billets, it is necessary to ensure a symmetrical arrangement of the strip metal relative to the molding axis at least in the last technological forming transitions, which can be achieved by bending identical shelves at equal angles and transverse displacements of the formed strip in two technological forming transitions in opposite directions until a symmetrical arrangement of the moldable strip with respect to the axis of molding and CTBA shelves and their projections onto the plane of the molding and regulations thereto in the axial section of each of these transitions.

где: t номер промежуточного технологического формующего перехода;
M $\genfrac{}{}{0ex}{}{\text{(фс)}}{\text{t}}$ суммарный (по поперечному сечению полосы) формоизменяющий момент, приложенный к формуемой полосе в t-ом промежуточном технологическом формующем переходе;
Р_t поперечное сжимающее усилие, приложенное к полке в t-том промежуточном технологическом формующем переходе;
M $\genfrac{}{}{0ex}{}{\text{(Pt)}}{\text{t}}$ изгибающий момент поперечного сжимающего усилия, приложенный к формуемой полосе в t-том технологическом формующем переходе;
n количество технологических переходов.To ensure helical twisting of the finished bent unequal corner within the limits of acceptable values when manufacturing from a high-quality initial workpiece, it is necessary and sufficient that the system of total (along the strip cross sections) forming changes applied to the formed strip in all technological transitions is balanced, that is, so that equality was fulfilled

where: t is the number of the intermediate technological forming transition;
M $\genfrac{}{}{0ex}{}{\text{(fs)}}{\text{t}}$ the total (over the cross-section of the strip) form-changing moment applied to the moldable strip in the t-th intermediate technological forming transition;
P _t transverse compressive force applied to the shelf in the t-th intermediate technological forming transition;
M $\genfrac{}{}{0ex}{}{\text{(Pt)}}{\text{t}}$ a bending moment of the transverse compressive force applied to the moldable strip in the t-th technological molding transition;
n number of technological transitions.

где: M $\genfrac{}{}{0ex}{}{\text{(ф)}}{\text{t,δ}}$ формоизменяющий момент, необходимый для формоизменения большей полки профиля и его места изгиба на участке плавного перехода t-того промежуточного технологического формующего перехода;
M $\genfrac{}{}{0ex}{}{\text{(фс)}}{\text{t,м}}$ формоизменяющий момент, необходимый для формоизменения меньшей полки профиля и его места изгиба на участке плавного перехода t-того промежуточного технологического формующего перехода;
M $\genfrac{}{}{0ex}{}{\text{(фс)}}{\text{t}}$ суммарный (по поперечному сечению формуемой полосы) формоизменяющий момент, необходимый для формоизменения всех элементов профиля на участке плавного перехода t-того промежуточного технологического формующего перехода;
σ_т предел текучести материала исходной заготовки;
y модуль упругости второго рода материала исходной заготовки;
S толщина металла исходной заготовки;
l_t длина активной зоны участка плавного перехода места изгиба профиля в t-том промежуточном технологическом формующем переходе;
Δα_t и Δβ_t углы подгибки за проход соответственно большей и меньшей полок профиля в t-том промежуточном технологическом формующем переходе.When forming a profile bending point by bending adjacent profile shelves in opposite directions, the shaping moments necessary for shaping all strip elements in each t-th intermediate technological transition, as a first approximation, while holding the molded profile bending spot at a constant level in t- volume and (t-1) -th technological transitions are determined by the dependencies:

where: M $\genfrac{}{}{0ex}{}{\text{(f)}}{\text{t, δ}}$ the shaping moment necessary for shaping a larger profile shelf and its bending location in the smooth transition section of the t-th intermediate technological forming transition;
M $\genfrac{}{}{0ex}{}{\text{(fs)}}{\text{t, m}}$ the shaping moment necessary for shaping the smaller profile flange and its bending location in the smooth transition section of the t-th intermediate technological forming transition;
M $\genfrac{}{}{0ex}{}{\text{(fs)}}{\text{t}}$ the total (over the cross-section of the strip being formed) shape-changing moment necessary for the shape-changing of all profile elements in the smooth transition section of the t-th intermediate technological forming transition;
σ _{t the} yield strength of the material of the initial workpiece;
y is the elastic modulus of the second kind of material of the initial billet;
S is the thickness of the metal of the original billet;
l _{t the} length of the active zone of the smooth transition of the profile bending place in the t-th intermediate technological forming transition;
Δα _t and Δβ _t are the bending angles per pass, respectively, of the larger and smaller profile shelves in the t-th intermediate technological forming transition.

где α_k и β_k суммарные конечные углы подгибки соответственно большей и меньшей полок профиля.Summing the shape-changing moments M $\genfrac{}{}{0ex}{}{\text{(fs)}}{\text{t}}$ for all technological forming transitions, we obtain:

where α _k and β _{k are the} total final bending angles of the larger and smaller profile shelves, respectively.

При изготовлении гнутого неравнополочного уголка из качественной исходной заготовки поперечные сжимающие усилия Р_t во всех технологических переходах отсутствуют, а их моменты равны нулю:

Тогда из (6), (12) и (13) следует:

На основании экспериментальных исследований установлено, что вместо (14) необходимо принимать

Подставляя А_з 90^o в (15), получим:

При изготовлении гнутого неравнополочного уголка из качественной исходной заготовки проекции полок профиля с прилежащими частями места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, в предпоследнем технологическом формующем переходе определяются выражениями:
для большей полки профиля

для меньшей полки профиля

а в последнем технологическом формующем переходе выражениями:
для большей полки профиля

для меньшей полки профиля

Очевидно, что для получения качественного гнутого неравнополочного уголка из серповидной исходной заготовки необходимо в предпоследнем технологическом формующем переходе приложить поперечное сжимающее усилие Р_n-1 к кромке полки со стороны выпуклой кромки исходной заготовки и одновременно переместить полосу в поперечном направлении в сторону вогнутой кромки исходной заготовки до достижения в осевой плоскости технологического перехода положения полосы, характеризуемого проекциями полок на плоскость формовки и на нормаль к ней, величины которых соответствуют выражаниям (2) и (3), в последнем технологическом формующем переходе приложить поперечное сжимающее усилие Р_n к кромке полки со стороны вогнутой кромки исходной заготовки и одновременно переместить полосу в поперечном направлении в сторону выпуклой кромки исходной заготовки до достижения в осевой плоскости технологического перехода положения полосы, характеризуемого проекциями полок на плоскость формовки и на нормаль к ней, величины которых соответствуют выражениям (4) и (5), поскольку моменты поперечных сжимающих усилий Р_n-1 и Р_n примерно равны и направлены в противоположные стороны.Substituting
α _k = A _s -β _k (11)
in (10), we find:

In the manufacture of a bent unequal corner from a high-quality initial workpiece, there are no transverse compressive forces Р _t in all technological transitions, and their moments are equal to zero:

Then from (6), (12) and (13) it follows:

Based on experimental studies, it was found that instead of (14) it is necessary to take

Substituting A _z 90 ^o in (15), we obtain:

In the manufacture of a bent unequal corner from a high-quality initial workpiece, the projections of the profile shelves with adjacent parts of the bending point to the longitudinal plane, the normal molding plane and passing through the centers of the bending point in the penultimate technological forming transition are determined by the expressions:
for a larger profile shelf

for a smaller profile shelf

and in the last technological forming transition, the expressions:
for a larger profile shelf

for a smaller profile shelf

Obviously, to obtain a high-quality bent unequal angle from the sickle-shaped initial billet, it is necessary to apply a transverse compressive force P _n-1 to the edge of the shelf from the convex edge of the initial billet in the penultimate technological forming transition and at the same time move the strip in the transverse direction toward the concave edge of the initial billet the achievements in the axial plane of the technological transition of the strip position, characterized by the projections of the shelves on the molding plane and normal to it, led the terms of which correspond to expressions (2) and (3), in the last technological molding transition, apply a transverse compressive force P _n to the edge of the shelf from the side of the concave edge of the original workpiece and simultaneously move the strip in the transverse direction towards the convex edge of the original workpiece until it reaches the axial plane technological transition of the strip position, characterized by projections of the shelves on the molding plane and normal to it, the values of which correspond to expressions (4) and (5), since the moments of transverse compression boiling effort P _n-1 and P _n are approximately equal and oppositely directed.

 Thus, in the manufacture of a bent unequal corner from a sickle-shaped initial billet according to the claimed method, a stress-strain state of the metal is created in the strip that compensates for the defects in the shape of the initial billet, and the system of total (along the cross section of the strip being formed) forming changes applied to the strip being formed in all technological transitions, balanced, which, in turn, ensures the diversity of the bent unequal corner and its helical twisting within acceptable values and the achievement of the declared goal of improving the quality of bent unequal parts by reducing their helical twisting and raznoshirinnosti shelves profiles.

где: i номер технологического формующего перехода;
α_iи β_i суммарные углы подгибки соответственно большей и меньшей полок в i-том технологическом переходе.Considering the system of total (along the strip’s cross sections) shape-changing moments applied to the formed strip in the first i technological transitions, similarly to (10) we obtain:

where: i number of the technological forming transition;
α _i and β _{i are the} total bending angles of the larger and smaller shelves in the i-th technological transition, respectively.

From (16) it follows that the system of total (along the strip cross sections) shape-changing moments applied to the moldable strip in the first i technological forming transitions will be balanced when the shelves are bent by angles inversely proportional to the widths of the elements being bent (b ₁ α _i = b ₂ β _i ).
To ensure an asymmetric arrangement of the initial workpiece relative to the molding axis, and the difference in the distance of the edges of the initial workpiece from the molding axis is equal to the difference in the width of the profile shelves, it is necessary and sufficient to provide two pairs of vertical guide rollers installed in front of the first master technological transition in the tooling set.

 For bending the shelves of the profile to angles inversely proportional to their widths, until the final bending angle reaches the final bending angle of the smaller shelf of the profile, the value of which is calculated by formula (1), it is necessary and sufficient to provide the presence of conical elements with corresponding angles between the generatrices and the axis in a set of rolls for the manufacture of the profile.

 In order to maintain the apex of the bending point in the molding plane in the technological forming transitions, it is necessary and sufficient to ensure the constancy of the smallest diameter of the gauges in the set of rolls for manufacturing the profile.

 For applying transverse compressive force and lateral movement of the profile in the penultimate and last technological forming transitions and providing transverse movement of the profile in the same transitions to positions at which the projections of the profile shelves with adjacent parts of the bending point to the longitudinal plane, the normal molding plane and passing through the center of the place bending, determined by expressions (2) (5), it is necessary and sufficient to provide for the formation of the profile shelves in the conical rolls and closing the gauges of these transitions top roll. When forming a profile from a crescent-shaped initial preform in the penultimate technological forming transition, the edge of the strip from the side of the convex edge of the initial preform abuts against the limiting shoulder of the upper roll, resulting in a reactive transverse compressive force, under the influence of which the strip moves in the transverse direction toward the concave edge of the initial preform on the required distance, which ensures the position of the strip at which the projections of the shelves are determined according to (2) and (3). When forming a profile in the last technological forming transition, the edge of the strip abuts against the concave edge of the initial workpiece against the limiting shoulder of the upper roll, as a result of which there is a reactive transverse compressive force, under the influence of which the strip moves towards the convex edge of the original workpiece to the position of the strip, at which the projections of the shelves are determined according to (4) and (5).

The difference in the proportionality coefficient in formula (1) from 90 ^o is due to the absence of allowance for strain hardening of the metal of the profile bending point when calculating the shape-changing moments applied to the formed strip. The selection of this coefficient was carried out on the basis of the following considerations:
1) when the coefficient is less than 85.5 ^o , in some cases there is a helical twisting of the finished profile, the value of which is outside the permissible limits, in the direction from the larger shelf of the profile to its smaller shelf;
2) when the coefficient is greater than 94.5 ^o , in some cases there is a helical twisting of the finished profile, the value of which is outside the permissible limits, in the direction from the smaller shelf to its large shelf.

 The analysis of the proposed method for the manufacture of bent unequal corners indicates that the method is industrially applicable and a positive effect in the implementation of the invention will be obtained due to the mutual balancing of the total (along the cross section of the strip) form-changing moments applied to the formed strip in all technological transitions, and due to the combination of appropriate actions.

 The invention is illustrated by drawings.

In FIG. 1 shows a process flow diagram for forming a bent unequal corner according to the claimed method in the case where the convex edge of the initial billet is located on the side of the larger profile shelf;
figure 2 is a flow chart of the molding of a bent unequal corner according to the claimed method in the case where the convex edge of the original billet is located on the side of the smaller profile shelf;
figure 3 is a cross section of a finished bent unequal corner.

и отформовки места изгиба профиля, прикладывание поперечного сжимающего усилия и поперечное перемещение профиля осуществляют в предпоследнем и последнем технологических формующих переходах: в первом из них со стороны выпуклой кромки исходной заготовки в сторону ее вогнутой кромки до положения, при котором проекции полок профиля с прилежащими частями места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, определяются выражениями:
для большей полки профиля

для меньшей полки профиля

а втором из них со стороны вогнутой кромки исходной заготовки в сторону ее выпуклой кромки до положения, при котором проекции полок профиля с прилежащими частями места изгиба определяются выражениями:
для большей полки

для меньшей полки

где: n номер последнего технологического формующего перехода;
b₁ и b₂ ширина соответственно большей и меньшей полок профиля;
a_x,n и a_x,n-1 проекции большей полки профиля с прилежащей частью места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, на плоскость формовки соответственно в последнем и предпоследнем технологических формующих переходах;
a_y,n и a_y,n-1 проекции большей полки профиля с прилежащей частью места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, на нормаль к плоскости формовки соответственно в последнем и предпоследнем технологических формующих переходах;
b_x,n и b_x,n-1 проекции меньшей полки профиля с прилежащей частью места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, на плоскость формовки соответственно в последнем и предпоследнем технологических формующих переходах;
b_y,n и b_y,n-1 проекции меньшей полки профиля с прилежащей частью места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба, на нормаль к плоскости формовки соответственно в последнем и предпоследнем технологических формующих переходах;
β_k и β_n-1 углы подгибки меньшей полки соответственно в последнем и предпоследнем технологических формующих переходах;
R_n-1 наружный радиус места изгиба профиля в предпоследнем технологическом формующем переходе;
R_k наружный радиус места изгиба на готовом профиле;
S толщина металла исходной заготовки.In the manufacture of bent unequal corners according to the claimed method from sickle-shaped preforms having convex and concave edges, by successive bending transitions in rolls of shelves of a profile of different widths to different angles in opposite directions due to lateral movement of the profile simultaneously with its molding in two intermediate technological forming transitions under the influence of a transverse compressive force applied to the end of the profile shelf from the side of the convex edge of the initial workpiece in the first of these transitions and from the side of the concave edge in the subsequent, in the master technological transition, the initial workpiece is positioned asymmetrically with respect to the molding axis, and the difference in the distances of the edges of the original workpiece from the molding axis is equal to the difference in the width of the profile shelves, in the technological forming transitions the top of the bending point is held in the molding plane , the shelves of the profile are bent at angles inversely proportional to their widths, until the final bending angle is smaller in the last technological forming transition Profile ki, which value is calculated by the formula:

and molding the bending of the profile, applying transverse compressive forces and lateral movement of the profile is carried out in the penultimate and last technological forming transitions: in the first of them from the convex edge of the original workpiece towards its concave edge to the position at which the projection of the profile shelves with adjacent parts of the place bending to the longitudinal plane, the normal molding plane and passing through the centers of the bend, are determined by the expressions:
for a larger profile shelf

for a smaller profile shelf

and the second of them from the side of the concave edge of the original billet to the side of its convex edge to the position at which the projection of the profile shelves with adjacent parts of the bend are determined by the expressions:
for a larger shelf

for a smaller shelf

where: n is the number of the last technological forming transition;
b ₁ and b ₂ width respectively of the larger and smaller shelves of the profile;
a _{x, n} and a _{x, n-1} projections of a larger profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal plane of the molding and passing through the centers of the bend, onto the molding plane, respectively, in the last and penultimate technological molding transitions;
a _{y, n} and a _{y, n-1} projections of a larger profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal molding plane and passing through the centers of the bend, to the normal to the molding plane, respectively, in the last and penultimate technological forming transitions;
b _{x, n} and b _{x, n-1} projections of a smaller profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal plane of the molding and passing through the centers of the bend, onto the molding plane, respectively, in the last and penultimate technological molding transitions;
b _{y, n} and b _{y, n-1} projections of a smaller profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal plane of the molding and passing through the centers of the bend, normal to the molding plane, respectively, in the last and penultimate technological forming transitions;
β _k and β _n-1 are the bending angles of the smaller flange, respectively, in the last and penultimate technological forming transitions;
R _{n-1 is the} outer radius of the bend of the profile in the penultimate technological forming transition;
R _{k the} outer radius of the bend on the finished profile;
S is the thickness of the metal of the original billet.

There are two cases of the relative position of the larger profile flange and the convex edge of the initial blank:
1) the convex edge of the initial billet is located on the side of the larger profile shelf;
2) the convex edge of the initial preform is on the side of the smaller profile shelf.

 Consider the first case.

In the master technological transition Ia, the crescent-shaped initial blank 1 is positioned asymmetrically with respect to the axis of molding 2, and the difference in the distances B ₁ and B _{2 of the} edges 3 and 4 of the initial blank 1 from the axis of molding 2 is equal to the difference in widths b ₁ and b _{2 of the} shelves 5 and 6 of the profile. In the master process transition Ia, the sickle-shaped preform 1 is moved along the roll forming mill.

In the technological forming transitions IIa, IIIa, IVa, they simultaneously maintain the vertex 7 of the bend point 8 of the profile in the molding plane MM, bend the large shelf 5 of the profile in the direction of arrow B by the total angle α _i and the smaller shelf 6 in the opposite direction (along arrow B) by the total angle β _i before molding in the last technological forming transition of profile IVa and reaching the final bending angle β _{k of the} smaller profile shelf 6, the value of which is calculated by formula (1). In all technological forming transitions IIa, IIIa, IVa, the total bending angles α _i and β _{i of the} shelves 5 and 6 of the profile are inversely proportional to their widths (b ₁ α _i = b ₂ β _i ).
Simultaneously with forming the profile in the penultimate technological forming transition IIIa, a transverse compressive force P _{n-1 is} applied to the edge 9 of the larger shelf 5 and the strip is moved in the transverse direction toward the concave edge 4 of the original workpiece 1 to a position at which the projection a _{x, n-1} , a _{y, n-1} , b _{x, n-1} , b _{y, n-1 of} shelves 5 and 6 of the profile with adjacent parts of the bend 7 to the longitudinal plane 10, the normal molding plane MM and passing through the centers 11 of the bend 7, are determined according to (2) and (3).

Simultaneously with the molding of the profile in the last technological molding transition IV, and the edge 12 of the smaller flange 6, a transverse compressive force P _{n is} applied and the strip is moved in the transverse direction towards the convex edge 3 of the initial blank 1 to the position at which the projections a _{x, n} , a _{y, n} , b _{x, n} , b _{y, n} shelves 5 and 6 with adjacent parts of the bend 7 to the longitudinal plane 10, the normal plane of the molding MM and passing through the centers 11 of the bend 7 are determined according to (4) and (5) .

 Consider the second case.

In the master technological transition Ib, the crescent-shaped initial blank 1 is positioned asymmetrically with respect to the axis of molding 2, and the difference in the distances B ₁ and B _{2 of the} edges 3 and 4 of the initial blank 1 from the axis of molding 2 is equal to the difference in widths b ₁ and b _{2 of the} shelves 5 and 6 of the profile. In the master process transition Ib, the sickle-shaped preform 1 is moved along the roll forming mill.

In the technological forming transitions Ib, IIIb, IVb, they simultaneously maintain the vertex 7 of the bend point 8 of the profile in the molding plane MM, bend the large shelf 5 of the profile in the direction of arrow B by the total angle α _i and the smaller shelf 6 in the opposite direction (along arrow B) by the total angle β _i otformovki until the last mold IVb transition profile and achieve the final angle β _k hem flange at the profile 6, the value of which is calculated by the formula (1). In all technological forming transitions IIb, IIIb, IVb, the total bending angles α _i and β _{i of the} shelves 5 and 6 of the profile are inversely proportional to their widths (b ₁ α _i = b ₂ β _i ).
Simultaneously with forming the profile in the penultimate technological forming transition IIIb, a transverse compressive force P _{n-1 is} applied to the edge 12 of the smaller flange 6 and the strip is moved in the transverse direction towards the concave edge 4 of the original workpiece 1 to a position at which the projection a _{x, n-1} , a _{y, n-1} , b _{x, n-1} , b _{y, n-1 of} shelves 5 and 6 of the profile with adjacent parts of the bend 7 to the longitudinal plane 10, the normal molding plane MM and passing through the centers 11 of the bend 7, are determined according to (2) and (3).

Simultaneously with the molding of the profile in the last technological forming transition IVb, a transverse compressive force P _{n is} applied to the edge 9 of the larger shelf 5 and the strip is moved in the transverse direction towards the convex edge 3 of the initial blank 1 to the position at which the projections a _{x, n} , a _{y, n} , b _{x, n} , b _{b, n of} shelves 5 and 6 with adjacent parts of the bend 7 to the longitudinal plane 10, the normal plane of the molding MM and passing through the centers 11 of the bend 7, are determined according to (4) and (5).

 The inventive method can be carried out using a device containing a set of rolls for the manufacture of a bent unequal corner with at least two closed gauges.

So, for example, the mode of forming a bent unequal angle of 50 • 34 • 3 mm from 3SP low-carbon steel (with the widths of flat elements and the reamers of the bend located between them b ₁ 44.0 mm, b ₂ 28.0 mm, b ₃ 6.6 mm, with a final bending angle _of bending points a 90 ^o, finite outer radius bending points R _k 6,0 mm, metal thickness of the original blank S 3,0 mm, a width of the original blank B 78,6 mm) from the initial billet with crescent specific crescent of 3.5 mm / m with an interstand distance of 1 m, determined according to the claimed method, for the case when The sharp edge of the initial blank is located on the side of the larger profile shelf, is given in Table 2.

Приняли β_k= 55^°.
Затем по формулам (2) (5) были вычислены проекции полок профиля с прилежащими частями места изгиба до продольной плоскости, нормальной плоскости формовки и проходящей через центры места изгиба:

Профиль формовали непрерывным способом на профилегибочном стане 1.4•50. 300 из рулонной заготовки.Prior to profile forming, the number of the last technological forming transition and the total bending angles of the smaller flange in the last two technological forming transitions were determined: n = 5, β _n-1 = β ₄ = 41 ^° , β _k = 55 ^° .
By the formula (1), the value of the final bending angle of the smaller profile shelf was calculated:

We took β _k = 55 ^° .
Then, according to formulas (2) (5), the projections of the profile shelves with adjacent parts of the bend to the longitudinal plane, the normal molding plane and passing through the centers of the bend were calculated:

The profile was formed in a continuous manner on a 1.4 • 50 roll forming mill. 300 from a roll stock.

In the first technological master transition Ia, the crescent-shaped preform 1 was positioned asymmetrically relative to the axis of molding 2, and the difference in the distances B ₁ and B _{2 of the} edges 3 and 4 of the initial preform 1 from the axis of molding 2 is equal to the difference in widths b ₁ and b _{2 of} shelves 5 and 6 of the profile. In the master process transition Ia, the sickle-shaped preform 1 was moved along the roll forming mill.

In the second fifth technological forming transitions IIa, IIIa, IVa simultaneously maintained the vertex 7 of the bend of the profile 8 in the molding plane MM, fold the large shelf 5 of the profile in the direction of arrow B by the total angle α _t and the smaller shelf 6 in the opposite direction (in arrow B ) by the total angle β _t before molding in the fifth last technological forming transition of the IVa profile and reaching the final bending angle β _k 55 ^{o of the} smaller flange 6 of the profile, the value of which was calculated by the formula (1). In the second fifth technological forming transitions IIa, IIIa, IVa, the total bending angles α _t and β _{t of the} shelves 5 and 6 of the profile are inversely proportional to their widths (b ₁ α _t = b ₁ β _t ).

In the fourth penultimate technological forming transition IIIa, simultaneously with the profile formation, a transverse compressive force P _{4 of} 10 kN was applied to the edge 9 of the larger shelf 5 and the strip was moved in the transverse direction towards the concave edge 4 of the initial workpiece 1 to a position at which the projections a _{x, 4} 42 , 6 mm, a _{y, 4} 20.0 mm, b _{x, 4} 25.7 mm, b _{y, 4} 20.1 mm of shelves 5 and 6 of the profile with adjacent parts of the bending point 7 to the longitudinal plane 10, the normal molding plane MM and passing through the centers 11 of the bend 7, were determined according to (2) and (3).

In the fifth last technological forming transition IVa, simultaneously with the profile formation, a transverse compressive force P _{5 of} 8 kN was applied to the edge 12 of the smaller flange 6 and the strip was moved in the transverse direction towards the convex edge 3 of the initial blank 1 to a position at which the projection a _{x, 5} 39 , 5 mm, a _{y, 5} 26.3 mm, b _{x, 5} 20.4 mm, b _{y, 5} 25.5 mm of shelves 5 and 6 with adjacent parts of the bending point 7 to the longitudinal plane 10, the normal plane of the molding MM and passing through the centers 11 of the bend 7, were determined according to (4) and (5).

To obtain a finished profile according to the claimed method in the case when the convex edge of the initial billet is located on the side of the larger shelf, 5 technological transitions were required. The helical twisting of the finished profile was 0 ^o 20 '0 ^o 50' per 1 meter of length, which is within the requirements of GOST 19772-74 "Steel bent unequal corners. Assortment" (permissible helical twisting of 1 ^o per 1 meter of length). The maximum deviations of the width of the shelves of the finished profile amounted to ± 1.0 mm when manufacturing it from a sickle-shaped initial workpiece with a specific crescent g 3.5 mm / m, which is within the requirements of the above GOST (permissible maximum deviations of the width of the shelf not more than ± 1.0 mm for shelves up to 50 mm wide with continuous profiling).

And now we will consider the case when the convex edge of the initial workpiece is located on the side of the smaller profile shelf. So, for example, the profiling mode in the manufacture of a bent unequal angle of 50 • 34 • 3 mm from mild steel CT3sp (with the widths of flat elements and the sweep of the bend located between them b ₁ 44.0 mm, b ₂ 28.0 mm, b ₃ 6 , 6 mm, with a final bending angle of the bending point A _z 90 ^o , with a finite outer radius of the bending place A _z 6.0 mm, the thickness of the metal of the initial workpiece S 3.0 mm, the width of the initial workpiece B _zag 78.6 mm), crescent-shaped initial billet with specific crescent g 3.5 mm / m with an inter-stand distance l 1 m, determined according to the claimed CB method for the case where the convex edge of the original blank is the part of the shelf at the profile given in Table 3.

R
Приняли γ_к 55^o.Before the start of profile forming, the number of the last technological forming transition and the total bending angles of the smaller shelf in the last two technological forming transitions were determined:
n = 5, β _n-1 = β ₄ = 41 ^° , β _k = 55 ^° .
By the formula (1), the value of the final bending angle of the smaller profile shelf was calculated:

R
Took γ _to 55 ^o .

Профиль формовали непрерывным способом на профилегибочном стане 1.4•50. 300 из рулонной заготовки.Then, according to formula (2) (5), the projections of the profile shelves with adjacent parts of the bend to the longitudinal plane, the normal molding plane and passing through the centers of the bend were calculated:

The profile was formed in a continuous manner on a 1.4 • 50 roll forming mill. 300 from a roll stock.

In the first technological mastering transition Ib, the crescent-shaped initial blank 1 was positioned asymmetrically relative to the axis of molding 2, and the difference in the distances B ₁ and B _{2 of the} edges 3 and 4 of the initial blank 1 from the axis of molding 2 is equal to the difference in widths b ₁ and b _{2 of} shelves 5 and 6 of the profile. In the master technological transition Ib, the sickle-shaped preform 1 was moved along the roll forming mill.

In the second fifth technological forming transitions II b, IIIb, IVb, they simultaneously supported the vertex 7 of the bend of profile 8 in the molding plane MM, folded a large shelf 5 of the profile in the direction of arrow B by the total angle α _t and the smaller shelf 6 in the opposite direction (in the direction of the arrow C) the total angle β _t before molding in the fifth last technological forming transition of the IVa profile and reaching the final bending angle β _k 55 ^{o of the} smaller flange 6 of the profile, the value of which was calculated by the formula (1). In the second fifth technological forming transitions IIb, IIIb, IVb, the total bending angles α _t and β _{t of the} shelves 5 and 6 of the profile are inversely proportional to their widths (b ₁ α _t = b ₂ β _t ) ..

In the fourth penultimate technological forming transition IIIb, simultaneously with the profile formation, a transverse compressive force P ₄ 10 kN was applied to the edge 12 of the smaller flange 6 and the strip was moved in the transverse direction toward the concave edge 4 of the initial workpiece 1 to a position at which the projections a _{x, 4} 42 , 6 mm, a _{y, 4} 20.0 mm, b _{x, 4} 25.7 mm, b _{y, 4} 20.1 mm of shelves 5 and 6 of the profile with adjacent parts of the bending point 7 to the longitudinal plane 10, the normal molding plane MM and passing through the centers 11 of the bend 7, were determined according to (2) and (3).

In the fifth, last technological molding transition IVb, simultaneously with the molding of the profile, a transverse compressive force P _{5 of} 8 kN was applied to the edge 9 of the larger shelf 5 and the strip was moved in the transverse direction towards the convex edge 3 of the initial blank 1 to the position at which the projection a _{x, 5} 39.5 mm, a _{y, 5} 26.3 mm, b _{x, 5} 20.4 mm, b _{y, 5} 25.5 mm of shelves 5 and 6 with adjacent parts of the bend 7 to the longitudinal plane 10, the normal molding plane MM and passing through the centers 11 of the bend 7, were determined according to (4) and (5).

To obtain a finished profile according to the claimed method in the case when the convex edge of the initial billet is located on the side of the smaller shelf, 5 technological transitions were required. The helical twisting of the finished profile was 0 ^o 20 '0 ^o 50' per 1 meter of length, which is within the requirements of GOST 19772-74 "Steel bent unequal corners. Assortment" (permissible helical twisting of 1 ^o per 1 meter of length). The maximum deviations of the width of the shelves of the finished profile amounted to ± 1.0 mm when manufacturing it from a sickle-shaped initial workpiece with a specific crescent g 3.5 mm / m, which is within the requirements of the above GOST (permissible maximum deviations of the width of the shelf not more than ± 1.0 mm for shelves up to 50 mm wide with continuous profiling).

According to the experimental verification on the roll forming mill 1.4 • 50.300, the inventive manufacturing method allows, in comparison with the prototype:
a) to improve the quality of bent unequal corners by reducing their helical twisting and the width of the shelves (for example, in the manufacture of a bent unequal corner of 50 • 34 • 3 mm from 3SP mild steel according to the claimed method, screw twisting amounted to 0 ^o 20 '- 0 ^o 50' per meter lengths, marginal deviations of the width of the shelves amounted to ± 1.0 mm when manufacturing profiles from a sickle-shaped initial workpiece with a specific crescent g 3.5 mm / m, and in the manufacture according to the prototype method, helical twisting amounted to 1 ^o 20 '1 ^o 50' per 1 meter of length, the maximum deviations of the width of the shelves of the finished profile were ± 2.0 mm when manufacturing it from a sickle-shaped initial workpiece with a specific crescent shape of 3.5 mm / m);
b) to expand the assortment of complex asymmetric bent profiles by profiles, the production of which was not mastered earlier due to technological difficulties.

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

Claims (1)

A method of manufacturing bent unequal corners from sickle-shaped preforms having convex and concave edges, by successively bending transitions in rolls of profile shelves of different widths to different angles in opposite directions, including lateral movement of the profile simultaneously with its molding in two intermediate technological forming transitions under the influence of the transverse the compressive force applied to the end of the profile shelf from the side of the convex edge of the original workpiece in the first of these transitions and with on the side of the concave edge in the subsequent, characterized in that in the master technological transition, the initial workpiece is positioned asymmetrically with respect to the molding axis, and the difference in the distance of the edges of the original workpiece from the molding axis is equal to the difference in the width of the profile shelves, in the technological forming transitions the top of the bending point is held in the molding plane, profile shelves are bent at angles inversely proportional to their widths until the final bending angle is less than half in the last technological forming transition and profile, which value is calculated by the formula

and molding the bending of the profile, applying transverse compressive forces and lateral movement of the profile is carried out in the penultimate and last technological forming transitions: in the first of them from the convex edge of the original workpiece towards its concave edge to the position at which the projection of the profile shelves with adjacent parts of the place bending to the longitudinal plane, the normal molding plane and passing through the centers of the bend, are determined by the expressions
for a larger profile shelf

for a smaller profile shelf

and in the second of them, from the side of the concave edge of the initial billet to the side of its convex edge, to the position at which the projections of the profile shelves with adjacent parts of the bend are determined by the expressions
for a larger shelf

for a smaller shelf

where n is the number of the last technological forming transition;
b ₁ and b ₂ are the widths of the larger and smaller profile shelves, respectively;
a _{x, n} and a _{x, n-1} projections of a larger profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal plane of the molding and passing through the centers of the bend, onto the molding plane, respectively, in the last and penultimate technological molding transitions;
a _{y, n} and a _{y, n-1} projections of a larger profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal molding plane and passing through the centers of the bend, to the normal to the molding plane, respectively, in the last and penultimate technological forming transitions;
b _{x, n} and b _{x, n-1} projections of a smaller profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal plane of the molding and passing through the centers of the bend, onto the molding plane, respectively, in the last and penultimate technological forming transitions;
b _{y, n} and b _{y, n-1} projections of a smaller profile shelf with an adjacent portion of the bend to the longitudinal plane, the normal plane of the molding and passing through the centers of the bend, normal to the molding plane, respectively, in the last and penultimate technological forming transitions;
β _k and β _n-1 are the bending angles of the smaller flange, respectively, in the last and penultimate technological forming transitions;
R _{n-1 is the} outer radius of the bend of the profile in the penultimate technological forming transition;
R _{to the} outer radius of the bend on the finished profile;
S is the thickness of the metal of the original billet.

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