RU2113927C1 - High-rigidity bar manufacture method - Google Patents

Abstract

FIELD: plastic working of metals, in particular, manufacture of bent sheet billets with longitudinal repeated closed corrugations. SUBSTANCE: method involves measuring extent of falciform of strip along its datum length; forming corrugations by rolls arranged with predetermined roll space. When strips with falciform extent exceeding allowable value by Δ S mm are formed, corrugations of different height are made along strip width by skewing rolls in vertical plane for an angle of α determined by empiric dependence. Roll space on bent edge of billet is set to be equal to minimum thickness δ of billet and on opposed edge - equal to δ+Btgα, where δ is minimum thickness of billet, mm; B is space between edges, mm. EFFECT: wider operational capabilities and reduced metal usage by using billets with increased falciform extent. 2 dwg

Description

 The invention relates to rolling production and can be used in the manufacture of sheet profiles of high rigidity.

 High stiffness profiles (LSS) contain one or more closed longitudinal, periodically repeating longitudinal corrugations with a trapezoidal or circular cross-sectional width and are made of strip rolled steel. Corrugations are formed by local metal drawing using rolls of the corresponding design. The production technology of DRI is described, for example, in the book of S. Berezovsky. Production of bent profiles. - Metallurgy, 1985, p. 102-104.

 A known method of manufacturing corrugated sheets with closed corrugations (LIF), in which to eliminate defects such as twisting and local expansion when extruding corrugations, the workpiece is stretched in two mutually perpendicular directions (ed. St. USSR N 620308, class B 21 D 5/08 from 08/25/78). There is also a known method of manufacturing corrugated products with stiffness corrugations (LIF), in which a portion of the workpiece sections from the side of the outer side faces of the corrugations, comprising 0.2-0.5 of the width of each section, is subjected to compression by 0.2-2.0% more than the rest (ed. St. USSR N 713634, class B 21 D 5/06 from 08.02.80).

 A disadvantage of the known methods is the impossibility of producing with their help high-quality DRI from a strip billet with increased sickle shape (threaded curvature).

 Closest to the proposed is a method of manufacturing sheets with stiff corrugations according to ed. St. USSR N 965546, class B 21 D 5/06 dated 09.03.81, BI N 38, 1982.

 This method includes a preliminary measurement of the magnitude of the crescent shape of the strip and the formation of corrugations on it by rolls installed with a given roll gap, and is characterized in that when manufacturing profiles with trapezoidal corrugations, the inclined elements of the molded corrugations are also crimped simultaneously with the compression of flat sections. The disadvantage of this method is the impossibility of obtaining with its use high-quality DRI, molded from a workpiece with high sickle shape.

Since hot rolled coiled strip steel is used for the production of high rigidity profiles, the assortment of which is stipulated by GOST 19903, the magnitude of its crescent, according to paragraph 13 of the standard, should not exceed 10 mm at a base length of l _m = 3 m. Therefore, a mandatory operation in the production of DRI is a preliminary measurement of the magnitude of the crescent (S, mm) of the original workpiece.

 The technical task of the invention is to expand the technological capabilities of the process of production of DRI through the use of a strip billet with a sickle shape exceeding the permissible, which reduces the consumption of metal.

устанавливая межвалковый зазор на вогнутой кромке заготовки равным минимальной толщине профиля δ, а на противоположной кромке - равным δ+Btgα, где h - минимально-допустимая высота гофра, l_г - заданная его длина, b - расстояние между гофрами по ширине B профиля.To solve this problem, in a method of producing VZH with two closed longitudinal corrugations along the profile width from strips with a given crescent shape, including preliminary measurement of the crescent shape of a strip at a base length of l _m and the formation of corrugations on it with rolls installed with a given roll gap, when forming strips with the value of the crescent, exceeding the permissible by ΔS mm, form corrugations of different height along the width of the strip by distorting the rolls in the vertical plane at an angle

setting the roll gap on the concave edge of the workpiece equal to the minimum profile thickness δ, and on the opposite edge equal to δ + Btgα, where h is the minimum allowable height of the corrugation, l _g is its specified length, b is the distance between the corrugations along the width B of the profile.

 The mathematical dependence for determining the angle of skew angle α obtained in the processing of experimental data is empirical.

 The essence of the technical solution found is the shaping along the width of the crescent-shaped strip billet of corrugations of different heights, which reduces the rib curvature (crescent) of the finished sheet profiles.

 Obviously, with the same width and length of both corrugations, the higher of them will have a larger volume (the difference in the height of the corrugations should be within the permissible values). Since the curved (crescent) strip in the horizontal plane has different lengths of near-edge sections (the length is longer on the convex edge of the strip), on which the corrugations are formed, the corrugation, which has a larger volume and requires more metal to form, will take some of the "excess metal" ", which will lead to some alignment of the lengths of both edges, i.e. to reduce the crescent-shaped finished profile (compared with the magnitude of the crescent of the workpiece).

 Since it is not possible to theoretically determine the skew angle of the forming rolls by which it is possible to obtain different-height corrugations, it is advisable to find the relationship between the value of this angle and some parameters of the corrugations and the sickle-shaped strip billet empirically.

 In FIG. 1 shows the layout of the corrugations in the crescent band; in FIG. 2 is a diagram showing the formation of corrugations of different heights along the profile width using roll forming rolls.

The crescent-shaped strip 1 (Fig. 1) of width B has a crescent shape S, mm, on a length l _M , moreover, the left (in Fig. 1) edge 2 of the strip is curved, and the right 3 is convex and longer. Corrugations 4 are formed on the strip (for example, of a trapezoidal section) with a length of l _g , the distance between them along the width of the strip is equal to b.

 When forming the corrugations, the work rolls 5 and 6 (Fig. 2) are warped in the vertical plane with the help of pressure devices so that the angle between their axes is equal to α deg. This leads to the formation of corrugations of different heights: left 7 (in Fig. 2) with height h and right 8 with height H> h, since the size of the roll gap on the edge 2 side is set to the minimum thickness (taking into account the minus tolerance) of the profile δ, and from the side of the edge 3, the gap Δ = δ + Btgα.

Before profiling, the actual crescent shape of the strip billet is measured at the base length l _n specified by the relevant standard or technical specifications, and if it exceeds the permissible value, by the difference ΔS, the given length of the corrugations l _g , the distance between them b, and the minimum allowable height of the corrugations h, the angle α of the warps of the forming rolls is calculated. Then a variable roll gap is set and the profiling process begins. At the same time, a higher corrugation is formed by raising the forming protrusion of the lower roll.

 An experimental verification of the found technical solution was carried out on a flexible bending unit 1–5 • 300–1650 of OJSC Magnitogorsk Iron and Steel Works in the manufacture of DRI with two corrugations along the width of the strip and with various profile parameters. In the experiments, the values of the crescent shape of the initial billet and finished profiles were recorded, as well as the height of the corrugations. The experiments showed that, depending on the assortment of DRI, the use of the proposed method in their manufacture allows to obtain high-quality profiles from sickle-shaped strips with ΔS up to 5 mm. Control profiling using known technology has shown that using it is impossible to obtain the required geometry of the DRI, formed from a sickle-shaped workpiece.

 Thus, to confirm the acceptability of the claimed object to solve the problem and its advantages over the known object.

 According to the data of Rolled Bent Profile CJSC MMK, the use of the present invention in the production of DRI allows reducing metal consumption during profiling by about 2%, which accordingly will increase the profitability of this type of rolled products.

Example. A high rigidity profile is formed with two trapezoidal corrugations along the strip width B = 1260 mm; the length of the corrugations (Fig. 1 and 2) l _g = 1230 mm, the minimum height h = 34 mm, b = 600 mm

The permissible crescent rate of 10 mm over a length l _M = 3000 mm, the actual - 13 mm, i.e. Δ S = 3 mm.

Допуск на толщину полосы: 4 $\genfrac{}{}{0ex}{}{\text{+0,3}}{\text{-0,5}}$ мм, т.е. величина δ = 4 - 0,5 = 3,5 мм (зазор со стороны вогнутой кромки), а Δ = δ+Btgα = 3,5 + 1260 • tg 0,0065 рад ≈ 11,6 мм.Swash angle:

Thickness Tolerance: 4 $\genfrac{}{}{0ex}{}{\text{+0.3}}{\text{-0.5}}$ mm i.e. the value δ = 4 - 0.5 = 3.5 mm (clearance from the side of the concave edge), and Δ = δ + Btgα = 3.5 + 1260 • tg 0.0065 rad ≈ 11.6 mm.

H = h + btgα = 34 + 600 • tg0.0065 rad ≈ 38 mm,
which corresponds to the tolerance on the height of the corrugations (36 ± 2 mm).

Claims (1)

A method for the production of high rigidity profiles with two closed longitudinal corrugations in width, which includes preliminary measurement of the crescent shape of the strip at the base length l _m and the formation of corrugations on it with rolls installed with a given roll gap, characterized in that at a difference ΔS of the measured crescent shape and the allowable one they form uneven along the width of the corrugation strip by skewing the rolls in a vertical plane at an angle

where α is the skew angle of the rolls, rad .;
ΔS is the difference between the measured and given crescent, mm;
h is the minimum allowable height of the corrugation, mm;
l _g - the specified length of the corrugation, mm;
b is the distance between the corrugations, mm;
l _m - base length, mm;
B - profile width, mm;
δ is the minimum thickness of the profile, mm,
setting the roll gap on the concave edge of the workpiece, equal to the minimum profile thickness -δ + βtgα, and on the opposite δ.

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