SU1480918A1 - Method of producing bent rolled shapes - Google Patents

Abstract

The invention relates to the processing of sheet material in rolls of a special shape and is intended for use in the ferrous metallurgy, transport engineering and construction. The purpose of the invention is the expansion of technological capabilities by forming profiles, in which the width of the flat elements of the tops of the corrugations exceeds eight times the radius of the bend sites while maintaining their quality. First, oval shaped corrugations are formed into which excess metal is put. Then these corrugations are reformed into semicircular, and then they are upsetted to form 79 ... 83% of the total width of all flat elements with simultaneous bending of the side elements by an angle at which the height of the corrugations is 1.2 ... 1.5% less than the specified one. The remaining curvilinear sections on the elements of the corrugations are straightened out and at the same time the side elements are flexed, increasing the height of the corrugations to the desired one. The step of the corrugations on the transitions is reduced. The magnitude of the relative pitch reduction and the magnitude of the excess metal deposited in the oval corrugations are determined from the calculated dependencies. 1 hp f-ly, 4 ill., 1 tab.

Description

The invention relates to the processing of sheet material in rolls of a special shape and is intended for use in the ferrous metallurgy, transport engineering and construction.

The aim of the invention is the expansion of technological capabilities by forming profiles, in which the width of the flat elements of the tops of the corrugations exceeds eight times the radius of the bend, while maintaining their quality.

FIG. 1 shows the profile molding scheme; in fig. 2 - diagram of the corrugation at the stage of precipitation; in fig. 3 - the same, in the last passage; in fig. 4 is a diagram of the sweep of a bend site on a corrugation.

In the manufacture of curved profiles with trapezoidal corrugations having flat areas on tops with a width of more than eight bend radii, the following sequence of operations of the method is expedient.

First, the magnitude of the excess metal is found across the width of the sweep of the oval corrugations of the first transition according to the calculated dependence

), with

So

where ai - the tensile strength of the material of the workpiece;

as-yield strength of the workpiece material;

S is the thickness of the workpiece;

B is the width of the sweep of bending points;

x - current coordinate; D5 - thinning of the material at the bend for a radius and angle of bending set on the finished profile.

J

00 About CD

OO

After that, the width of the profile blank is determined taking into account the total excess metal for all the corrugations across the width of the profile.

B3 Bi + Ab.fc, (2)

where Si is the width of the profile blank;

k - the number of corrugations profile. Then, based on the total number of transitions equal to 4, and having entered the corrugations in the last transition equal to the corrugations on the finished profile, the change in the transition step and the absolute values of the corrugations in each transition according to

(l-1) 2-7.4 (p -1) +8.2,

(3)

where DG is the relative decrease in the corrugation step between previous transitions,%; n is the order number of the transition (n

2, 3, 4 ...).

Further, all transitions are calculated, the bending angles, the radii and dimensions of the elements of the corrugations are determined, taking into account that the sweep width of the oval corrugations on L is greater than the sweep width of the corrugations on the finished profile. Here, using these experiments, that the relative radii of the bases of the oval corrugations should be at least 6-6.5, find the radii of the vertices of the corrugations by the formula

(180 (B + DB) 65 + | 1 (4)

x idt., J

where B - the width of the sweep corrugation at the ready

profile, mm ;. "1 is the angle of the hem in the first transition,

hail;

S is the thickness of the workpiece, mm, and also from the condition that the 1c height of the oval corrugations is 29-32% less than the specified height of the trapezoidal corrugations. Accepting an average of 30%, this condition is expressed by the dependence

(6S-f / 2 + S) -smai 0.7 / i.

Solving together equations (4) and (5), find the value and ai for the first transition.

Exact correspondence of the corrugation pitch to the calculated value is provided by choosing the radii and the bending angle of the flat elements between the corrugations to obtain in the first transition a wavy profile with oval corrugations.

In the second transition, the oval corrugations are reformed into semicircular. At the same time, based on the experimental data, the magnitude of the relative radii of bending of the bases of the corrugations is 4.5-5.5, and the radii of the vertices of the corrugations Rz and the fit angle az in this transition are determined from the condition of the constant sweep length of the corrugations as well as exceeding the height of the semicircular

a corrugation of a given value for trapezoidal by 11 -13%, solving the equations

five

five

0

five

 + f,

(6)

(5S + / M-S) -sma2 l, ll.

By calculating the dimensions of the elements of the corrugations in the second transition, the radius and angle of bending of the sections of the profile between the corrugations and the conditions for obtaining the exact correspondence of the step of the corrugations to the calculated value in this transition are determined.

In the third transition, the profile is precipitated using the calculated amount of the hem angle in this transition, and, setting the width of the corrugation flat elements within 79-83% of their size on the finished profile, also fulfills the condition that the corrugation is 1.2-1 , 5% less than the specified value, find the values of the radii of bending points on the corrugations. The radii of the bases and the vertices of the trapezoidal corrugations are the same, i.e., therefore, the bending angle, in this transition, and the bending radii are found by solving the equations

25

thirty

40

35

45

50

B ± jla3 + 0.85nf 80

(7)

(1Rz + S), 987ft where TSP is the sum of the widths of straight sections on the finally formed trapezoidal corrugation. In this transition, the relative decrease in pitch between the corrugations, determined by formula (3), should be minimal. Correspondence of the corrugation pitch to its calculated value in this transition is ensured by appropriate selection of the radii and bending angles of the profile sections between the corrugations.

The elements of the fourth transition are calculated from the condition that the dimensions of the corrugations and the step between them in this transition correspond to the dimensions of the finished profile.

The proposed method can be implemented on any roll forming mill having at least four forming stands, in the manufacture of sets of rolls of the form described above and design dimensions.

For example, the method was tested in the manufacture of a 1094ХУХ1 mm profile that has six trapezoid corrugations with radii of curvature mm with a width of flat sections of the vertices of the corrugations of 18 mm, i.e., multiple to 9 radii of bending points. The bending angle of the side portions of the corrugations is 80 °, thickness is mm, the material is steel of the Stzkp brand with a tensile strength of a & 470 kN / mm2, yield strength as 270 kN / mm2. The corrugation pitch of the profile is 158 mm, the height of the corrugation is mm, the width of the corrugation is 29.52, the width of the sweep of the corrugation is 41.84 mm, the width of the sweep of bending points, 5 mm, the width of the flat inclined sections of the corrugation is 4.94 mm, the width of the blank profile is 156.4 mm.

By integrating equation (1) over x and substituting the limits from 0 to b / 2, we obtained the expression for calculating the excess metal for oval corrugations

D6

b

3AS-6

(eight)

by gz

After substitution in the expression of the values of its components, the magnitude of the excess metal was determined

, 91. (9)

The width of the workpiece, taking into account the excess metal width of the corrugation in accordance with formula (2)

, 86. (10)

According to dependency (3), the relative reduction of the corrugation step in transitions was calculated, starting from the second. After that, using the known, specified, step size of the corrugations in the last transition, taken equal to the step on the finished profile, the step of the corrugations was determined by transitions using the formula

t shtpp

y "- -100-DGP UU

where TP- is the step size of the corrugation in the previous transition, mm;

TP - the step size of the corrugation in the subsequent transition, mm;

DTP is the relative decrease in the corrugation step in the subsequent, th, transition,%.

The calculated values of the relative reduction of the corrugation pitch, the absolute values of the corrugation pitch for transitions, the hem angles, the radii of the bend points, the height of the corrugations, the widths of the flat elements of the corrugations and the aspect ratios of the elements of the corrugations are shown in the table.

As shown by measurements and quality analysis, the pilot batch profiles produced by the proposed method by molding with subsequent slump were of good quality and fully met the requirements of TU.

The proposed method allows making bent profiles with trapezoidal corrugations having flat widths of tops of more than eight times the bend radius for four transitions without degrading their quality, which reduces the number of forming stands, and consequently, the time for assembly, adjustment, disassembly and provides increased productivity .

Claims (2)

1. The method of manufacturing curved profiles with trapezoid corrugations is divided five 0 five 0 five 0 five 0 straight flat plots and flat side portions, by bending with rolls of sheet material of a wavy profile with corrugations, in which an excess of metal is laid across the width of their sweep, exceeding the width of the sweep of the corrugations on the finished profile, followed by reshaping the corrugations into a trapezoidal pattern, differing from that, with the aim of expanding technological capabilities by forming profiles, in which the width of the flat elements of the tops of the corrugations exceeds eight times the radius of the bend, while maintaining the quality sirloin, first form oval corrugations, then reshape them into semicircular, and during the subsequent draft, 79 ... 83% of the total width of all flat elements are formed with simultaneous bending of the side elements of the corrugation at an angle at which the height of the corrugations is 1.2 ... 1 , 5% less than the specified, then straighten the remaining curvilinear sections on the corrugation elements and at the same time bend the side elements, increasing the height of the corrugations to the given, while the corrugations are formed with a decrease in the step size for transitions eats according to addiction (/ g- I) 2-7.4 (jV-1) +8.2, where DG is the relative decrease in the corrugation step between the previous and subsequent transitions,%; n is the order number of the transition (starting from the second). 2. A method according to claim 1, characterized in that the magnitude of the excess sweep width of the oval corrugations over the sweep width of the trapezoid corrugations is determined by the dependence Chg (S-cos4-), about where AB is the magnitude of the excess sweep width of the oval corrugations over the sweep width of the trapezoidal corrugations; 06 and crs are respectively the limits of strength and fluidity of the material of the workpiece, mm; 5 - blank thickness, mm; D5 is the maximum amount of thinning at the point of bend for the radius and angle of bending set on the finished profile, mm; b - the width of the sweep of the bend, mm; x is the current coordinate defining the place of the bend when counting from the middle, mm. Fi.2 )