SU1683837A1 - Method of producing bent shapes - Google Patents

Abstract

The invention relates to the processing of metals by pressure in the rolls of roll forming mills and is intended for use in the ferrous metallurgy and construction industry in the production of curved rolled sections. The purpose of the invention is to improve the quality of the profiles by eliminating their deplanation. In accordance with the configuration of the profile, the number of transitions for the formation of bending and the values of the angles for the transitions are determined. Then the maximum values of thinning in the middle of the bend points at the transitions are found. Calculate the thickness of the profile after each transition. Then, from the condition of equality of radial deformations over the entire formable cross section, the reduction in each transition for all sections of the cross section is calculated for each point as the difference between the profile thickness in the previous transition and the metal thickness at the bend with the greatest thinning in this transition. 3 il. 2 tab. S yo

Description

The invention relates to the processing of metals by pressure in the rolls of roll forming mills and is intended for use in the ferrous metallurgy and construction industry in the production of curved rolled sections.

The aim of the invention is to improve the quality of the profiles by eliminating their non-bulkiness.

Figure 1 shows the profile profile formed in the (n-1) transition; Fig. 2 is a diagram of the deformation of a metal over the thickness of a profile in the nth transition from bending and from reduction; FIG. 3 is a caliber diagram with a shed for forming a bend simultaneously with compression.

In carrying out the method, the following sequence of actions is appropriate.

In accordance with the configuration of profile 1, the number of transitions for bending forming and the values of the hem angles for transitions are determined. Then the maximum thinning values are found at the middle of the bend points at the transitions. Calculate the thickness of the profile after each transition.

Then, from the condition of equality of radial deformations over the entire formable cross section, the reduction in each transition for all sections of the cross section is calculated, found for each point, as the difference between the thickness (Sn-i) profile in the previous transition and the thickness of the metal at the bend with the greatest thinning in this transition

In connection with the variable value of thinning across the width of the bend points, and, consequently, the varying amount of compression of these

About 00 CJ 00

co VI

plots for accurate profiling of rollers Construct plots of compression of bending points for each transition.

In accordance with the selected bending mode and diagrams of the distribution of radial deformations on transitions, the roll calibration and the 2 calibration gauge sheds are calculated to create plastic reduction by a corresponding reduction in gaps along the gauge perimeter in certain areas. In framed and computed beams, profiling is carried out similarly to existing known methods: by successively passing a strip through a series of pairs of work rolls.

So, for example, according to the described method. On a 1-4 x 50-300 mill, a channel of 120 x 80 x 6 mm was manufactured from StZKp steel, having radii at bend points of 6 mm, a sweep width of bending points 14.13 mm.

Forming was performed by a constant bending radius (6 mm) in all transitions in the mode: 0 °; 20 °; 45 °; 65 °; 85 °; 90 °.

The maximum amount of thinning in the middle of the bend points at the transitions:

(Sn} 0 09

(

(2

(So

where So is the thickness of the workpiece, mm;

OS - angle of hem, grad .;

bn - width of the bent shelf, mm;

RB is the internal radius of bending, mm and the thickness of the molded profile after compression at the transitions are given in table 1.

The degree of flattening of flat elements (shelves, wall) at the transitions was determined by the value of the maximum bend thinning in this transition, shown in Table 2.

The magnitude of the shrinkage across the width of the rim-curvature of the bend points at the transitions was determined by the dependency, which is the formula for the diagram of the inverse thinning distribution:

D5x A5max {1-со84 -), (2)

where X is the current value of the distance from the origin of coordinates located at the middle of the sweep of the bend site, mm;

bn - bend sweep width, mm.

DZmax - 0.0032 So

0.55

0)

In accordance with the profile configuration, the width of the sweep of the sections of the bend point is 14.13 mm, the calculations of the current values of reduction across the width of these sections

produced for half of their width 7.065 mm due to the same values of reduction relative to the midpoint of the width. The intervals of the current X values were taken over 1 mm. and the last - through 1,065 mm.

As shown by the experimental test data on a 1-4 x 50-300 mill in the manufacture of a 120 x 80 x 6 mm channel by the prototype method, the shelf waviness at 40% of the lot was 2 mm per 1 m length, longitudinal

a deflection of 50% of profiles was 0.1% of the length (6 m). Such deviations are the limits allowed by GOST 8278-83.

And in 10% of the batch of profiles, the maximum deviations of the waviness and longitudinal deflections exceeded the standard values and were rejection signs.

In the manufacture of the channel 120 x 80 x 6 mm according to the described method, the waviness on

the shelves were absent on all profiles of the lot, and the longitudinal deflection did not exceed 0.04% of the length by 50% of the lot, and was not observed in the remaining profiles x.

Thus, the invention allows

prevent shelf undulation, reduce

longitudinal deflection 2.5 times and completely

avoid marriage from sagging and undulation.

Claims (1)

Invention Formula The method of making curved profiles including gradual hemming of the strip elements along transitions and plastic reduction along the thickness of the workpiece, while the amount of plastic reduction across the width of the curvilinear sections of the bend sites increases from zero in the middle of the bend points to the maximum value along the edges corresponding to in order to improve the quality of the profiles due to the exclusion of their non-flatness, plastic reduction is carried out in each transition simultaneously with the bending of the profile elements, and the amount of reduction of flat sections in each transition is equal to the difference between the thickness of these sections in the previous transition and the minimum profile thickness in the middle of curvilinear sections of the bend points this transition. Table 1 VI l to / 7- / S table 2 one I figure 1 2 fiez