RU2301717C1 - Tool for shaping high-hardness sections - Google Patents

Abstract

FIELD: equipment for plastic working of metals, namely manufacture of high-rigidity sections.

SUBSTANCE: tool includes upper and lower rolls mounted with gap. Lower roll has shaping protrusions arranged on preset part of roll barrel circumference. Upper roll has cover plates in its grooves. Length of shaping protrusion of lower roll consists of 0.69 - 0.71 of its barrel circumference. Cover plate in each groove of upper roll is arranged along 0.17 - 0.18 of barrel circumference and it is spaced by minimally possible distance from front (along rolling direction) end of shaping protrusion of lower roll.

EFFECT: lowered consumption of rolls, improved geometry of high-rigidity sections.

1 dwg, 1 ex

Description

The invention relates to rolling equipment, in particular to a tool for the production of cold-formed profiles of high stiffness (DRI).

These sheet profiles contain longitudinal periodically repeating corrugations of various shapes (triangular, trapezoidal, semicircular) and are made on special molding mills by local deformation (drawing) of individual sections of the strip billet.

The tool of such mills are the forming rolls installed in the stands with a gap - upper and lower. In this case, the lower roll is made with forming protrusions that occupy a given part of the circumference of the roll barrel and the number of which corresponds to the number of corrugations along the width of the profile; the upper roll is brook, with removable overlays in the streams, which are located opposite the sections of the lower roll between the ends of its protrusions.

The design features of the tool (rolls) for the production of DRI are described in sufficient detail, for example, in the book of V.I. book., 1980, p. 120-125.

Known rolls for molding by local extraction of DRI, consisting of individual elements and containing protrusions on part of the circumference of the barrel of the lower roll and their corresponding depressions on the upper, in which the end part of the protrusions forming the front ends of the corrugations are made of removable steel and increased hardness (see USSR AS No. 1174119 class B21D 5/06, published in BI No. 31, 1985). The disadvantage of this tool is the possibility of a characteristic defect appearing on the DRI - local swelling of the metal (“bubble”) at the front ends.

Closest to the claimed object is a tool (rolls) for molding the DRI, described in the book of A. F. Rashnikov and others. "Production of bent profiles at MMK", Magnitogorsk, MSTU, 1999, p.100-101.

This tool contains a lower roll installed with a gap with forming protrusions that occupy a given part of the circumference of the barrel, and an upper stream roll with overlays in the streams and is characterized in that the overlays are made with a variable height along their length, decreasing from the ends of the lining to its middle. A disadvantage of such a design tool is the possibility of the appearance of the indicated defects of the DRI geometry and the increased consumption of rolls due to the relatively large length of the pads.

An object of the present invention is to reduce the consumption of rolls and to improve the geometry of high rigidity profiles.

To solve this problem, the tool for forming high-rigidity profiles with longitudinal corrugations, containing a lower roll with a clearance with forming protrusions that occupy a given part of the barrel circumference and an upper groove roll with overlays in streams, has a protrusion length on the lower roll of 0.69 ... 0.71 of the circumference of its barrel, and the plate in the stream of the upper roll takes 0.17 ... 0.18 of the circumference of its barrel, while the plate is installed at the minimum possible distance from the front along the end of the protrusion of the lower on the roll.

The given ratios of the roll parameters are obtained as a result of processing the experimental data and are empirical.

The essence of the proposed technical solution is to optimize the length of the protrusions on the lower roll and the length of the pads on the upper roll. Moreover, the pad does not occupy the entire length of the portion of the stream corresponding to the length of the portion l between the ends of the protrusion on the lower roll, but only 58 ... 59% of this value. As a result of this, the “bubble” defect is eliminated on the finished profiles (the reasons for its appearance are described in the aforementioned book of V.I. Anisimov et al. P.138-140), which improves the geometry of the DRI. In addition, due to the reduced length of the linings, the roll consumption is reduced (see below), and the absence of a “bubble” during molding reduces their wear.

The proposed tool is schematically shown in the drawing (arrow - the direction of movement of the strip).

Upper 2 and lower 3 forming rolls are installed in the supports of the bed 1 of the stand. The projections 4 are made on the lower roll, the length of which around the circumference of the barrel depends on the length of the periodic corrugation on the profile, i.e. the protrusion 4 occupies only a given part of this circle. At the ends of the protrusions 4 there are bevels 5 (inclined flat faces) corresponding to the shape of the front and rear ends of the corrugations.

In the streams 6 of the upper roll 2 are pads 7 also of a given length, made with the possibility of adjusting movement along the stream 6 due to the ovality of the mounting holes 8 of the pads 7. The pads 7 are installed at a minimum distance from the front ends 9 of the protrusions 4.

The proposed tool works as follows.

Before the work of the mill, the rolls 2, 3 are installed with the required gap δ between them vertically, the value of which corresponds to the actual thickness of the formed strip. After this, the overlays 7 of the upper roll 2 are installed in the streams 6 at the minimum possible distance from the end 9 of the ledge 4 of the lower roll 3, which is determined using a feeler gauge for the gap between the flat face of the bevel 5 and the cover 7. The plates 7 are fixed in the streams 6 with mounting bolts and the molding process begins. If, at the same time, inter-ridge (along the strip length) sections with their required plane are not obtained on the DRI, the pads 7 are moved to new positions until the desired result is achieved.

An experimental verification of the proposed tool was carried out during the molding of various types of livestock on the mill 1-5 × 300-1650 OJSC "Magnitogorsk Iron and Steel Works".

For this purpose, when forming strips with trapezoidal periodic corrugations, the length of the protrusions on the lower roll (within the permissible length of the corrugations: l _g ± 10 mm) and the length of the overlays on the upper rolls were varied. The results of the pilot molding were evaluated by the yield of life-proof materials, the wear of the rolls and their consumption.

The best results (yield of life span of at least 99.7% with minimal wear of the rolls and their consumption) were obtained using the inventive stand. Deviations from the recommended roll parameters (see above) worsened the achieved indicators.

So, when the length of the protrusions is less than 0.69 and more than 0.71 of the circumference of the barrel of the lower roll, the length of the corrugations of the finished DRIs exceeded the permissible values. When the length of the pads on the upper roll is less than 0.17 of the circumference of its barrel, the flatness of the inter-ridge sections of the DRI (with the appearance of a “bubble”) worsened with a simultaneous increase in wear of the rolls. With the length of the linings more than 0.18 of the indicated value, the flatness of these sections did not change, but the consumption of material for the manufacture of linings increased (i.e., the consumption of rolls increased). The appearance of the “bubble” was also facilitated by the removal of the pads from the front (along the rolling) ends of the protrusions on the lower roll.

Comparative tests of the device selected as the closest analogue (see above) gave a maximum yield of life span of no less than 98.8% (sorting was mainly due to a defect "bubble"), and the consumption of rolls increased by almost 7%.

Thus, an experimental verification confirmed the acceptability of the technical solution found to achieve the goal and its advantages over a known object.

According to economic studies conducted by OJSC MMK, the use of the inventive tool in the production of DRI with trapezoidal corrugations increases the yield of rolled products by almost 1 abs.% While reducing the consumption of rolls by at least 6%. As a result of this, accordingly, the profit from the sale of sheet profiles with improved geometry and from the reduction of production costs increases.

Concrete example

The cage of the mill for forming high rigidity profiles has the form shown in the drawing.

The protrusions on the lower roll are made with the coverage of the angle α = 253 °, i.e. about 0.7 of the circumference of the roll barrel (253: 360 ~ 0.7).

The pads installed in the streams of the upper roll cover an angle β = 63 °, i.e. about 0.175 of the circumference of the barrel of this roll (63: 360 ~ 0.175). In this case, the pads are separated from the yy vertical by an angle γ = 27 °, i.e. located at the minimum possible distance from the front along the rolling ends of the protrusions of the lower rolls.

Claims (1)

A tool for forming high rigidity profiles with longitudinal corrugations comprising a lower roll with a clearance with forming protrusions occupying a predetermined part of the circumference of the barrel, and an upper groove roll with overlays in the streams, characterized in that the length of the forming protrusion on the lower roll is 0.69 -0.71 of the circumference of its barrel, and the pad in each stream of the upper roll takes 0.17-0.18 of the circumference of its barrel, while the pad is installed at the minimum possible distance from the front end of the rolling end uyuschego protrusion of the lower roll.