RU2407605C1 - Helical mill roll - Google Patents

Abstract

FIELD: process engineering. ^ SUBSTANCE: proposed mill roll comprises cylindrical body with ledge made on the body generatrix along spiral line. Invention aims at increasing mechanical properties of rolled strip and ruling out strip displacement along roll axis. To this end, said spiral line features elevation angle of 30-60, while ledge height does not exceed 25% roll body diametre. Spiral ledge can have rounded shape of profile nearby crest and mate adjacent rounded-bottom recesses. Besides, said ledges are made along multi-start spiral lines. ^ EFFECT: higher mechanical properties of rolled metal strips. ^ 3 cl, 3 dwg, 1 tbl, 2 ex

Description

The invention relates to rolling production, and more particularly to the design of rolling rolls, and can be used in the manufacture of metal strips with enhanced mechanical and functional properties.

To increase the complex of mechanical properties of metal strips, their rolling is carried out in two stages. At the first stage, the workpiece is crimped using a roll, the barrel of which contains protrusions. The introduction of protrusions into the metal creates in the volume of the workpiece an increased study of the microstructure and local hardening of its individual sections. Due to this, after annealing and ironing pass in rolls with a smooth barrel, the strip acquires higher strength properties, provided by the presence of local hardened sections in it, in combination with high ductility and viscosity.

A rolling roll is known, on the barrel of which annular protrusions alternating with a constant pitch are formed, formed by band braces, the diameter of which is 1,00096-1,00444 greater than the diameter of the band braces adjacent to them, and the planes of all band braces are mounted with an inclination to the axis roll at an angle of 55-83 ° [1].

The disadvantages of such a roll are that the sinusoidal grooves of a rectangular profile formed during the rolling process on the surface of the metal strip have insufficient depth, because the diameters of the disk bandages of larger and smaller diameters are close to each other. As a result, local hardening of individual sections of the strip is small. This reduces its strength properties. In addition, during the rolling process, there is a shift of the strip along the axis of the roll, which complicates its direction strictly along the axis of the rolling mill.

The closest analogue to the present invention is a rolling roll containing a cylindrical barrel, on the generatrix of the surface of which a protrusion is made along the helical line, enclosed between the turns of the spiral groove, while the helical line has an elevation angle of 80-88 ° [2].

The disadvantages of this rolling roll are the displacement of the strip along its axis during the rolling process, as well as the low complex of mechanical properties of the strip due to non-optimal parameters and the shape of the profile of the screw protrusion.

The technical problem solved by the invention is to eliminate strip displacements along the axis of the roll during rolling and to increase the complex of its mechanical properties.

To solve the technical problem in the known design of a rolling roll containing a cylindrical barrel, on the forming surface of which a protrusion is made along the helical line, according to the proposal, the helical line has an elevation angle of 30-60 °, and the height of the protrusion does not exceed 25% of the diameter of the cylindrical barrel. The protrusion can have a rounded profile shape at the apex and be mated with adjacent cavities with a rounded bottom shape, and the protrusions can be made on multi-helix lines.

Figure 1 presents a helicoidal rolling roll, front view; figure 2 is an enlarged sectional section A in figure 1; figure 3 is an enlarged sectional section A in figure 1 in an embodiment of a helicoidal rolling roll.

The helicoidal rolling roll consists of a cylindrical barrel 1 with a diameter D and necks 2. On the generatrix surface of the cylindrical barrel 1, ledges 3 are made along a helical line, having generally a trapezoidal cross-sectional shape (Fig. 2). The helix of the protrusion 3 has an elevation angle φ = 30-60 °. Moreover, the height h of the screw protrusion 3 does not exceed 25% of the diameter D of the cylindrical barrel, i.e. h≤0.25 · D.

In an embodiment of the device, the protrusion 3 has a rounded profile shape at the apex and is mated with adjacent cavities with a rounded bottom shape (Fig. 3).

At an angle of elevation of вин = 30-60 ° of the helical line of the protrusion 3, displacement of the strip along the axis of the helicoidal rolling roll is eliminated, and the formation of sections reinforced by deformation in the rolled strip of high density is achieved. An increase in the angle φ of more than 60 ° is accompanied by the formation of strain-hardened sections of the strip with excess density, which leads to a deterioration in its mechanical properties - loss of ductility and toughness. In addition, the transverse components of the rolling force are unbalanced friction forces, which leads to a shift of the strip along the axis of the roll. In the case of a decrease in the angle φ less than 30 °, a transverse displacement of the strip also takes place, since the helicoidal rolling roll begins to exhibit the properties of a screw, and the density of the strain-hardened sections of the strip decreases, which reduces its overall strength.

The density of the hardened sections and the total strength of the finished strip can be increased in the case of the protrusions 3 on multi-helix lines.

Increasing the height h of the protrusion 3 more than 25% of the diameter D of the cylindrical barrel 2 reduces the strength and operational stability of the helicoidal rolling roll. In addition, in this case, the formation of defects in the form of folds and “sunsets” on the strip during subsequent ironing in the rolls with a smooth barrel is not excluded.

It should also be noted that for cases of rolling highly plastic metals, the greatest local strain hardening is provided by a helicoidal roll with a trapezoidal cross-sectional shape of the protrusion 3 (figure 2). The helicoidal roll, the protrusion 3 of which has a rounded cross-sectional shape and is interfaced with adjacent cavities with a rounded shape 2, has an increased operational stability and is most suitable for rolling high-strength metal materials.

The device operates as follows

Option 1. For rolling using a pair of helicoidal rolling rolls with cylindrical barrels 1 with a diameter of D = 100 mm On the cylindrical barrels 1, protrusions 3 of a trapezoidal shape with a height of h = 4 mm are made along eight-helix lines (FIG. 2). The angle of elevation of the helical lines of the protrusions is φ = 45 °, and the relative height of the protrusion 3 is ε = 4% of the diameter D of the barrel 1.

On the necks of 2 helicoidal rolling through bearings, mount pillows, after which the roll with pillows is dumped into a sheet rolling stand.

The rolls are driven from the electric motor and set a rolled strip of 15 mm thick made of highly plastic aluminum with a purity of 99.8% into the roll gap. During the rolling process, the rolls pull the aluminum strip into the deformation zone. In this case, the protrusions 3 are embedded in the rolled aluminum, forming sections of smaller thickness with a high degree of strain hardening. The rolled strip acquires a corrugated surface shape.

During the rolling process, the protrusions 3 introduced into the metal keep the strip from lateral displacements.

The strip with a corrugated surface is annealed at a temperature of t = 470 ° C, after which it is ironed in work rolls with a smooth cylindrical barrel and annealed again. By using the proposed design of helicoidal rolls, an increase in the yield strength of the finished aluminum strip is achieved by Δσ _t = 40% (up to σ _t = 28 MPa) while maintaining high ductility δ = 47%. Rolling proceeds without lateral displacement of the strips.

Option 2. With other equal parameters of the helicoidal rolls, as in option 1, the protrusions 3 have a rounded profile at the top and are associated with adjacent depressions with a rounded bottom shape (figure 3).

A 15 mm thick strip of high-strength VT1D grade titanium alloy is set into the roll gap and it is rolled.

The corrugated strip is annealed at a temperature of t = 710 ° C, subjected to smoothing rolling in rolls with smooth barrels, and annealed again.

By using the proposed design of helical rollers achieved increase the yield stress of the finished strip for Δσ = _t 35% (up to the value σ _m = 47 MPa), while maintaining high ductility δ = 45%. Rolling proceeds without lateral displacement of the strips.

Implementation options for the proposed design of the helicoidal rolling roll and indicators of their effectiveness are presented in the table.

Option No. Roll Parameters Performance indicators φ, deg. ε,% protrusion sectional shape strip offset Δσ _t ,% δ,% one 29th twenty trapezoidal. presence. 12 42 2 thirty 2 trapezoidal. absent. 36 45 3 45 four trapezoidal. absent. 40 47 four 60 25 trapezoidal. absent. 38 46 5 62 27 trapezoidal. presence. fourteen 42 6 28 fifteen rounded presence. 10 32 7 thirty 22 rounded absent. 34 44 8 45 four rounded absent. 35 45 9 60 25 rounded absent. 34 44 10 61 26 rounded presence. twenty 28

From the data presented in the table, it follows that the use of a helicoidal roll of the proposed design (options 2-4, 7-9) ensures the exclusion of strip offsets along the axis of the roll during rolling and an increase in the complex of its mechanical properties. With exorbitant values of the declared parameters of the helicoidal roll (options 1, 5, 6, 10), there is a transverse displacement of the strip from the longitudinal axis of rolling, the mechanical properties of the finished strip deteriorate. The application of the prototype method leads to lateral movements of the strip during the rolling process, and its mechanical properties remain low.

The technical and economic advantages of the helicoidal rolling roll of the proposed design are that when it is used, simultaneous elimination of strip displacement along the roll barrel and maximum increase in the complex of mechanical properties of the rolled strip are achieved. If necessary, one helicoidal roll can be used in the design, and the second with a smooth barrel or plate.

Information sources

1. Patent of the Russian Federation No. 2006302, IPC ВВВ 27/02, 1994

2. Patent of the Russian Federation No. 2094142, IPC В21В 27/10.

Claims (3)

1. Helical rolling roll containing a cylindrical barrel, on the forming surface of which a protrusion is made along a helical line, characterized in that the helical line has an elevation angle of 30-60 °, and the height of the protrusion does not exceed 25% of the diameter of the cylindrical barrel. 2. The roll according to claim 1, characterized in that the protrusion has a rounded profile shape at the apex and is associated with adjacent cavities with a rounded bottom shape. 3. The roll according to claim 1, characterized in that on its generatrix surface, protrusions along multiple helical lines are additionally made.

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