RU108326U1 - TECHNOLOGICAL TOOL OF A THREE-SWEEL CROSS-SCREW ROLLING MACHINE - Google Patents

Abstract

 A technological tool of a three-roll cross-helical rolling mill, including work rolls containing crimp and gauge sections, characterized in that the first crimp section of the roll has a cup-shaped profile in the form of a truncated cone, which is connected with its smaller base to a smaller base of the mushroom-shaped section of the roll, also made in a truncated cone, and the calibrating roll section is connected to a large base of the mushroom-shaped roll section; the angle between the lines forming the crimp sections is 110-160 °, and the rolls are installed in a rolling stand of a three-roll cross-helical rolling mill so that the contact point of the workpiece with the roll is on the transition line of the cup-shaped section of the roll into the mushroom section and is a projection onto this line of the point of intersection of the axis of the rolled billet and the projection of the axis of the roll in a plane containing the axis of rolling and normal to the plane of rotation of the roll at the angle of rolling.

Description

The utility model relates to the field of deformation processing of metals by pressure and can be used in metallurgy for the production of long products from various metal materials, including difficult to deform.

As a rule, for cross-helical rolling use:

- a mushroom-shaped roll in the form of two truncated cones, the cone with a large angle of inclination of the generatrix (input) combined with its large base with a small base of the cone with a smaller angle of inclination of the generatrix (output) so that the diameter of the roller from the entrance to the deformation zone to the exit from it increases ;

- a cup-shaped roll in the form of two truncated cones; a cone with a smaller angle of inclination of the generatrix (input) is combined with its small base with a large base of the cone with a large angle of inclination of the generatrix (output) so that the diameter of the roll from the entrance to the deformation zone to the exit from it decreases.

In the working stand, the above rolls are set so that the axis of the roll is in a vertical plane that forms a certain angle, called the rolling angle, with the rolling axis.

It is known from the prior art that the level of technological deformation of billets of alloyed metals and alloys limits the allowable drawing coefficients per pass, which leads to the need to use at least 3-11 passes. The best results are obtained by alternating a cup-shaped and mushroom-like rolling patterns, the so-called reverse. The roll for the implementation of such a rolling scheme contains three working sections:

- crimp for direct passes;

- calibrating for all passes;

- crimp for reverse passages. (Reverse radial-shear rolling. Essence, capabilities, advantages., S.P. Galkin, E.A. Kharitonov, V.K. Mikhailov, Titan Magazine, No. 1, 2003)

Rolls according to SU patent No. 1817709 are also known having two conical crimp sections and a calibrating section located between them, which form conical foci of deformation with calibration zones. This shape of the rolls allows the workpiece to be deformed in straight (odd) passages along the cup-shaped pattern with the axis of the rolls approaching along the rolling path - that is, with positive twisting, and in the reverse passages along the mushroom-shaped pattern with the axis of the rolls diverging - with negative twisting. The deformation is carried out with alternating the direction of rotation of the workpiece, but with a constant direction of twisting. The disadvantage of this form of rolls is the need to use at least two transitions in order to provide the roll with deformation during rolling with both negative and positive twisting.

The objective of the utility model is the creation of a technological tool of a three-roll mill of cross-helical rolling allowing to implement the method of cross-helical rolling with negative and positive twisting in one transition.

Technical result:

- reduction of power parameters of the process;

- provided in one transition, such a reduction in the diameter of the workpiece, which in other methods requires at least two transitions. The synthesis in one pass of both positive and negative twisting eliminates almost all the disadvantages of the methods where this twisting occurs in only one direction (positive or negative), but retains all the advantages of these methods:

- good surface quality of the bars after hire;

- a diagram of the stress-strain state characterized by large quasi-hydrostatic compression, which allows processing with a large value of the true strain (e> 1);

- the presence of a strong component of shear deformation, which allows you to effectively grind the workpiece structure.

Moreover, in the deformation zone, in the region where the negative twisting is replaced by the positive, the strain rate field ruptures — the deformation conditions become substantially non-monotonic, which also favorably affects the grinding of the structure of the rolled billet.

The objective is achieved by the fact that the proposed roll has a complex profile and contains crimp and gauge sections, while the first crimp section of the roll has a cup-shaped profile in the form of a truncated cone, which is connected with its smaller base to the smaller base of the second crimp section with a mushroom profile, also made in the form of a truncated cone, and the calibrating section is connected to the large base of the second crimp section with a mushroom-shaped roll profile. Moreover, the angle between the lines forming the crimp sections is 110-160 °. Three rolls of the proposed shape are installed in a rolling stand of a three-roll cross-helical rolling mill so that the contact point of the workpiece with the roll is on the line of transition of the cup-shaped section of the roll to the mushroom section and is the projection onto this line of the intersection point of the axis of the rolled workpiece and the projection of the roll axis in the plane containing the axis of rolling and normal to the plane of rotation of the roll at the angle of rolling.

The utility model is characterized by the following graphic materials:

Figure 1 - image of the proposed roll;

Figure 2 - schematic representation of the installation of the roll;

Figure 3 - image of the direction of twisting of the rod in the zone of the deformation zone of the cup-shaped portion of the roll;

Figure 4 - image of the directions of twisting of the rod in the deformation zone of the cup-shaped and mushroom-shaped sections of the roll.

The technological tool of a three-roll mill of cross-helical rolling includes a roll of complex profile, geometrically consisting of a cup-shaped, mushroom-shaped 2 and calibrating 3 sections (figure 1). The cup-shaped portion 1 of the roll is a truncated cone, which is connected with its smaller base to the smaller base of the mushroom-shaped portion 2 of the roll, also made in the form of a truncated cone. The angle α between the generatrix of the cup-shaped portion 1 and the generatrix of the mushroom-shaped portion 2 of the roll is 110-160 °. The calibrating portion 3 of the roll is connected to the large base of the mushroom-shaped portion 2 of the roll. Three rolls of the proposed shape are installed in the rolling stand so that the contact point of the workpiece 4 and the roll (not visible in the figure) is on line 5 of the transition of the cup-shaped section 1 of the roll to the mushroom-shaped section 2 and is the projection of the point 6 of the intersection of axis 7 of the rolled billet and the axis projection 8 roll in a plane containing the axis of rolling and normal to the plane of rotation of the roll at an angle of rolling.

Rolling the workpiece 4 using the claimed technological tool three roll mill transverse helical rolling is as follows.

For the compression values specified by the technological conditions, the heated continuous billet 4 is set in rolls, where it is captured on the inlet cone of the cup-shaped section 1 and rotates in the direction of the axis 7 to the mushroom-shaped section 2 of the roll. Further, the workpiece 4 is deformed simultaneously by the cones of the cup-shaped section 1 and the mushroom-shaped section 2. When processing with the calibrating section 3, the surface of the workpiece 4 receives a flat and smooth surface along the entire length. Thus, when rolling, all three sections of the roll are used, and the deformation is carried out with a constant direction of rotation and with alternating directions of twisting - that is, the sign of shear deformations that occur during this processing changes directly during processing. This phenomenon, reducing the yield strength of the metal, facilitates its shape-changing, which reduces the energy-power parameters of the process, and also increases the deformability of the material. Due to the alternating shear deformation, the evolutionary processes of the microstructure restructuring occur with less accumulated deformation, which allows efficient processing of even hardly deformed materials.

As a specific example of the feasibility of implementing the utility model, finite element modeling of rolling a billet with an initial diameter of 50 mm by a diameter of 10 mm is shown (Figs. 3 and 4), where the change in the direction of twisting is clearly traced after the bar line 5 passes the transition of the cup-shaped section 1 of the roll to mushroom section 2. In figure 3 it is seen that before the line 5 of transition of the cupped section 1 to the mushroom section 2, negative twisting of the workpiece 4 is carried out, shown by arrow 9. In figure 4 it is seen that the section the workpiece that received in the zone of the cup-shaped section 1 of the roll the negative direction of twisting (arrow 9), in the zone of the deformation zone, the mushroom-shaped section 2 of the roll, while maintaining the direction of rotation of the workpiece 4, undergoes deformation with a positive direction of twisting (arrow 10).

The developed method is more productive and economical, as it allows to obtain in one transition such a reduction in the diameter of the workpiece, which in other methods requires at least two transitions.

Claims (1)

A technological tool of a three-roll cross-helical rolling mill, including work rolls containing crimp and gauge sections, characterized in that the first crimp section of the roll has a cup-shaped profile in the form of a truncated cone, which is connected with its smaller base to a smaller base of the mushroom-shaped section of the roll, also made in a truncated cone, and the calibrating roll section is connected to a large base of the mushroom-shaped roll section; the angle between the lines forming the crimp sections is 110-160 °, and the rolls are installed in a rolling stand of a three-roll cross-helical rolling mill so that the contact point of the workpiece with the roll is on the transition line of the cup-shaped section of the roll into the mushroom section and is a projection onto this line of the point of intersection of the axis of the rolled billet and the projection of the axis of the roll in a plane containing the axis of rolling and normal to the plane of rotation of the roll at the angle of rolling.