SU1047557A1 - Three-high roller mill roll - Google Patents

Abstract

THREE TRAIL MILLING MILL, containing working areas and areas of non-contact profile forming on the barrel, - and so on, so that, in order to improve the stability of pipe rolling, with respect to diameter to wall thickness greater than 12, areas of contact forming profiles are made with a surface roughness of 15-25 times greater than the surface roughness of the working areas. .

Description

 The invention relates to the production of hot rolled seamless pipes. and can be used on roll mowers.

Rolls of rolling mill and gauge mills are known, whose profile is formed from alternating sections: workers, where radial deformation of the metal is performed, and non-working for the contact panel; 1; for changing the profile of the workpiece.

. The rolls of the three-roll mill are known, containing two working sections separated by a non-contact forming section. The use of such rolls for tube rolling allows one to expand their range to more thin-walled tubes by creating a non-contact section forming a profile directly behind the intensive deformation section 1.

However, the known rolls do not provide a further increase in the speed of rolling thin-walled pipes due to increased transverse deformation (especially in unsteady rolling phases), which leads to facetting of the pipe and overfilling of the gauge of metal

Known roll three-roll. sizing mill, imkvdiy on the barrel a few working areas, separated by interfocal gap. The known roller makes it possible to improve the quality of the pipe during the calibration process with increased cuts by reducing the lateral deformation of the pipe in the interfocal gap 2.

However, the use of the known roll does not ensure the stability of the calibration of the end sections of thin-walled pipes due to significant differences in the magnitude of the radial compression of the pipe in the middle part and at the end sections, which is associated with an increased diameter and differences in these sections.

Closest to the proposed. the technical essence is a roll of a three-roll rolling mill that contains working areas: an input cone, a ridge, a rolling section, a calibration section; and a non-contact section forming a pipe profile located between the roll and calibration section. The sufficient length of the non-contact section of profile formation, as a result of reducing alternating stresses, reduces the lateral deformation and overfill size of the caliber, rounds the profile of the pipe and allows rolling: pipes with a ratio of diameter to thickness: 8-12 G 3.

However, the further growth of thin bones of pipes is limited by the final stage of the process, which is inherent

the intense growth of transverse deformation of the metal, leading to overfilling of the caliber of caliber, to an increase in the slip of the metal in the rolls. In this case, the non-working area on the roll, which shows a restraining effect on the development of transverse deformation in. the stabilization phase of the process plays a negative role: it causes an increase in the contact resistance forces in the axial direction, thereby preventing the pipe from moving in the rolling direction.

Therefore, the instability of the rolling of tubes with D / S 12, the facetedness of the end sections, the loss of the rolling rate and productivity are the main drawbacks of the known roll, the surface roughness of which is 1.5-6.0 microns.

The purpose of the invention is to increase the stability of pipe rolling with the ratio D / S .12.

The goal is achieved by the fact that in the roll of a three-roll rolling mill containing working sections on the barrel, and areas of non-contact profile formation, areas of non-contact profile formation are made from a surface roughness of 15-25 times greater than the surface roughness of working areas.

In the unsteady phases of the process, the level of axial friction forces increases with the contact interaction of the seamed cross-section tubes with the rough surface of the non-working section, which reduces the metal slip relative to the roll and ensures a reliable and stable process flow.

In the schematic drawing, a roll is shown in the established period of tube expansion.

The roller includes a working section — an inlet cone 1, a non-working section for non-contact forming a profile, a reverse cone 2, working sections for a ridge 3, a rolling section 4, a non-contact section 5 for non-contact forming a profile. Non-working areas 2 and 5 are made with a surface roughness of 15-25 greater surface roughness of the working areas

The amount of surface roughness in areas of non-contact profile formation in. 15-25 times more than in work areas, selected on the basis of experiments to change the coefficient of friction depending on the surface roughness

The surface roughness of the non-working area of non-contact forming profile provides an increase in the coefficient of friction in l, 8-l3 P

The surface of the non-working area of the rolls, the roughness of which is less than 15 times the shero; hawkishness; working areas, will increase the coefficient of friction by only 5-20%, which is completely insufficient for axial pulling forces and reliable Q top of the process of rolling a thin-walled tube.1 Performing a section with a non-contact forming a profile with a roughness of T1 / greater than 25 times does not result A further increase in the coefficient of external friction and, in addition, degrades the quality of the outer surface of the pipe. The roller works as follows. The sleeve with the mandrel is gripped by the working section — the inlet cone G on which the wall is reduced. sleeve. In this case, the BO3HHtcai6 stress from deformation is sufficient to overcome the resistance of the working section — ridge 3, on which the main deformation along the wall is carried out. With further advancement of the front end of the pipe along the deformation zone, the frictional interaction of the ovalized end of the pipe with the surface of the non-working section 5 occurs. As the coefficient of friction increases, the metal decreases relative to the roll, which contributes to the stability of the filling process. In the established stage of the process, non-working areas do not contact the surface of the rolled pipe due to the slight ovality of the cube sections in these zones. At the end of the pipe rolling, the perimeter of the rear end increases, its surface contacts the non-working areas, resulting in the completion of the process stage steadily., with a sufficiently high speed. Example. As an example of a roll mill roll, a three roll mill roll with lengths th barrel of 370 mm and diameter (maximum 450 mm. For rolling hot rolled pipes of size (60-180; x (6-16)) the roll is made of the following consecutive sections, with a surface roughness, m: Input taper 1-2.5 , Non-working area 2-40, Comb 3 - 2.5 Spread area 4-2.5, Non-working area 5-60 Calibration section 6-2.5, Non-working sections 2 and 5 are made with surface roughness, respectively, 16 and 24 times as large than working sites. The values of the coefficient of three. The roll areas for rolling pipes from carbon steels in the temperature range -1100-1200С are presented in the table in comparison with the known roller-protot.yp. The proposed roll allows an increase in the axial rolling speed by 14-18%, does not require significant costs, and can be used on rolling mill, gauge and piercing mills. The annual economic effect of the proposed technical solution is about 36 thousand rubles. in year.

Claims (1)

A three-roll roll RASKAT- 'MILL-TERM comprising working on the barrel portions and non-contact portions form a profile -o r l and h and D with Yui I that, in order to increase the stability of rolling tubes with a ratio of diameter to wall thickness, Major ¹ 12, sections of non-contact profile formation are made with a surface roughness of 15-25 times greater than the surface roughness of the working sections.