RU2405637C1 - Method of rolling - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: rolling of dual sectional bars comprises billet heating, rolling the biller at rough intermediate gages of the stand to form dual roll stock, lengthwise separation into two lines and rolling said lines at leader gages and finishing gage "square". Elimination of barbs resulted from separation into two lines is made by rolling said lines through leader gages "square-rhomb". Note here that finishing gages "square" is adjusted prior to rolling by means of lengthwise displacement of one roll relative to another so that top edge of square on top roll is displaced for 0.10-0.15 mm with respect to bottom edge of square on bottom roll. Note also that in rolling aforesaid lines through leader gage "square", every line is canted for 90 degrees at 5.5 m to the next leader gage "rhomb" so that rolling-up of the separation traces on each line is performed at leader gage "rhomb" and finishing gage "square".

EFFECT: higher quality of sectional bars.

5 dwg

Description

The invention relates to rolling production, and in particular to methods of rolling varietal profiles in double form with a longitudinal division of the roll in the mill stream, namely square profiles.

A known method of rolling according to the patent of the Russian Federation No. 2164177, IPC B21B 1/02 with a priority date of 02.16.1999, in which, to improve the quality of finished profiles obtained by double-thread rolling-separation, a technological process for reducing burrs at the point of separation of articulated workpieces is proposed. To do this, before separating the articulated workpieces from both sides of the connecting jumper, they roll V-shaped risks, which, when the jumper is stretched in the separating gauge, limit the propagation of plastic shear deformation along the width of the jumper, which reduces the burrs at the junction break point. When implementing this method in production, a high-quality smooth rolled surface is not provided, because In this invention, the task of reducing the size of the burrs, and not the complete elimination of the burrs on the surface of the finished product, is solved.

Known small-section mill "320" company STG (Italy), in which the technological process of rolling an assortment in a "single thread" includes heating the workpiece, rolling the workpiece through rough, intermediate, finishing and finishing rolls. After transshipment of the mill, it is possible to implement a method of rolling a twin bar, which passes through heating the workpiece, rolling the workpiece through rough, intermediate rolls, on which the double rolling is formed, which is divided into two threads before the prefinishing rolls. For all rolled product assortments in one thread, there are no complaints about the quality of the finished product, just as there are no claims to double rolling, except for making hot rolled 10 × 10 mm square bars in the method of rolling a double bar with separation of the roll in cages and passing through the finishing rolls “rhombus (oval ) ”-“ square ”-“ rhombus ”and finishing rolls“ square ”. With this rolling technology, there is no complete “roll-in” of separation traces, since the roll-in of tracks itself is assigned to the prefinishing rolls, the first “square” and the second “square” plus the finishing rolls “square”. The practice of operating the “320” mill has shown a sufficient level of output of low-quality products in order to set the task of increasing the output of high-quality rolled square products, as double rolling increases the “hot productivity” of the finishing mill (and the rolling mill as a whole) by 2 times, which, taking into account technological pauses between the billets entered into the mill, increases the hourly output by not less than 40% compared to single-strand rolling. At a bar exit speed of 10 m / s and production of a 10 × 10 mm square profile, the metal exit speed from the first (rough) mill stand is 0.17 m / s, which, due to an increase in the speed of rotation of the rolls of the first stand, reduces heat cast iron rolls in the deformation zone (shorter contact time between the hot workpiece and the gauge sections), reduces the temperature drop of the metal when passing through the mill stands, thereby facilitating the deformation process.

The objective of the invention is to improve the quality of the surface of the rolled product of the finished product by rolling down the burrs from a longitudinal rupture into two threads of square profiles in double form into the rolled body while reducing the number of passes of the formed square rolled at the stage of pre-treatment.

The technical result achieved by using the invention consists in rolling the burrs into the body of the rolled square-shaped threads due to the high degree of deformation in the pre-finishing caliber "rhombus" and the finishing caliber "square".

This problem is solved by the fact that in the method of rolling double square profiles, including heating the workpiece, rolling the workpiece through draft, intermediate gauges forming double rolled products, its longitudinal separation into two threads, rolling the threads through the finishing and finishing caliber "square", according to the invention, rolling the thread is guided through the square-rhombus pre-finishing gauges, while the square pre-finishing gauge is adjusted before rolling by longitudinally displacing one roll relative to another by an amount in the range it is 0.10-0.15 mm, and when rolling the threads through the pre-finishing square gauge, turn each thread 90 ° at a distance of 5.5 m to the next pre-finishing stand with the rhombus gauge, and the separation traces are rolled up on each thread in the final caliber “rhombus” and the final caliber “square”.

Figure 1 presents the layout of the equipment of the mill "320" company STG (Italy).

Figure 2 presents the scheme of double thread rolling of a square profile of 10 × 10 according to the technological instructions of the company STG (Italy).

Figure 3 presents according to the invention a scheme of double-thread rolling of a square profile of 10 × 10.

Figure 4 presents the geometric parameters of the "square" of the final group of rolls.

Figure 5 presents a system of forces creating a tilting of the thread of a square of 10 × 10 after exiting from the rolls "square" of the final group of rolls.

The mill "320" (figure 1) consists of a furnace 21 for heating billets, from a sequence of stands of continuous numbering from 1 to 20.

For rolling in one thread, the draft group of calibers 22 is placed in stands 1 to 6, the intermediate group of calibers 23 is placed in stands 7 to 14, the finishing group of calibers 24 is located in stands 15 to 17, the finishing group of calibers 25 is located in stands 18 20. The distance between the stands is fixed.

When rolling at the “320” mill, section profiles are doubled, the mill is transshipped by connecting a box (not shown) between stands 14 and 15 with non-driven wedge rollers that break the two-strand rolling into two threads in the longitudinal direction.

Figure 2 shows the gauges 14, 15, 16, 17, 18 stands used when using the technological scheme of the company STG (Italy).

Figure 3 shows the gauges 14, 15, 16, 17, 18 stands according to the invention, namely, when transshipment of the mill "320" for rolling a double square profile rolls with caliber profile "rhombus" are removed from stand 15, rolls with caliber profile " square ”from stand 16 are rearranged into stand 15, and the rolls removed from stand 16 are replaced by a tray that provides a high-quality task for the end of hire in the pre-finished gauge 17“ rhombus ”. The square gauge in stand 15 is adjusted by longitudinally displacing the rolls relative to each other by a longitudinal displacement in the range of 0.10-0.15 mm, as shown in FIG. 4. Such a small violation of the symmetry of the "square" with respect to the vertical axis creates a pair of forces, as shown in Fig. 5, and leads to a tilt of each filament along the longitudinal axis. When turning the square rolled filament by 90 °, the burr from a horizontal position in the gauge “square” of stand 15 goes into a vertical position in gauge “rhombus” of stand 17, which provides a significant (about 35% of the diagonal of the square coming out of stand 15) transverse deformation sections of the square along the vertical axis when turning it into a rhombus.

Experimentally, a range of 0.10-0.15 mm of longitudinal displacement of rolls with caliber “square” of stand 15 was established, providing a tilting of 90 ° of the rolled wire and a high-quality task of the end of rolling in caliber “rhombus” of stand 17 installed at a distance of 5.5 m from stand 15.

Using this method actually ensured a high-quality surface of the faces of square rolled products on the mill "320" in the case of using double rolled.

Claims (1)

A method of rolling double square profiles, including heating the workpiece, rolling the workpiece through draft, intermediate gauges forming double hire, its longitudinal separation into two threads, rolling the threads through the pre-finishing and finishing caliber "square", characterized in that the rolling of the threads is carried out through pre-finishing calibers "Square-rhombus", while the final square gauge is adjusted before rolling by longitudinally displacing one roll relative to another so that the upper edge of the square the upper roll is offset by 0.10-0.15 mm relative to the lower edge of the remaining part of the square on the lower roll, and when rolling the threads through the pre-square gauge, each thread is turned 90 ° at a distance of 5.5 m to the next final gauge "Rhombus" for seaming traces of separation on each thread in the pre-finishing caliber "rhombus" and the final caliber "square".

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