RU2157282C1 - Roll grooved pass system of continuous rolling mill - Google Patents

Abstract

FIELD: plastic metal working, namely manufacture of rolled bars. SUBSTANCE: system includes successively arranged roll grooved passes formed by roll pairs mounted with predetermined gap in rolling stands. Some rolls of roll pairs have cut-in portions in upper or lower roll. System includes in addition grooved passes formed by vertical rolls between which there are rolling stands with smooth horizontal rolls. First pass and pass arranged in front of shaped grooved passes have vertical rolls; last passes are shaped ones, they have alternating cut-in portions in upper and lower rolls. Transporting pass with vertical rolls is arranged in front of finishing passes. EFFECT: enhanced efficiency, geometry and properties of rolled sections due to high accuracy of deformation process. 1 dwg

Description

 The invention relates to rolling production and can be used in the manufacture of hot-rolled strip sections.

 Such profiles are characterized by the fact that the width of their cross section is much greater than the height, and the shape of this section can be very diverse (see, for example, the reference book of V.V. Lempitsky et al. “High-quality rolled profiles.” M., “Metallurgy”, 1981, p. 461-464). Strip profiles are usually produced on high-quality continuous mills (such as mill 300-2 of OJSC Magnitogorsk Iron and Steel Works), duo stands of which contain both rolls with a smooth barrel, and with cuts (streams) of a certain configuration, forming successive calibers, with calibrated cuts complex shape is called shaped. The combination of all mill calibers forms a system suitable for rolling a specific profile. Some gauge systems are given, for example, in the book by P.I. Polukhin "Rolling production". M., "Metallurgy", 1982, p. 276-301.

 A known system of draft calibers of rolling rolls for rolling flange asymmetric profiles, containing closed gauges with alternating disclosure of flanges in the direction of short and long flanges, some of the gauges are located at a certain angle to their neutral line (see A.S. USSR N 1380812, class. B 21 V 1/08, dated December 16, 85). A double-roll exhaust gauge system is also known, containing successively arranged round (or rib oval) gauges with a given ratio of caliber height to diameter, as well as flat oval gauges with a convexity of the bottom, determined by mathematical dependence (see A.S. USSR N 1360829, class . At 21 V 1/00, dated December 27, 85).

 These gauge systems are not applicable for the production of strip section profiles on continuous hot rolling mills.

 The closest analogue to the claimed object is a gauge system (calibration scheme) for rolling the grooved spring, given in the book of N. V. Litovchenko "Calibration of profiles and rolling rolls." M., "Metallurgy", 1990, p. 248, fig. 131a.

 This gauge system of a continuous hot rolling mill contains successively arranged gauges formed by pairs of rolls installed in stands with a given gap, some of which are made with cuts on the upper or lower roll and are characterized by the fact that the second gauge is formed by two groove rolls, and the subsequent shaped gauges are closed (i.e., the lines of the connector of their rolls are outside the caliber).

 The disadvantage of such a gauge system is the impossibility of obtaining using it some special strip profiles, for example, a ploughshare profile for a plow (see the aforementioned reference book of V.V. Lempitsky, p. 462, Fig. 360).

 A modern continuous varietal mill consists of a sufficiently large number of sequentially installed successive stands. For effective rolling of strip profiles on such a mill at higher (compared to non-continuous mills) speeds, an increased roll length is required, which reduces pauses (ie, increases productivity in the “hot” hour) and optimizes the temperature of the rolls heated by the metal (the smaller changes in this temperature - the higher the accuracy of rolling). This is possible when large (11 ... 12-fold) hoods are achieved, which forces the use of stands with smooth roll barrels, providing large reductions and a hood of up to 50%. But after several passes in such stands, “control” of the width of the roll is necessary, which is carried out by vertical rolls with small (within 0.5 ... 5.0%) hoods.

 An object of the invention is to increase productivity and improve the geometry and properties of strip shaped sections rolled on a continuous mill.

 To solve this problem, the gauge system of a continuous mill, containing successively arranged gauges formed by pairs of rolls installed in stands with a given gap, some of which are made with cuts on the upper or lower roll, additionally contains gauges formed by vertical rolls, between which stands with horizontal smooth rolls, while the first gauge and located in front of the shaped gauges are made with vertical rollers, and the last calibers are shaped, with alternating cuts on the upper and lower rolls, and in front of the finishing gauges is a transport gauge with vertical rolls.

 The essence of the claimed technical solution, first of all, consists in the fact that calibers with vertical rolls are added to the system, providing the necessary accuracy along the strip width (for large reductions by rolls with smooth barrels, the strip broadens from passage to passage, which must be periodically "controlled"). In addition, gauges (vertical and shaped), as well as rolls with smooth barrels, are located in a certain sequence.

 So, the first caliber - with vertical rolls, compressing the side faces of the original workpiece. This, as shown by experiments (see below), contributes to the "rolling out" of some defects inherent in a hot-rolled billet and most manifesting itself during large reductions by horizontal rolls (cracks, hairlines, etc.), i.e. after the first pass, the strip can pass through several (two to four) pairs of horizontal rolls with a significant exhaust. A gauge with vertical rolls is also located in front of the shaped gauges, in which it is difficult to “control” the width of the roll.

 In order to maintain a given speed mode (which is especially important for a continuous mill), a transport gauge with vertical rolls is installed in front of the finishing (usually two) gauges, which eliminates any undesirable effects on the shaped upper and lower faces of the profile, and improves its geometry. The caliber is called "transport", since it does not have deformations of the cross section of the rolled strip.

 The alternation of cuts into the rolls of shaped calibers (with the simultaneous alternation of the direction of inclination of the side walls of the calibers - see the drawing) was done to prevent the metal from “flowing” into the connectors between the rollers, which prevents the appearance of a characteristic defect “mustache”.

 The proposed gauge system is schematically shown in the drawing (the most characteristic calibers are given).

 The first gauge (I) of the system is formed by vertical rolls 1, forming the side faces 2 of the rolled strip 3. After this gauge, there are pairs (II) of horizontal rolls 4, compressing the upper 5 and lower 6 faces of the roll, and after them again caliber (III) with vertical rolls preceding the following pairs (IV) of horizontal rolls. In front of the first shaped gauge (VI), there is another gauge with vertical rolls (V). The cuts in the rolls of shaped gauges alternate - with caliber VI, the cut is made in the lower roll 8, and the protrusion on the upper roll 7; while the connector 9 between the rollers is at the top, and the inclination of the side walls of the 10 gauge is out. In the subsequent shaped gauge (VIII), the cut-in is made in the upper roll 7, the protrusion on the lower roll 8, the connector 9 between the rollers is at the bottom, and the side walls of the 10 gauge are inclined in the opposite direction than that of the caliber VI. The transport gauge (VII) is located between the shaped gauges and before the first finishing gauge. Shaded sections - peals.

 An experimental verification of the found technical solution was carried out on a continuous high-grade mill 300-2 of OJSC MMK during rolling in 14 stands of an asymmetric share plow from station 50 (profile 142 СУх9х5.5 mm) with a finished profile width of 142 mm, its maximum height (along the protrusion on the upper edge) is 12.5 mm and the thickness of the side edges is 5.5 and 9 mm. Section of the original blank; height - 124 mm, width 124 mm. For this purpose, the location of calibers with vertical rolls and stands with horizontal rolls, as well as the transport caliber, were varied. The best results (maximum performance and the geometry of the plowskin strip, fully meeting the requirements of consumers) were obtained using the inventive caliber system. Other options for the location of these calibers, as well as the presence of similar cuts into the rolls of at least one pair of adjacent shaped calibers, led to a decrease in productivity by 8 ... 23% (depending on the chosen option), as well as to a deterioration in the geometry of the finished profiles and their sorting (within 1.5 ... 7%) by size and various surface defects.

 Rolling according to the well-known scheme, taken as the closest analogue (see above) and not containing calibers with vertical rolls and transport gauge, gave the productivity in the "hot hour" less than when using the inventive system, by almost 60%; up to 6% of the profiles were sorted by size and defects.

 Thus, the experiments confirmed the acceptability of the proposed system of calibers for solving the task and its advantages over the known object.

 According to the Central Control Laboratory of OJSC Magnitogorsk Iron and Steel Works, the use of the claimed technical solution when rolling 300-2 shaped strip steel (plowskin type) at the mill increases productivity by an average of 1.3 times and yield to 99.5% with the corresponding reducing the cost of rental and increasing profits from its sale.

Concrete example
Shaped plowskin strip from st. 50 (profile 142СУх9х5.5 mm) is rolled from a billet with a section of 124x124 mm and a length of 8 m on a continuous high-quality mill with a rolling diameter of horizontal rolls of 300 mm.

 Rolling is carried out in 14 stands, of which: I, V, VIII and XII - with vertical rolls, II, III, IV, VI and VII - with smooth rolls, and IX, X, XI, XIII, XIV have rolls with shaped gauges , with alternating cuts (in the upper or lower roll); XII crate - transport.

 Total hood in calibers = 12.0.

 Range hoods (during rolling): 1.004 (B - caliber with vertical rolls); 1.235; 1,331; 1.490; 1.029 (B); 1.295; 1,325; 1.044 (B); 1,253 (this and further - shaped closed gauges); 1.285; 1.222; 1.225; 1,072.

 The average rolling speed (at the exit) is 2.8 m / s.

Claims (1)

 A system of gauges of a continuous mill for hot rolling of strip profiles, comprising successively arranged gauges formed by pairs of rolls installed in stands with a given gap, some of which are made with cuts on the upper or lower roll, characterized in that the system further comprises calibers formed by vertical rolls, between which stands with horizontal smooth rolls are installed, while the first caliber and located in front of the shaped gauges are made with vertical rolls, and ednie gauges - shaped, with alternating incisions on the upper and lower rollers, and is located upstream of the finishing caliber transport caliber with vertical rolls.