RU2710410C1 - Method of rolling rails - Google Patents

Abstract

FIELD: transportation; technological processes.

SUBSTANCE: invention relates to rolling of railway rails at rail rolling mills equipped with continuous-reverse set of stands. Method involves production of initial rail billet in duo-reversing stands, its further rolling in continuous-reverse group of stands in three passes, where in the first and second passes formation of the profile is carried out in the following sequence: universal four-roll gauge – auxiliary two-roll gauge – universal four-roll gauge, and in third pass: universal four-high-speed gauge – auxiliary two-roll gauge – finishing universal three-roll gauge, where universal rolls of universal four-roll and final three-roll gauges are made with slopes to vertical of side faces forming internal faces of flanges of profile bottom. Possibility of improvement of straightness, geometry of profile and mechanical is ensured by the fact that in the third pass the profile is further formed with a pre-clean universal four-roll gauge according to the scheme including the following sequence: universal four-roll gauge – two-roll auxiliary – pre-clean four-roll gauge – finishing three-roll gauge, at that, the value of the slopes of side faces of horizontal rolls of universal four-roll gauges, including those of pre-cleaning, is 1.14÷1.30 of slope value of corresponding lateral faces of horizontal rolls of finishing three-roll gauge.

EFFECT: possibility of improving straightness, profile geometry.

1 cl, 12 dwg

Description

The invention relates to the field of ferrous metallurgy, in particular to methods for rolling railway rails, and can be used in the manufacture of rails with increased requirements for the straightness of rails, profile geometry and mechanical properties on rail and beam mills equipped with a continuously reversible group of stands and a stand-alone finishing universal three-roll crate.

A known method of rolling rails using universal stands (Svejkowski U., Nerzak T. Production of high quality rails using compact universal stands and Rail Cool technologies. Metallurgical production and technology (MRI). Russian edition. 2006, No. 2. P. 50- 56), (Svejkowski U., Nerzak T. Production of rails using cassette stands and modern cooling technologies // Ferrous metals. 2008, No. 1. P. 32-36). This method is illustrated by the diagrams in FIG. 1 and 2.

In FIG. Figure 1 shows the layout of the working stands of a typical rail and beam mill, which consists of a crimping reversible stand duo I, a rough stand duo II and a continuously reversing stand group including a universal reversing stand III, an auxiliary (edger) stand duo IV and a universal three-roll non-reversing stand V.

In FIG. 2 shows the rolling scheme in the indicated stands (arrows indicate the sequence of passage of calibers, Arabic numerals indicate the numbers of passes in the continuously reversing group of stands).

The rolling method is implemented as follows (Fig. 2). In roughing stand II, a rough rail profile is obtained, which is transferred along the rolling process to a continuously reversible group of stands and rolled in it in three passes, the first pass being carried out in a universal four-roll gauge of stand III and an auxiliary two-gauge gauge in stand IV (universal stand V is not used , its rolls are divorced), in the second reverse passage one universal four-roll caliber of stand III is used (auxiliary stand IV is not used, its rolls are divorced), the third pass is carried out with Using all three crates in the universal four-high, auxiliary and a two-roll finishing universal three-roll calibers. Thus, with three passes in the continuously reversing group of stands, two reverses are performed, and stands IV and V are not used in two passes, i.e. in three passes, three stands are not used in rolling.

The use of significant profile compression at the last stages of its formation in universal and edger calibers using reverse rolling in these stands according to this method leads to the fact that the rail head lengthens more than the sole. In this regard, the roll tends to bend, and this bend is the greater, the more significant the compression profile during rolling. Under the conditions of reverse rolling and the impossibility of directing the roll in the cages of a continuously reversing group with the help of rolling reinforcement, due to the invariance of its position, the rolling process by this method is characterized by instability and great complexity when setting up the mill. In addition, rolls are injured due to improper grip of the roll in the caliber, which leads to defects on the finished rails in the form of foam and imprint.

In addition to the disadvantages of the rail rolling scheme without the use of a stand-alone finishing stand, there is also the presence of a continuous rolling mode in the last pass in a continuously reversing group of stands with the participation of the finishing gauge. As a result of the failure to provide a stable minimum tension when the rolled stock is in the last pass in the rolls of three stands of a continuously reversible group due to changing rolling conditions in the form of wear of the rolls, temperature difference along the length of the roll, fluctuations in the chemical composition of steel and other factors affecting rolling, the output of rails of increased accuracy along the profile is significantly reduced, and the metal consumption per ton of suitable products increases due to increased end trim.

A known method of rolling rails using a continuously reversible group of stands and a stand-alone finishing stand. In connection with such a layout of the mill, the pattern of rolling the rails at the finishing stage also changes. This rolling process is called the PSM (Profile Sizing Process) (Profile sizing process for high-quality medium / heavy sections rails / Nigris G, Schroder I // MFT International. 2002, No. 3. C. 48-54), (Zinoviev AB The PSP process for the production of medium and large sections and rails // News of the steel industry abroad. 2003, No. 2. S. 69-72), presented in the diagrams of FIG. 3 and 4. The method is implemented on a mill (Fig. 3), including a draft reversing stand I, a continuously reversing group of stands consisting of two universal four-roll stands II and an auxiliary stand duo III located between them, as well as a stand-alone finishing universal three-roll stand IV .

In FIG. 4 shows a diagram of the rolling of rails in the indicated stands (arabic numbers indicate the numbers of passes). The draft roll from the reversing stand I is rolled in a continuously reversing group of stands in 5 passes. In this case, in the first pass, only auxiliary stand III is used (both universal stands II are not used in work, their rolls are divorced), in the second and fourth passes only rear stand II is used (auxiliary and front universal stands are not used in work, their rolls are divorced) , and in the third and fifth passes, rolling is carried out in the front universal stand II and auxiliary stand III (do not use the rear universal stand, its rolls are divorced).

The disadvantages of this method are:

- reduction in mill productivity due to the use of five passes with four reverse rolls in a continuously reversing stand group;

- an intensive decrease in the temperature of the roll in a continuously reversing group of stands in connection with an increase in the rolling cycle of the profile.

Another very important drawback of the above analogues is the consistent use in the last pass of two calibers with a horizontal connector on the head side: auxiliary pre-finishing two-roll caliber of stand III and the final universal three-roll caliber of stand IV (Fig. 2 and 4). In this case, the rolling surface of the head of the rail profile in the gauge is not controlled and is formed due to the flow of metal across the width in the direction of the gap, which makes it possible to overfill the head into the gap, as well as the oscillation of the width of the head in the gauge along the rail length under the influence of an inevitable change in technological factors (for example temperature of the roll) during the rolling process. This makes it difficult to obtain the required shape and high accuracy of rail head dimensions, which must be made in accordance with GOST R 51685-2013 and have stable dimensions along the length of the rail.

There is also known a method of rolling rails, including obtaining a draft rail roll in a crimping and rough reversing stands and rolling this roll in a continuously reversible group of stands, where the resulting draft roll is set in a continuously reversing group of stands by the rear side (against the rolling direction) and rolled into it in two passes using the following rolling scheme:

- in the first pass: a universal four-roll caliber - an auxiliary two-roll caliber - a universal four-roll caliber;

- in the second pass: a universal four-roll caliber - an auxiliary two-roll caliber - a universal four-roll caliber - a final universal three-roll caliber.

The essence of the method is illustrated by the diagrams in FIG. 5 and 6. FIG. 5 shows a layout of stands of a rail rolling mill. To implement the proposed method, a U-shaped stand arrangement is used. On the first line, there is a crimping reversible stand I and a draft reversing stand II, and on the second (return) line, a continuously reversible group of stands is set consisting of two universal four-roll stands УК1 and УК2, an auxiliary stand duo VK and a finishing universal three-roll stand УК3. Moreover, the universal universal stand can be installed both as part of a continuous group or separately (Patent 2429090 of the Russian Federation, IPC B21B 1/08. Method for rolling rails / Kushnarev A.V., Kirichkov A.A., Egorov V.D. [and dr.] No.2010114609 / 02; claimed on April 12, 2010; published on September 20, 2011, Bull. No. 26).

In FIG. 6 shows a rolling scheme for this method. In roughing stand II receive a rough rail peal. The resulting roll is passed by the slappers to the second line and set from the back into a continuously reversible group of stands, and in the first pass the finishing stand УК3 is not used (its rolls are separated), rolling is carried out in a universal four-roll caliber of stand УК2, two-roll auxiliary caliber of stand ВК and universal four-roll caliber of stand UK1. After the reverse, the roll in the second pass is rolled in a universal four-roll gauge of a stand of UK1, a two-roll auxiliary gauge of a stand of VK, a universal four-roll gauge of a stand of UK2 and in a finishing universal three-roll gauge of a stand of UK3.

The disadvantages of this method are:

- a limited number of universal calibers involved in the formation of the profile in a continuously reversing group of stands, which impairs the accuracy of the formation of the geometry of the profile;

- The U-shaped arrangement of the mill stands in comparison with the sequential arrangement requires the expansion of the spans of the building, which leads to a rise in the cost of crane facilities and maintenance of communications, as well as the need to install additional transmission mechanical equipment on the site of the mill.

A known method of rolling rails, including obtaining a draft rail roll in a crimp duo-reversing stand and its further rolling in a continuously reversible group of stands, consisting of two universal four-roll stands, located between them auxiliary stands duo and finishing universal three-roll stand (Patent 2668626 RF, IPC B21B 1/08. Method of rolling rails / Mikhailenko AM, Schwartz DL No. 2017115538; claimed 02.05.2017; publ. 02.10.2018 Bull. No. 28).

In FIG. 7 shows a diagram of rolling rails in said stands. The draft roll from the reversing stand I is rolled in a continuously reversing group of stands (II-IV), and the final profile formation is carried out in a finishing three-roll stand (V). The first pass in the continuously reversing group of stands is performed using the auxiliary duo (III) stand and the second, in the main direction of rolling, universal four-roll stand, the second pass is using two universal four-roll stands (II and IV) and the auxiliary duo (III) stand between them, the third pass - using the first universal four-roll (II), auxiliary (III) and final three-roll universal (V) stands. With this rolling scheme, the width of the crests of the horizontal rolls of the universal four-roll stands II and IV forming the neck of the profile is set larger than the width of the neck of the profile of the roll set in the caliber of the universal four-roll stands during rolling. Expansion of the neck of the crests of horizontal rolls of universal four-roll stands is carried out to a width calculated by mathematical expressions, depending on the compression of the neck in the first universal four-roll calibers of these stands during rolling.

The presented method of rolling rails allows to stabilize the rolling process in the first passes in the rolls of universal four-roll stands (II and IV) of a continuously reversible group.

The disadvantages of this method are:

- limiting the number of universal four-roll calibers involved in the formation of the profile in a continuously reversible group of stands, which leads to greater deformation of the profile elements, the development of calibers and the failure to obtain the required geometric dimensions of the profile;

- the use in the last pass of two calibers with a horizontal connector on the head side: an auxiliary two-roll caliber of stand IV and a finishing universal three-roll caliber of stand V leads to an overflow of caliber.

The closest in its technical essence and the achieved results to the proposed invention (prototype) is a method of rolling rails using a continuously reversible group of stands and a finishing stand for the final formation of a profile located in close proximity to a continuous group (Improving the quality and operating conditions of rails and rail fastenings : Collection of scientific reports. - Yekaterinburg: OAO UIM. 2016. P. 45-49). The method includes heating the workpiece, rolling to obtain a rough rail profile in a two-roll stand, which is transferred along the rolling process to a continuously reversible group of stands and rolled in it in three passes, the first pass being carried out in a universal four-roll gauge of stand UR1, an auxiliary two-roll gauge of stand EDGER and in the universal four-roll gauge of the UR2 stand, in the second reversing passage, the universal four-roll gauge of the UR2 stand, the auxiliary two-roll caliber of the EDGER stand and uni rsalny four-high stand caliber UR1, a third pass is performed using a universal four-high stand UR1 caliber auxiliary EDGER twin roll stand and the finishing universal caliber three-roller stand caliber UF (UR2 universal stand is not used, it rolls diluted) Fig. 8.

The disadvantages of the prototype method are:

- a limited number of calibers involved in the formation of the profile at the last stage of rolling in a continuously reversible group of stands, which leads to an unstable obtaining of the geometric dimensions of the profile;

- sequential use in the last pass of two calibers with a horizontal connector on the head side: an auxiliary two-roll caliber of the EDGER stand and a finishing universal three-roll caliber of the UF stand, which leads to overflow of the gauge on the side of the profile head during the rolling process;

- when forming the final profile of the rail in the continuous rolling mode, a stable minimum tension is not ensured when the rolled stock is in the last pass in the rolls of three stands due to changing rolling conditions in the form of wear of the rolls, temperature, fluctuations in the chemical composition of steel and other factors affecting the rolling , the yield of rails of increased accuracy along the profile is significantly reduced, and the metal consumption per ton of suitable products also increases due to increased end trim.

Rolling of rails in universal stands on modern rolling mills equipped with continuously reversible groups of stands is carried out in different ways, but with an equal slope of the internal profile flanges (side faces of horizontal rolls) in all universal calibers (Smirnov V.K., Shilov V.A., Inatovich Yu.V. Calibration of rolling rolls. Textbook for universities. 2nd edition revised and supplemented. Moscow: Teplotekhnik, 2010. - 490 p.).

Under such rolling conditions, the absolute compression of the flanges along the length in universal calibers is carried out by the same amount, while the coefficient of height deformation along the length of the flange increases from the base to the edge. The highest value of the coefficient of vertical deformation corresponds to the edge of the flange, which has the smallest size in thickness. Due to the smallest size in thickness, the edge of the flange during the rolling process loses temperature faster and when rolling the rails in the final universal gauge, the temperature difference along the edge and base of the flanges of the base of the profile can be 35–40 ° С. The combination of factors such as the highest coefficient of height deformation of the edges of the flanges of the sole and the lowest temperature during rolling of this profile element during the forming process of the roll in universal gauges leads to the intensive development of horizontal rolls in places corresponding to the formation of the edges of the flanges of the sole of the rail profile, which is the main factor determining the rolling resistance rolls. When rolling rails in universal gauges, horizontal finishing rolls have the least resistance. To the above factors that increase the production of rolls of the finishing universal stand, it is also necessary to add the factor of additional compression in the finishing gauge of the flange edge due to the forced broadening of this edge in the prefabricated two-roll edger caliber during compression of the flange in height, which also applies to the prototype.

This is due to the fact that in the known methods of rolling rails, where the two-roll caliber of the edger stand is used as the finishing gauge, in which the flange is compressed in height without lateral support, the flange broadening consists of natural and forced broadening (V. Smirnov, Shilov V.A., Inatovich Yu.V. Calibration of rolling rolls. Textbook for universities. 2nd edition revised and supplemented. M: Teplotekhnik, 2010. - 490 p.). The forced broadening appears as a result of vertical compression of the sole in the horizontal auxiliary stand, as a result of which local metal flows are formed at the top of the flanges (edges), which aggravates the intensity of the rolls in the places of the corresponding deformation of the edges of the flanges of the sole of the rail profile in universal gauges. This leads to a distortion of the profile shape along the length and the formation of surface defects of the rails, as well as to an increased consumption of rolling rolls.

The aim of the invention is a more efficient use of stands in a continuously reversible group, increasing the straightness of the rails, the accuracy of the dimensions of the finished profile and increasing the resistance of the rolls of the finishing universal stand.

The technical result consists in the fact that the proposed method of rolling the rails allows to achieve high-quality design of the geometric parameters of the profile during the rolling process and to increase the resistance of the rolls of the finishing universal stand.

The technical result is achieved by the fact that in the method of rolling rails, including obtaining the original rail billet in the duo-reversing stands and further rolling in a continuously reversing group of stands in three passes, where in the first and second passes the profile is formed sequentially in a universal four-roll, auxiliary two-roll, universal four-roll calibers, and in the third pass: universal four-roll caliber - auxiliary two-roll caliber - final universal three-roll caliber, g de horizontal rolls of universal four-roll and fair three-roll calibers are performed with slopes to the vertical of the side faces forming the inner faces of the flanges of the sole of the profile, characterized in that in the third pass, the profile is additionally formed with a pre-clean universal four-roll caliber according to a scheme that includes the following sequence: universal four-roll caliber - auxiliary two-roll - prefinishing universal four-roll caliber - finishing universal tr ehalkovy caliber, while the slopes of the side faces of the horizontal rolls of universal four-roll calibers, including the pre-clean, set as 1.14 ÷ 1.30 the slope of the corresponding side faces

horizontal rolls of a finishing universal three-roll caliber.

The design of universal four-roll calibers in which horizontal rolls are performed with slopes of the side edges forming the inner faces of the flanges of the sole of the profile and constituting 1.14 ÷ 1.30 of the slope of the side faces of the horizontal rolls in the finishing universal three-roll caliber allows the deformation of the flanges of the sole in the finishing universal three-roll caliber with the equality of the coefficients of height deformation of the thickness of the flanges along the base and edges, which approximately halves the absolute compression of the cut Mock and roll production.

Performing slopes of the side faces of horizontal rolls for all universal four-roll calibers, including for prefinishing, less than 1.14 values of the slope of the side faces of horizontal rolls of a clean universal three-roll caliber does not sufficiently reduce edge compression and, therefore, the production of rolls in a finishing universal three-roll gauge.

Performing slopes of the side faces of horizontal rolls for all universal four-roll calibers, including for prefinishing, more than 1.30 of the slope of the side faces of horizontal rolls of a clean universal three-roll gauge leads to the absence of compression of the edges of the flanges of the bottom of the rail and the geometry profile is not performed due to significant tightening metal along the edge from the side of the inner face of the flange.

A comparative analysis of the proposed technical solution with the prototype shows that the proposed method of rolling the rails allows more efficient use of the stands in a continuously reversible group of stands, which improves the quality of the rails by improving the accuracy of the shape and size of the rails, to increase their straightness, and the design of the slopes of the side faces forming the inner faces of the flanges of the sole of the profile, horizontal rolls of universal four-roll calibers are 1.14 ÷ 1.30 times the size of the slopes of the similar side faces of horizontal rolls in a finishing universal three-roll gauge allows to reduce the compression of the edges of the flanges of the sole in a finishing universal three-roll gauge and to increase the resistance of the rolls.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information and identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find a source characterized by features identical to all the essential features of the claimed invention. The definition from the list of identified analogues of the prototype, as the closest in the totality of the characteristics of the analogue, made it possible to establish a set of significant distinguishing features in relation to the technical result established by the applicant in the claimed method set forth in the claims, therefore they provide a technical solution that meets the criterion of "inventive step".

The essence of the invention is illustrated by the diagrams in FIG. 9-12. In FIG. 9 shows a layout of stands of a rail rolling mill. In FIG. 10 presents a rolling scheme of the claimed method. In the BD2 duo-reversing stand, an initial rail blank is obtained. The resulting roll is rolled in a continuously reversible group of stands in three passes, and the final profile is produced in a stand-alone finishing universal three-roll stand U0. In this case, rolling in a continuously reversing group of stands is carried out according to the scheme using six universal four-roll calibers, three auxiliary two-roll calibers and one finishing universal three-roll caliber.

In the proposed method, in universal four-roll gauges of UR and TJF stands, the head surface is formed by a vertical roll, the stream configuration of which corresponds to the profile of the rail head, which ensures the correct shape and stable dimensions of the head surface along the entire length of the finished rail in the final universal three-roll gauge, and the formation of the outer part the sole of the rail is carried out by a vertical cylindrical roll, which ensures the outer faces of the flanges of the sole without local influx metal along the edges, in contrast to the shape change of the flanges in the auxiliary two-roll caliber edger stand, which is the pre-clean prototype.

In FIG. 11 is a diagram for determining the value of the slope of the side face that forms the inner face of the profile flange, the horizontal roll of the prefinishing universal four-roll caliber, which constructs the slopes of the corresponding side faces of the horizontal rolls for all universal four-roll calibers.

The solid line shows the contour of the finishing universal three-roll rail gauge, and the dashed line shows the contour of the set profile from the pre-finishing universal four-gauge caliber. The slopes of the inner faces of the flanges of the head and sole in the finishing universal three-roll caliber are tgα and tgβ, respectively, and the slopes of the side faces forming the inner faces of the flanges of the sole of the profile, horizontal rolls of the prefabricated, further for all universal four-roll calibers, are determined by the relation tgγ = (1,14 ÷ 1.30) tgα.

The process of three-pass rolling in a continuously reversible group of stands, including six universal four-roll calibers, three auxiliary two-roll calibers and one finishing universal three-roll gauge, with side face deviations forming the inner faces of the flanges of the sole of the horizontal roll profile in universal four-roll calibers of 1.14 ÷ 1 , 30 the values of the slopes of the corresponding side faces of the horizontal rolls in the finishing universal three-roll caliber, allows you to ensure uniform low engine load due to the formation of a profile with reduced metal deformation forces in universal calibers, reduction in the production of horizontal rolls of a finishing universal three-roll stand, reduce technological downtime for setting up the mill and cleaning the rolling rolls, increase the yield on the profile and straightness of rails, and reduce the expenditure coefficient of rolls.

An example implementation of the method.

The proposed method for rolling rails is implemented at the universal rail and beam mill of EVRAZ United West Siberian Metallurgical Plant JSC during the production of P65 type rails with a length of 100 m.

Rail steel was smelted in 100 tons of an electric arc furnace and cast on a continuous casting machine into a billet with a cross section of 300 × 365 mm. The resulting billets were heated to a temperature of 1170 ÷ 1190 ° C and rolled in a duo-reversible stands BD1 and BD2 for 10 passes into a rough rail profile with dimensions of 160 × 45 × 100/240,

where 160 is the width of the sole, mm;

45 - neck thickness, mm;

100 - head width, mm;

The resulting roll was transferred to a continuously reversible group of stands and rolled in three passes, where in the first and second passes the profile is formed sequentially in a universal four-roll, auxiliary two-roll, universal four-roll gauge, and the third pass was carried out according to a scheme including the formation of a profile with an additional pre-finish universal four-roll caliber in the following sequence: four-roll universal caliber - two-roll auxiliary gauge - prefilter four-roll universal caliber - the final universal three-roll caliber in the free-standing stand U0.

The slopes of the inner faces of the flanges of the head and sole of the rail profile type P65 are equal to the ratio 1: 4 (GOST R 51685-2013), i.e. tgα = tgβ = 0.25 (Fig. 11).

Dimensions caliber three-roller finishing universal rolling R65 type rails with the linear expansion of the metal along the edge of the base flange and soles have dimensions: a _DOS = 30.32 mm, and _kr = 11.34 mm flange height to gauge axis _fl = 75 h, 9 mm, neck thickness d = 17.68 mm.

(Смирнов В.К. Калибровка прокатных валков / В.К. Смирнов, В.А. Шилов, Ю.В. Инатович. М: Теплотехника, 2008. 490 с.).The calculation of the metal shape during rolling in universal four-roll rail gauges was carried out according to the methodology, which is based on the condition for the equality of the coefficients of the neck, head and sole extracts (λ _w = λ _g = λ _fl ), which ensures uniform deformation across all elements of the profile. In the calculation, the following assumption was made - the increment of the flanges of the sole in the finishing universal three-roll caliber is quite small compared to their height and can be neglected, therefore,

(Smirnov V.K. Calibration of rolling rolls / V.K. Smirnov, V.A. Shilov, Yu.V. Inatovich. M: Heat engineering, 2008. 490 p.).

The construction of the slope lines of the inner faces of the flanges of the sole and rail head relative to the vertical axis in the pre-finish universal four-roll gauge is carried out from points C and D (Fig. 11), which are offset to each other symmetrically relative to the vertical axis of the final universal three-roll gauge by the value according to the accepted neck extension ΔV _w = 2.9 mm in this caliber (Schwarz strain DL new method rail peal in caliber universal / DL Schwartz, AM Mikhaylenko CO. Nepryakhin. Production rental . 2018. №4. Pp 8-13).

The slopes of the side faces forming the inner faces of the flanges of the profile head, horizontal rolls in the prefinishing universal four-roll and finishing universal three-roll calibers are taken equal to the slopes of these elements in the finished profile tgβ = 0.25.

The slopes of the side faces forming the inner faces of the flanges of the sole of the profile, horizontal rolls in the pre-finish universal four-roll gauge are taken within 1.14 ÷ 1.30 of the slope of the corresponding side faces of the horizontal rolls in the fine universal three-roll gauge.

We draw a line through point C with a slope to the vertical equal to tgγ = 1.22⋅tgα = 1.22 ... 0.25 = 0.305, and we obtain a slope of 30.5%.

Due to the envisaged neck broadening in the finishing universal three-roll gauge, the drawing coefficient will be correspondingly lower than the height-strain coefficient by an amount depending on the broadening in this gauge, therefore, the neck thickness in the finishing four-roll universal gauge is determined by the formula through the neck drawing in the finishing universal three-roll caliber (Golovatenko A.V. Development of rolling technology and processes for calibrating railway rails / A.V. Golovatenko, K.V. Volkov, V. .V. Dorofeev [et al.]. Production of rolled products, 2014. No. 2. P. 25-39.).

и основанию

в предчистовом универсальном четырехвалковом калибре воспользуемся геометрическими соотношениями, приравняв вытяжки по фланцам и шейке раската в чистовом универсальном трехвалковом калибре

To determine the thickness of the flanges of the sole at the edge

and the foundation

in the prefabricated universal four-roll caliber, we use the geometric relations, equating the hoods along the flanges and the neck of the peal in the final universal three-roll caliber

,

и АВ).Thus, based on the peculiarities of the shape of the flanges of the sole, which are a rectangular trapezoid, we calculate their main dimensions (

,

and AB).

Since the head in the finishing universal three-roll gauge is rolled in the two-roll part of this caliber, its deformation is calculated according to the formulas for the closed flange (V. Smirnov, Calibration of the rolling rolls / V.K. Smirnov, V.A. Shilov, Yu.V. Inatovich . M: Heat engineering, 2008.490 s.).

In FIG. 12, a, b, c shows the dimensions of the universal flange Predchistovaya caliber four-high rolling type P65 rails at values of slope of the side faces forming the flanges of the inner edges of the sole, universal horizontal rolls in four-high caliber for the following values of slopes:

a - when unchanged during the rolling process, i.e. tgα = tgγ;

b - at tgγ = 1.14⋅tgα;

c - at tgγ = 1.30⋅tgα.

The calculation of the sizes of the flanges of the sole of the finishing universal three-roll and pre-cleaning universal four-roll calibers was determined from the geometric relationships according to FIG. eleven.

As can be seen from the calculations, provided that the coefficients of the draw neck and the bottom of the rail are equal and the side edges are identical slopes forming the inner faces of the sole flanges, horizontal rolls, when rolling the roll in the finishing universal three-roll and pre-cleaning universal four-roll calibers, the compression of the edge of the sole flange is Δ a _cr = 14.21-11.34 = 2.87 mm; when the slopes of the same lateral faces of the horizontal rolls of the prefabricated universal four-roll caliber are equal to 1.14 of the slope of the corresponding side faces of the horizontal rolls in the finishing universal three-roll caliber, the compression of the edge of the flanges of the sole in the finishing gauge is Δ and _cr = 12.88-11.34 = 1.54 mm; when the slopes of the lateral faces of the horizontal rolls of the prefabricated universal four-roll caliber are equal to 1.30 the slope of the corresponding side faces of the horizontal rolls in the finishing universal three-roll caliber, the compression of the edge of the flanges of the sole in the final universal three-roll caliber is Δ and _cr = 11.37-11.34 = 0, 03 mm.

Thus, at tgγ = 1.14⋅tgα, the compression of the edge of the flanges of the sole in the universal universal three-roll caliber is less by 2.87-1.54 = 1.33 mm than with the same slopes (tgγ = tgα), which corresponds to a decrease in compression by 46%, and at tgγ = 1.30⋅tgα, the compression of the edge of the sole flanges in the finishing universal three-roll caliber is less by 2.87-0.03 = 2.84 mm than with the same slopes (tgγ = tgα), which corresponds to a reduction in compression by 99%.

The inventive method of rolling rails allowed to obtain the following technical result:

- more efficient use of stands in a continuously reversible group of stands;

- to improve the quality of the rails by improving the accuracy of the shape and size of the rail head when machining the rolling surface with a vertical roll in the prefabricated universal four-roll caliber;

- to increase the straightness and accuracy of the profile along the entire length of long rails due to the formation of a rail profile with reduced deformation forces in gauges at the last rolling stage in combination with the absence of tension in the finishing universal three-roll gauge when passing in a separate stand U0;

- to provide a stable rolling process without injuring the rolls due to an increase in the rolling pattern of forming rail gauges;

- to reduce the production of horizontal rolls of the finishing universal three-roll stand, which increased the resistance and reduced downtime of the mill for cleaning the rolls.

Claims (1)

A method of rolling rails, including the manufacture of the original rail billet in duo-reversible stands, its further rolling in a continuously reversible group of stands in three passes, in which the profile is formed in the first and second passes in the following sequence: universal four-roll gauge - auxiliary two-roll gauge - universal four-roll caliber, and in the third pass in the following sequence: universal four-roll caliber - auxiliary two-roll caliber - pure the universal three-roll gauge, while the horizontal rolls of the universal four-roll and finishing three-roll calibers are performed with slopes to the vertical of the side faces forming the inner faces of the flanges of the sole of the profile, characterized in that in the third pass, the profile is additionally formed in the pre-finished universal four-roll gauge according to a scheme including the following sequence: universal four-roll caliber - auxiliary two-roll caliber - prefilter universal etyrehvalkovy caliber - finishing universal triple roll caliber, the slope value of lateral faces of the horizontal rolls of the universal four-high caliber, including Predchistovaya is 1.14 ÷ 1.30 bias value of the respective side faces of the horizontal rolls of the universal finishing three-roller caliber.

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