Vertical roll pairing method for steel rail universal rolling mill

Abstract

The invention relates to a vertical roll pairing method for a steel rail universal mill, and belongs to the technical field of profile steel rolling processes in the metallurgical industry. According to the technical scheme, head vertical roll rolling reduction and bottom vertical roll rolling reduction are determined according to the specification and the steel type of a steel rail; the initial roller diameter is determined according to the rolling reduction size relation; deducing the deformation area length based on a chord length formula of a circle, namely the chord length corresponding to the arc length of the contact area of the vertical roll and the steel rail; according to the principle that the lengths of deformation areas on the two sides of the vertical roller are consistent, the Pythagorean theorem is combined to reversely deduce and match the radius of the vertical roller; and selecting the vertical roll with the corresponding specification according to the calculated vertical roll. The method has the beneficial effects that the head deviation phenomenon generated when the tail of the steel rail is separated from the universal pass in the rolling process of the universal rolling mill can be eliminated, and the situation that in the reciprocating rolling process of the steel rail, the tail of the last pass of the steel rail as the head collides with the roller when being engaged with the pass of the next rolling mill, so that the surface of the roller is gouged is avoided; the stability in the steel rail rolling process is improved, and the steel rail quality precision is improved.

Description

Technical Field

[0001] This invention relates to a method for matching vertical rolls in a universal rail rolling mill, belonging to the technical field of section steel rolling process adjustment in the metallurgical industry. Background Technology

[0002] In the universal rolling mill process for rails, the universal rolling mill pass consists of two horizontal rolls and two vertical rolls. The pass patterns of these four rolls together form the universal rail pass pattern. The upper and lower horizontal rolls must ensure consistent roll diameters and symmetrical pass profiles to avoid defects such as upturned or buckled ends during rail rolling. The two vertical rolls are designated as the head roll and the bottom roll according to the rolling section. The head roll, which rolls the rail head, has arc-shaped grooves machined into its body due to the complex contours on both sides of the rail head. The actual effective range of the working roll diameter is 10%-15% smaller than the nominal roll diameter. The bottom roll only rolls the rail bottom and adopts a flat roll body design, with a working roll diameter deviation from the nominal roll diameter ≤0.5mm.

[0003] Because the original diameters of the two vertical rolls are the same, the working diameter of the grooved vertical roll is usually inconsistent with that of the flat vertical roll. Furthermore, due to the different reduction amounts of the two vertical rolls, the lengths of the metal deformation zones are also different. This causes the rail to bend left and right when exiting the universal pass. When entering the next mill pass, this results in the rail impacting the rolls. When the rail bends severely impact the rolls, it causes surface damage to the rolls, ultimately creating surface defects on the rail. This leads to the rail being scrapped and downgraded, affecting continuous production and product quality stability.

[0004] Currently, the industry mainly uses a "trial and error" method to adjust vertical roll pairing, which involves trial rolling by replacing vertical rolls with different diameters and repeatedly adjusting based on the rail bends. This method cannot meet the demands of multi-variety, fast-paced production. Furthermore, some companies have attempted to compensate for vertical roll deformation differences by adjusting the horizontal roll reduction, but this leads to deviations in rail cross-sectional dimensions. Therefore, a vertical roll pairing method based on precise calculations is urgently needed to fundamentally solve the problem of inconsistent deformation zone lengths. Summary of the Invention

[0005] The purpose of this invention is to provide a method for pairing vertical rolls in a universal rail rolling mill, which eliminates the head-off phenomenon that occurs when the rail tail detaches from the universal pass during the universal rolling process, and avoids the rail tail from impacting the rolls and causing damage to the roll surface when it bites into the next rolling pass during reciprocating rolling. This solves the problems existing in the background art.

[0006] The technical solution of this invention is:

[0007] A method for pairing vertical rolls in a universal rail rolling mill, comprising the following steps:

[0008] Step 1: Determining the amount of compression

[0009] Determine the head roll reduction Δ based on the rail specifications and steel type. Bottom vertical roller pressing amount Δ ;

[0010] Step 2: Select the initial roller diameter

[0011] The initial roller diameter is determined based on the relationship between the amount of reduction and the initial roller diameter. When Δ ≤Δ Using the head vertical roller as the initial roller diameter R When Δ >Δ The initial roller diameter R is taken from the bottom vertical roller. ;

[0012] Step 3: Calculation of the length of the deformation zone

[0013] The length of the deformation zone is derived based on the chord length formula of a circle, that is, the chord length corresponding to the arc length of the contact area between the vertical roller and the rail; when Δ ≤Δ At that time, the length L of the deformation zone on the head vertical roller side = ,; when Δ >Δ At that time, the length L of the deformation zone on the bottom vertical roller side = ;

[0014] Step 4: Matching the vertical roller radius

[0015] Based on the principle that the deformation zones on both sides of the vertical roller are of equal length, i.e., L =L Using the Pythagorean theorem, the radius of the paired vertical rollers is derived in reverse; when Δ ≤Δ At that time, the radius R of the bottom vertical roller =( ) / ( This formula uses L =L Substituting into the formula for the length of the deformation zone of the bottom vertical roller, and simplifying, we get: When Δ >Δ At that time, the radius R of the head vertical roller =( ) / ( );

[0016] Step 5: Vertical Roller Assembly

[0017] Based on the calculated R or R Select the vertical roller of the corresponding specification and install it in the vertical roller box.

[0018] In step one, the rail specification is 60kg / m, the material is U75V, and the head vertical roller reduction is Δ. The thickness is 4mm-8mm, and the bottom vertical roller pressing amount Δ It is 3mm-6mm.

[0019] In step one, the rail specification is 50kg / m, the material is U71Mn, and the head vertical roll reduction is Δ. The thickness is 3mm-7mm, and the bottom vertical roller pressing amount Δ It is 2mm-5mm.

[0020] In step one, the rail specification is 75kg / m, the material is U71Mn, and the head vertical roll reduction is Δ. The thickness is 5mm-9mm, and the bottom vertical roller pressing amount Δ It is 4mm-7mm.

[0021] The beneficial effects of this invention are as follows: Based on the reduction of each vertical roll of the universal rolling mill, the length of the rail deformation zone corresponding to different vertical rolls is calculated. Then, by adjusting the diameter of the vertical rolls, the length of the rail deformation zone in the universal pass is kept consistent, eliminating the head-off phenomenon that occurs when the rail tail leaves the universal pass during the universal rolling process. This also prevents the rail tail from impacting the rolls during the reciprocating rolling process, thus avoiding damage to the roll surface. This improves the stability of the rail rolling process and enhances the quality and precision of the rail. Attached Figure Description

[0022] Figure 1 A schematic diagram of universal vertical roll rolling;

[0023] Figure 2 This is an enlarged view of the deformation zone during universal vertical roll rolling.

[0024] In the diagram: 1. Rail; 2. Bottom vertical roll box; 3. Bottom vertical roll; 4. Deformation length L of the bottom vertical roll. Length of deformation of the head vertical roller L 4. Head vertical roller box; 5. Head vertical roller. Detailed Implementation

[0025] The invention will be further described below with reference to the accompanying drawings and examples.

[0026] See attached document Figure 1 , 2 A method for pairing vertical rolls in a universal rail rolling mill, comprising the following steps:

[0027] Step 1: Determining the amount of compression

[0028] Determine the head roll reduction Δ based on the rail specifications and steel type. Bottom vertical roller pressing amount Δ ;

[0029] Step 2: Select the initial roller diameter

[0030] The initial roller diameter is determined based on the relationship between the amount of reduction and the initial roller diameter. When Δ ≤Δ Using the head vertical roller as the initial roller diameter R When Δ >Δ The initial roller diameter R is taken from the bottom vertical roller. ;

[0031] Step 3: Calculation of the length of the deformation zone

[0032] The length of the deformation zone is derived based on the chord length formula of a circle, that is, the chord length corresponding to the arc length of the contact area between the vertical roller and the rail; when Δ ≤Δ At that time, the length L of the deformation zone on the head vertical roller side = ,; when Δ >Δ At that time, the length L of the deformation zone on the bottom vertical roller side = ;

[0033] Step 4: Matching the vertical roller radius

[0034] Based on the principle that the deformation zones on both sides of the vertical roller are of equal length, i.e., L =L Using the Pythagorean theorem, the radius of the paired vertical rollers is derived in reverse; when Δ ≤Δ At that time, the radius R of the bottom vertical roller =( ) / ( This formula uses L =L Substituting into the formula for the length of the deformation zone of the bottom vertical roller, and simplifying, we get: When Δ >Δ At that time, the radius R of the head vertical roller =( ) / ( );

[0035] Step 5: Vertical Roller Assembly

[0036] Based on the calculated R or R Select the vertical roller of the corresponding specification and install it in the vertical roller box.

[0037] In step one, the rail specification is 60kg / m, the material is U75V, and the head vertical roller reduction is Δ. The thickness is 4mm-8mm, and the bottom vertical roller pressing amount Δ It is 3mm-6mm.

[0038] In step one, the rail specification is 50kg / m, the material is U71Mn, and the head vertical roll reduction is Δ. The thickness is 3mm-7mm, and the bottom vertical roller pressing amount Δ It is 2mm-5mm.

[0039] In step one, the rail specification is 75kg / m, the material is U71Mn, and the head vertical roll reduction is Δ. The thickness is 5mm-9mm, and the bottom vertical roller pressing amount Δ It is 4mm-7mm.

[0040] Example 1:

[0041] (1) Production scenario: 60N 100-meter ordinary speed steel rail is produced by rolling using a universal four-roll mill and the material is U75V.

[0042] (2) Parameter acquisition: head vertical roller pressing amount Δ =4mm, bottom vertical roller pressing amount Δ =5mm, the above two sets of data are from the rolling table in the universal rolling mill TCS control system. Because Δ (4mm)≤Δ (5mm), select the head vertical roller as the initial roller diameter, R =395mm (The standard vertical roll radius of the rolling mill is 400mm. The head vertical roll has a perforated shape, so the nominal roll diameter of the unmachined head vertical roll is 395mm)

[0043] (3) Precise calculation: bottom vertical roller radius

[0044] R =( ) / ( )=( ) / ( )=317mm

[0045] (4) Assembly: Select a bottom vertical roller with a radius of 317mm and a head vertical roller with a radius of 395mm for pairing.

[0046] The rails did not deviate during the rolling process on the universal rolling mill. After a batch production of 600 rails, the maximum depth of the dent on the roll surface was 0.11mm (compared to 0.3-0.5mm using traditional methods), indicating good surface quality control of the rails.

[0047] Example 2:

[0048] (1) Production scenario: 60N 100-meter ordinary speed steel rail is produced by rolling using a universal four-roll mill and the material is U71Mn.

[0049] (2) Parameter acquisition: head vertical roller pressing amount Δ =3mm, bottom vertical roller pressing amount Δ =4mm, the above two sets of data are from the rolling table in the universal rolling mill TCS control system. Because Δ (5mm) > Δ (4mm), select the bottom vertical roller as the initial roller diameter, R =400mm (The standard vertical roll radius of the rolling mill is 400mm, undone)

[0050] (3) Precise calculation: radius of the head vertical roller

[0051] R =( ) / ( )=( ) / ( )=321mm

[0052] (4) Assembly: Select a head bottom vertical roller with a radius of 321mm and a bottom vertical roller with a radius of 400mm for pairing and use.

[0053] The rails did not exhibit any deviation during the universal rolling process. After a batch production of 300 rails, an inspection was conducted, and the maximum depth of dents on the roll surface was 0.08 mm (compared to 0.2-0.4 mm using traditional methods), indicating good surface quality control of the rails.

[0054] Example 3:

[0055] (1) Production scenario: Rolling production of 50kg / m short rails, using a universal four-roll mill, with U71Mn material.

[0056] (2) Parameter acquisition: head vertical roller pressing amount Δ =4mm, bottom vertical roller pressing amount Δ =3mm, the above two sets of data are from the rolling table in the universal rolling mill TCS control system. Because Δ (4mm) > Δ (3mm), select the bottom vertical roller as the initial roller diameter, R =390mm (The standard vertical roll radius of the rolling mill is 400mm, and the cutting allowance is 10mm.)

[0057] (3) Precise calculation: radius of the head vertical roller

[0058] R =( ) / ( )=( ) / ( )=293mm

[0059] (4) Assembly: Select a head bottom vertical roller with a radius of 293mm and a bottom vertical roller with a radius of 380mm for pairing.

[0060] The rails showed no deviation during the universal rolling process. After 100 rails were produced, the surface of the rolls was found to be virtually free of damage (0.1-0.3mm under traditional methods), indicating good surface quality control of the rails.

[0061] Example 4:

[0062] (1) Production scenario: 75kg / m short rails are produced by rolling using a universal four-roll mill and the material is U75V.

[0063] (2) Parameter acquisition: head vertical roller pressing amount Δ =5mm, bottom vertical roller pressing amount Δ =6mm, the above two sets of data are from the rolling table in the universal rolling mill TCS control system. Because Δ (5mm)≤Δ (6mm), select the head vertical roller as the initial roller diameter, R =390mm (The standard vertical roll radius of this mill is 400mm. The head vertical roll has a perforated shape, so the nominal roll diameter of the unmachined head vertical roll is 390mm)

[0064] (3) Precise calculation: bottom vertical roller radius

[0065] R =( ) / ( )=( ) / ( )=326mm

[0066] (4) Assembly: Select a bottom vertical roller with a radius of 326mm and a head vertical roller with a radius of 390mm for pairing and use.

[0067] The rails did not deviate during the rolling process on the universal rolling mill. After a batch production of 600 rails, the maximum depth of the dent on the roll surface was 0.18mm (compared to 0.3-0.5mm using traditional methods), indicating good surface quality control of the rails.

[0068] Example 5:

[0069] (1) Production scenario: 60E1 short rails are produced by rolling using a universal four-roll mill and the material is R260.

[0070] (2) Parameter acquisition: head vertical roller pressing amount Δ =6mm, bottom vertical roller pressing amount Δ =5mm, the above two sets of data are from the rolling table in the universal rolling mill TCS control system. The above two sets of data are from the rolling table in the universal rolling mill TCS control system. Because Δ (6mm) > Δ (5mm), select the bottom vertical roller as the initial roller diameter, R =390mm (The standard vertical roll radius of the rolling mill is 400mm, and the cutting allowance is 10mm).

[0071] (3) Precise calculation: radius of the head vertical roller

[0072] R =( ) / ( )=( ) / ( )=326mm

[0073] (4) Assembly: Select a head bottom vertical roller with a radius of 326mm and a bottom vertical roller with a radius of 380mm for pairing and use.

[0074] The rails did not exhibit any deviation during the universal rolling process. After a batch production of 700 rails, an inspection was conducted, and the maximum depth of dents on the roll surface was 0.15mm (compared to 0.3-0.5mm using traditional methods), indicating good surface quality control of the rails.

Claims

1. A method for pairing vertical rolls in a universal rail rolling mill, characterized in that: Follow these steps: Step 1: Determining the amount of compression Determine the head roll reduction Δ based on the rail specifications and steel type. Bottom vertical roller pressing amount Δ ; Step 2: Select the initial roller diameter The initial roller diameter is determined based on the relationship between the amount of reduction and the initial roller diameter. When Δ ≤Δ Using the head vertical roller as the initial roller diameter R When Δ >Δ The initial roller diameter R is taken from the bottom vertical roller. ; Step 3: Calculation of the length of the deformation zone The length of the deformation zone is derived based on the chord length formula of a circle, that is, the chord length corresponding to the arc length of the contact area between the vertical roller and the rail; when Δ ≤Δ At that time, the length L of the deformation zone on the head vertical roller side = ,; when Δ >Δ At that time, the length L of the deformation zone on the bottom vertical roller side = ; Step 4: Matching the vertical roller radius Based on the principle that the deformation zones on both sides of the vertical roller are of equal length, i.e., L =L Using the Pythagorean theorem, the radius of the paired vertical rollers is derived in reverse; when Δ ≤Δ At that time, the radius R of the bottom vertical roller =( ) / ( This formula uses L =L Substituting into the formula for the length of the deformation zone of the bottom vertical roller, and simplifying, we get: When Δ >Δ At that time, the radius R of the head vertical roller =( ) / ( ); Step 5: Vertical Roller Assembly Based on the calculated R Or R Select the vertical roller of the corresponding specification and install it in the vertical roller box.

2. The method for pairing universal vertical rollers for rails according to claim 1, characterized in that: In step one, the rail specification is 60kg / m, and the head vertical roller reduction is Δ. The thickness is 4mm-8mm, and the bottom vertical roller pressing amount Δ It is 3mm-6mm.

3. The method for pairing universal vertical rollers for rails according to claim 1, characterized in that: In step one, the rail specification is 50kg / m, and the head vertical roller reduction is Δ. The thickness is 3mm-7mm, and the bottom vertical roller pressing amount Δ It is 2mm-5mm.

4. The method for pairing universal vertical rollers for rails according to claim 1, characterized in that: In step one, the rail specification is 75kg / m, and the head vertical roller reduction is Δ. The thickness is 5mm-9mm, and the bottom vertical roller pressing amount Δ It is 4mm-7mm.

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