A method for checking and calculating rolling force of H-shaped steel rectangular billet hot rolling breakdown

Abstract

This invention discloses a method for calculating and verifying the rolling force of hot-rolled H-beam rectangular billets. The method includes: 1) calculating basic parameters; 2) calculating the temperature of the rolled piece; and 3) calculating the rolling force parameters. Combining existing theoretical calculation formulas and practical experience, a simple and effective method for calculating rolling force is proposed. The calculation results fully meet the needs of verifying the rolling force of hot-rolled H-beam rectangular billets, and can provide a reference for adjusting production processes and for production line design and planning.

Description

Technical Field

[0001] This invention relates to the field of hot-rolled H-beam production, and more particularly to a method for verifying and calculating the rolling force energy of hot-rolled rectangular H-beam billets. Background Technology

[0002] H-beams are an economical and efficient structural steel profile with an optimized cross-sectional area distribution and a more reasonable strength-to-weight ratio. They are named for their cross-section resembling the letter "H". Due to their cross-sectional shape, H-beams have significantly better section modulus, moment of inertia, and corresponding strength than ordinary I-beams of the same weight. H-beams offer advantages such as wide flanges, thin walls, light weight, a wide height range, various specifications, and flexible application. Used in truss structures with different requirements, they demonstrate superior performance under bending moments, compressive loads, and eccentric loads, significantly increasing load-bearing capacity compared to ordinary I-beams while saving 10% to 40% of metal. Furthermore, because their flanges are parallel on both sides and have right angles at the ends, they are easy to assemble into various components, saving approximately 25% of welding and riveting work. This greatly accelerates construction speed, saves costs, and shortens the construction period, leading to their widespread application.

[0003] Rectangular billets (including square billets) are one of the most important billet types for producing small and medium-sized H-beams. Before starting universal continuous rolling of small H-beams, the continuously cast rectangular billets first need to be roughened to obtain the dimensions and shape required for universal continuous rolling, i.e., intermediate billets. The roughing rolling of H-beams is mainly a single-stand reversible rolling process, with changes in the roll pass and adjustment of the roll gap during the reciprocating rolling process. When designing and selecting the roughing mill and its supporting equipment, optimizing the roll pass, or adjusting the material shape, it is necessary to verify and calculate the rolling force capacity of the roughing mill, and check whether the selected motor meets the rolling force capacity requirements, thereby ensuring scientific validity and feasibility.

[0004] However, the method of calculating the rolling force energy of H-beam rectangular billets using finite element numerical simulation is complex and time-consuming, requiring simulation software and specialized researchers, making it difficult to promote and apply. Therefore, there is currently no efficient and convenient systematic method for verifying the rolling force energy parameters of H-beam rectangular billet mills. Summary of the Invention

[0005] This invention addresses the rectangular billets of hot-rolled H-beams, proposing a simple and effective method for calculating the rolling force energy of a single-stand two-roll reversible billet mill, based on existing material processing theories and practical experience. For the billet rolling of small and medium-sized H-beam rectangular billets, the upper and lower rolls of the two-roll reversible billet mill can be equipped with 2 to 4 passes simultaneously, depending on the specifications of the finished product or billet. Figure 1This is a typical roll arrangement diagram for rectangular billet. G is a box-type vertical rolling pass, mainly used to pre-roll the flange prototype on the rectangular billet; F is a flat rolling deep cutting pass, mainly used to roll the "dog bone" prototype through multi-pass deep cutting rolling; E is a flat rolling pass, mainly used to further roll the "dog bone" billet into the web prototype to adapt to the pass shape of subsequent rolling passes.

[0006] Before the verification calculation, the known data are:

[0007] (1) The length (A), width (B), length (L), and cross-sectional area (S) of the rectangular billet section are all cold-state dimensions, i.e., dimensions measured at room temperature;

[0008] (2) Weight of the rectangular blank (G);

[0009] (3) Basic roll height (g) at the center of symmetry of each roll, basic roll height (q) at the flange flat rolling roll, and basic roll gap (e) at the edge of the roll;

[0010] (4) Total number of rolling passes (N), working pass height (k) at the center of symmetry of each pass;

[0011] (5) Initial diameter (D0) of the roll before machining the pass, rated power of the motor (W) m ), motor base speed (V) b ) and maximum speed (V m ), speed ratio i of the reducer;

[0012] (6) Rolling temperature (T), including initial rolling temperature, final rolling temperature, etc.;

[0013] The specific calculation process of this invention is divided into the following three parts, and the calculation results of the three parts refer to each other:

[0014] Part 1 – Basic Parameter Calculation:

[0015] Step A1: Calculate the reduction of area (R&A) for each pass from the 1st to the nth pass. The R&A of the nth pass is μ. n The calculation formula is:

[0016]

[0017] In the formula, S n-1 S n These are the hot cross-sectional areas of the rolled piece after the (n-1)th and nth passes, respectively, in mm. 2 When n = 1, μ1 is calculated using the following formula:

[0018]

[0019] In the formula, α is the coefficient of thermal expansion, usually taken as 1.005 to 1.02; S0 is the initial cross-sectional area of ​​the rectangular billet in the cold state, and S1 is the cross-sectional area of ​​the workpiece after the first pass, in mm. 2 The initial cross-sectional area S0 is calculated using the following formula:

[0020] S0=A0B o

[0021] In the formula, A0 is the length of the cross-section of the cold rectangular billet, and B0 is the width of the cross-section of the cold rectangular billet, both in mm.

[0022] Step A2, based on the section reduction rate μ of each pass n Calculate the length of the rolled piece after each pass, and the length L of the rolled piece after the nth pass. n The calculation formula (unit: m) is as follows:

[0023]

[0024] When n=1, the length L1 of the workpiece after the first pass is calculated using the following formula:

[0025]

[0026] In the formula, L0 is the initial cold length of the rectangular billet, in meters.

[0027] Step A3, when the nth pass is a flat rolling pass, the web thickness T of the rolled piece after the nth pass is... w(n) for:

[0028] T w(n) =k n

[0029] In the formula, n≠1; k n The working pass height at the center of symmetry of the nth pass is expressed in mm. The working pass height at the center of symmetry refers to the actual height of the pass at the center of symmetry, set according to the rolling process. However, when k... n ≥T w(n-1) At that time, T w(n) Calculate using the following formula:

[0030] T w(n) =T w(n-1)

[0031] T w(n-1) T represents the web thickness of the rolled piece in the (n-1)th pass, and when n=2 is a flat rolling pass, T w(1) The width after rolling for the first pass G-pass flange is measured in mm.

[0032] Step A4, when the nth pass is a vertical rolling pass, the web thickness T of the rolled piece after the nth pass is... w(n) for:

[0033] T w(n) =T w(n-1)

[0034] In the formula, n≠1; when n=2 is also a vertical rolling mill, T w(1) The width after rolling for the first pass G-pass flange is measured in mm.

[0035] Step A5, when the nth pass is a flat rolling pass, the reduction Δk generated by the roll at the center of symmetry of the nth pass is... n for:

[0036] Δk n =T w(n-1) -k n

[0037] In the formula, n≠1; when n=2 is flat rolling, T w(1) The width after rolling for the first pass G-pass flange, in mm; k n The working hole height at the center of symmetry of the nth hole is in mm; however, when k n ≥T w(n-1) When, Δk n It is always 0.

[0038] Step A6, when the nth pass is a vertical rolling pass, the reduction Δk generated by the roll at the center of symmetry of the nth pass pass. n for:

[0039] Δk n =H w(n-1) -k n

[0040] In the formula, k n H is the working hole height at the center of symmetry of the nth hole, in mm. w(n～1) Here is the web height of the workpiece after the (n-1)th pass, in mm. When n = 1, the first pass is usually a G-pass flange rolling pass. The reduction Δk1 produced by the roll at the center of symmetry of the G-pass is calculated by the following formula:

[0041] Δk1 = 0.56(αA0 - k1)

[0042] In the formula, A0 is the cross-sectional length of the cold rectangular billet, in mm; k1 is the working pass height at the center of symmetry of the G pass in the first pass, in mm. Furthermore, the web height H of the rolled piece in the nth pass... w(n) =k n .

[0043] Step A7, the absolute adjustment value s of the roll pass height at the center of symmetry of the nth pass. n for:

[0044] s n =k n -g n +e

[0045] In the formula, g n The basic roll gap height at the center of symmetry of the nth pass is denoted as g; e is the basic roll gap at the edge of the mill, in mm. The basic roll gap e at the edge of the roll refers to the mill roll gap set according to the roll pass diagram during roll assembly, and e > 0 mm; the basic roll gap height g at the center of symmetry of the pass is denoted as g. n The height of the roll pass at the center of symmetry, in mm, is the roll pass height when the roll gap is set to the basic gap e according to the roll pass diagram; the absolute adjustment value s of the roll pass height at the center of symmetry. n When the roll gap is 0, the working pass height at the center of symmetry of the nth pass is adjusted to k. n The required absolute adjustment amount, in mm.

[0046] Step A8, when both the (n-1)th and nth passes are flat rolling passes, the pre-roll width B of the workpiece in the nth pass... n for:

[0047] B n =b n-1

[0048] In the formula, n≠1; b n-1 This refers to the width of the rolled piece after the (n-1)th pass, in mm. However, when the (n-1)th pass is a vertical rolling pass, the width of the rolled piece before the nth pass, B, is... n for:

[0049] B n =k n-1

[0050] In the formula, n≠1; k n-1 The working hole height is located at the hole symmetry center of the (n-1)th pass, in mm.

[0051] Step A9, when both the (n-1)th and nth passes are vertical rolling passes, the pre-roll width B of the workpiece in the nth pass... n for:

[0052] B n =b n-1

[0053] In the formula, b n-1 b0 is the width of the rolled piece after the (n-1)th pass, in mm; when n=1, b0 is calculated using the following formula:

[0054] b0=αB0

[0055] In the formula, B0 is the cross-sectional width of the cold rectangular billet, in mm. However, when the (n-1)th pass is a flat rolling pass, the pre-rolling width B of the workpiece in the nth pass... n for:

[0056] B n =q n-1 +k n-1 -g n-1

[0057] In the formula, n≠1 and n≠2; q n-1 When the roll gap is the basic roll gap e, the basic height of the flange flat rolling pass of the (n-1)th pass is in mm.

[0058] Step A10, the average height H of the workpiece before rolling in the nth pass. n for:

[0059]

[0060] S n-1 The cross-sectional area of ​​the workpiece after rolling in the (n-1)th pass, in mm. 2 When n=1, the first pass is usually a G-pass flange rolling pass, and the pre-rolling height H1 of the workpiece is calculated using the following formula:

[0061] H1=αA0

[0062] In the formula, A0 is the cross-sectional length of the cold rectangular billet, in mm.

[0063] Step A11, when the nth pass is a vertical rolling pass, the width b of the rolled piece after the nth pass is... n (Unit: mm)

[0064] b n =B n +βΔk n +γ

[0065] In the formula, β and γ are the expansion coefficients, with values ​​ranging from 0.01 to 0.02 and 0.5 to 1.2, respectively.

[0066] Step A12, the average height h of the rolled piece after the nth pass. n (Unit: mm)

[0067]

[0068] S n The cross-sectional area of ​​the workpiece after the nth pass, in mm. 2 .

[0069] Step A13, the average reduction Δh after the nth pass of the rolled piece n (Unit: mm)

[0070] Δh n =H n -h n

[0071] Step A14, when the nth pass is a flat rolling pass, the working roll diameter D of the nth pass... k(n) (Unit: mm)

[0072] D k(n) =D0-h n +s n

[0073] Step A15, when the nth pass is a vertical rolling pass, the working roll diameter D of the nth pass... k(n) (Unit: mm)

[0074] D k(n) =D0-k n +s n

[0075] Step A16, the roll bite angle θ of the nth pass. n ,

[0076] like but

[0077] like but

[0078] bite angle θ n The unit is degrees (°); where, The critical bite angle can be 12° to 18°.

[0079] Step A17, the bite speed υ of the nth pass of the rolled piece 1(n) (Unit: m / s), if

[0080] (δ-2.34θ n +0.19θ n 2 -0.00094θ n 3 +0.00026θ n 4 -0.0000034θ n 5 +0.00000001θ n 6 <1.3

[0081] but

[0082] υ 1(n) =δ-2.34θ n +0.19θ n2 -0.00094θ n 3 +0.00026θ n 4 -0.0000034θ n 5 +0.00000001θ n 6

[0083] Otherwise, υ 1(n) Take 1.3 m / s. In the formula, δ is the velocity constant, which is usually taken as 10 to 20 m / s.

[0084] Step A18, the bite speed υ of the nth pass of the rolled piece 1(n) The corresponding roll speed V 1(n) :

[0085]

[0086] The unit is rpm.

[0087] Step A19, maximum speed V of the roll Dm :

[0088] V Dm =V m (100%-u) / i

[0089] In the formula, u is the rotational speed margin, which is usually taken as 10% to 20%.

[0090] Step A20, the stable rolling speed υ of the nth pass. 2(n) :

[0091]

[0092] In the formula, V Dk(n) The operating speed of the nth pass roll is expressed in rpm, and its maximum value is equal to V. Dm .

[0093] Step A21, the steel-throwing speed υ of each pass of the rolled piece 3(n) The speed is generally taken as 2.0 m / s, but when n = N, that is, the speed of the steel throwing in the last pass is:

[0094] υ 3(N) =υ 2(N)

[0095] Steel throwing speed υ 3(n) The corresponding roll speed V 3(n) :

[0096]

[0097] In step A22, during the nth pass, the roll speed changes from the bite speed V within 1 second. 1(n) Accelerate to (V) b / i) The time t 1(n) :

[0098]

[0099] In the formula, the speed ratio i of the reducer can be taken as 1.

[0100] In step A23, during the nth pass, the roll speed changes from (V) to (V) within 1 second. b / i) Accelerate to a stable rolling speed V Dk(n) Time t 2(n) (Unit: seconds)

[0101]

[0102] In step A24, during the nth pass, the roll speed changes from the stable rolling speed V within 1 second. Dk(n) Reduce speed to (V) b / i) The time t 4(n) (Unit: seconds)

[0103] t 4(n) =t 2(n)

[0104] But when n = N, t 4(N) =0s.

[0105] In step A25, during the nth pass, the roll speed changes from the steel throwing speed V3 within 1 second. (n) Reduce speed to (V) b / i) The time t 5(n) (Unit: seconds)

[0106]

[0107] But when n = N, t 5(N) =0s.

[0108] Step A26, the nth pass, the distance L traveled by the workpiece during the roll speed acceleration process. 1-2(n) :

[0109]

[0110] The unit is meters (m).

[0111] Step A27, nth pass, the distance L traveled by the workpiece during the roll speed reduction process. 2-3(n) :

[0112]

[0113] The unit is meters (m).

[0114] In step A28, during the nth pass, the roll speed is the stable rolling speed υ. 2(n) At that time, the distance L traveled by the rolled piece 2(n) :

[0115] L 2(n) =L n -L 1-2(n) -L 2-3(n) -jυ 1(n)

[0116] The unit is m; where j is the time it takes for the workpiece to be bitten by the rolls, which is generally taken as 0.1 to 0.5 s.

[0117] Step A29, the nth pass, the time t experienced by the workpiece during the steady rolling process. 3(n) :

[0118]

[0119] The unit is seconds (s).

[0120] Step A30, nth pass, total rolling time t of the workpiece z(n) :

[0121] t z(n) =t i(n) +t 2(n) +t 3(n) +t 4(n) +t 5(n) +j+Δt n

[0122] In the formula, Δt n This is the rolling gap time, which is usually taken as 3 to 15 seconds.

[0123] Part Two – Calculation of Rolled Part Temperature, including:

[0124] Step B1, calculate the surface area (F) of the rolled piece after each pass. s The calculation formula can be found in the following formula:

[0125] 1) Flat rolling pass:

[0126] F s(n) =L n (2b n +4(q n +k n -g n ))×10 -3 The unit is m 2

[0127] 2) Vertical rolling pass type:

[0128] F s(n) =L n (2k n +4b n )×10 -3 The unit is m 2

[0129] When n=1, the surface area of ​​the rolled piece after the G-pass flange rolling pass

[0130] F s(1) =2α(L1(A0+b) n )+A0b1×10 -3 )×10 -3 The unit is m 2

[0131] 3) Initial surface area F of the rectangular blank s(0) :

[0132] F s(0) =2α(L0(A0+B0)+A0B0×10 -3 )×10 -3 The unit is m 2

[0133] Step B2, calculate the effect of the roll cooling water on the workpiece temperature ΔT w(n) :

[0134] Using empirical formulas:

[0135]

[0136] In the formula, the coefficient 'a' is an empirical value, usually taken as 20–50; n The contact arc length of the deformation zone in the rolling pass is expressed in mm.

[0137] The constant 1000 is l n The unit conversion is in meters (m). Contact arc length l n Calculate using the following formula:

[0138]

[0139] Step B3: Calculate the temperature drop ΔT caused by the high-temperature rolled workpiece radiating heat in the air. f(n) :

[0140]

[0141] In the formula, T n The temperature of the rolled piece before the nth rolling pass is in K; the coefficient b is an empirical value, usually taken as 70-80; G is the weight of the rolled piece in kg.

[0142] Step B4: Calculate the temperature drop ΔT caused by convective heat dissipation of the high-temperature rolled workpiece in the air. d(n) :

[0143]

[0144] In the formula, T a Ambient temperature, in Kelvin (K); v n-1 ε is the stable rolling speed for the nth pass, which is also the exit speed of the (n-1)th stand; r The relative blackness of the rolled surface is 0.8, which is taken here.

[0145] Step B5: Calculate the temperature rise ΔT of the workpiece during the hot rolling process. b(n) :

[0146] ΔT b(n) =0.184p n (1-c)ln(H n / h n )

[0147] In the formula, p n The average unit pressure during rolling on the nth stand is expressed in MPa; the coefficient c is related to the average strain rate during rolling. The correlation coefficient indicates the relative portion of the deformation energy absorbed by the rolled piece, and the average strain rate. The larger the value, the larger the coefficient c. In this invention, when... When c is 0.12; When c is 0.15.

[0148] Step B6, heat conduction temperature drop

[0149]

[0150] Step B7: Calculate the temperature change ΔT of the workpiece before the nth rolling pass. n :

[0151] ΔT n =ΔT w(n-1) +ΔT f(n) +ΔT d(n) +ΔT c(n) -ΔT b(n-1)

[0152] However, before starting the first rolling pass, the temperature change ΔT1 of the rolled piece must be calculated using the following formula:

[0153] ΔT1=ΔT f(1) +ΔT d(1) +ΔT c(n)

[0154] Calculate the temperature T of the workpiece after the nth rolling pass. n :

[0155] T n =T (n-1) -ΔT n

[0156] In the formula, when n=1, T0 is the initial temperature of the rectangular billet, in K. Furthermore, to meet the rolling process requirements, the temperature T of each rolling pass can be manually adjusted. n Adjustments will be made.

[0157] Part Three – Rolling Force and Energy Parameters:

[0158] Step C1, average unit pressure p for each pass n The calculations were performed using Ekrond's average unit pressure formula (adjustments were made to the calculation of certain parameters in this invention):

[0159]

[0160] The parameters in the formula are calculated as follows:

[0161] Step C11, the external friction of each pass to p n The coefficient of influence m n Correction:

[0162]

[0163] The friction coefficient f for each pass in the formula n Calculate using the following formula:

[0164] f n =d(1.05-0.0005(T) n -273)-λv n )

[0165] In the formula, the coefficient d is a coefficient related to the material of the roll, usually 1 for steel rolls and 0.8 for cast iron rolls; the constant 273 is used to convert the open temperature (K) to the Celsius temperature (°C); the coefficient λ is the influence coefficient of the rolling speed on the friction coefficient proposed in this invention, and the value range is 0.0001-0.0015.

[0166] Step C12, Deformation resistance K for each pass n Calculation of value (unit: MPa):

[0167] K n =9.8(14-0.01T) n )(1.4+C%+Mn%+0.3Cr%)(MPa)

[0168] In the formula, C%, Mn%, and Cr% are the mass fractions of three alloying elements in the rolled material.

[0169] Step C13, viscosity coefficient η for each pass n Calculation:

[0170] η n =0.1(14-0.01(T) n -273))

[0171] Step C14, average deformation rate of each pass The calculation is performed using the following formula:

[0172]

[0173] In the formula, υ n The values ​​of follow the following pattern:

[0174] When υ 2(n) When <4m / s, υ n =υ 2(n)

[0175] When υ 2(n) When >10m / s, υ n =8m / s

[0176] When 4m / s < υ 2(n) When <10m / s,

[0177] Step C2, the deformation zone area F of each rolling pass. b Calculation:

[0178] F b(n) =l n (h (n-1) +b n ) / 2

[0179] Step C3, rolling pressure P for each pass n Calculation:

[0180] When the average height h of the rolled piece n When ≤120mm,

[0181] P n =p n F b(n) / 1000

[0182] When the average height h of the rolled piece n When >120mm,

[0183]

[0184] In the formula, x is the influence coefficient of the cross-sectional shape of the rolled piece, which is usually taken as 1.35 to 2.0; the constant 1000 is the value of P. n The unit conversion is kN.

[0185] Step C4, rolling torque M for each pass z(n) Calculation:

[0186] M z(n) =2ψ n P n l n / 1000

[0187] In the formula, the coefficient ψ n This is the lever arm coefficient; the constant 1000 represents the length l of the deformation zone. n The unit conversion is in meters. In this invention, ψ is used for different rolling passes of different pass types. n Values ​​are taken according to the following pattern:

[0188] When the working roller diameter D k(n) When <650mm, ψ n It is 0.5;

[0189] When the working roller diameter D k(n) When >800mm, ψ n It is 0.625;

[0190] When the working roller diameter is 650mm < D k(n) When <800mm, ψ n for:

[0191]

[0192] Step C5, friction torque M for each pass f(n) Calculation:

[0193] M f(n) =0.0000032p n D0

[0194] Step C6, dynamic torque M for each pass d(n) Calculation:

[0195] Step C61, the moment of inertia of the motor GD 2 m Unit: kg / m 2 :

[0196]

[0197] Step C62, the moment of inertia of the rolls GD 2 D Unit: kg / m 2 :

[0198]

[0199] Step C63, dynamic torque M d(n) for:

[0200]

[0201] Step C7, the total rolling torque M for each pass n Calculation:

[0202] The total rolling torque is:

[0203] M n =xM z(n) +M f(n) +M d(n) +M0

[0204] In the formula, M0 is the idling torque, and the unit is kNm.

[0205] Step C8, rolling power W for each pass n Calculation:

[0206] Attached Figure Description

[0207] Figure 1 This is a schematic diagram of a roll configuration for a roughing mill roll pass according to an embodiment of the present invention;

[0208] Figure 2 This is a schematic diagram of the dimensions of the G-type hole according to an embodiment of the present invention;

[0209] Figure 3 This is a schematic diagram of the dimensions of the F-hole type according to an embodiment of the present invention;

[0210] Figure 4 This is a schematic diagram of the dimensions of the E-hole type according to an embodiment of the present invention. Detailed Implementation

[0211] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0212] Taking the rolling of Q235 rectangular billets for producing HN400×200×7×11 H-beams as an example, calculations are performed. The rectangular billet has a cross-sectional dimension of 410mm×310mm, a cold-state length of 6.7m, a weight of 6645kg, and a cold-state cross-sectional area of ​​127100mm². 2 The initial rolling temperature is 1180℃.

[0213] The two-roll reversible billet mill has a motor power of 6000kW, a maximum rolling force of 8150kN, a rolling torque range of 900~1600kN·m, a base speed of 60.0rpm, a maximum speed of 100.0rpm, a speed allowance u of 14%, a transmission speed ratio of 1, and a maximum roll speed of 86.0rpm. Figure 1 In this example, the original diameter of the roll is 850mm, the basic roll gap e is 20mm, and the dimensions of the G-type, F-type, and E-type rolls are shown in the figure below. The calculation process is shown in Tables 1 to 3 respectively.

[0214]

[0215] Table 2. Calculation of rolling temperature for each pass.

[0216]

[0217] Table 3 Calculation of Rolling Power for Each Pass

[0218]

[0219] It is evident that a two-roll reversible billet mill with a motor power of 6000kW, a maximum rolling force of 8150kN, a rolling torque range of 900~1600kN·m, and a base speed of 60.0rpm (maximum speed of 100.0rpm) can fully meet the billet rolling requirements of HN400×200×7×11 specification H-beam Q235 rectangular billets at 1180℃.

[0220] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications are all within the protection scope of the claims of the present invention.

Claims

1. A method for verifying and calculating the rolling force energy of hot-rolled H-beam rectangular billets, characterized in that, include: Basic parameter calculation: Step A1: Calculate the reduction of area (R&A) for each pass from the 1st to the nth pass. The R&A of the nth pass is μ. n The calculation formula is: In the formula, S n-1 S n These are the hot cross-sectional areas of the rolled piece after the (n-1)th and nth passes, respectively, in mm. 2 When n = 1, μ1 is calculated using the following formula: In the formula, α is the coefficient of thermal expansion, ranging from 1.005 to 1.02; S0 is the initial cross-sectional area of ​​the rectangular billet in the cold state, and S1 is the cross-sectional area of ​​the workpiece after the first pass, in mm. 2 ; Step A2, based on the section reduction rate μ of each pass n Calculate the length of the rolled piece after each pass, and the length L of the rolled piece after the nth pass. n The calculation formula is as follows: When n=1, the length L1 of the workpiece after the first pass is calculated using the following formula: In the formula, L0 is the initial cold length of the rectangular billet; Step A3, when the nth pass is a flat rolling pass, the web thickness T of the rolled piece after the nth pass is... w(n) for: T w(n) =k n In the formula, n≠1; k n The working pass height at the center of symmetry of the nth pass is in mm. This working pass height at the center of symmetry refers to the actual height of the pass at the center of symmetry according to the rolling process, but when k... n ≥T w(n-1) At that time, T w(n) Calculate using the following formula: T w(n) =T w(n-1) T w(n-1) T represents the web thickness of the rolled piece in the (n-1)th pass, and when n=2 is a flat rolling pass, T w(1) The width after rolling for the first pass G-pass flange, in mm. Step A4, when the nth pass is a vertical rolling pass, the web thickness T of the rolled piece after the nth pass is... w(n) for: T w(n) =T w(n-1) In the formula, n≠1; when n=2 is also a vertical rolling mill, T w(1) The width after rolling for the first pass G-pass flange, in mm; Step A5, when the nth pass is a flat rolling pass, the reduction Δk generated by the roll at the center of symmetry of the nth pass is... n for: Δk n =T w(n-1) -k n In the formula, n≠1; when n=2 is flat rolling, T w(1) The width after rolling for the first pass G-pass flange, in mm; k n The working hole height at the center of symmetry of the nth hole is in mm; however, when k n ≥T w(n-1) When, Δk n It is always 0; Step A6, when the nth pass is a vertical rolling pass, the reduction Δk generated by the roll at the center of symmetry of the nth pass pass. n for: Δk n =H w(n-1) -k n In the formula, k n H is the working hole height at the center of symmetry of the nth hole, in mm. w(n-1) Here is the height of the web of the workpiece after rolling in the (n-1)th pass, in mm. When n = 1, the first pass is the G-pass flange rolling pass. The reduction Δk1 produced by the roll at the center of symmetry of the G-pass is calculated by the following formula: Δk1 = 0.56(αA0 - k1) In the formula, A0 is the cross-sectional length of the cold rectangular billet, in mm; k1 is the working pass height at the center of symmetry of the G pass in the first pass, and H is the web height H of the rolled piece after the nth pass. w(n) =k n ; Step A7, the absolute adjustment value s of the roll pass height at the center of symmetry of the nth pass. n for: s n =k n -g n +e In the formula, g n The basic pass height is located at the center of symmetry of the nth pass; e is the basic roll gap at the edge of the mill, where the basic roll gap e refers to the mill roll gap set according to the roll pass diagram during roll assembly, and e>0mm; the basic pass height g at the center of symmetry of the pass is... n The height of the roll pass at the center of symmetry, in mm, is the roll pass height when the roll gap is set to the basic gap e according to the roll pass diagram; the absolute adjustment value s of the roll pass height at the center of symmetry. n When the roll gap is 0, the working pass height at the center of symmetry of the nth pass is adjusted to k. n The required absolute adjustment amount Step A8, when both the (n-1)th and nth passes are flat rolling passes, the pre-roll width B of the workpiece in the nth pass... n for: B n =b n-1 In the formula, n≠1; b n-1 The width of the rolled piece after the (n-1)th pass is in mm. However, when the (n-1)th pass is a vertical rolling pass, the width of the rolled piece before the nth pass is B. n for: B n =k n-1 In the formula, n≠1; k n-1 The working hole height at the hole symmetry center of the (n-1)th pass, in mm; Step A9, when both the (n-1)th and nth passes are vertical rolling passes, the pre-roll width B of the workpiece in the nth pass... n for: B n =b n-1 In the formula, b n-1 b0 is the width of the rolled piece after the (n-1)th pass, in mm; when n=1, b0 is calculated using the following formula: b0=αB0 In the formula, B0 is the cross-sectional width of the cold rectangular billet, in mm. However, when the (n-1)th pass is a flat rolling pass, the pre-rolling width B of the nth pass is... n for: B n =q n-1 +k n-1 -g n-1 In the formula, n≠1 and n≠2; q n-1 When the roll gap is the basic roll gap e, the basic height of the flange flat rolling pass of the (n-1)th pass is in mm; Step A10, the average height H of the workpiece before rolling in the nth pass. n for: S n-1 The cross-sectional area of ​​the workpiece after rolling in the (n-1)th pass, in mm. 2 When n=1, the first pass is usually a G-pass flange rolling pass, and the pre-rolling height H1 of the workpiece is calculated using the following formula: H1=αA0 In the formula, A0 is the cross-sectional length of the cold rectangular billet, in mm; Step A11, when the nth pass is a vertical rolling pass, the width b of the rolled piece after the nth pass is... n : b n =B n +βΔk n +g In the formula, β and γ are the broadening coefficients, with values ​​ranging from 0.01 to 0.02 and 0.5 to 1.2, respectively; Step A12, the average height h of the rolled piece after the nth pass. n : S n The cross-sectional area of ​​the workpiece after the nth pass, in mm. 2 ; Step A13, the average reduction Δh after the nth pass of the rolled piece n : Δh n =H n -h n Step A14, when the nth pass is a flat rolling pass, the working roll diameter D of the nth pass... k(n) : D k(n) =D0-h n +s n Step A15, when the nth pass is a vertical rolling pass, the working roll diameter D of the nth pass... k(n) : D k(n) =D0-k n +s n 。 2. The method for verifying and calculating the rolling force energy of hot-rolled H-beam rectangular billets according to claim 1, characterized in that, The calculation of basic parameters also includes: Step A16, the roll bite angle θ of the nth pass. n , like but like but In the formula, φ is the critical bite angle, which ranges from 12° to 18°; Step A17, the bite speed υ of the nth pass of the rolled piece 1(n) ,like (δ-2.34θ n +0.19θ n 2 -0.00094θ n 3 +0.00026θ n 4 -0.0000034θ n 5 +0.00000001θ n 6 )<1.3 Then υ 1(n) = δ - 2.34θ n + 0.19θ n 2 - 0.00094θ n 3 + 0.00026θ n 4 - 0.0000034θ n 5 + 0.00000001θ n 6 Otherwise, υ 1(n) Take 1.3 m / s, where δ is the velocity constant, with a value ranging from 10 to 20 m / s; Step A18, the bite speed υ of the nth pass of the rolled piece 1(n) The corresponding roll speed V 1(n) : Step A19, the maximum speed V of the roll Dm : V Dm =V m (100%) / i In the formula, u is the rotational speed margin, which ranges from 10% to 20%. Step A20, the stable rolling speed υ of the nth pass. 2(n) : In the formula, V Dk(n) The operating speed of the nth pass roll is expressed in rpm, and its maximum value is equal to V. Dm ; Step A21, the steel-throwing speed υ of each pass of the rolled piece 3(n) The value is 2.0 m / s, but when n = N, that is, the throwing speed of the last pass is: v 3(N) =v 2(N) Steel throwing speed υ 3(n) The corresponding roll speed V 3(n) : In step A22, during the nth pass, the roll speed changes from the bite speed V within 1 second. 1(n) Accelerate to V b / i Time elapsed t 1(n) : In the formula, the speed ratio i of the reducer is taken as 1. In step A23, during the nth pass, the roll speed changes from (V) to (V) within 1 second. b / i) Accelerate to a stable rolling speed V Dk(n) Time t 2(n) : In step A24, during the nth pass, the roll speed changes from the stable rolling speed V within 1 second. Dk(n) Reduce speed to V b / i Time elapsed t 4(n) : t 4(n) =t 2(n) But when n = N, t 4(N) =0s; In step A25, during the nth pass, the roll speed changes from the steel throwing speed V within 1 second. 3(n) Reduce speed to V b / i Time elapsed t 5(n) : But when n = N, t 5(N) =0s; Step A26, the nth pass, the distance L traveled by the workpiece during the roll speed acceleration process. 1-2(n) : Step A27, nth pass, the distance L traveled by the workpiece during the roll speed reduction process. 2-3(n) : In step A28, during the nth pass, the roll speed is the stable rolling speed υ. 2(n) At that time, the distance L traveled by the rolled piece 2(n) : L 2(n) =L n -L 1-2(n) -L 2-3(n) -jυ 1(n) In the formula, j is the time when the workpiece is bitten by the roll, and its value ranges from 0.1 to 0.5 s; Step A29, the nth pass, the time t experienced by the workpiece during the steady rolling process. 3(n) : Step A30, nth pass, total rolling time t of the workpiece z(n) : t z(n) =t 1(n) +t 2(n) +t 3(n) +t 4(n) +t 5(n) +j+Δt n In the formula, Δt n This is the rolling gap time, ranging from 3 to 15 seconds.

3. The method for verifying and calculating the rolling force energy of hot-rolled H-beam rectangular billets according to claim 2, characterized in that, It also includes the calculation of the rolling temperature: Step B1: Calculate the surface area F of the rolled piece after each pass. s(n) The calculation formula is as follows: 1) Flat rolling pass: F s(n) =L n (2b n +4(q n +k n -h n ))×10 -3 , 2) Vertical rolling pass type: F s(n) =L n (2k n +4b n )×10 -3 , When n=1, the surface area of ​​the rolled piece after the G-pass flange rolling pass F s(1) =2α(L1(A0+b n )+A0b n ×10 -3 )×10 -3 , 3) Initial surface area F of the rectangular blank s(0) : F s(0) =2α(L0(A0+B0)+A0B0×10 -3 )×10 -3 , Step B2, calculate the effect of the roll cooling water on the workpiece temperature ΔT w(n) : Using empirical formulas: In the formula, the coefficient 'a' is an empirical value, ranging from 20 to 50; n This is the contact arc length of the deformation zone in the rolling pass; the constant 1000 is the value of l. n Unit conversion to meters, contact arc length l n Calculate using the following formula: Step B3: Calculate the temperature drop ΔT caused by the high-temperature rolled workpiece radiating heat in the air. f(n) : In the formula, T n The temperature of the rolled piece before the nth rolling pass; the coefficient b is an empirical value, ranging from 70 to 80; G is the weight of the rolled piece; Step B4: Calculate the temperature drop ΔT caused by convective heat dissipation of the high-temperature rolled workpiece in the air. d(n) : In the formula, T a Ambient temperature; υ 2(n) ε is the stable rolling speed for the nth pass, which is also the exit speed of the (n-1)th stand; r The relative emissivity of the rolled surface; Step B5: Calculate the temperature rise ΔT of the workpiece during the hot rolling process. b(n) : ΔT b(n) =0.184p n (1-c)ln(H n / h n ) In the formula, p n The average unit pressure during rolling on the nth stand; coefficient c is related to the average rolling strain rate. The correlation coefficient indicates the relative portion of the deformation energy absorbed by the rolled piece, and the average strain rate. The larger the value, the larger the coefficient c becomes. When c is 0.12; When c is 0.15; Step B6, heat conduction temperature drop Step B7: Calculate the temperature change ΔT of the workpiece before the nth rolling pass. n : ΔT n =ΔT w(n-1) +ΔT f(n) +ΔT d(n) +ΔT c(n) -ΔT b(n-1) However, before starting the first rolling pass, the temperature change ΔT1 of the rolled piece must be calculated using the following formula: ΔT1=ΔT f(1) +ΔT d(1) +ΔT c(n) Calculate the temperature T of the workpiece after the nth rolling pass. n : T n =T (n-1) -ΔT n In the formula, when n=1, T0 is the initial temperature of the rectangular billet.

4. The method for verifying and calculating the rolling force energy of hot-rolled H-beam rectangular billets according to claim 3, characterized in that, It also includes the calculation of rolling force and energy parameters: Step C1, average unit pressure p for each pass n : The parameters in the formula are calculated as follows: Step C11, the external friction of each pass to p n The coefficient of influence m n Correction: The friction coefficient f for each pass in the formula n Calculate using the following formula: f n =d(1.05-0.0005(T n -273)-λv n ) In the formula, the coefficient d is related to the roll material, typically 1 for steel rolls and 0.8 for cast iron rolls; the constant 273 is used to convert the open temperature to Celsius; the coefficient λ is the influence coefficient of rolling speed on the friction coefficient, with a value range of 0.0001-0.0015; l n It is the contact arc length of the deformation zone in the rolling pass, Δh n H is the average reduction of the workpiece after the nth pass. n h is the average height of the workpiece before rolling in the nth pass. n T is the average height of the rolled piece after the nth pass, both in mm; n It is the temperature of the workpiece after the nth rolling pass; Step C12, Deformation resistance K for each pass n The value is calculated in MPa. K n =9.8(14-0.01(T n -273))(1.4+C%+Mn%+0.3Cr%) In the formula, C%, Mn%, and Cr% are the mass fractions of three alloying elements in the rolled material, respectively. Step C13, viscosity coefficient η for each pass n Calculation: or n =0.1(14-0.01(T n -273)) Step C14, average deformation rate of each pass The calculation is performed using the following formula: In the formula, υ n The values ​​of follow the following pattern: When υ 2(n) <4 m / s, υ n = υ 2(n) When υ 2(n) When >10m / s, υ n =8m / s When 4m / s < υ 2(n) When <10m / s 5. The method for verifying and calculating the rolling force energy of hot-rolled H-beam rectangular billets according to claim 4, characterized in that, The calculation of rolling force and energy parameters also includes: Step C2, the deformation zone area F of each rolling pass. b(n) Calculation: F b(n) =l n (h (n-1) +b n ) / 2 Step C3, rolling pressure P for each pass n Calculation: When the average height h of the rolled piece n When ≤120mm, P n =p n F b(n) / 1000 When the average height h of the rolled piece n When >120mm, In the formula, x is the influence coefficient of the cross-sectional shape of the rolled piece, with a value ranging from 1.35 to 2.0; the constant 1000 is the value of P. n The unit conversion is kN.

6. The method for verifying and calculating the rolling force energy of hot-rolled H-beam rectangular billets according to claim 5, characterized in that, The calculation of the rolling force energy parameters also includes: Step C4, rolling torque M for each pass z(n) Calculation: M z(n) =2ψ n P n l n / 1000 In the formula, the coefficient ψ n This is the lever arm coefficient; the constant 1000 represents the length l of the deformation zone. n Unit conversion to m, ψ for different rolling passes n Values ​​are taken according to the following pattern: When the working roller diameter D k(n) When <650mm, ψ n It is 0.5; When the working roller diameter D k(n) When >800mm, ψ n It is 0.625; When the working roller diameter is 650mm <D k(n) When <800mm, ψ n for: Step C5, friction torque M for each pass f(n) Calculation: M f(n) =0.0000032p n D0 Step C6, dynamic torque M for each pass d(n) Calculation: Step C61, the moment of inertia of the motor GD 2 m Unit: kg / m 2 : Step C62, the moment of inertia of the rolls GD 2 D Unit: kg / m 2 : Step C63, dynamic torque M d(n) for: Step C7, the total rolling torque M for each pass n Calculation: The total rolling torque is: M n =xM z(n) +M f(n) +M d(n) +M0 In the formula, M0 is the idling torque, and the unit is kNm; Step C8, rolling power W for each pass n Calculation:

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