A calculation method for checking rolling force during hot rolling of H-beam profiled blanks

Abstract

The present invention discloses a method for calculating and verifying the rolling force and energy of hot-rolled H-shaped steel profiled blanks. The method comprises the following steps: 1) calculating basic parameters; 2) calculating the temperature of the rolled piece; and 3) calculating the rolling force and energy parameters. Combining existing theoretical calculation formulas with practical experience, a set of simple and effective rolling force and energy calculation methods is proposed. The calculation results fully meet the needs for verifying the rolling force and energy parameters of hot-rolled H-shaped steel profiled blanks, can provide a reference for process adjustment in production practice, and can also provide a reference for production line design and planning.

Description

Technical Field

[0001] The present invention relates to the field of hot-rolled H-shaped steel production, and in particular to a rolling force energy verification calculation method for a hot-rolled H-shaped steel profile blank during a blanking process. Background Art

[0002] H-beams are economical, high-performance profiles with optimized cross-sectional area distribution and a more reasonable strength-to-weight ratio. They are named because their cross-section resembles the letter "H." Determined by their cross-sectional shape, H-beams have significantly superior section modulus, moment of inertia, and corresponding strength to conventional I-beams of the same unit weight. H-beams offer advantages such as wide flanges, thin walls, low unit weight, a wide range of heights, a wide variety of specifications, and flexible application. They exhibit remarkable superior performance in truss structures with diverse requirements, whether withstanding bending moments, compressive loads, or eccentric loads. They can significantly increase load-bearing capacity compared to conventional I-beams while saving 10% to 40% of metal. Furthermore, their parallel inner and outer flanges and right-angled ends facilitate assembly into various components, saving approximately 25% in welding and riveting work. This significantly accelerates construction, reduces costs, and shortens construction schedules, making them widely used.

[0003] Shaped blanks, which closely resemble the cross-section of finished H-beams, are one of the most important billet shapes used in H-beam production. Before commencing universal rolling of H-beams, the continuously cast billets must first be opened to achieve the required size and shape for universal rolling. H-beam opening rolling primarily involves single-stand reversible rolling, with the pass profile changed and the roll gap adjusted during the reciprocating rolling process. When designing and selecting the opening mill and its supporting equipment, optimizing the pass profile, or adjusting the material profile, the rolling force required for opening rolling must be verified and calculated to verify that the motor selection meets the required rolling force requirements, thereby ensuring scientific and feasible design.

[0004] Currently, the force and energy of billet rolling are primarily calculated through finite element numerical simulation. However, this calculation process is complex and time-consuming, failing to meet practical needs. Furthermore, it requires simulation software and specialized researchers, making it difficult to promote and apply. Consequently, there is currently no systematic method for efficiently and conveniently calibrating the rolling force and energy parameters of H-beam profile billet mills. Summary of the Invention

[0005] The present invention combines existing material processing theory and practical experience to propose a simple and effective rolling force and energy calculation method. The calculation results fully meet the needs of rolling force and energy parameter verification of H-beam special-shaped billet opening mills, and can provide a reference for design planning and hole process adjustment of actual production lines.

[0006] This embodiment proposes a simple and effective method for calculating the rolling force energy of a single-stand two-roller reversible blanking machine for hot-rolled H-shaped steel, combining existing theoretical calculation formulas and empirical formulas. The upper and lower rolls of the two-roller reversible blanking machine can be set with 1 to 4 hole shapes at the same time according to the specifications of the finished product or blank. Figure 2 As shown in the figure, A, B, and C are all flat-rolled pass types. Depending on the process requirements, one or more passes can be rolled in the same pass type. They are mainly used to compress the flange height, thickness, and web thickness of the rolled product. E is a vertical rolling pass type, which is mainly used to compress the web height of the billet after it is turned over by the steel turning machine.

[0007] The cross-sectional dimensions of the profiled blanks involved in the present invention are as follows: Figure 1 As shown, H ch is the web groove height, H w is the web height, T w is the web thickness, W f is the flange width, T f is the flange thickness, L f The flange leg length.

[0008] Before the verification calculation, the known data are:

[0009] (1) Web groove height H of the profiled blank ch , web height H w , web thickness T w , flange width W f , flange thickness T f 、Flange leg length L f , length L, cross-sectional area S——all are cold dimensions, that is, dimensions measured at room temperature;

[0010] (2) Weight of the profiled blank G;

[0011] (3) The basic pass height g at the symmetric center of each pass, the basic height q of the flange flat rolling pass, and the basic roll gap e at the edge of the rolling mill;

[0012] (4) The total number of rolling passes N, and the working pass height k at the symmetric center of each pass;

[0013] (5) Roller nominal diameter D0, motor rated power W m , motor base speed Vb and maximum speed Vm, transmission speed ratio i;

[0014] (6) Rolling temperature T, including starting rolling temperature, finishing rolling temperature, etc.

[0015] The rolling force and energy verification calculation method for H-beam hot rolling blanking of the present invention includes three parts: basic parameter calculation, temperature parameter calculation and rolling force and energy calculation. There are cases where some calculation results are referenced to each other among these three parts. The calculation process is explained below respectively.

[0016] Part 1 - Calculation of basic parameters:

[0017] Step A1: Calculate the cross-sectional shrinkage of each pass from the 1st pass to the nth pass. The cross-sectional shrinkage of the nth pass is μ n The calculation formula is:

[0018]

[0019] Where S n-1 、S n The hot cross-sectional area of ​​the rolled piece after the n-1th and nth passes, in mm 2 ; When n = 1, μ1 is calculated as follows:

[0020]

[0021] Where α is the thermal expansion coefficient, usually 1.005 to 1.02; S0 is the cold initial cross-sectional area of ​​the profiled blank, and S1 is the cross-sectional area of ​​the first pass rolled piece, both in mm. 2 .

[0022] Step A2: According to the cross-sectional shrinkage μ of each pass n , calculate the length of the rolled piece after each rolling pass, the length of the rolled piece after the nth rolling pass L n Calculation formula (unit: m):

[0023]

[0024] When n=1, the length L1 of the rolled piece after the first pass is calculated as follows:

[0025]

[0026] Where L0 is the cold initial length of the profiled blank, in m.

[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] Where k n The working hole height at the symmetric center of the nth hole, in mm.

[0030] The actual height of the hole at the symmetric center is set according to the rolling process. n ≥T w(n-1) When T w(n) Calculate as follows:

[0031] T w(n) =T w(n-1)

[0032] T w(n-1) is the web thickness of the rolled piece after the n-1th pass; when n=1, the web thickness of the rolled piece after the first pass is T w(1) Calculate as follows:

[0033]

[0034] Where, T w(0) It is the cold initial web thickness of the profiled blank, in mm.

[0035] 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:

[0036] T w(n) =T w(n-1)

[0037] When n=1, T w(1) Calculate as follows:

[0038]

[0039] Step A5: When the nth pass is a flat rolling pass, the reduction Δk generated by the roller at the symmetric center of the nth pass is n for:

[0040] Δk n =T w(n-1) -k n

[0041] Where k n is the working hole height at the symmetrical center of the nth hole, in mm. When n = 1, Δk1 is calculated as follows:

[0042]

[0043] Where k1 is the height of the working hole at the symmetric center of the first hole, in mm. n ≥T w(n-1) When Δk n Always 0.

[0044] Step A6: When the nth pass is a vertical rolling pass, the reduction Δk generated by the roller at the symmetric center of the nth pass is n for:

[0045] Δk n =H w(n-1) -k n

[0046] Where k n H is the height of the working hole at the symmetric center of the nth hole, in mm; w(n-1) is the web height of the rolled piece after the n-1th pass,

[0047] When n=1, the reduction Δk1 produced by the roller at the symmetrical center of the first pass is calculated as follows:

[0048]

[0049] Where H w(0) is the initial web height of the cold blank of the special-shaped blank, in mm; k1 is the working hole height at the symmetry center of the first hole, in mm.

[0050] At this time, the web height H of the rolled piece after the nth pass is w(n) =k n .

[0051] Step A7: The absolute adjustment value s of the roll pass height at the symmetric center of the nth pass n for:

[0052] s n =k n -g n +e

[0053] Where g n is the basic pass height at the symmetrical center of the nth pass; 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 when the roll is assembled, and e>0mm; the basic pass height g at the symmetrical center of the pass n , refers to the hole height at the symmetric center of the hole when the roll gap is set to the basic roll gap e according to the roll hole diagram, in mm; the absolute adjustment value s of the roll hole height at the symmetric center of the hole n , when the roll gap is 0, the working pass height at the symmetric center of the nth pass is adjusted to k n , the required absolute adjustment amount, unit is mm.

[0054] Step A8: When the n-1th pass and the nth pass are both flat rolling pass, the width B before rolling of the rolled piece in the nth pass is n for:

[0055] B n =b n-1

[0056] b n-1 is the width of the rolled piece after rolling in the n-1th pass, in mm. When n = 1, b0 is the web height of the rolled piece before rolling in the first pass, calculated as follows:

[0057]

[0058] However, when the n-1th pass is a vertical rolling pass, the width B of the rolled piece before the nth pass is n for:

[0059] B n =k n-1

[0060] Where k n-1 It is the working hole height at the symmetric center of the hole of the n-1th pass, in mm.

[0061] Step A9: When both the n-1th pass and the nth pass are vertical rolling pass, the width B before rolling of the rolled piece in the nth pass is n for:

[0062] B n =b n-1

[0063] b n-1 is the width of the rolled piece after the n-1th pass, in mm. When n = 1, b0 is calculated as follows:

[0064]

[0065] Where W f(0) The initial flange width of the cold blank of the profiled blank, in mm. However, when the n-1 pass is a flat rolling pass, the width of the rolled piece before rolling B in the n pass is n for:

[0066] B n =q n-1 +k n-1 -g n-1

[0067] Where q n-1 It is the basic height of the flat rolling pass of the flange at the n-1th pass when the roll gap is the basic roll gap e, in mm.

[0068] Step A10: Average height H of the rolled piece before the nth pass n for:

[0069]

[0070] S n-1 The cross-sectional area of ​​the rolled piece after the n-1th pass, in mm 2 When n=1, the height H1 of the first rolling piece before rolling is calculated as follows:

[0071]

[0072] Where B1 is the width of the first rolled piece before rolling, in mm.

[0073] 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):

[0074] b n =B n +βΔk n +γ

[0075] Where β and γ are broadening coefficients, and their value ranges are 0.01-0.02 and 0.5-1.2 respectively.

[0076] Step A12: Average height h of the rolled piece after the nth pass n (Unit: mm):

[0077]

[0078] S n is the cross-sectional area of ​​the rolled piece after the nth pass, in mm 2 .

[0079] Step A13: Average reduction Δh of the rolled piece after the nth pass n (Unit: mm):

[0080] Δh n =H n -h n

[0081] Step A14: When the nth pass is a flat rolling pass, the working roll diameter D of the nth pass is k(n) (Unit: mm):

[0082] D k(n) =(D0-e)-h n +s n

[0083] is also equivalent to:

[0084] D k(n) =D0-h n +(k n -g n )

[0085] Step A15: When the nth pass is a vertical rolling pass, the working roll diameter D of the nth pass is k(n) (Unit: mm):

[0086] D k(n) =(D0-e)-k n +s n

[0087] is also equivalent to:

[0088] D k(n) =D0-g n

[0089] Step A16, the n-th roll bite angle θ n ,

[0090] like but

[0091] like but

[0092] Bite angle θ n The unit is degree (°); where, The critical bite angle can be 12°~18°.

[0093] Step A17, the biting speed v of the rolled piece in the nth pass 1(n) (unit: m / s), if

[0094] (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

[0095] Then 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 6Otherwise, u 1(n) Take 1.3m / s. Where δ is the velocity constant, usually 10-20m / s.

[0096] Step A18, the nth pass of the rolled piece bites into the speed v 1(n) Corresponding roller speed V 1(n) :

[0097]

[0098] The unit is rpm.

[0099] Step A19, the maximum speed V of the roller Dm :

[0100] V Dm =V m (100%-u) / i

[0101] Where u is the speed reserve margin, usually 10% to 20%.

[0102] Step A20, the stable rolling speed u of the rolled piece in the nth pass 2(n) :

[0103]

[0104] Where V Dk(n) is the stable rolling speed of the nth roll, in rpm, and its maximum value is equal to V Dm .

[0105] Step A21, the casting speed v of each pass of the rolled piece 3(n) Generally, it is taken as 2.0m / s, but when n=N, that is, the throwing speed of the last pass is:

[0106] v 3(N) =v 2(N)

[0107] Throwing speed v 3(n) Corresponding roller speed V 3(n) :

[0108]

[0109] Step A22: In the nth pass, the roller speed is increased from the biting speed V to the rolling speed V within 1s. 1(n) Accelerate to (V b / i) The time t 1(n) :

[0110]

[0111] In the formula, the transmission speed ratio i can be taken as 1.

[0112] Step A23: In the nth pass, the roller speed is increased from (V b / i) Accelerate to the stable rolling speed V of the nth roll Dk(n) The time t 2(n) (Unit: s)

[0113]

[0114] Step A24: In the nth pass, the roller speed is increased from the stable rolling speed V to the rolling speed V within 1s. Dk(n) Reduce speed to (V b / i) The time t 4(n) (Unit: s)

[0115] t 4(n) =t 2(n)

[0116] But when n=N, t 4(N) =0s.

[0117] Step A25: In the nth pass, the roller speed is increased from the steel throwing speed V to the rolling speed V within 1s. 3(n) Reduce speed to (V b / i) The time t 5(n) (Unit: s)

[0118]

[0119] But when n=N, t 5(N) =0s.

[0120] Step A26, the distance L that the rolled piece travels during the roll speed acceleration process at the nth pass 1-2(n) :

[0121]

[0122] The unit is m.

[0123] Step A27, the distance L that the workpiece travels during the roll speed reduction process at the nth pass 2-3(n) :

[0124]

[0125] The unit is m.

[0126] Step A28, in the nth pass, the roller speed is the stable rolling speed v 2(n) When the rolled piece travels a distance L 2(n) :

[0127] L 2(n) =L n -L 1-2(n)-L 2-3(n) -jv 1(n)

[0128] The unit is m; where j is the time the workpiece is bitten by the roll, generally 0.1 to 0.5s.

[0129] Step A29, the time t that the rolled piece experiences during the stable rolling process at the nth pass 3(n) :

[0130]

[0131] The unit is s.

[0132] Step A30, nth pass, total rolling time t z(n) :

[0133] t z(n) =t 1(n) +t 2(n) +t 3(n) +t 4(n) +t 5(n) +j+Δt n

[0134] Where, Δt n The rolling interval time is usually 3 to 15 seconds.

[0135] Part II - Calculation of rolled piece temperature:

[0136] Step B1, calculate the surface area F of the rolled piece after each pass s(n) , the calculation formula can refer to the following formula:

[0137] 1) Flat rolling pass:

[0138] F s(n) =L n (2b n +4(q n +k n -g n )) / 1000(m 2 )

[0139] 2) Vertical rolling pass:

[0140] F s(n) =L n (2k n +4b n ) / 1000(m 2 )

[0141] 3) Initial surface area F of the profiled blank s(0) :

[0142] F s(0)=αL0(2H w(0) +4W f(0) ) / 1000(m 2 )

[0143] Step B2: Calculate the effect of roller cooling water on the temperature of the rolled piece ΔT w(n) :

[0144] Using the empirical formula:

[0145]

[0146] Where, coefficient a is an empirical value, usually ranging from 20 to 50; n is the contact arc length of the deformation zone of the rolling pass, in mm; the constant 1000 is the length of the contact arc of the deformation zone of the rolling pass, in mm; n The unit of is converted to m. Contact arc length l n Calculate as follows:

[0147]

[0148] Step B3: Calculate the temperature drop ΔT caused by the radiation heat dissipation of the high-temperature rolled piece in the air. f(n) :

[0149]

[0150] Where, T n is the temperature of the rolled piece before the nth rolling pass, in K; the coefficient b is an empirical value, usually 70 to 80; G is the weight of the rolled piece, in kg.

[0151] Step B4: Calculate the temperature drop ΔT caused by convection heat dissipation of the high-temperature rolled piece in the air. d(n) :

[0152]

[0153] Where, T a is the ambient temperature, in K; v n-1 is the stable rolling speed of the nth pass, that is, the exit speed of the (n-1)th stand; r It is the relative blackness of the rolled piece surface, which is taken as 0.8 here.

[0154] Step B5, calculate the temperature rise ΔT of the rolled piece during hot rolling b(n) :

[0155] ΔF b(n) =0.184p n (1-c)ln(H n / h n )

[0156] Where p nis the average unit pressure of the rolling mill in the n# stand, in MPa; coefficient c is the average strain rate of rolling The coefficient of correlation, indicating the relative portion of deformation energy absorbed by the rolled piece, the average strain rate The larger the value is, the larger the coefficient c is. When , c is 0.12; When , c is taken as 0.15.

[0157] Step B6: Heat conduction temperature drop

[0158]

[0159] Step B7, calculate the temperature change ΔT of the rolled piece before the nth rolling pass n :

[0160] ΔT n =ΔT w(n-1) +ΔT f(n) +ΔT d(n) +ΔT c(n) -ΔT b(n-1)

[0161] However, before starting the first rolling pass, the temperature change ΔT1 of the rolled piece must be calculated as follows:

[0162] ΔT1=ΔT f(1) +ΔT d(1) +ΔT c(n)

[0163] Calculate the temperature T of the rolled piece after the nth rolling pass. n :

[0164] T n =T (n-1) -ΔT n

[0165] Where, when n=1, T0 is the initial temperature of the profiled blank, in K. In addition, in order to meet the requirements of the rolling process, the temperature T of each pass can be manually adjusted. n Make adjustments.

[0166] Part III - Rolling force parameters:

[0167] Step C1, average unit pressure p of each pass n Calculate with reference to the Eklund average unit pressure formula (the present invention makes adjustments to the calculation of individual parameters):

[0168]

[0169] The calculation of each parameter in the formula is as follows:

[0170] Step C11, each pass of external friction n The coefficient of influence m n Corrections:

[0171]

[0172] The friction coefficient of each pass f n Calculate as follows:

[0173] f n =d(1.05-0.0005(T n -273)-λv n )

[0174] Wherein, the coefficient d is 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 Kelvin temperature (K) to Celsius temperature (°C); the coefficient λ is the influence coefficient of the rolling speed on the friction coefficient proposed in the present invention, and the value range is 0.0001-0.0015.

[0175] Step C12, deformation resistance K of each pass n Calculation of value (unit: MPa):

[0176] K n =9.8(14-0.01T n )(1.4+C%+Mn%+0.3Cr%)(MPa)

[0177] Where C%, Mn%, and Cr% are the mass fractions of the three alloying elements in the rolled product.

[0178] Step C13, calculation of viscosity coefficient ηn for each pass:

[0179] η n =0.1(14-0.01(T n -273))

[0180] Step C14, average deformation rate of each pass The calculation method of is not used in the Eklund formula, but the following formula is used:

[0181]

[0182] Where, v n The value of is determined according to the following rules:

[0183] When v 2(n) When <4m / s, v n =v 2(n)

[0184] When v 2(n) >10m / s, vn =8m / s

[0185] When 4m / s<v 2(n) When the speed is less than 10m / s,

[0186] Step C2, the deformation area F of each rolling pass b Calculation:

[0187] F b(n) =l n (h (n-1) +b n ) / 2

[0188] Step C3, rolling pressure P of each pass n Calculation:

[0189] When the average height of the rolled piece after rolling is h n When ≤120mm,

[0190] P n =p n F b(n) / 1000

[0191] When the average height of the rolled piece after rolling is h n >120mm,

[0192]

[0193] Where x is the cross-sectional shape influence coefficient of the rolled piece, which is usually 1.35 to 2.0; the constant 1000 is the coefficient of P n The unit is converted to kN.

[0194] Step C4, rolling torque M of each pass z(n) Calculation:

[0195] M z(n) =2ψ n P n l n / 1000

[0196] In the formula, the coefficient ψ n is the force arm coefficient; the constant 1000 is the length of the deformation zone l n The unit of is converted to m. In the present invention, the ψ of different groove rolling passes is n The values ​​are taken according to the following rules:

[0197] When the working roll diameter D k(n) When <650mm, ψ n is 0.5;

[0198] When the working roll diameter D k(n) >800mm, ψn is 0.625;

[0199] When the working roll diameter is 650mm<D k(n) When <800mm, ψ n for:

[0200]

[0201] Step C5, friction torque M of each pass f(n) Calculation:

[0202] M f(n) =0.0000032p n D0

[0203] Step C6, each pass torque M d(n) Calculation:

[0204] Step C61, the motor's moment of inertia GD 2 m , unit kgm 2 :

[0205]

[0206] Step C62, the moment of inertia GD of the roller 2 D , unit kgm 2 :

[0207]

[0208] Step C63, power torque M d(n) for:

[0209]

[0210] Step C7, the total rolling torque M of each pass n Calculation:

[0211] The total rolling torque is:

[0212] M n =xM z(n) +M f(n) +M d(n) +M0

[0213] Where M0 is the idling torque, unit is kNm.

[0214] Step C8, rolling power W of each pass n Calculation:

[0215]

[0216] The present invention combines existing theoretical calculation formulas with practical experience to propose a simple and effective rolling force and energy calculation method. The calculation results fully meet the needs of rolling force and energy parameter verification of H-beam special-shaped billet opening mill and can provide a reference for production line design and planning. BRIEF DESCRIPTION OF THE DRAWINGS

[0217] Figure 1 This is a schematic diagram of the cross-sectional shape and marking of an H-shaped steel blank;

[0218] Figure 2 A schematic diagram of a roll pass profile for a slab mill;

[0219] Figure 3 This is a diagram showing the shape and size of the profiled blank according to the first embodiment of the present invention;

[0220] Figure 4 The shape and size diagram of the first embodiment of the present invention after blanking;

[0221] Figure 5 Schematic diagram of the roll matching of the first embodiment of the present invention;

[0222] Figure 6 This is a diagram showing the shape and size of the special-shaped blank according to the second embodiment of the present invention;

[0223] Figure 7 The shape and size diagram of the second embodiment of the present invention after blanking;

[0224] Figure 8 Schematic diagram of the roll matching of the second embodiment of the present invention;

[0225] Figure 9 This is a diagram showing the shape and size of the special-shaped blank according to the third embodiment of the present invention;

[0226] Figure 10 This is a diagram showing the shape and size of the blank after blanking according to the third embodiment of the present invention;

[0227] Figure 11 This is a schematic diagram of the roll matching of the third embodiment of the present invention. DETAILED DESCRIPTION

[0228] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0229] Example 1

[0230] Take the production of H-shaped steel with specification HM350×250 and weight per meter of 78.1kg / m as an example for calculation. The shape and size of the shaped blank are as follows: Figure 3 As shown (all marked dimensions are cold dimensions, unit is mm):

[0231] The cold length of the profiled blank is 12.58m, the weight is 11535kg, and the cold cross-sectional area is 118290mm 2 The rolling temperature is 1180℃. The shape and size after billet opening are as follows Figure 4 As shown (all marked dimensions are cold dimensions, unit is mm).

[0232] The motor power of the two-roll reversible cogging machine is 5500kW, and the motor base speed is V b The maximum speed V is 60.0 rpm. m The speed reserve u is 14%, the transmission ratio i is 1, and the maximum speed of the roll is 86.0 rpm. Figure 5 As shown in Figure 1, the nominal roll diameter D0 is 1100 mm. The right side is the motor drive side, and to the left are hole types B, E, and A, respectively. The basic roll gap e is 18 mm. The calculation process is shown in Tables 1 to 3.

[0233]

[0234] Table 2 Calculation table of temperature of rolled piece in each pass

[0235]

[0236] Table 3 Calculation table of rolling force for each pass

[0237]

[0238] Example 2

[0239] Furthermore, the calculation is carried out by taking the production of H-shaped steel with specification HN500×200 and weight per meter of 101.5kg / m as an example. The shape and size of the shaped blank are as follows: Figure 6 As shown (all marked dimensions are cold dimensions, unit is mm):

[0240] The cold length of the profiled blank is 13.18m, the weight is 12492kg, and the cold cross-sectional area is 122336mm 2 The rolling temperature is 1180℃. The shape and size after billet opening are as follows Figure 7 As shown (all marked dimensions are cold dimensions, unit is mm):

[0241] The motor power of the two-roll reversible cogging machine is 5500kW, and the motor base speed is V b The maximum speed V is 60.0 rpm. mThe speed reserve u is 14%, the transmission ratio i is 1, and the maximum speed of the roll is 86.0 rpm. Figure 8 As shown, the nominal roll diameter D0 is 1100 mm. The right side is the motor drive side, and to the left are hole types B, E, and A, respectively. The basic roll gap e is 18 mm. The calculation process is shown in Tables 4 to 6 below.

[0242]

[0243] Table 5 Calculation table of temperature of rolled piece in each pass

[0244]

[0245] Table 6 Calculation table of rolling force for each pass

[0246]

[0247] Example 3

[0248] Take the production of H-shaped steel with specification HN850×300 and weight per meter of 178.6kg / m as an example for calculation. The shape and size of the shaped blank are as follows: Figure 9 As shown (all marked dimensions are cold dimensions, unit is mm):

[0249] The cold length of the profiled blank is 10.5m, the weight is 13189kg, and the cold cross-sectional area is 162771mm 2 The rolling temperature is 1180℃. The shape and size after billet opening are as follows Figure 10 As shown (all marked dimensions are cold dimensions, unit is mm):

[0250] The motor power of the two-roll reversible cogging machine is 5500kW, and the motor base speed is V b The maximum speed V is 60.0 rpm. m The speed reserve u is 14%, the transmission ratio i is 1, and the maximum speed of the roll is 86.0 rpm. Figure 11 As shown, the nominal diameter of the roll D0 is 1100 mm, the right side is the motor drive side, and to the left are hole type B and hole type A, respectively. The basic roll gap e is 18 mm. The calculation process is shown in Tables 7 to 9 respectively.

[0251]

[0252] Table 8 Calculation table of temperature of rolled pieces in each pass

[0253]

[0254]

[0255] Table 9 Calculation table of rolling force for each pass

[0256]

[0257] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications shall fall within the scope of protection of the claims of the present invention.

Claims

1. A method for calculating the rolling force during hot rolling of H-beam, characterized in that: Including calculation of rolling force and energy parameters: Step C1, average unit pressure p of each pass n , unit is MPa: The calculation of each parameter in the formula is as follows: Step C11, each pass of external friction n Influence coefficient m n Corrections: The friction coefficient of each pass f n Calculate as follows: f n =d(1.05-0.0005(T n -273)-λv n ) Where, coefficient d is a coefficient related to the roll material, which is 1 for steel rolls and 0.8 for cast iron rolls; constant 273 is used to convert the Kelvin temperature to Celsius temperature; coefficient λ is the influence coefficient of rolling speed on the friction coefficient, which ranges from 0.0001 to 0.0035; n is the contact arc length of the deformation zone in the rolling pass, Δh n is the average reduction of the rolled piece after the nth pass, H n is the average height of the rolled piece before rolling in the nth pass, h n is the average height of the rolled piece after the nth pass, in mm; T n is the temperature of the workpiece after the nth rolling pass; Step C12, deformation resistance K of each pass n Calculation of the value, in MPa: K n =9.8(14-0.01T n )(1.4+C%+Mn%+0.3Cr%) Where, C%, Mn%, and Cr% are the mass fractions of the three alloying elements in the rolled product. Step C13, viscosity coefficient η of each pass n Calculation: or n =0.1(14-0.01(T n -273)) Step C14, average deformation rate of each pass Use the following formula to calculate, the unit is s -1 : Where, v n The value of is determined according to the following rules: When v 2(n) When <4m / s, v n =v 2(n) When v 2(n) >10m / s, v n =8m / s When 4m / s<v 2(n) When the speed is less than 10m / s, Among them, v 2(n) It is the stable rolling speed of the rolled piece in the nth pass.

2. The method for calculating the rolling force of H-beam hot rolling cogging according to claim 1 is characterized in that: The calculation of rolling force parameters also includes: Step C2, the deformation area F of each rolling pass b(n) Calculation, unit is mm 2 : F b(n) =l n (h (n-1) +b n ) / 2 Among them, b n is the width of the rolled piece after the nth pass; Step C3, rolling pressure P of each pass n Calculation of kN: When the average height of the rolled piece after rolling is h n When ≤120mm, P n =p n F b(n) / 1000 When the average height of the rolled piece after rolling is h n >120mm, Where x is the cross-sectional shape influence coefficient of the rolled piece, and its value ranges from 1.35 to 2.

0.

3. The calculation method for checking the rolling force of H-beam hot rolling cogging according to claim 2 is characterized in that: The calculation of rolling force parameters also includes: Step C4, rolling torque M of each pass z(n) Calculation of the unit is kN·m: M z(n) =2ψ n P n l n / 1000 In the formula, the coefficient ψ n is the force arm coefficient; ψ of different groove rolling passes n The values ​​are taken according to the following rules: When the working roll diameter D k(n) When <650mm, ψ n is 0.5; When the working roll diameter D k(n) >800mm, ψ n is 0.625; When the working roll diameter is 650mm<D k(n) When <800mm, ψ n for: Step C5, friction torque M of each pass f(n) Calculation of the unit is kN·m: M f(n) =0.0000032p n D0 Where D0 is the nominal diameter of the roll, in mm; Step C6, each pass torque M d(n) Calculation: Step C61, the motor's moment of inertia GD 2 m : Among them, W m is the rated power of the motor, V b is the motor base speed; Step C62, the moment of inertia GD of the roller 2 D : Step C63, power torque M d(n) for: Step C7, the total rolling torque M of each pass n Calculation: M n =xM z(n) +M f(n) +M d(n) +M0 Where M0 is the idling torque, Step C8, rolling power W of each pass n Calculation: V Dk(n) is the stable rolling speed of the nth roll.

4. The calculation method for checking the rolling force of H-beam hot rolling cogging according to claim 3 is characterized in that: Before calculating the rolling force and energy parameters, basic parameter calculation is also included, which includes the following known parameters: Web groove height H of cold sized profile blank ch , web height H w , web thickness T w , flange width W f , flange thickness T f 、Flange leg length L f , length L, cross-sectional area S, weight G of the profiled blank; basic pass height g at the symmetrical center of each pass, basic height q of the flange flat rolling pass, basic roll gap e at the edge of the rolling mill, total number of rolling passes N, working pass height k at the symmetrical center of each pass; nominal diameter D0 of the roll, rated power W of the motor m , motor base speed V b , maximum speed V m , transmission speed ratio i; rolling temperature T, including starting rolling temperature and finishing rolling temperature; The basic parameter calculation includes: Step A1, from the 1st pass to the nth pass, calculate the cross-sectional shrinkage of each pass in turn, the cross-sectional shrinkage of the nth pass μ n The calculation formula is: Where S n-1 、S n are the hot cross-sectional areas of the rolled product after the n-1th and nth passes, respectively; when n = 1, μ1 is calculated as follows: Where α is the thermal expansion coefficient, ranging from 1.005 to 1.02; S0 is the cold initial cross-sectional area of ​​the profiled blank, and S1 is the cross-sectional area of ​​the first-pass rolled piece; Step A2: According to the cross-sectional shrinkage μ of each pass n , calculate the length of the rolled piece after each rolling pass, the length of the rolled piece after the nth rolling pass L n The calculation formula is: When n=1, the length L1 of the rolled piece after the first pass is calculated as follows: Where L0 is the cold initial length of the profiled blank; Step A3, calculate the web thickness T of the flat rolling groove nth pass rolled product after rolling w(n) ; Step A4, calculate the web thickness T of the rolled product after the nth pass of the vertical rolling groove w(n) ; Step A5: Calculate the reduction Δk generated by the roller at the symmetric center of the nth pass of the flat rolling pass n ; Step A6: Calculate the reduction Δk generated by the roller at the symmetric center of the nth pass of the vertical rolling pass n ; Step A7: The absolute adjustment value s of the roll pass height at the symmetric center of the nth pass n for: s n =k n -g n +e Where g n is the basic pass height at the symmetrical center of the nth pass; e is the basic roll gap at the edge of the mill, the basic roll gap e at the edge of the roll refers to the mill roll gap set according to the roll pass diagram when the roll is assembled, and e>0mm; the basic pass height g at the symmetrical center of the pass n It refers to the hole height at the symmetric center of the hole when the roll gap is set to the basic roll gap e according to the roll hole diagram; the absolute adjustment value s of the roll hole height at the symmetric center of the hole n When the roll gap is 0, the working pass height at the symmetric center of the nth pass is adjusted to k n , the absolute amount of adjustment required.

5. The method for calculating the rolling force during hot rolling of H-beam according to claim 4, characterized in that: Basic parameter calculations also include: Step A8, calculate the width B of the rolled piece before rolling in the nth pass when both the n-1th pass and the nth pass are flat rolling pass. n ; Step A9, calculate the width B of the rolled piece before rolling in the nth pass when both the n-1th pass and the nth pass are vertical rolling pass. n ; Step A10, calculate the average height H of the rolled piece before rolling for the nth pass n for: S n-1 is the cross-sectional area of ​​the rolled piece after the n-1th pass; when n=1, the height H1 of the rolled piece before the first pass is calculated as follows: Where, B1 is the width of the first rolling piece before rolling; Step A11, calculate the width b of the rolled piece after the nth pass when the nth pass is a vertical rolling pass. n : b n =B n +βΔk n +g Where β and γ are the broadening coefficients, with value ranges of 0.01 to 0.02 and 0.5 to 1.2 respectively; When the nth pass is a flat rolling pass, the width b of the rolled piece after the nth pass is n : b n =B n +βΔh n +g Where β and γ are the broadening coefficients, with values ​​ranging from 0.1 to 0.6 and 1 to 5 respectively; Step A12, calculate the average height h of the rolled piece after the nth pass n : S n is the cross-sectional area of ​​the rolled piece after the nth pass; Step A13, calculate the average reduction Δh of the rolled piece after the nth pass n : Δh n =H n -h n Step A14, calculate the working roll diameter D of the nth pass when the nth pass is a flat rolling pass. k(n) ; Step A15, calculate the working roll diameter D of the nth pass when the nth pass is a vertical rolling pass. k(n) ; Step A16, the n-th roll bite angle θ n , like but like but Where, is the critical bite angle, ranging from 12° to 18°; Step A17, the biting speed v of the rolled piece in the nth pass 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 v 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, v 1(n) Take 1.3m / s, where δ is the velocity constant, ranging from 10 to 20m / s; Step A18, the nth pass of the rolled piece bites into the speed v 1(n) Corresponding roller speed V 1(n) : Step A19, the maximum speed V of the roller Dm : V Dm =V m (100%) / i Where, u is the speed reserve margin, ranging from 10% to 20%; Step A20, the stable rolling speed v of the rolled piece in the nth pass 2(n) : Where V Dk(n) is the stable rolling speed of the nth roll, and its maximum value is equal to V Dm ; Step A21, the casting speed v of each pass of the rolled piece 3(n) is 2.0m / s, but when n=N, that is, the throwing speed of the last pass is: v 3(N) =v 2(N) Throwing speed v 3(n) Corresponding roller speed V 3(n) : Step A22: In the nth pass, the roller speed is increased from the biting speed V to the rolling speed V within 1s. 1(n) Accelerate to V b / iThe time elapsed t 1(n) : Step A23: In the nth pass, the roller speed is increased from V to b / i Accelerate to the stable rolling speed V of the nth roll Dk(n) The time t 2(n) : Step A24: In the nth pass, the roller speed is increased from the stable rolling speed V of the nth pass roller to the stable rolling speed V of the nth pass roller within 1 second. Dk(n) Reduce speed to V b / iThe time elapsed 4(n) : t 4(n) =t 2(n) But when n=N, t 4(N) =0s; Step A25: In the nth pass, the roller speed is increased from the steel throwing speed V to the rolling speed V within 1s. 3(n) Reduce speed to V b / iThe time elapsed 5(n) : But when n=N, t 5(N) =0s; Step A26, the distance L that the rolled piece travels during the roll speed acceleration process at the nth pass 1-2(n) : Step A27, the distance L that the workpiece travels during the roll speed reduction process at the nth pass 2-3(n) : Step A28, in the nth pass, the roller speed is the stable rolling speed v 2(n) When the rolled piece travels a distance L 2(n) : 50 2(n) =L n -L 1-2(n) -L 2-3(n) -jv i(n) Where, j is the time when the workpiece is bitten by the roll, and its value range is 0.1~0.5s; Step A29, the time t that the rolled piece experiences during the stable rolling process at the nth pass 3(n) : Step A30, nth pass, total rolling time t z(n) : t z(n) =t 1(n) +t 2(n) +t 3(n) +t 4(n) +t 5(n) +j+Δt n Where Δtn is the rolling gap time, ranging from 3 to 15s.

6. The method for calculating the rolling force during hot rolling of H-beam according to claim 5, characterized in that: The calculation of rolled piece temperature parameters also includes: 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 -g n )) / 1000(m 2 ) 2) Vertical rolling pass: F s(n) =L n (2k n +4b n ) / 1000(m 2 ) 3) Initial surface area F of the profiled blank s(0) : F s(0) =αL0(2H w(0) +4W f(0) ) / 1000(m 2 )。 7. The method for calculating the rolling force of H-beam hot rolling cogging according to claim 6, characterized in that: Before calculating the rolling force and energy parameters, the temperature parameters of the rolled piece are also calculated: Step B2: Calculate the effect of roller cooling water on the temperature of the rolled piece ΔT w(n) : Wherein, coefficient a is an empirical value, ranging from 20 to 50; n is the contact arc length of the deformation zone in the rolling pass; Contact arc length l n Calculate as follows: Step B3: Calculate the temperature drop ΔT caused by the radiation heat dissipation of the high-temperature rolled piece in the air. f(n) : Where, T n is 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 convection heat dissipation of the high-temperature rolled piece in the air. d(n) : Where, T a is the ambient temperature; v 2(n) is the stable rolling speed of the rolled piece in the nth pass, that is, the exit speed of the (n-1)th stand; ε r is the relative blackness of the rolled piece surface; Step B5, calculate the temperature rise ΔT of the rolled piece during hot rolling b(n) : ΔT b(n) =0.184p n (1-c)ln(H n / h n ) Where p n is the average unit pressure of the rolling mill stand n#; coefficient c is the average strain rate of rolling The coefficient of correlation, indicating the relative portion of deformation energy absorbed by the rolled piece, the average strain rate The larger it is, the larger the coefficient c is; Step B6: Heat conduction temperature drop Step B7, calculate the temperature change ΔT of the rolled piece 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 as follows: ΔT1=ΔT f(1) +ΔT d(1) +ΔT c(n) Calculate the temperature T of the rolled piece after the nth rolling pass. n : T n =T (n-1) -ΔT n Wherein, when n=1, T0 is the initial temperature of the profiled blank.

8. The method for calculating the rolling force during hot rolling of H-beam according to claim 4, characterized in that: Steps A3 and A4 include: 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 Where k n is the working hole height at the symmetric center of the nth hole, and the working hole height at the symmetric center of the hole refers to the actual hole height set according to the rolling process at the symmetric center of the hole. However, when k n ≥T w(n-1) When T w(n) Calculate as follows: T w(n) =T w(n-1) T w(n-1) is the web thickness of the rolled piece after the n-1th pass; when n=1, the web thickness of the rolled piece after the first pass is T w(1) Calculate as follows: Where, T w(0) is the cold initial web thickness of the beam blank; 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) When n=1, T w(1) Calculate as follows: Step A5: When the nth pass is a flat rolling pass, the reduction Δk generated by the roller at the symmetric center of the nth pass is n for: Δk n =T w(n-1) -k n Where k n is the working hole height at the symmetrical center of the nth hole. When n=1, Δk1 is calculated as follows: Where k1 is the working hole height at the symmetric center of the first hole, but when k n ≥T w(n-1) When Δk n Always 0; Step A6: When the nth pass is a vertical rolling pass, the reduction Δk generated by the roller at the symmetric center of the nth pass is n for: Δk n =H w(n-1) -k n Where k n H is the height of the working hole at the symmetric center of the nth hole, w(n-1) is the web height of the rolled piece after the n-1th pass, and when n=1, the reduction Δk1 generated by the roller at the symmetric center of the first pass is calculated as follows: Where H w(0) is the initial web height of the cold blank, k1 is the working hole height at the symmetric center of the first pass, and H is the web height of the rolled piece after the nth pass. w(n) =k n .

9. The method for calculating the rolling force during hot rolling of H-beam according to claim 5, characterized in that: Step A8: When the n-1th pass and the nth pass are both flat rolling pass, the width B before rolling of the rolled piece in the nth pass is n for: B n =b n-1 b n-1 is the width of the rolled piece after rolling in the n-1th pass. When n=1, b0 is the web height of the rolled piece before rolling in the first pass, which is calculated as follows: However, when the n-1th pass is a vertical rolling pass, the width B of the rolled piece before the nth pass is n for: B n =k n-1 Where k n-1 The working pass height at the symmetric center of the pass of the n-1th pass; Step A9: When both the n-1th pass and the nth pass are vertical rolling pass, the width B before rolling of the rolled piece in the nth pass is n for: B n =b n-1 b n-1 is the width of the rolled piece after the n-1th pass. When n=1, b0 is calculated as follows: Where W f(0) is the initial flange width of the cold blank of the profiled blank. However, when the n-1 pass is a flat rolling pass, the width B before rolling of the rolled piece in the n pass is n for: B n =q n-1 +k n-1 -g n-1 Where q n-1 It is the basic height of the flat rolling pass of the n-1th flange when the roll gap is the basic roll gap e.

10. The method for calculating the rolling force during hot rolling of H-beam according to claim 5, characterized in that: In step A14, when the nth pass is a flat rolling pass, the working roll diameter D of the nth pass is k(n) : D k(n) =(D0-e)-h n +s n or: D k(n) =D0-h n +(k n -g n ) Step A15: When the nth pass is a vertical rolling pass, the working roll diameter D of the nth pass is k(n) : D k(n) =(D0-e)-k n +s n or: D k(n) =D0-g n 。

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