A method for designing the working layer thickness of hot-rolled finishing support rolls

Abstract

This invention relates to a method for designing the working layer thickness of support rolls in hot-rolled finishing mills, comprising the steps of: calculating allowable rolling conditions, calculating allowable roll changing conditions, calculating the maximum possible increase in work rolls, determining whether support rolls can be increased, and calculating the possible increase in the working layer thickness of support rolls. The method for designing the working layer thickness of support rolls in hot-rolled finishing mills provided by this invention allows the maximum work roll diameter of a hot continuous rolling mill to be increased from the original d2 to the manufacturing limit capacity d3, while simultaneously increasing the effective working layer thickness of the support rolls and reducing mill roll consumption by more than 10%.

Description

Technical Field

[0001] This invention relates to a method for designing the working layer thickness of a hot-rolled finishing support roll, belonging to the technical field of metal rolling equipment. Background Technology

[0002] To reduce roll consumption, the effective working layer of rolls in newly built hot strip mills has been significantly improved. For example, the effective working layer of the front section work rolls in the finishing mill reaches 100mm, the effective working layer of the rear section work rolls reaches 90mm, and the effective working layer of the support rolls reaches 150mm. To pursue ultimate performance and reduce roll costs, the effective diameter of the work rolls can be increased by utilizing the mill window space. However, calculations based on window dimensions show that increasing the work roll diameter requires significant mill adjustments. Often, limitations in roll manufacturing capabilities or mill spindle angles restrict the extent to which the effective working layer can be increased, making further reductions in roll consumption difficult. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the above-mentioned technologies and provide a method for designing the thickness of the working layer of the support roller while satisfying the maximum working layer of the working roller.

[0004] To solve the above-mentioned technical problems, the technical solution proposed by this invention is: a method for designing the working layer thickness of a hot-rolled finishing support roll, comprising the following steps:

[0005] (1) Define hot strip mill F i -F j The support roll diameter is D, the maximum design diameter of the support roll is D2, and the minimum design diameter of the support roll is D1. Define the hot strip mill F. i -F j The working roll diameter is d, the maximum designed diameter of the working roll is d2, the minimum designed diameter of the working roll is d1, and the maximum achievable diameter of the working roll is d3.

[0006] (2) The allowable condition for steel rolling is the working roll diameter plus half the support roll diameter, i.e., D / 2+d. The maximum value of the allowable condition for steel rolling is D2 / 2+d2, and the minimum value is D1 / 2+d1. The range of variation is (D2-D1) / 2+(d2-d1).

[0007] (3) The allowable condition for changing rolls is half the diameter of the working roll plus half the effective diameter of the support roll, i.e., D / 2+d / 2. The maximum value of the allowable condition for changing rolls is D2 / 2+d2 / 2, and the minimum value is D1 / 2+d1 / 2. The range of variation is (D2-D1) / 2+(d2-d1) / 2.

[0008] (4) Let the effective working layer of the working roller increase by x. Then x needs to satisfy: x / (x+d2-d1)≤(D2-3x-D1) / (D2-D1), to get the maximum value of x;

[0009] (5) Calculate the ratio k of the maximum achievable diameter of the work roll to x: k = (d3 - d2) / x; if k < 0.7, then the diameter of the support roll can be increased;

[0010] (6) If the effective working layer of the support roller increases by y, then y needs to satisfy:

[0011] (d3-d2) / (d3-d1)≤(D2-3*(d3-d2)-D1) / (D2+y-D1), and,

[0012] (y / (D2-D1+y))≤(d2-y / 2-d1) / (d3-d1);

[0013] Calculate the maximum value of y;

[0014] (7) The increase in the diameter of the support roller is a = m * y; where m is the effective coefficient, and the value is from 0.3 to 0.9.

[0015] The further improvement of the above scheme is that after step (7), step (8) is also included to confirm that the rolling mill has the ability to produce an effective working layer of (D2-D1+a), otherwise the capacity range is reduced.

[0016] The design method for the working layer thickness of the hot-rolled finishing support roll provided by this invention can increase the maximum working roll diameter of the hot continuous rolling mill from the original d2 to the manufacturing limit capacity d3, while increasing the effective working layer of the support roll and reducing the consumption of the rolling mill roll by more than 10%. Detailed Implementation Example

[0017] The design method for the working layer thickness of the hot-rolled finishing support rolls in this embodiment is applied to a hot strip finishing mill. A hot strip finishing mill is typically a four-high mill, consisting of upper and lower work rolls and a support roll. The diameter range of the work rolls and support rolls must meet at least two conditions: rolling conditions and roll changing conditions. Rolling conditions require meeting the rolling line height requirements, and roll changing conditions require meeting roll replacement requirements. Generally, in newly built mills, any size within the roll design range meets both rolling and roll changing conditions. New work rolls (largest diameter) and new support rolls (largest diameter) meet these conditions, as do the soon-to-be-retired rolls (smallest diameter). In actual production, roll diameters have both maximum and minimum values, and the distribution of roll diameters follows a certain pattern according to the usage plan. Utilizing the space between the maximum and actual roll diameters, the maximum work roll diameter is increased, increasing the effective working layer. Since work rolls consume a significant amount of power, increasing the effective working layer has a better effect on reducing roll consumption. However, due to roll manufacturing limitations, directly increasing the work roll diameter is restricted, and the surplus space cannot be fully utilized.

[0018] The design method for the working layer of the hot-rolled finishing support roll in this embodiment specifically includes:

[0019] (1) Define hot strip mill F i -F j The support roll diameter is D, the maximum design diameter of the support roll is D2, and the minimum design diameter of the support roll is D1. Define the hot strip mill F. i -F j The working roll diameter is d, the maximum designed diameter of the working roll is d2, the minimum designed diameter of the working roll is d1, and the maximum achievable diameter of the working roll is d3.

[0020] (2) The allowable condition for steel rolling is the working roll diameter plus half the support roll diameter, i.e., D / 2+d. The maximum value of the allowable condition for steel rolling is D2 / 2+d2, and the minimum value is D1 / 2+d1. The range of variation is (D2-D1) / 2+(d2-d1).

[0021] (3) The allowable condition for changing rolls is half the diameter of the working roll plus half the effective diameter of the support roll, i.e., D / 2+d / 2. The maximum value of the allowable condition for changing rolls is D2 / 2+d2 / 2, and the minimum value is D1 / 2+d1 / 2. The range of variation is (D2-D1) / 2+(d2-d1) / 2.

[0022] (4) If the effective working layer of the working roll increases by x, then the center distance of the lower working roll must be increased by at least x when changing the roll, while the position of the lower working roll remains unchanged; if the diameter of the support roll is Dx at this time, then according to the allowable conditions of steel rolling, we get: Dx / 2+d2+x≤D2 / 2+d2, which simplifies to: Dx≤D2-2x;

[0023] Based on the roll changing condition, we get: Dx / 2+(d2+x) / 2≤D2 / 2+d2 / 2-x, which simplifies to: Dx2≤D2-3x;

[0024] This satisfies both the rolling conditions and the roll changing conditions: Dx≤D2-3x;

[0025] During normal production, the diameters of the work rolls and support rolls can be considered to be evenly distributed; the proportion of support rolls that meet the requirements of the large work roll range is greater than or equal to the proportion of the large work rolls, otherwise there will be a lack of small support rolls; thus, we can further obtain that: x needs to satisfy: x / (x+d2-d1)≤(D2-3x-D1) / (D2-D1), which gives the maximum value of x;

[0026] (5) Calculate the ratio k of the maximum achievable diameter of the work roll to x: k = (d3 - d2) / x; if k < 0.7, then the diameter of the support roll can be increased;

[0027] (6) The working roll bearing housing separation pile is raised by d3-d2, and the working roll flat head fixing device on the roll changer is raised by d3-d2; assuming the effective working layer of the support roll increases by y, and assuming the diameters of the working roll and the support roll are evenly distributed, then the proportion of small-sized support rolls that meet the conditions for a large working roll must be greater than or equal to the proportion of the large working roll, and the proportion of small-sized working rolls that meet the conditions for a large support roll must be greater than or equal to the proportion of the large support roll. Therefore, y needs to satisfy:

[0028] (d3-d2) / (d3-d1)≤(D2-3*(d3-d2)-D1) / (D2+y-D1), and,

[0029] (y / (D2-D1+y))≤(d2-y / 2-d1) / (d3-d1);

[0030] Calculate the maximum value of y;

[0031] (7) Then the increase in the diameter of the support roller is a = m * y; where m is the effective coefficient, and the value is between 0.3 and 0.9;

[0032] Step (8) confirm that the roll mill has the capacity to produce an effective working layer of (D2-D1+a), otherwise adjust it to the capacity range; that is, redetermine the increase in the support roll diameter b (a or the production capacity of the roll mill).

[0033] Taking the F5-F7 mills in the latter part of Meigang's 1780 production line as an example, the maximum support roll diameter is 1550mm and the minimum is 1400mm. The maximum work roll diameter is 720mm and the minimum is 630mm. The maximum work roll manufacturing diameter and rolling swing angle requirement can be up to 740°. The method to improve the effective working layer is as follows:

[0034] (1) Determine the permissible conditions for steel rolling:

[0035] The maximum range of D / 2+d is 1550 / 2+720=1495;

[0036] The minimum range of D / 2+d is 1400 / 2+630=1330;

[0037] The change range is 165;

[0038] (2) Allowable conditions for changing rolls:

[0039] The maximum range of D / 2+d / 2 is 1550 / 2+720 / 2=1135;

[0040] The minimum range of D / 2+d / 2 is 1400 / 2+630 / 2=1015;

[0041] The range of change is 120;

[0042] (3) Suppose that the effective working layer of the working roll increases by x. At this time, the center distance of the working rolls must be increased by at least x when changing rolls. Assume that the center of the upper working roll increases by x.

[0043] The rolling conditions require: Dx / 2+d2+x≤D2 / 2+d2, so Dx≤1550-2x;

[0044] The roll changing condition requirement is: Dx / 2+(d2+x) / 2≤D2 / 2+d2 / 2-x, so Dx≤1550-3x;

[0045] The diameter of the support roll that meets both the rolling and roll changing requirements is: Dx≤1550-3x;

[0046] (4) During normal production, the diameters of the work rolls and support rolls are evenly distributed. The proportion of support rolls that meet the requirements of the large work roll range is greater than or equal to the proportion of the large work rolls; otherwise, small support rolls are lacking.

[0047] x / (x+90)≤(150-3x) / 150; Solve for x=35.78

[0048] (5) Compare the ratio of the increase in the maximum achievable diameter roller diameter to x, k: k=20 / 35.78=0.559<0.7, the excess space can be used to increase the diameter of the support roller;

[0049] (6) The working roll bearing seat separation pile is raised by 20, and the working roll flat head fixing device on the roller change is raised by 20; if the effective working layer of the support roller increases by y, and the diameters of the working roll and the support roller are evenly distributed, then the proportion of small-sized support rollers that meet the conditions of large working rolls must be greater than or equal to the proportion of large working rolls, and the proportion of small-sized working rolls that meet the conditions of large support rollers must be greater than or equal to the proportion of large support rollers.

[0050] (d3-d2) / (d3-d1)≤(D2-3*(d3-d2)-D1) / (D2+y-D1); get:

[0051] y≤(d2-d1)*(D2-D1) / (d3-d2)-3*(d3-d1)=90*150 / 20-3*120=315;

[0052] (y / (D2-D1+y))≤(d2-y / 2-d1) / (d3-d1); Therefore:

[0053] y≤=72;

[0054] Therefore, y=72

[0055] (7) Take the range of increase in the support roller diameter as a = m * y = 0.6944 * 72 = 50;

[0056] (8) Confirm that the rolling mill has the capacity to produce an effective working layer of 180 and increase the diameter of the support roll by 30.

[0057] After implementation, the diameter of the work rolls (F5 to F7) in the latter part of the 1780 production line can be increased to the manufacturing limit of 740 mm, and the diameter of the support rolls can be increased to the limit of 1580 mm. Roll consumption will decrease by more than 10%.

[0058] This invention is not limited to the embodiments described above. All technical solutions formed by equivalent substitutions fall within the scope of protection claimed by this invention.

Claims

1. A method for designing the working layer thickness of a hot-rolled finishing support roll, characterized in that, Includes the following steps: (1) Define hot strip mill F i -F j The support roll diameter is D, the maximum design diameter of the support roll is D2, and the minimum design diameter of the support roll is D1. Define the hot strip mill F. i -F j The working roll diameter is d, the maximum designed diameter of the working roll is d2, the minimum designed diameter of the working roll is d1, and the maximum achievable diameter of the working roll is d3. (2) The allowable condition for steel rolling is the working roll diameter plus half the support roll diameter, i.e., D / 2+d. The maximum value of the allowable condition for steel rolling is D2 / 2+d2, and the minimum value is D1 / 2+d1. The range of variation is (D2-D1) / 2+(d2-d1). (3) The allowable condition for changing rolls is half the diameter of the working roll plus half the diameter of the support roll, i.e., D / 2+d / 2. The maximum value of the allowable condition for changing rolls is D2 / 2+d2 / 2, and the minimum value is D1 / 2+d1 / 2. The range of variation is (D2-D1) / 2+(d2-d1) / 2. (4) Let the effective working layer of the working roller increase by x. Then x needs to satisfy: x / (x+d2-d1)≤(D2-3x-D1) / (D2-D1), to get the maximum value of x; (5) Calculate the ratio k of the maximum achievable diameter of the work roll to x: k = (d3 - d2) / x; if k < 0.7, then the diameter of the support roll can be increased; (6) If the effective working layer of the support roller increases by y, then y needs to satisfy: (d3-d2) / (d3-d1)≤(D2-3*(d3-d2)-D1) / (D2+y-D1), and, (y / (D2-D1+y))≤(d2-y / 2-d1) / (d3-d1); Calculate the maximum value of y; (7) The increase in the diameter of the support roller is a = m * y; where m is the effective coefficient, and the value is from 0.3 to 0.

9.

2. The method for designing the working layer thickness of the hot-rolled finishing support roll according to claim 1, characterized in that: After step (7), there is also step (8), which confirms that the roll mill has the capability to produce a support roll with an effective working layer of (D2-D1+a), otherwise the capability range is reduced.