Method for controlling ovality during production of round billet by using continuous casting machine

Abstract

A method for controlling ovality during production of a round billet by using a continuous casting machine. The method comprises the following steps: step 1, determining the total reduction amount of a round billet on the basis of a total reduction amount calculation formula, wherein the total reduction amount calculation formula is: H=D×3.0%; and step 2, distributing the total reduction amount to appropriate withdrawal and straightening machines for reduction implementation, and determining the withdrawal and straightening machines for implementing a reduction operation from among a plurality of withdrawal and straightening machines (1), and reduction amounts thereof. Reduction amount control and a displacement control mode ensure that the ovality of round billets is controlled within 3.0%, so as to meet the standard requirement of less than 3.5%, so that all the round billets can meet the ovality requirement during production.

Description

Method for controlling ovality of round billet produced by continuous casting machine

[0001] Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202410600950.1, filed on May 15, 2024, and incorporates by reference the entire disclosure of the aforementioned patent application as part of this application. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of metallurgical equipment, in particular to a method for controlling ovality of round billet produced by continuous casting machine. BACKGROUND

[0004] Most steel plants produce square billets and round billets using separate square billet continuous casting machines and separate round billet continuous casting machines. In order to improve production efficiency and adapt to product diversity, a continuous casting machine that can produce both square billets and round billets has appeared, for example, Chinese Patent CN111360218A, published on July 3, 2020, discloses a "withdrawal and straightening machine and square-round billet continuous casting machine". When the manufacturer produces square billets and round billets using the same continuous casting machine, it is common to replace the mold, clamping section and other equipment. The rollers of the withdrawal and straightening machine are either grooved rollers or flat rollers. Especially for special steel enterprises, light pressing is required when producing square billets, and the pressing capacity of the withdrawal and straightening machine is designed to be relatively large. However, when producing round billets, the required pressure is relatively small. If the withdrawal and straightening machine only uses pressure control, the pressure fluctuation increases when a small pressure is output, and the ovality control of small-section round billets may not be stable. When round billets are used for seamless steel pipe rolling, the ovality requirement cannot be met. SUMMARY

[0005] In order to solve the problem of poor ovality control when producing round billets by the continuous casting machine, the present disclosure provides a method for controlling ovality of round billets produced by continuous casting machine. Through the displacement control mode and the pressing amount control mode, the ovality of the round billets is controlled within 3.0%, meeting the standard requirement of less than 3.5%, and the ovality requirement of all round billets can be met.

[0006] The technical solution adopted by the embodiments of the present disclosure to solve the technical problems is as follows:

[0007] A method for controlling ovality of round billets produced by continuous casting machine, the continuous casting machine contains multiple withdrawal and straightening machines, and the method for controlling ovality of round billets produced by continuous casting machine comprises the following steps in sequence:

[0008] Step 1, determining the total pressing amount of the round billet according to the total pressing amount calculation formula:

[0009] The calculation formula of the total pressing amount is: H=Dx3.0%;

[0010] Wherein, H is the total amount of reduction of the round billet, in mm; D is the diameter of the round billet, in mm;

[0011] Step 2, determining the reduction mill and the reduction amount of the reduction mill that implements the reduction operation in the plurality of reduction mills:

[0012] When H S <N, the first reduction mill to the Xth reduction mill along the direction of the round billet do not implement the reduction operation, X = [N-H S ]+1; the X+1th reduction mill to the Nth reduction mill implement the reduction operation, and the reduction amount of the X+1th reduction mill to the Nth reduction mill is 1mm;

[0013] N is the total number of reduction mills, without unit; H S is the numerical part of the total reduction amount of the round billet in mm;

[0014] When H S ≥N, each reduction mill implements the reduction operation along the direction of the round billet, and the reduction amount of each reduction mill is M, M = H / N; the unit of M is mm.

[0015] The beneficial effect of the embodiment of the present disclosure is that, through the reduction amount control and displacement control mode, the ovality control of the round billet is guaranteed to be 3.0%, which meets the standard requirement of less than 3.5%, and the requirement of ovality can be met during the production of all round billets. BRIEF DESCRIPTION OF DRAWINGS

[0016] The drawings accompanying the specification of the present disclosure serve to provide further understanding of the present disclosure, and the illustrative embodiments of the present disclosure and the description thereof serve to explain the present disclosure, and do not constitute an improper limitation on the present disclosure.

[0017] Fig. 1 is a schematic view of a plurality of reduction mills in a continuous casting machine of the present disclosure.

[0018] The reference signs are explained as follows: 1, reduction mill; 2, round billet. DETAILED DESCRIPTION

[0019] It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict. The present disclosure will be described in detail below with reference to the drawings and in combination with the embodiments.

[0020] As shown in Fig. 1, the control method of the ovality of a round billet produced by a continuous casting machine of an embodiment of the present disclosure includes the following steps in sequence along the direction A of the round billet of the continuous casting machine, which contains a plurality of reduction mills 1:

[0021] Step 1, determining the total reduction amount of the round billet 2 according to the reduction total amount calculation formula:

[0022] According to the control requirement of the ovality, the ovality of the round billet 2 needs to be controlled within 3.5%, and the calculation formula of the total reduction amount is: H=Dx3.0%;

[0023] Wherein, H is the total reduction amount of the round billet 2, unit: mm; D is the diameter of the round billet 2, unit: mm;

[0024] Step 2, distribute the total reduction amount to the appropriate frame of the straightening press 1 to implement the reduction, considering a certain error, the reduction amount of each straightening press is not less than 1mm, determine the straightening press 1 that implements the reduction operation in multiple straightening presses 1 and the reduction amount:

[0025] When H S <N, along the billet direction A, the first straightening press 1 to the Xth straightening press 1 are all lifted and do not implement the reduction operation, X=[N-H S ]+1, [N-H S ] is the integer part of the difference of N-H S , for example, [8-5.4]=[2.6]=[2]; the X+1th straightening press 1 to the Nth straightening press 1 all implement the reduction operation, and the reduction amount of the X+1th straightening press 1 to the Nth straightening press 1 is all 1mm;

[0026] Wherein, N is the total number of straightening presses 1, unitless; H S is the numerical part of the total reduction amount of the round billet 2 in mm;

[0027] When H S ≥N, along the billet direction A, each straightening press 1 implements the reduction operation, and the reduction amount of each straightening press 1 is M, M=H / N; the unit of M is mm.

[0028] When producing the round billet 2, through the above reduction amount control method and the displacement control mode of the straightening press 1, the ovality of the round billet is controlled within 3.0%, meeting the standard requirement of less than 3.5%, and realizing the ovality requirement of all round billets. The continuous casting machine can produce both square billets and round billets. In some embodiments of the present disclosure, the continuous casting machine can use the continuous casting machine disclosed in Chinese patent CN 111360218A, published on July 3, 2020, a kind of _ straightening press and square round billet continuous casting machine. The following takes the radius R of the continuous casting machine as 12m, the production section as 240mmx300mm, the maximum reduction force of the straightening press 1 as 140t, and the number of straightening presses 1 as 8 as an example to introduce in detail the control method of the ovality of the continuous casting machine when producing round billets.

[0029] When the diameter of the round billet is 180mm, and the total number of straightening presses 1 is 8 (the total number of straightening presses 1 can also be other values, such as 5, 6, 7, 9, 10, 11, 12, etc.), the control method of the ovality of the continuous casting machine when producing round billets comprises the following steps in turn:

[0030] Step 1, determining the total reduction amount of the round billet according to the total reduction amount calculation formula:

[0031] The total reduction amount H = 180 mm x 3.0% = 5.4 mm;

[0032] Step 2, determining the stretcher levelers 1 that implement the reduction operation and the reduction amount in the plurality of stretcher levelers 1:

[0033] At this time, 5.4 < 8, X = [8-5.4] + 1 = 3, the first stretcher leveler 1 to the third stretcher leveler 1 (the first stretcher leveler 1, the second stretcher leveler 1 and the third stretcher leveler 1) are lifted in the outgoing direction A and do not implement the reduction operation; the fourth stretcher leveler 1 to the eighth stretcher leveler 1 (the fourth stretcher leveler 1, the fifth stretcher leveler 1, the sixth stretcher leveler 1, the seventh stretcher leveler 1 and the eighth stretcher leveler 1) all implement the reduction operation, and the reduction amount of the fourth stretcher leveler 1 to the eighth stretcher leveler 1 is 1 mm, as shown in FIG. 1. The reduction amount of each stretcher leveler 1 is 1 mm, and the actual total reduction amount is 5 mm. Displacement control is used to ensure the ovality of the round billet production. The displacement control is to control the reduction position of the hydraulic cylinder through the displacement sensor in the hydraulic cylinder, and to adjust the position of the hydraulic cylinder by accepting the position target value, and to approach the target value. The control accuracy of the reduction is within the range of the target value ± 0.05 mm. Specifically, the hydraulic cylinder can be installed on the stretcher leveler for controlling the reduction action of the stretcher leveler. In some embodiments, the hydraulic cylinder is installed on the frame of the stretcher leveler and connected to the reduction mechanism of the stretcher leveler.

[0034] When the diameter of the round billet is 200 mm and the total number of the stretcher levelers 1 is 8, the ovality control method of the round billet produced by the continuous casting machine comprises the following steps in sequence:

[0035] Step 1, determining the total reduction amount of the round billet according to the total reduction amount calculation formula:

[0036] The total reduction amount H = 200 mm x 3.0% = 6 mm;

[0037] Step 2, determining the stretcher levelers 1 that implement the reduction operation and the reduction amount in the plurality of stretcher levelers 1:

[0038] At this time, 6 < 8, X = [8-6] + 1 = 3, along the direction of the blank, the first to the third straightening machine 1 (the first straightening machine 1, the second straightening machine 1 and the third straightening machine 1) are lifted without carrying out the pressing operation; the fourth to the eighth straightening machine 1 (the fourth straightening machine 1, the fifth straightening machine 1, the sixth straightening machine 1, the seventh straightening machine 1 and the eighth straightening machine 1) all carry out the pressing operation, and the pressing amount of the fourth to the eighth straightening machine 1 is 1mm, as shown in FIG. 1. The pressing amount of each straightening machine 1 is 1mm, and the actual total pressing amount is 5mm, displacement control is used to ensure the ovality of the round billet production.

[0039] When the diameter of the round billet is 220mm and the total number of the straightening machines 1 is 8, the ovality control method of the continuous casting machine for producing the round billet comprises the following steps in turn:

[0040] Step 1, the total pressing amount of the round billet is determined according to the total pressing amount calculation formula:

[0041] The total pressing amount H = 220mm x 3.0% = 6.6mm;

[0042] Step 2, the straightening machines 1 carrying out the pressing operation and the pressing amount in the plurality of straightening machines 1 are determined:

[0043] At this time, 6.6 < 8, X = [8-6.6] + 1 = 2, along the direction of the blank, the first and the second straightening machine 1 do not carry out the pressing operation; the third to the eighth straightening machine 1 (the third straightening machine 1, the fourth straightening machine 1, the fifth straightening machine 1, the sixth straightening machine 1, the seventh straightening machine 1 and the eighth straightening machine 1) all carry out the pressing operation, and the pressing amount of the third to the eighth straightening machine 1 is 1mm, as shown in FIG. 1. The pressing amount of each straightening machine 1 is 1mm, and the actual total pressing amount is 6mm, displacement control is used to ensure the ovality of the round billet production.

[0044] When the diameter of the round billet is 250mm and the total number of the straightening machines 1 is 8, the ovality control method of the continuous casting machine for producing the round billet comprises the following steps in turn:

[0045] Step 1, the total pressing amount of the round billet is determined according to the total pressing amount calculation formula:

[0046] The total pressing amount H = 250mm x 3.0% = 7.5mm;

[0047] Step 2, the straightening machines 1 carrying out the pressing operation and the pressing amount in the plurality of straightening machines 1 are determined:

[0048] At this time, 7.5 < 8, X = [8-7.5]+1 = 1, along the direction of the blank, the first frame of the stretcher 1 does not implement the reduction operation; the second frame of the stretcher 1 to the eighth frame of the stretcher 1 (the second frame of the stretcher 1, the third frame of the stretcher 1, the fourth frame of the stretcher 1, the fifth frame of the stretcher 1, the sixth frame of the stretcher 1, the seventh frame of the stretcher 1 and the eighth frame of the stretcher 1) all implement the reduction operation, and the reduction amount of the second frame of the stretcher 1 to the eighth frame of the stretcher 1 is 1mm, as shown in FIG. 1. The reduction amount of each frame of the stretcher 1 is 1mm, and the actual total reduction amount is 7mm, using displacement control to ensure the ovality of the round billet production.

[0049] When the diameter of the round billet is 280mm, and the total number of the stretcher 1 is 8, the control method of the ovality of the round billet produced by the continuous casting machine comprises the following steps in turn:

[0050] Step 1, determining the total reduction amount of the round billet according to the total reduction amount calculation formula:

[0051] The total reduction amount H = 280mm x 3.0% = 8.4mm;

[0052] Step 2, determining the stretcher 1 implementing the reduction operation and the reduction amount in the plurality of stretchers 1:

[0053] At this time, 8.4 > 8, along the direction of the blank, each frame of the stretcher 1 (the first frame of the stretcher 1, the second frame of the stretcher 1, the third frame of the stretcher 1, the fourth frame of the stretcher 1, the fifth frame of the stretcher 1, the sixth frame of the stretcher 1, the seventh frame of the stretcher 1 and the eighth frame of the stretcher 1) all implement the reduction operation, using displacement control, and the reduction amount of each frame of the stretcher 1 is M, M = 8.4mm / 8 = 1.1mm, as shown in FIG. 1.

[0054] When the diameter of the round billet is 300mm, and the total number of the stretcher 1 is 8, the control method of the ovality of the round billet produced by the continuous casting machine comprises the following steps in turn:

[0055] Step 1, determining the total reduction amount of the round billet according to the total reduction amount calculation formula:

[0056] The total reduction amount H = 300mm x 3.0% = 9.0mm;

[0057] Step 2, determining the stretcher 1 implementing the reduction operation and the reduction amount in the plurality of stretchers 1:

[0058] At this time, 9.0 > 8, along the direction of the blank, each frame of the stretcher 1 (the first frame of the stretcher 1, the second frame of the stretcher 1, the third frame of the stretcher 1, the fourth frame of the stretcher 1, the fifth frame of the stretcher 1, the sixth frame of the stretcher 1, the seventh frame of the stretcher 1 and the eighth frame of the stretcher 1) all implement the reduction operation, using displacement control, and the reduction amount of each frame of the stretcher 1 is M, M = 9.0mm / 8 = 1.1mm, as shown in FIG. 1.

[0059] When the diameter of the round billet is 350 mm and the total number of the stretch levers 1 is 8, the method for controlling the ovality when the continuous casting machine produces the round billet comprises the following steps in sequence:

[0060] Step 1, determining the total reduction amount of the round billet according to the reduction amount calculation formula:

[0061] The total reduction amount H = 350 mm x 3.0% = 10.5 mm;

[0062] Step 2, determining the stretch levers 1 that implement the reduction operation and the reduction amount in the plurality of stretch levers 1:

[0063] At this time, 10.5 > 8, each of the stretch levers 1 (the first stretch lever 1, the second stretch lever 1, the third stretch lever 1, the fourth stretch lever 1, the fifth stretch lever 1, the sixth stretch lever 1, the seventh stretch lever 1 and the eighth stretch lever 1) implements the reduction operation along the billet outgoing direction, displacement control is used, and the reduction amount of each of the stretch levers 1 is M, M = 10.5 mm / 8 = 1.3 mm, as shown in FIG. 1.

[0064] When the diameter of the round billet is 380 mm and the total number of the stretch levers 1 is 8, the method for controlling the ovality when the continuous casting machine produces the round billet comprises the following steps in sequence:

[0065] Step 1, determining the total reduction amount of the round billet according to the reduction amount calculation formula:

[0066] The total reduction amount H = 380 mm x 3.0% = 11.4 mm;

[0067] Step 2, determining the stretch levers 1 that implement the reduction operation and the reduction amount in the plurality of stretch levers 1:

[0068] At this time, 11.4 > 8, each of the stretch levers 1 (the first stretch lever 1, the second stretch lever 1, the third stretch lever 1, the fourth stretch lever 1, the fifth stretch lever 1, the sixth stretch lever 1, the seventh stretch lever 1 and the eighth stretch lever 1) implements the reduction operation along the billet outgoing direction, displacement control is used, and the reduction amount of each of the stretch levers 1 is M, M = 11.4 mm / 8 = 1.4 mm, as shown in FIG. 1.

[0069] The above is only a specific embodiment of the present disclosure, which cannot limit the range of the present disclosure, so the replacement of equivalent components or equivalent changes and modifications made within the protection range of the present disclosure should still belong to the scope covered by the present disclosure. In addition, the technical features in the present disclosure can be freely combined between the technical features and the technical features, the technical features and the technical solutions, the technical solutions and the technical solutions, the embodiments and the embodiments.

Claims

1. A method of controlling the ovality of round billets produced by a continuous casting machine, said continuous casting machine comprising a plurality of withdrawal-straightening machines (1), characterized in that, The method for controlling the ovality of the continuous casting machine when producing round billets comprises the following steps in sequence: Step 1: determining the total reduction amount of the round billet according to the total reduction amount calculation formula: The total reduction amount calculation formula is H=D*3.0%; Wherein, H is the total reduction amount of the round billet, unit: mm; D is the diameter of the round billet, unit: mm; Step 2: determining the tension leveler (1) that implements the reduction operation and the reduction amount in the plurality of tension levelers (1): When H S <N, in the direction of the outgoing blank, the first to the Xth draw straightener (1) do not perform the press-down operation, X = [N - H S ]+1; the X+1th to the Nth draw straightener (1) perform the press-down operation, and the press-down amount of the X+1th to the Nth draw straightener (1) is 1 mm; N is the total number of stands of the straightening and temper mill (1), unitless; H S is the numerical part of the total reduction of the round billet in mm; When H S When H ≥ N, each stretcher leveler (1) performs a reduction operation in the direction of the outgoing blank, and the reduction amount of each stretcher leveler (1) is M, M = H / N; the unit of M is mm.

2. The method of controlling the ovality of a continuously cast round billet according to claim 1, characterized in that, When the diameter of the round billet is 180mm, and the total number of the tension levelers (1) is 8, the method for controlling the ovality of the continuous casting machine when producing round billets comprises the following steps in sequence: Step 1: determining the total reduction amount of the round billet according to the total reduction amount calculation formula: The total reduction amount H=180mm*3.0%=5.4mm; Step 2: determining the tension leveler (1) that implements the reduction operation and the reduction amount in the plurality of tension levelers (1): At this time, 5.4<8, X=[8-5.4]+1=3, along the direction of the billet, the first tension leveler (1) to the third tension leveler (1) do not implement the reduction operation; the fourth tension leveler (1) to the eighth tension leveler (1) all implement the reduction operation, and the reduction amount of the fourth tension leveler (1) to the eighth tension leveler (1) is 1mm.

3. The method of controlling the ovality of a continuously cast round billet according to claim 1, characterized in that, When the diameter of the round billet is 200mm, and the total number of the tension levelers (1) is 8, the method for controlling the ovality of the continuous casting machine when producing round billets comprises the following steps in sequence: Step 1: determining the total reduction amount of the round billet according to the total reduction amount calculation formula: The total reduction amount H=200mm*3.0%=6mm; Step 2: determining the tension leveler (1) that implements the reduction operation and the reduction amount in the plurality of tension levelers (1): At this time, 6<8, X=[8-6]+1=3, along the direction of the billet, the first tension leveler (1) to the third tension leveler (1) do not implement the reduction operation; the fourth tension leveler (1) to the eighth tension leveler (1) all implement the reduction operation, and the reduction amount of the fourth tension leveler (1) to the eighth tension leveler (1) is 1mm.

4. The method of controlling the ovality of a continuously cast round billet according to claim 1, characterized in that, When the diameter of the round billet is 220mm, and the total number of the tension levelers (1) is 8, the method for controlling the ovality of the continuous casting machine when producing round billets comprises the following steps in sequence: Step 1: determining the total reduction amount of the round billet according to the total reduction amount calculation formula: The total reduction amount H=220mm*3.0%=6.6mm; Step 2: determining the tension leveler (1) that implements the reduction operation and the reduction amount in the plurality of tension levelers (1): At this time, 6.6<8, X=[8-6.6]+1=2, along the direction of the billet, the first tension leveler (1) and the second tension leveler (1) do not implement the reduction operation; the third tension leveler (1) to the eighth tension leveler (1) all implement the reduction operation, and the reduction amount of the third tension leveler (1) to the eighth tension leveler (1) is 1mm.

5. The method of controlling the ovality of a continuously cast round billet according to claim 1, wherein When the diameter of the round billet is 250mm, and the total number of the tension levelers (1) is 8, the method for controlling the ovality of the continuous casting machine when producing round billets comprises the following steps in sequence: Step 1: determining the total reduction amount of the round billet according to the total reduction amount calculation formula: The total reduction amount H=250mm*3.0%=7.5mm; Step 2, determining the tension leveler (1) that implements the press-down operation among the plurality of tension levelers (1) and the press-down amount: At this time, 8.4>8, each tension leveler (1) implements the press-down operation along the direction of the billet, and the press-down amount of each tension leveler (1) is M, M=8.4mm / 8=1.1mm.

6. The method of controlling the ovality of a continuously cast round billet according to claim 1, wherein When the diameter of the round billet is 300mm and the total number of the tension levelers (1) is 8, the method for controlling the ovality of the round billet produced by the continuous caster comprises the following steps in sequence: Step 1, determining the total press-down amount of the round billet according to the total press-down amount calculation formula: The total press-down amount H=300mm×3.0%=9.0mm; Step 2, determining the tension leveler (1) that implements the press-down operation among the plurality of tension levelers (1) and the press-down amount: At this time, 9.0>8, each tension leveler (1) implements the press-down operation along the direction of the billet, and the press-down amount of each tension leveler (1) is M, M=9.0mm / 8=1.1mm.

7. The method of controlling the ovality of a continuously cast round billet according to claim 1, wherein When the diameter of the round billet is 300mm and the total number of the tension levelers (1) is 8, the method for controlling the ovality of the round billet produced by the continuous caster comprises the following steps in sequence: Step 1, determining the total press-down amount of the round billet according to the total press-down amount calculation formula: The total press-down amount H=300mm×3.0%=9.0mm; Step 2, determining the tension leveler (1) that implements the press-down operation among the plurality of tension levelers (1) and the press-down amount: At this time, 9.0>8, each tension leveler (1) implements the press-down operation along the direction of the billet, and the press-down amount of each tension leveler (1) is M, M=9.0mm / 8=1.1mm.

8. The method of controlling the ovality of a continuously cast round billet according to claim 1, wherein When the diameter of the round billet is 300mm and the total number of the tension levelers (1) is 8, the method for controlling the ovality of the round billet produced by the continuous caster comprises the following steps in sequence: Step 1, determining the total press-down amount of the round billet according to the total press-down amount calculation formula: The total press-down amount H=300mm×3.0%=9.0mm; Step 2, determining the tension leveler (1) that implements the press-down operation among the plurality of tension levelers (1) and the press-down amount: At this time, 9.0>8, each tension leveler (1) implements the press-down operation along the direction of the billet, and the press-down amount of each tension leveler (1) is M, M=9.0mm / 8=1.1mm.

9. The method of controlling the ovality of a continuously cast round billet according to claim 1, wherein When the diameter of the round billet is 300mm and the total number of the tension levelers (1) is 8, the method for controlling the ovality of the round billet produced by the continuous caster comprises the following steps in sequence: Step 1, determining the total press-down amount of the round billet according to the total press-down amount calculation formula: The total press-down amount H=300mm×3.0%=9.0mm; Step 2, determining the tension leveler (1) that implements the press-down operation among the plurality of tension levelers (1) and the press-down amount: At this time, 9.0>8, each tension leveler (1) implements the press-down operation along the direction of the billet, and the press-down amount of each tension leveler (1) is M, M=9.0mm / 8=1.1mm.

10. The method of controlling the ovality of a continuously cast round billet according to claim 1, wherein The continuous caster can produce both the square billet and the round billet.

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