Method of controlling ovality in production of round blank using continuous casting machine

Abstract

FIELD: foundry production.SUBSTANCE: method for controlling the ovality of a round continuously cast billet on a continuous casting machine containing straightening stands (1) includes a step of determining the total amount of reduction of the round billet (2) and a step of determining the straightening stands from said straightening stands by means of which the reduction of the billet is performed, as well as the reduction values. The total compression value is determined by the formula H = D×3.0%, where H is the total compression value, mm; D is the diameter of the workpiece, mm. At the stage of determining the straightening stands by means of which the reduction is performed, in the case of HS < N, where HS is the numerical value of the total reduction value H, N is the total number of straightening stands, the reduction operation in stands from the first to the Xth in the direction of unloading the workpiece is not performed. Stand X is determined by the formula X = [NHS]+1. The workpiece is compressed in stands X+1 to N-th in the direction of workpiece unloading with a compression value of 1 mm for each stand. In case of HS ≥ N compression is performed in each stand in the direction of unloading the workpiece, and the amount of compression M (mm) of each stand is determined by the formula M = H / N.EFFECT: provides control over the ovality of a round workpiece.10 cl, 1 dwg

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This disclosure claims priority to Chinese Patent Application No. 202410600950.1, filed on May 15, 2024, which is incorporated herein by reference in its entirety. AREA OF TECHNOLOGY

[0002] The present disclosure relates to the technical field of metallurgical equipment, in particular to a method for controlling ovality in the production of a round blank using a continuous casting machine. LEVEL OF TECHNOLOGY

[0003] Most steel mills produce square and round blanks by using separate continuous casting machines for square blanks and round blanks. To improve production efficiency and product diversification, a continuous casting machine capable of producing both square and round blanks has been proposed, such as the "Square / Round Blank Continuous Casting Machine and Straightening Stand" disclosed in Chinese Patent CN 111360218 A, published on July 3, 2020. When a manufacturer uses the same continuous casting machine to produce square and round blanks, it usually adapts equipment replacement methods, such as the mold and clamping section, and adapts the groove roll or flat roll for the straightening stand roll.Specifically, a special steel production plant requires light reduction when producing square billets, and the leveling stand's reduction volume must be relatively high. However, when producing round billets, lower pressure is required. The leveling stand uses pressure control only. When lower pressure is applied, pressure fluctuations increase, and this can lead to uncontrollable ovality. When producing small-section round billets, and when round billets are used for seamless rolling of steel pipes, the ovality requirement cannot be met. DISCLOSURE OF THE ESSENCE OF THE INVENTION

[0004] To address the problem of insufficient ovality control when continuous casting machines produce round blanks, the present disclosure proposes a method for controlling ovality in the production of round blanks using continuous casting. By controlling the reduction amount and offset, the ovality of the round blank is controlled to 3.0%, which meets the standard requirement of less than 3.5%. This ensures that all round blanks can meet the ovality requirements during production.

[0005] The technical solution proposed by the embodiments of the present disclosure for solving the said technical problem is as follows:

[0006] a method for controlling ovality in the production of a round blank using continuous casting, wherein the continuous casting machine comprises a plurality of straightening stands (1), and the method for controlling ovality in the production of a round blank using continuous casting includes the following sequential steps:

[0007] Step 1, determine the total reduction amount of the round workpiece according to the calculation formula for the total reduction amount:

[0008] The formula for calculating the total compression amount: H=D×3.0%;

[0009] where, H is the total value of the round workpiece compression, unit of measurement is mm; D is the diameter of the round workpiece, unit of measurement is mm;

[0010] Step 2, determine which correct cages from the set perform the crimping operations and the crimping values:

[0011] when H S <N, в направлении выгрузки заготовки первая правильная клеть по X-ю правильную клеть не выполняют операцию обжатия, где X=[N-H S]+1, X+1 straightening stand along the N-th straightening stand performs the compression operation, and the compression values ​​for each of the X+1 straightening stand along the N-th straightening stand are 1 mm;

[0012] N - total number of correct cages, without units of measurement; H S - a numerical value when mm is taken as the unit of measurement of the total amount of compression of a round workpiece;

[0013] when H S ≥N, in the direction of unloading the workpiece, each straightening stand performs a reduction operation, and the reduction value of each straightening stand is M, where M=H / N; the unit of measurement of M is mm.

[0014] An advantageous result of the embodiments of the present disclosure is that, by controlling the amount of reduction and offset, the ovality of the round workpiece is controlled to 3.0%, which meets the standard requirement of less than 3.5%, so that all round workpieces can meet the ovality requirements in their production. BRIEF DESCRIPTION OF DRAWINGS

[0015] The description drawings that form part of the present disclosure are intended to provide a further understanding of the present disclosure, the schematic embodiments of the present disclosure and the descriptions thereof are used to explain the present disclosure and do not constitute undue limitations with respect to the present disclosure.

[0016] Fig. 1 is a schematic diagram of a plurality of straightening stands in a continuous casting machine according to the present disclosure.

[0017] Description of reference positions: 1 - straightening stand; 2 - round blank. IMPLEMENTATION OF THE INVENTION

[0018] It should be noted that, in the absence of contradictions, the embodiments in the present disclosure and the features in the embodiments may be combined with each other. The present disclosure is described in detail below with reference to the drawings and in combination with the embodiments.

[0019] As shown in Fig. 1, in the method for controlling the ovality in producing a round blank using continuous casting in the embodiments of the present disclosure, in the blank discharging direction A of the continuous casting machine, the continuous casting machine comprises a plurality of straightening stands 1, and the method for controlling the ovality in producing a round blank using continuous casting includes the following sequential steps:

[0020] Step 1, determine the total amount of compression of round workpiece 2 according to the calculation formula for the total amount of compression:

[0021] According to the requirement of ovality control, the ovality of round workpiece 2 should be controlled within 3.5%, and the calculation formula for the total reduction amount is: H=D×3.0%;

[0022] where, H is the total compression value of the round workpiece 2, unit of measurement is mm; D is the diameter of the round workpiece 2, unit of measurement is mm;

[0023] Step 2, assigning a total reduction amount to the appropriate straightening stands to perform the reduction by taking into account a specific error, wherein the reduction amount of each straightening stand is not less than 1 mm, and determining which straightening stands (1) of the plurality perform the reduction operations and the reduction amounts:

[0024] when H S <N, в направлении А выгрузки заготовки первая правильная клеть 1 по X-ю правильную клеть 1 поднимаются и не выполняют операцию обжатия, где X=[N-H S ]+1, [NH S ] represents the integer part of the difference NH S , for example, [8-5,4]=[2,6]=2; X+1 straightening stand 1 to N-th straightening stand 1 perform the compression operation, and the compression values ​​for each of X+1 straightening stand 1 to N-th straightening stand 1 are 1 mm;

[0025] where N is the total number of correct cells 1, without units of measurement; H S- the numerical part of the value when mm is taken as the unit of measurement of the total amount of compression of a round workpiece 2;

[0026] when H S ≥N, in the direction A of unloading the workpiece, each straightening stand 1 performs a compression operation, and the compression value of each straightening stand 1 is equal to M, where M=H / N; the unit of measurement of M is mm.

[0027] When producing a round blank 2, the above-mentioned reduction amount control method and the offset control mode of the straightening stands 1 enable the round blank ovality control to be 3.0%, which meets the standard requirement of less than 3.5%, in order to achieve the ovality requirements for the production of all round blanks. The continuous casting machine is capable of producing both square blanks and round blanks. In some embodiments of the present disclosure, the continuous casting machine may be the continuous casting machine disclosed in Chinese Patent CN 111360218 A, published on July 3, 2020, entitled "Straightening Stand and Continuous Casting Machine for Square / Round Blanks."The following describes in detail the ovality control method in the production of round blanks using continuous casting by taking the following as an example: “the radius R of the continuous casting machine is 12 m, the production section is 240 × 300 mm, the maximum pressing force of the straightening stands 1 is 140 t, and the number of straightening stands 1 is 8.”

[0028] When the diameter of the round workpiece is 180mm and the total number of straightening stands 1 is 8 (the total number of straightening stands 1 can also be other numerical value such as 5, 6, 7, 9, 10, 11, 12, etc.), the ovality control method in producing the round workpiece using continuous casting includes the following sequential steps:

[0029] Step 1, determine the total reduction amount of the round workpiece according to the calculation formula for the total reduction amount:

[0030] Total compression value H=180mm×3.0%=5.4mm;

[0031] Step 2, determining which correct cages 1 of the plurality perform the crimping operations, and the crimping values:

[0032] at this step 5.4<8, X=[8-5.4]+1=3, in the workpiece unloading direction A, the first straightening stand 1 to the third straightening stand 1 (the first straightening stand 1, the second straightening stand 1 and the third straightening stand 1) are lifted and do not perform the reduction operation; the fourth straightening stand 1 to the eighth straightening stand 1 (the fourth straightening stand 1, the fifth straightening stand 1, the sixth straightening stand 1, the seventh straightening stand 1 and the eighth straightening stand 1) perform the reduction operation, and the reduction amounts for each of the fourth straightening stand 1 to the eighth straightening stand 1 are 1 mm, as shown in Fig. 1. The reduction amount of each straightening stand 1 is 1 mm, the actual total reduction amount is 5 mm, to ensure the ovality of the round blanks produced, offset control is used.The offset control regulates the compression position of the hydraulic cylinder via a offset sensor in the hydraulic cylinder. By receiving a target position value, the hydraulic cylinder continuously adjusts its position to approach the target value. The offset control accuracy is maintained within ±0.05 mm of the target value. Specifically, the hydraulic cylinder can be mounted on a straightening stand to control the straightening stand's compression operation. In some embodiments, the hydraulic cylinder is mounted on the straightening stand frame and connected to the straightening stand's compression mechanism.

[0033] When the diameter of the round blank is 200mm and the total number of straightening stands 1 is 8, the ovality control method in producing the round blank using continuous casting includes the following sequential steps:

[0034] Step 1, determine the total reduction amount of the round workpiece according to the calculation formula for the total reduction amount:

[0035] Total compression value H=200mm×3.0%=6mm;

[0036] Step 2, determining which correct cages 1 of the plurality perform the crimping operations, and the crimping values:

[0037] at this step 6<8, X=[8-6]+1=3, in the workpiece unloading direction A, the first straightening stand 1 to the third straightening stand 1 (the first straightening stand 1, the second straightening stand 1 and the third straightening stand 1) are lifted and do not perform the reduction operation; the fourth straightening stand 1 to the eighth straightening stand 1 (the fourth straightening stand 1, the fifth straightening stand 1, the sixth straightening stand 1, the seventh straightening stand 1 and the eighth straightening stand 1) perform the reduction operation, and the reduction amounts for each of the fourth straightening stand 1 to the eighth straightening stand 1 are 1 mm, as shown in Fig. 1. The reduction amount of each straightening stand 1 is 1 mm, the actual total reduction amount is 5 mm, to ensure the ovality of the round blanks produced, offset control is used.

[0038] When the diameter of the round blank is 220mm and the total number of straightening stands 1 is 8, the ovality control method in producing the round blank using continuous casting includes the following sequential steps:

[0039] Step 1, determine the total reduction amount of the round workpiece according to the calculation formula for the total reduction amount:

[0040] Total compression value H=220mm×3.0%=6.6mm;

[0041] Step 2, determining which correct cages 1 of the plurality perform the crimping operations, and the crimping values:

[0042] at this step, 6.6<8, X=[8-6.6]+1=2, in the workpiece unloading direction A, the first straightening stand 1 and the second straightening stand 1 do not perform the reduction operation; the third straightening stand 1 to the eighth straightening stand 1 (the third straightening stand 1, the fourth straightening stand 1, the fifth straightening stand 1, the sixth straightening stand 1, the seventh straightening stand 1 and the eighth straightening stand 1) perform the reduction operation, and the reduction amounts for each of the third straightening stand 1 to the eighth straightening stand 1 are 1 mm, as shown in Fig. 1. The reduction amount of each straightening stand 1 is 1 mm, the actual total reduction amount is 6 mm, to ensure the ovality of the round workpiece production, the offset control is used.

[0043] When the diameter of the round blank is 250mm and the total number of straightening stands 1 is 8, the ovality control method in producing the round blank using continuous casting includes the following sequential steps:

[0044] Step 1, determine the total reduction amount of the round workpiece according to the calculation formula for the total reduction amount:

[0045] Total compression value H=250mm×3.0%=7.5mm;

[0046] Step 2, determining which correct cages 1 of the plurality perform the crimping operations, and the crimping values:

[0047] at this step, 7.5<8, X=[8-7.5]+1=1, in the workpiece unloading direction A, the first straightening stand 1 does not perform the reduction operation; the second straightening stand 1 to the eighth straightening stand 1 (the second straightening stand 1, the third straightening stand 1, the fourth straightening stand 1, the fifth straightening stand 1, the sixth straightening stand 1, the seventh straightening stand 1 and the eighth straightening stand 1) perform the reduction operation, and the reduction amounts for each of the second straightening stand 1 to the eighth straightening stand 1 are 1 mm, as shown in Fig. 1. The reduction amount of each straightening stand 1 is 1 mm, the actual total reduction amount is 7 mm, to ensure the ovality of the round workpiece production, the offset control is used.

[0048] When the diameter of the round blank is 280mm and the total number of straightening stands 1 is 8, the ovality control method in producing the round blank using continuous casting includes the following sequential steps:

[0049] Step 1, determine the total reduction amount of the round workpiece according to the calculation formula for the total reduction amount:

[0050] Total compression value H=280mm×3.0%=8.4mm;

[0051] Step 2, determining which correct cages 1 of the plurality perform the crimping operations, and the crimping values:

[0052] at this step 8.4>8, in the workpiece unloading direction A, each straightening stand 1 (the first straightening stand 1, the second straightening stand 1, the third straightening stand 1, the fourth straightening stand 1, the fifth straightening stand 1, the sixth straightening stand 1, the seventh straightening stand 1 and the eighth straightening stand 1) performs a reduction operation, uses offset control, and the reduction amount of each straightening stand 1 is M, where M=8.4 mm / 8=1.1 mm, as shown in Fig. 1.

[0053] When the diameter of the round blank is 300mm and the total number of straightening stands 1 is 8, the ovality control method in producing the round blank using continuous casting includes the following sequential steps:

[0054] Step 1, determine the total reduction amount of the round workpiece according to the calculation formula for the total reduction amount:

[0055] Total compression value H=300mm×3.0%=9.0mm;

[0056] Step 2, determining which correct cages 1 of the plurality perform the crimping operations, and the crimping values:

[0057] at this step 9.0>8, in the workpiece unloading direction A, each straightening stand 1 (the first straightening stand 1, the second straightening stand 1, the third straightening stand 1, the fourth straightening stand 1, the fifth straightening stand 1, the sixth straightening stand 1, the seventh straightening stand 1 and the eighth straightening stand 1) performs a reduction operation, uses offset control, and the reduction amount of each straightening stand 1 is M, where M=9.0 mm / 8=1.1 mm, as shown in Fig. 1.

[0058] When the diameter of the round blank is 350mm and the total number of straightening stands 1 is 8, the ovality control method in producing the round blank using continuous casting includes the following sequential steps:

[0059] Step 1, determine the total reduction amount of the round workpiece according to the calculation formula for the total reduction amount:

[0060] Total compression value H=350mm×3.0%=10.5mm;

[0061] Step 2, determining which correct cages 1 of the plurality perform the crimping operations, and the crimping values:

[0062] at this step 10.5>8, in the workpiece unloading direction A, each straightening stand 1 (the first straightening stand 1, the second straightening stand 1, the third straightening stand 1, the fourth straightening stand 1, the fifth straightening stand 1, the sixth straightening stand 1, the seventh straightening stand 1 and the eighth straightening stand 1) performs a reduction operation, uses offset control, and the reduction amount of each straightening stand 1 is M, where M=10.5 mm / 8=1.3 mm, as shown in Fig. 1.

[0063] When the diameter of the round blank is 380mm and the total number of straightening stands 1 is 8, the ovality control method in producing the round blank using continuous casting includes the following sequential steps:

[0064] Step 1, determine the total reduction amount of the round workpiece according to the calculation formula for the total reduction amount:

[0065] Total compression value H=380mm×3.0%=11.4mm;

[0066] Step 2, determining which correct cages 1 of the plurality perform the crimping operations, and the crimping values:

[0067] at this step 11.4>8, in the workpiece unloading direction A, each straightening stand 1 (the first straightening stand 1, the second straightening stand 1, the third straightening stand 1, the fourth straightening stand 1, the fifth straightening stand 1, the sixth straightening stand 1, the seventh straightening stand 1 and the eighth straightening stand 1) performs a reduction operation, uses offset control, and the reduction amount of each straightening stand 1 is M, where M=11.4 mm / 8=1.4 mm, as shown in Fig. 1.

[0068] The above-mentioned embodiments of the present disclosure are only specific embodiments of the present disclosure and cannot be used to determine the scope of implementation of the present disclosure. Therefore, replacing them with equivalent components or equivalent changes and modifications made in accordance with the protection scope of the present disclosure shall fall within the scope contained in the present disclosure. In addition, one technical feature and another technical feature, a technical feature and a technical solution, one technical solution and another technical solution, one embodiment and another embodiment in the present disclosure can be freely combined and used.

Claims

1. A method for controlling the ovality of a round continuously cast billet on a continuous casting machine containing straightening stands, characterized in that it includes the following steps: stage 1 - determination of the total amount of compression of a round workpiece according to the formula H = D×3.0%, where H is the total value of compression of a round workpiece, mm; D - diameter of the round workpiece, mm; stage 2 - determination of the straightening stands from the mentioned straightening stands by means of which the round blank is compressed, as well as the compression values, in case the condition is met H S < N, where H S - the numerical value of the total value H of the compression of a round workpiece; N is the total number of correct cells, dimensionless; the operation of squeezing the round blank by means of straightening stands from the first to the Xth in the direction of unloading the blank is not performed, and the straightening stand X is determined by the formula X = [NH S ]+1, perform the operation of pressing the round workpiece by means of straightening stands from X+1 to N-th in the direction of unloading the workpiece with the amount of pressing for each straightening stand being 1 mm, in this case, if the condition is met H S ≥ N the operation of pressing the round workpiece is carried out by means of each straightening stand in the direction of unloading the workpiece, and the amount of pressing of each straightening stand is determined by the formula M = H / N, where M is the compression value of each straightening cage, mm.

2. The method according to paragraph 1, characterized in that for a round workpiece with a diameter of 180 mm with a total number of straightening stands equal to 8, the following steps are carried out: At stage 1, the total amount of compression of the round workpiece is determined: H = 180×3.0% = 5.4 mm; At stage 2, the straightening stands are determined, by means of which the round blank is compressed, as well as the amount of compression of each straightening stand: 5.4 < 8, X = [8-5.4]+1 = 3, thus, in the direction of unloading the workpiece, no compression is performed by means of straightening stands from the first to the third, while by means of straightening stands from the fourth to the eighth, compression is performed with the compression value for each of the straightening stands from the fourth to the eighth being 1 mm.

3. The method according to paragraph 1, characterized in that for a round workpiece with a diameter of 200 mm with a total number of straightening stands equal to 8, the following steps are carried out: At stage 1, the total amount of compression of the round workpiece is determined: H = 200×3.0% = 6 mm; At stage 2, the straightening stands are determined, by means of which the round blank is compressed, as well as the amount of compression of each straightening stand: 6 < 8, X = [8-6]+1 = 3, thus, in the direction of unloading the workpiece, no compression is performed by means of straightening stands from the first to the third, while by means of straightening stands from the fourth to the eighth, compression is performed with the compression value for each of the straightening stands from the fourth to the eighth being 1 mm.

4. The method according to paragraph 1, characterized in that for a round workpiece with a diameter of 220 mm with a total number of straightening stands equal to 8, the following steps are carried out: At stage 1, the total amount of compression of the round workpiece is determined: H = 220×3.0% = 6.6 mm; At stage 2, the straightening stands are determined, by means of which the round blank is compressed, as well as the amount of compression of each straightening stand: 6.6 < 8, X = [8-6.6]+1 = 2, thus, in the direction of unloading the workpiece by means of the first and second straightening stands, no compression is performed; by means of straightening stands from the third to the eighth, compression is performed with a compression value for each of the straightening stands from the third to the eighth, amounting to 1 mm.

5. The method according to paragraph 1, characterized in that for a round workpiece with a diameter of 250 mm with a total number of straightening stands equal to 8, the following steps are carried out: At stage 1, the total amount of compression of the round workpiece is determined: H = 250×3.0% = 7.5 mm; At stage 2, the straightening stands are determined, by means of which the round blank is compressed, as well as the amount of compression of each straightening stand: 7.5 < 8, X = [8-7.5]+1 = 1, thus, by means of the first straightening stand in the direction of unloading the workpiece, no compression is performed; by means of the straightening stands from the second to the eighth, compression is performed with the compression value for each of the straightening stands from the second to the eighth being 1 mm.

6. The method according to paragraph 1, characterized in that for a round workpiece with a diameter of 280 mm with a total number of straightening stands equal to 8, the following steps are carried out: At stage 1, the total amount of compression of the round workpiece is determined: H = 280×3.0% = 8.4 mm; At stage 2, the straightening stands are determined, by means of which the round blank is compressed, as well as the amount of compression of each straightening stand: 8.4 > 8, thus, the compression of the workpiece is carried out by means of each straightening stand in the direction of unloading the workpiece, while the amount of compression of each straightening stand is M = 8.4 / 8 = 1.1 mm.

7. The method according to paragraph 1, characterized in that for a round workpiece with a diameter of 300 mm with a total number of straightening stands equal to 8, the following steps are carried out: At stage 1, the total amount of compression of the round workpiece is determined: H = 300×3.0% = 9.0 mm; At stage 2, the straightening stands are determined, by means of which the round blank is compressed, as well as the amount of compression of each straightening stand: 9.0 > 8, thus, the compression of the workpiece is carried out by means of each straightening stand in the direction of unloading the workpiece, while the amount of compression of each straightening stand is M = 9.0 / 8 = 1.1 mm.

8. The method according to paragraph 1, characterized in that for a round workpiece with a diameter of 350 mm with a total number of straightening stands equal to 8, the following steps are carried out: At stage 1, the total amount of compression of the round workpiece is determined: H = 350×3.0% = 10.5 mm; At stage 2, the straightening stands are determined, by means of which the round blank is compressed, as well as the amount of compression of each straightening stand: 10.5 > 8, thus, the compression of the workpiece is carried out by means of each straightening stand in the direction of unloading the workpiece, while the amount of compression of each straightening stand is M = 10.5 / 8 = 1.3 mm.

9. The method according to paragraph 1, characterized in that for a round workpiece with a diameter of 380 mm with a total number of straightening stands equal to 8, the following steps are carried out: At stage 1, the total amount of compression of the round workpiece is determined: H = 380×3.0% = 11.4 mm; At stage 2, the straightening stands are determined, by means of which the round blank is compressed, as well as the amount of compression of each straightening stand: 11.4 > 8, thus, the compression of the workpiece is carried out by means of each straightening stand in the direction of unloading the workpiece, while the amount of compression of each straightening stand is M = 11.4 / 8 = 1.4 mm.

10. The method according to paragraph 1, characterized in that by means of the said continuous casting machine both a square blank and a round blank are produced.

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