A method for controlling the head of a flying shear to enter the rolling channel line during shearing.

Abstract

A method for controlling the shear head from being drawn into the rolling channel during flying shear shearing, relating to the field of bar production. The method includes the following steps: controlling the micro-tension setting of the roughing mill to 0.2–0.8 N / mm. 2 The micro-tension setting value for the rolling mill unit is 1~1.8N / mm. 2 After the rolls are replaced in the pre-finishing mill, the speed of the rolls on the stand upstream of the stand where the rolls are replaced is reduced by 0.8-1.2%. The method provided in this application for controlling the head of the flying shear during shearing adopts micro-piling rolling and micro-pulling rolling to adapt to both roughing and intermediate mills. This is beneficial for the dimensional stability of the downstream stand in the roughing mill and prevents steel piling in the intermediate mill. After the rolls are replaced in the pre-finishing mill, the speed of the rolls on the upstream stand is reduced to facilitate the bite of the workpiece and prevent steel piling. This avoids large changes in the actual speed of the workpiece caused by excessive forward slip after pulling rolling, which can lead to fluctuations in the length of the flying shear head.

Description

Technical Field

[0001] This application relates to the field of bar production, and more specifically, to a method for controlling the head of a flying shear to be drawn into the rolling channel line during shearing. Background Technology

[0002] High-speed flying shear is one of the important pieces of equipment in high-speed bar production lines. Its main function is to remove the black head and defects of the rolled piece before it enters the finishing mill. Due to the high speed of the rolled piece (10-25m / s) and the short cutting length, it is very easy for the cut head of the rolled piece to be carried into the rolling line, causing steel accumulation on the rolling line. Flying shear head is a common problem faced by high-speed bar production lines in China.

[0003] Currently, other domestic manufacturers' measures to prevent high-speed flying shear heads from slipping during high-speed bar milling are generally to lengthen the guide groove after the flying shear, leaving enough length for the cut head to fall off. Another method is to use a cylinder to move the guide groove, lowering it during cutting and then raising it after cutting. However, existing high-speed flying shear head-slipping prevention devices all increase the failure rate during use. At the same time, both of the above methods increase equipment investment, leading to higher costs. Summary of the Invention

[0004] The purpose of this application is to provide a method for controlling the head of the workpiece to be carried into the rolling channel line during flying shear shearing, which can help stabilize the dimensions of the downstream stand of the roughing mill and prevent steel from piling up in the intermediate mill group, and prevent the head of the rolled piece from being carried into the rolling channel line after shearing, thus causing scrap steel, thereby reducing scrap steel and stabilizing production.

[0005] This application is implemented as follows:

[0006] This application provides a method for controlling the head of a flying shear to enter the rolling channel line during shearing, including the following steps:

[0007] The micro-tension setting for the roughing mill is 0.2–0.8 N / mm. 2 The micro-tension setting value for the rolling mill unit is 1~1.8N / mm. 2 After the rolls are replaced in the pre-finishing mill, the roll speed of the stand upstream of the stand where the rolls are replaced is reduced by 0.8-1.2%.

[0008] In some alternative implementations, the step of setting the lead factor of the pinch rolls before the finishing mill to 1.07 to 1.1 is also included.

[0009] In some alternative implementations, the step of setting the roll gap of the pinch rolls before the finishing mill to be 5 to 7 mm smaller than that of the standard profile is also included.

[0010] In some optional implementations, the method further includes the following steps: detecting the actual moving speed of the workpiece between the hot metal detector after the pre-finishing mill and the hot metal detector before the flying shear as the calibration speed; when the error between the calibration speed and the speed of the workpiece after passing through the pre-finishing mill is <1%, the speed of the flying shear and the switch is not calibrated; when the error between the calibration speed and the speed of the workpiece after passing through the pre-finishing mill is ≥1%, the speed of the flying shear and the switch is matched and calibrated according to the calibration speed.

[0011] In some optional implementations, the following steps are also included: when the rolling speed is ≥15m / s, the distance between the outer edges of the shear blades of the switch in the rolling position and the flying shear in the cutting position is controlled to be 28-30mm.

[0012] In some optional implementations, the following step is also included: when the rolling speed is <15m / s, the distance between the outer edges of the shear blades of the switch in the rolling position and the flying shear in the cutting position is controlled to be 31-33mm.

[0013] The beneficial effects of this application are as follows: The method provided in this application for controlling the head of the flying shear to enter the rolling channel line during shearing includes the following steps: controlling the micro-tension setting of the roughing mill to be 0.2~0.8N / mm 2 The micro-tension setting value for the rolling mill unit is 1~1.8N / mm. 2 After the rolls are replaced in the pre-finishing mill, the speed of the rolls on the stand upstream of the stand where the rolls are replaced is reduced by 0.8-1.2%. The method provided in this application for controlling the head of the flying shear from entering the rolling channel line during shearing employs micro-piling rolling and micro-pulling rolling to adapt to both roughing and intermediate mills. This method is beneficial for dimensional stability of the downstream stand in the roughing mill and prevents steel piling in the intermediate mill. After the rolls are replaced in the pre-finishing mill, the speed of the rolls on the upstream stand is reduced to facilitate the bite of the workpiece and prevent steel piling. This avoids large changes in the actual speed of the workpiece caused by excessive forward slip after pulling rolling, which can lead to fluctuations in the length of the flying shear head. This also prevents the head of the workpiece from entering the rolling channel line after shearing, resulting in scrap steel, thereby reducing scrap steel and stabilizing production. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of a high-speed bar production line in the method for controlling the head of the flying shear to enter the rolling channel line during shearing, as provided in the embodiments of this application.

[0016] Labels: 100, Roughing mill; 110, No. 1 flying shear; 120, Intermediate mill; 130, No. 2 flying shear; 140, Pre-finishing mill; 150, No. 3 pinch roll; 160, No. 3 flying shear; 170, Finishing mill; 180, No. 4 pinch roll; 190, No. 4 flying shear; 200, Finishing mill. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0019] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0020] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0021] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0022] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0023] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] The following describes in further detail the features and performance of the method for controlling the head of the flying shear to enter the rolling channel line during shearing, in conjunction with embodiments.

[0025] This application provides a method for controlling the head of a flying shear to enter the rolling channel line during shearing, which is for situations such as... Figure 1 The high-speed bar mill shown is implemented in this embodiment. This high-speed bar mill includes a six-pass roughing mill 100, a first flying shear 110, a four-pass intermediate mill 120, a second flying shear 130, and a six-pass pre-finishing mill 140 arranged sequentially along the rolling direction. Following the six-pass pre-finishing mill 140, two parallel finishing mills are arranged. Each finishing mill includes a third pinch roll 150, a third flying shear 160, a two-pass finishing mill 170, a fourth pinch roll 180, a fourth flying shear 190, and a two-pass finishing mill 200 arranged sequentially along the rolling direction. Because the rolling speeds of the third flying shear 160 and the fourth flying shear 190 are high, it is very easy for scrap to be carried into the rolling channel during shear cutting, resulting in scrap steel. The method provided in this application for controlling the scrap carried into the rolling channel during flying shear cutting is mainly aimed at solving the scrap carrying problem of the third flying shear 160 and the fourth flying shear 190.

[0026] The method for controlling the flying shear head to enter the rolling channel line during shearing includes the following steps:

[0027] The micro-tension setting for the roughing mill 100 is 0.2–0.8 N / mm. 2The micro-tension setting value for the intermediate rolling mill 120 is 1~1.8 N / mm. 2 The roughing mill 100 has a large cross-sectional size of rolled pieces, making it difficult for steel to accumulate. It adopts micro-accumulation rolling, which is beneficial to the stability of the downstream stand size. The intermediate mill 120 adopts micro-pulling rolling, which can prevent steel accumulation in the intermediate mill 120.

[0028] After the rolls are replaced on the stand of the pre-finishing mill 140, the speed of the corresponding roll on the stand upstream of the stand where the rolls are replaced is reduced by 0.8-1.2%. That is, after the rolls are replaced on the second stand of the pre-finishing mill 140, the speed of the rolls on the first stand is reduced by 0.8-1.2%. After the rolls are replaced on the third stand of the pre-finishing mill 140, the speed of the rolls on the second stand is reduced by 0.8-1.2%, and so on. After the rolls are replaced on the sixth stand of the pre-finishing mill 140, the speed of the rolls on the fifth stand is reduced by 0.8-1.2%. By reducing the speed of the upstream stand rolls by about 1% after changing the rolls in the pre-finishing mill 140, it is beneficial to bite the workpiece and prevent steel piling. After biting, the tension of the pre-finishing mill 140 can be quickly restored to the normal value through the stand quick adjustment function. This avoids the large change in the actual speed of the workpiece caused by excessive forward slip after steel pulling and rolling, which leads to fluctuations in the length of the flying shear head and avoids increasing the risk of the flying shear head being carried into the rolling line.

[0029] The lead factor of the pinch rolls before the finishing mill is set to 1.07 to 1.1, and the roll gap of the pinch rolls before the finishing mill is set to be 5 to 7 mm smaller than that of the standard material type. In this embodiment, the pinch rolls refer to the No. 3 pinch roll 150 and the No. 4 pinch roll 180 before the finishing mill 170 and finishing mill 200. The roll gap of the pinch rolls in the finishing mill is set to be 5-7 mm smaller than that of the standard material type. This is mainly because the actual speed of the pinch roll ring will drop rapidly after the pinch rolls are over-clamped. However, the speed after the drop must be greater than the actual speed of the rolled piece, otherwise there will be a risk of steel piling up. After multiple tests, when the lead coefficient is increased to 1.07-1.1, the speed of the pinch rolls after the speed drop is about 3% higher than the speed of the last stand in the 140th pre-finishing mill. At this time, the workpiece pinch rolls and the last stand in the 140th pre-finishing mill operate stably under a slight tension, ensuring stable and reliable flying shear shearing. The roll gap is set to be 5-7 mm smaller than that of the standard material type to prevent slippage between the pinch rolls and the workpiece during the clamping process, which would cause the actual speed of the workpiece to be unstable and affect the flying shear shearing.

[0030] The actual moving speed of the workpiece between the hot metal detector after the pre-finishing mill 140 and the hot metal detector before the flying shear is used as the calibration speed. When the error between the calibration speed and the speed of the workpiece after passing through the pre-finishing mill is <1%, the speeds of the flying shear and the switch are not calibrated. When the error between the calibration speed and the speed of the workpiece after passing through the pre-finishing mill is ≥1%, the speeds of the flying shear and the switch are matched and calibrated according to the calibration speed. Using the actual moving speed of the workpiece between the hot metal detector after the pre-finishing mill 140 and the hot metal detector before the flying shear as the calibration speed is to prevent significant changes in the actual speed of the workpiece due to abnormal conditions, such as operator speed adjustment errors or roll gap errors, which could lead to large changes in the flying shear's cutting accuracy and increase the risk of lead-out.

[0031] When the rolling speed is ≥15m / s, the distance between the switch at the rolling position and the outer edge of the flying shear blade at the cutting position is controlled at 28-30mm. When the rolling speed is <15m / s, the distance between the switch at the rolling position and the outer edge of the flying shear blade at the cutting position is controlled at 31-33mm. The distance between the switch and the flying shear blade is determined according to the different rolling speeds because the distance from the end of the switch to the guide tip of the flying shear exit is constant. The faster the rolling speed, the shorter the time it takes for the piece to travel from the end of the switch to the guide tip. This requires the switch to have a corresponding time to travel from the break-off position to the rolling position. Therefore, through calculation and on-site measurement, a standard distance between the switch and the blade matching the rolling speed is designed to avoid scrap steel caused by improper cutting positions.

[0032] Example 1

[0033] This application provides a method for controlling the head of a flying shear to enter the rolling channel line during shearing, which is for situations such as... Figure 1 The high-speed bar production line shown is implemented to produce HRB400E steel with a finished product size of 12mm, rolling 22,361 tons. The rolling speed before the flying shear is 18.4m / s. The distance between the zero position of the switch (the rolling position of the switch) and the outer edge of the shear blade when the flying shear is in the head-cutting position is 29mm. The micro-tension settings of the roughing mill 100 and the intermediate mill 120 are shown in Table 1 below.

[0034] Table 1. Micro-tension settings for the roughing mill and intermediate mill in Example 1.

[0035]

[0036]

[0037] After the rolls are replaced in the pre-finishing mill 140, the roll speed of the first upstream stand is reduced by 1%. After the rolls bite in, the speed is quickly increased to restore the stacking relationship between the stands.

[0038] The lead factor of the pinch roller is set to 1.07, and the roller gap of the pinch roller is 5mm smaller than the material size. After clamping, a test using a sample bar shows no slippage between the sample roller and the roller ring.

[0039] Results: During the production of 12mm rebar, there was no issue of scrap steel being carried into the rolling line after the flying shear was used.

[0040] Example 2

[0041] This application provides a method for controlling the head of a flying shear to enter the rolling channel line during shearing, which is for situations such as... Figure 1 The high-speed bar production line shown is implemented to produce HRB400E steel with a finished product size of 16mm, rolling 25,603 tons, with a rolling speed of 16.31m / s before the flying shear, and a distance of 29mm between the zero position of the switch (switcher rolling position) and the outer edge of the shear blade when the flying shear is in the head-cutting position. The micro-tension settings of the roughing mill 100 and the intermediate mill 120 are shown in Table 2 below.

[0042] Table 2. Micro-tension settings for the roughing mill and intermediate mill in Example 2.

[0043]

[0044]

[0045] After the rolls are replaced in the pre-finishing mill 140, the roll speed of the first upstream stand is reduced by 1%. After the rolls bite in, the speed is quickly increased to restore the stacking relationship between the stands.

[0046] The lead factor of the pinch rollers was set to 1.08, and the roller gap was 5.3 mm smaller than the material size. After clamping, a test using a sample bar showed no slippage between the sample rollers and the roller ring.

[0047] Results: During the production of 16mm rebar, there was no issue of scrap steel being carried into the rolling line after the flying shear shear cut.

[0048] Example 3

[0049] This application provides a method for controlling the head of a flying shear to enter the rolling channel line during shearing, which is for situations such as... Figure 1 The high-speed bar production line shown is implemented to produce HRB400E steel with a finished product size of 22mm. The rolling volume is 16,841 tons. The rolling speed before the flying shear is 8.51m / s. The distance between the zero position of the switch (switcher rolling position) and the outer edge of the shear blade when the flying shear is in the head-cutting position is 33mm. The micro-tension settings of the roughing mill 100 and the intermediate mill 120 are shown in Table 3 below.

[0050] Table 3. Micro-tension settings for the roughing mill and intermediate mill in Example 3.

[0051]

[0052]

[0053] After the rolls are replaced in the pre-finishing mill 140, the roll speed of the first upstream stand is reduced by 1%. After the rolls bite in, the speed is quickly increased to restore the stacking relationship between the stands.

[0054] The lead factor of the pinch rollers was set to 1.10, and the roller gap was 5.7 mm smaller than the material size. After clamping, a test using a sample bar showed no slippage between the sample rollers and the roller ring.

[0055] Results: During the production of 22mm rebar, there was no issue of scrap steel being carried into the rolling line by the flying shear head after shearing.

[0056] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for controlling the head of a flying shear to enter the rolling channel line during shearing, characterized in that, Includes the following steps: The micro-tension setting for the roughing mill is 0.2~0.8 N / mm. 2 The micro-tension setting value for the rolling mill unit is 1~1.8 N / mm. 2 The lead factor of the pinch rolls before the finishing mill is set to 1.07~1.1; after the rolls are replaced in the pre-finishing mill, the roll speed of the stand upstream of the stand where the rolls are replaced is reduced by 0.8-1.2%.

2. The method for controlling the head of the flying shear to enter the rolling channel line during shearing according to claim 1, characterized in that, It also includes the following steps: The roll gap of the pinch rolls before the finishing mill is set to be 5-7 mm smaller than that of the standard material.

3. The method for controlling the head of the flying shear to enter the rolling channel line during shearing according to claim 1, characterized in that, It also includes the following steps: The actual moving speed of the workpiece between the hot metal detector after the pre-finishing mill and the hot metal detector before the flying shear is used as the correction speed. When the error between the correction speed and the speed of the workpiece after passing through the pre-finishing mill is <1%, the speed of the flying shear and the switch is not corrected. When the error between the correction speed and the speed of the workpiece after passing through the pre-finishing mill is ≥1%, the speed of the flying shear and the switch is matched and corrected according to the correction speed.

4. The method for controlling the head of the flying shear to enter the rolling channel line during shearing according to claim 1, characterized in that, It also includes the following steps: When the rolling speed is ≥15m / s, the distance between the outer edges of the shear blades when the switch is in the rolling position and the flying shear is in the cutting position is 28~30mm.

5. The method for controlling the head of the flying shear to enter the rolling channel line during shearing according to claim 1, characterized in that, It also includes the following steps: When the rolling speed is <15m / s, the distance between the outer edges of the shear blades when the control switch is in the rolling position and the flying shear is in the cutting position is 31~33mm.

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