Method for improving wire rod yield

Abstract

This invention discloses a method for improving wire rod yield, including controlling the uniform heating section of the heating furnace but excluding the No. 1 flying shear tail step; assisting production operators in adjusting the heating operation of the heating furnace in a timely manner according to the situation, reducing excess gas damage and burn costs caused by heating, reducing gas consumption while improving yield; the adjustment of the uniform heating section provides conditions for reducing the cutting damage at the tail of the No. 1 shear, reducing the cutting damage at the tail of the No. 1 shear, reducing the labor intensity of waste discharge and bucket changing personnel, and effectively improving the yield.

Description

Technical Field

[0001] This invention relates to the field of steel rolling technology, and more specifically, to a method for improving the yield of wire rod. Background Technology

[0002] Currently, the main methods used in the industry to improve the yield of bar and wire rod production lines are to reduce heat loss during heating and optimize the weight of the billet during rolling. Specifically, these include: 1. reducing heat loss in the furnace by adjusting the temperature of the heating furnace; 2. controlling the length of the shear head and tail by adjusting the length of the shear head and tail; and 3. controlling the amount of trimming at the head and tail of the rolled product by adjusting the shape of the rolling mill. However, these existing methods also have some drawbacks.

[0003] For example, during the heating process of steel billets, it is unavoidable that iron oxide scale will appear during the heating process, especially at the inlet and outlet of the furnace. The burners cannot effectively cover the billets, and rolling line failures and unplanned downtime may lead to uneven temperature differences throughout the steel, which is very detrimental to the control of burn-off in the furnace and seriously affects the production rhythm and increases gas costs.

[0004] For example, to ensure that each steel bar reaches the optimal minimum head and tail length, the shearing length can only be adjusted to a minimum value of 100mm. The minimum shearing length (79*80*100mm) weighs 13-15 kg. Simultaneously, due to the insertion of the tail section, the head of the next steel bar may be too close together, causing the shears to fail to return to the initial position in time. This can result in false signals from the detection elements, such as the next steel bar being too long or not cutting at all. This affects the rolling rhythm and yield.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a method for improving the yield of wire.

[0007] This invention is implemented as follows:

[0008] In a first aspect, the present invention provides a method for improving the yield of wire rod, including controlling the uniform heating section of the heating furnace but excluding the #1 flying shear tail step;

[0009] The heating furnace uniform heating section includes an upper uniform heating section burner and a lower uniform heating section burner. Both the upper and lower uniform heating section burners have 8 sets of burners. Each burner has a corresponding opening adjustment valve. The opening adjustment valves corresponding to each set of burners along the direction of billet movement are marked as 1#, 2#, 3#, 4#, 5#, 6#, 7# and 8#, respectively.

[0010] The opening degree of the lower regulating valves 1#, 2#, 6#, 7# and 8# is 38%-42%, the opening degree of the upper regulating valves 1# and 2# is 83%-86% of the opening degree of the corresponding lower regulating valves, the opening degree of the upper regulating valves 6#, 7# and 8# is 86%-90% of the opening degree of the corresponding lower regulating valves, and the air-coal ratio of the heating furnace fuel is 1-1.7.

[0011] In some embodiments, the steel billet is rolled after leaving the heating furnace. The rolling includes roughing. The rolls of the roughing roll are equipped with a roll cooling device. The roll cooling device includes a dispersion plate disposed above the outlet of the corresponding mill guide groove. A water storage cavity is disposed in the middle of the dispersion plate. A water inlet pipe is connected to the water storage cavity. Two or more high-pressure nozzles are disposed on the side of the water storage cavity near the roll. The outlet of the high-pressure nozzle is rectangular, and the long side of the rectangular high-pressure nozzle is parallel to the axis of the roll.

[0012] In some embodiments, the dispersion plate is arc-shaped, and the water spray direction of the high-pressure nozzle is tangential to the corresponding roller.

[0013] In some embodiments, there are two or more high-pressure nozzles arranged in an array on the dispersion plate.

[0014] In some embodiments, the dispersion plate is 165mm-175mm wide and 390mm-410mm long, the high-pressure nozzle is 21mm-23mm long and 7.5mm-8.5mm wide, and there are 16-20 high-pressure nozzles.

[0015] In some embodiments, the dispersion plate is provided with a water outlet, and the high-pressure nozzle is threadedly connected to the water outlet.

[0016] In some embodiments, a control valve is provided on the water inlet pipe. When the temperature of the billet is below 980°C when it leaves the heating furnace, the opening degree of the control valve is 55%-65%; when the temperature of the billet is above 980°C when it leaves the heating furnace, the opening degree of the control valve is greater than 95%.

[0017] In some implementations, the bridge exit corresponding to the No. 5-6 rolling mill is inclined upward, and the angle between the bridge exit and the plane where the rolling line is located is 55°-65°.

[0018] In some embodiments, a fixing plate is provided below the bridge outlet, the fixing plate is provided with a threaded hole, a screw is threadedly connected to the threaded hole, and the top end of the screw abuts against the lower surface of the bridge outlet.

[0019] In some implementations, the opening of the #6 guide is 67.5mm-68.5mm.

[0020] The present invention has the following beneficial effects:

[0021] In this application, the auxiliary production operators adjust the heating operation of the heating furnace in a timely manner according to the situation, reducing the damage and burning costs of excess gas caused by heating, reducing gas consumption while increasing the yield; the adjustment of the uniform heating section provides conditions for reducing the cutting damage at the tail of No. 1 shear, reducing the cutting damage at the tail of No. 1 shear, reducing the labor intensity of waste discharge and bucket changing personnel, and effectively increasing the yield while improving the operating rate. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0023] This application provides a method for improving wire yield, which includes controlling the uniform heating section of the heating furnace but does not include the #1 flying shear tail step;

[0024] The heating furnace uniform heating section includes an upper uniform heating section burner and a lower uniform heating section burner. Both the upper and lower uniform heating section burners have 8 sets of burners. Each burner has a corresponding opening adjustment valve. The opening adjustment valves corresponding to each set of burners along the direction of billet movement are marked as 1#, 2#, 3#, 4#, 5#, 6#, 7# and 8#, respectively.

[0025] The opening degree of the lower regulating valves 1#, 2#, 6#, 7# and 8# is 38%-42%, the opening degree of the upper regulating valves 1# and 2# is 83%-86% of the opening degree of the corresponding lower regulating valves, the opening degree of the upper regulating valves 6#, 7# and 8# is 86%-90% of the opening degree of the corresponding lower regulating valves, and the air-coal ratio of the heating furnace fuel is 1-1.7.

[0026] In this embodiment, the method to improve the yield of wire rod increases the opening of the regulating valves corresponding to the burners at both ends of the uniform heating section, so that the beginning and end of the billet can be fully heated, reducing the temperature difference between the beginning and end of the billet and the middle of the billet, improving the uniformity of heating of the billet, and thus preparing for the subsequent elimination of the #1 flying shear tail step.

[0027] Specifically, the opening degree of the lower regulating valves 1#, 2#, 6#, 7# and 8# is 38%-42%, specifically, it can be any value between 38%, 39%, 40%, 41%, 42% or 38%-42%.

[0028] In this embodiment, the opening degree of the upper regulating valves 1#, 2#, 6#, 7#, and 8# in the uniform heating section is slightly larger than the opening degree of the lower regulating valve, which is beneficial to the uniform heating of the upper and lower surfaces of the steel billet. Specifically, the opening degree of the upper regulating valves 1# and 2# is 83%-86% of the opening degree of the corresponding lower regulating valve, specifically, it can be any value between 83%, 84%, 85%, 86%, or 83%-86%, and the opening degree of the upper regulating valves 1# and 2# can be the same or different. For example, in some embodiments, the opening degree of the upper regulating valve 1# is 86% and the opening degree of the upper regulating valve 2# is 83%. The opening degree of the upper regulating valves #6, #7, and #8 is 86%-90% of the opening degree of the corresponding lower regulating valve. Specifically, it can be any value between 86%, 87%, 88%, 89%, 90%, or 86%-90%. The opening degrees of the upper regulating valves #6, #7, and #8 can be the same or different. For example, in some embodiments, the opening degree of the upper regulating valve #6 is 86%, the opening degree of the upper regulating valve #7 is 88%, and the opening degree of the upper regulating valve #8 is 90%.

[0029] In this embodiment, the air-coal ratio of the heating furnace is adjusted to 1-1.7. Increasing the air-coal ratio helps to reduce the oxidation loss of the steel billet, thereby increasing the yield. Specifically, the air-coal ratio can be any value between 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, or 1-1.7.

[0030] In this embodiment, the auxiliary production operators can adjust the heating operation of the heating furnace in a timely manner according to the situation, thereby reducing the damage and burning costs of excess gas caused by heating, reducing gas consumption and increasing the yield. The adjustment of the uniform heating section provides conditions for reducing the cutting damage at the tail of the No. 1 shear, which reduces the labor intensity of the waste discharge and bucket changing personnel, and effectively improves the yield.

[0031] In some embodiments, the steel billet is rolled after leaving the heating furnace. The rolling includes roughing. The rolls of the roughing roll are equipped with a roll cooling device. The roll cooling device includes a dispersion plate disposed above the outlet of the corresponding mill guide groove. A water storage cavity is disposed in the middle of the dispersion plate. A water inlet pipe is connected to the water storage cavity. Two or more high-pressure nozzles are disposed on the side of the water storage cavity near the roll. The outlet of the high-pressure nozzle is rectangular, and the long side of the rectangular high-pressure nozzle is parallel to the axis of the roll.

[0032] In this embodiment, the dispersion plate is equivalent to a temporary water storage container. Two or more high-pressure nozzles are provided on the dispersion plate. Compared with directly spraying water onto the rolls through the outlet pipe for cooling, the dispersion plate and multiple high-pressure nozzles help to increase the number or area of ​​contact between the cooling water and the rolls. On the other hand, the outlet of the high-pressure nozzle is rectangular and the long side is parallel to the axis of the rolls, which helps to increase the contact area between the water from a single high-pressure nozzle and the rolls, and further improves the uniformity of roll cooling.

[0033] In some embodiments, the dispersion plate is arc-shaped, and the water spray direction of the high-pressure nozzles is tangential to the corresponding rolls. The pressure of the water exiting the high-pressure nozzles is more effective in removing residual iron oxide scale from the rolls. In some embodiments, the arc-shaped dispersion plate can be coaxially arranged with the rolls, and the distance between each nozzle and the roll can be equal, maintaining an optimal range.

[0034] In some embodiments, there are two or more high-pressure nozzles arranged in an array on the dispersion plate, and the high-pressure nozzles are relatively evenly distributed on the dispersion plate to improve the uniformity of cooling.

[0035] In some embodiments, the dispersion plate is 165mm-175mm wide and 390mm-410mm long, the high-pressure nozzle is 21mm-23mm long and 7.5mm-8.5mm wide, and there are 16-20 high-pressure nozzles.

[0036] In some embodiments, the dispersion plate is provided with a water outlet, and the high-pressure nozzle is threadedly connected to the water outlet. The high-pressure nozzle is detachably connected, which facilitates maintenance and repair, allows for easy disassembly and repair of the spray nozzle assembly and the water control valve assembly, and reduces the difficulty of the operation.

[0037] In some embodiments, a control valve is provided on the water inlet pipe. When the temperature of the billet is below 980°C when it leaves the heating furnace, the opening degree of the control valve is 55%-65%, specifically, it can be any value between 55%, 57%, 59%, 61%, 63%, 65%, or 55%-65%. When the temperature of the billet is above 980°C when it leaves the heating furnace, the opening degree of the control valve is greater than 95%, specifically, it can be any value between 95%, 96%, 97%, 98%, 99%, 100%, or greater than 95%.

[0038] When the billet temperature is low, the opening degree of the control valve can be reduced. When the billet temperature is high, the opening degree of the control valve can be increased. This can prevent the billet temperature from being too high due to insufficient cooling water or to avoid the billet temperature from being too low due to excessive cooling water. While effectively cooling the rolls, the water flow rate should not be too large and overflow, and should not be unable to be drained in time, so that it can be retained at the outlet to reduce the surface temperature of the billet.

[0039] In this embodiment, the cooling water for roughing is stable and uniform, and there is no water leakage or overflow that would affect the temperature difference between the beginning and end of the billet, thus preventing the negative impact of temperature fluctuations on the equipment.

[0040] In some implementations, the bridge exit corresponding to the No. 5-6 rolling mill is inclined upward, and the angle between the bridge exit and the plane where the rolling line is located is 55°-65°, specifically any value between 55°, 57°, 59°, 61°, 63°, 65° or 55°-65°.

[0041] In this embodiment, the bridge exit is tilted upwards. When the tail of the rolled piece leaves the bridge exit, it vibrates due to the drop in a tension-free state, causing the iron oxide scale adhering to the tail of the rolled piece to fall into the slag pit at the exit base for easy cleaning. In this case, if the elevation angle of the bridge exit is too small, the drop at the tail of the rolled piece is small, and only a small amount of iron oxide scale adhering to the tail of the rolled piece falls off. If the elevation angle of the bridge exit is too large, it will affect the alignment of the rolled piece with the subsequent rolling mill. Therefore, the upward angle of the bridge exit needs to be set reasonably.

[0042] Apart from routine maintenance of the iron oxide scale between the roughing mill stands, the operators do not need to clean the iron oxide scale from the downstream stands at other times.

[0043] In some embodiments, a fixing plate is provided below the bridge outlet, the fixing plate is provided with a threaded hole, a screw is threadedly connected to the threaded hole, and the top end of the screw abuts against the lower surface of the bridge outlet.

[0044] When the tilt angle of the bridge outlet needs to be adjusted, the screw can be rotated. As the length of the screw extending beyond the fixed plate increases, the tilt angle of the bridge outlet increases. Reverse rotation decreases the length of the screw extending beyond the fixed plate, thus decreasing the tilt angle of the bridge outlet. In some embodiments, the cutting angle can also be correlated by calculating the number of screw rotations.

[0045] In some implementations, the opening of the #6 guide is 67.5mm-68.5mm, specifically any value between 67.5mm, 67.7mm, 67.9mm, 68.1mm, 68.3mm, 68.5mm or 67.5mm-68.5mm.

[0046] In the prior art, the opening size is adjusted to 70mm for every 2000 tons rolled. In this application, the opening size is checked and adjusted to 67.5mm-68.5mm, preferably 68mm, each time the machine is stopped. The purpose is to ensure that no aircraft tail or adhered iron oxide scale is generated under the tail support during the rolling process, so as not to affect the rolling process when it is carried to the downstream stand.

[0047] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0048] Example 1

[0049] This embodiment provides a method for improving the yield of wire rod, including the control of the uniform heating section of the heating furnace but excluding the No. 1 flying shear tail step;

[0050] The heating furnace uniform heating section includes upper uniform heating section burners and lower uniform heating section burners. Both the upper and lower uniform heating section burners have 8 sets of burners. Each burner corresponds to an opening adjustment valve. The opening adjustment valves corresponding to each set of burners along the direction of billet movement are marked as 1#, 2#, 3#, 4#, 5#, 6#, 7#, and 8#, respectively. The opening of the lower adjustment valves 1#, 2#, 6#, 7#, and 8# is 42%. The opening of the upper adjustment valves 1# and 2# is 86% of the opening of the corresponding lower adjustment valves. The opening of the upper adjustment valves 6#, 7#, and 8# is 90% of the opening of the corresponding lower adjustment valves. The air-to-coal ratio of the heating furnace fuel is 1.7.

[0051] After the steel billet leaves the heating furnace, it is rolled, including rough rolling. The rough rolling rolls are equipped with roll cooling devices. The roll cooling devices include a dispersion plate located above the outlet of the corresponding mill guide groove. A water storage cavity is located in the middle of the dispersion plate. A water inlet pipe is connected to the water storage cavity. Two or more water outlets are located on the side of the water storage cavity near the roll. A high-pressure nozzle is threaded to the water outlet. The outlet of the high-pressure nozzle is rectangular, and the long side of the rectangular high-pressure nozzle is parallel to the axis of the roll. The dispersion plate is arc-shaped, 170mm wide and 400mm long. There are 3 rows of 6 high-pressure nozzles, totaling 18. The outlet of the high-pressure nozzle is 22mm long and 8mm wide. The spray direction of the high-pressure nozzle is tangent to the corresponding roll.

[0052] The water inlet pipe is equipped with a control valve. When the temperature of the billet is below 980°C when it leaves the heating furnace, the opening degree of the control valve is 60%; when the temperature of the billet is above 980°C when it leaves the heating furnace, the opening degree of the control valve is 100%.

[0053] The bridge exits corresponding to rolling mills #5 and #6 are inclined upwards, and the angle between the bridge exit and the plane where the rolling line is located is 60°. A fixing plate is provided below the bridge exit, and a threaded hole is provided on the fixing plate. A screw is threaded into the threaded hole, and the top of the screw abuts against the lower surface of the bridge exit. The opening of the #6 guide is 68mm.

[0054] Comparative Example 1

[0055] This comparative example provides a bar processing method, including heating furnace uniform heating section control and No. 1 flying shear tail step;

[0056] The heating furnace uniform heating section includes upper uniform heating section burners and lower uniform heating section burners. Both the upper and lower uniform heating section burners have 8 sets of burners. Each burner corresponds to an opening regulating valve. The opening regulating valves corresponding to each set of burners along the direction of billet movement are marked as 1#, 2#, 3#, 4#, 5#, 6#, 7#, and 8#, respectively. The opening of the lower regulating valves 1#, 2#, 6#, 7#, and 8# is 50%. The opening of the upper regulating valves 1# and 2# is 56% of the opening of the corresponding lower regulating valves. The opening of the upper regulating valves 6#, 7#, and 8# is 58% of the opening of the corresponding lower regulating valves. The air-to-coal ratio of the heating furnace fuel is 1.1.

[0057] After the steel billet leaves the heating furnace, it is rolled, including rough rolling. The rolls of the rough rolling mill are equipped with a roll cooling device, which includes a water outlet pipe with its outlet aligned with the roll. A control valve is installed on the water outlet pipe, and the control valve is 100% open.

[0058] The bridge exits of rolling mills 5# and 6# are set horizontally, and the opening of guide 6# is 70mm.

[0059] Comparative Example 2

[0060] This comparative example provides a method for improving the yield of wire rod. The only difference from Example 1 is that the steel billet is rolled after leaving the heating furnace. The rolling includes rough rolling. The rolls of the rough rolling are equipped with a roll cooling device. The cylindrical water spray pipe of the roll cooling device, after its pressure is adjusted to 100%, will cause the cooling water to stagnate in the channel and outlet through the rolling groove, resulting in excessively low tail temperature and large temperature difference, which is detrimental to the rolling and the service life of the guide.

[0061] Comparative Example 3

[0062] This comparative example provides a method to improve the yield of wire rod. The only difference from Example 1 is that the bridge exit corresponding to the No. 5-6 rolling mill is set horizontally. When the tail passes through, it is easy for iron oxide scale in the channel to adhere to it, which is carried to the exit or adheres to the tail of the steel. The tail length needs to be cut by the No. 1 flying shear on site.

[0063] Comparative Example 4

[0064] This comparative example provides a method to improve the yield of wire rod. The only difference from Example 1 is that the opening of the 6# guide is 70mm. During the rolling process, the tail is prone to twisting and producing an "airplane ear". In order to ensure stable production, it needs to be removed in time.

[0065] The following table shows the statistical analysis of the bar yield in the above embodiments and comparative examples.

[0066] Serial Number Yield % Example 1 99.124 Comparative Example 1 98.842 Comparative Example 2 98.656 Comparative Example 3 98.501 Comparative Example 4 98.557

[0067] For a large steel rolling mill with an annual output of nearly one million tons, every 0.1% increase in yield can result in an additional 1,000 tons of finished steel produced annually. Based on current market prices for large steel products, this could generate nearly 5 million yuan in economic benefits. With an initial input of 2238 kg, after processing such as heating, rolling, collecting, and trimming, the finished product yields 2197 kg, resulting in a yield of 98.168%. By using the scheme in Example 1 without changing the initial input, the output is 13-15 kg more than that in Comparative Document 1, and the yield can be increased by 0.14%.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of improving the yield of wire rod, characterized by, Includes the heating furnace uniform heating section control but excludes the #1 flying shear tailing step; The heating furnace uniform heating section includes an upper uniform heating section burner and a lower uniform heating section burner. Both the upper and lower uniform heating section burners have 8 sets of burners. Each burner has a corresponding opening adjustment valve. The opening adjustment valves corresponding to each set of burners along the direction of billet movement are marked as 1#, 2#, 3#, 4#, 5#, 6#, 7# and 8#, respectively. The opening degree of the lower regulating valves 1#, 2#, 6#, 7# and 8# is 38%-42%, the opening degree of the upper regulating valves 1# and 2# is 83%-86% of the opening degree of the corresponding lower regulating valves, the opening degree of the upper regulating valves 6#, 7# and 8# is 86%-90% of the opening degree of the corresponding lower regulating valves, and the air-coal ratio of the heating furnace fuel is 1-1.7; After the steel billet leaves the heating furnace, it is rolled, including rough rolling. The rolls of the rough rolling mill are equipped with a roll cooling device. The roll cooling device includes a dispersion plate disposed above the outlet of the corresponding mill guide groove. A water storage cavity is disposed in the middle of the dispersion plate. A water inlet pipe is connected to the water storage cavity. Two or more high-pressure nozzles are disposed on the side of the water storage cavity near the roll. The outlet of the high-pressure nozzle is rectangular, and the long side of the rectangular high-pressure nozzle is parallel to the axis of the roll. The dispersion plate is arc-shaped, and the water spray direction of the high-pressure nozzle is tangent to the corresponding roller; The dispersion plate is 165 mm - 175 mm wide and 390 mm - 410 mm long, the high-pressure nozzle is 21 mm - 23 mm long and 7.5 mm - 8.5 mm wide, and there are 16-20 high-pressure nozzles; The water inlet pipe is equipped with a control valve. When the temperature of the billet is below 980°C when it leaves the heating furnace, the opening degree of the control valve is 55%-65%; when the temperature of the billet is above 980°C when it leaves the heating furnace, the opening degree of the control valve is greater than 95%.

2. The method of increasing the yield of wire rod according to claim 1, wherein, There are two or more high-pressure nozzles, which are arranged in an array on the dispersion plate.

3. The method for improving wire yield according to claim 1, characterized in that, The dispersion plate is provided with a water outlet, and the high-pressure nozzle is threadedly connected to the water outlet.

4. The method for improving wire yield according to claim 1, characterized in that, The bridge exits corresponding to rolling mills #5 and #6 are inclined upwards, and the angle between the bridge exits and the plane where the rolling line is located is 55°-65°.

5. The method for improving wire yield according to claim 4, characterized in that, A fixing plate is provided below the bridge outlet, and a threaded hole is provided on the fixing plate. A screw is threaded into the threaded hole, and the top of the screw abuts against the lower surface of the bridge outlet.

6. The method for improving wire yield according to claim 1, characterized in that, The opening of the #6 guide is 67.5mm-68.5mm.