A method for rolling a heat-treated wind tower steel

Abstract

The application provides a rolling method of a heat-treated wind tower steel, which comprises the following steps: heating a billet; performing primary descaling on the billet; performing fine descaling on the billet; rolling the billet to form a steel plate, and selecting a roll diameter of 1160 mm or above, wherein the upper roll diameter is greater than the lower roll diameter by 4 mm, a final pass uses a roll gap which is greater than the set thickness by 3-5 mm, and the rolling speed of the final pass is not greater than 3.5 m / s; cooling the steel plate; hot straightening the steel plate, setting the straightening roll gap to be greater than the set thickness of the steel plate by 5 mm, and straightening only one pass; and cutting and segmenting the steel plate after cooling on a cooling bed. The method can improve the surface quality and shape of the steel plate.

Description

Technical Field

[0001] This application relates to the field of metallurgy, and more particularly to a method for rolling heat-treated wind tower steel. Background Technology

[0002] The high final rolling temperature of heat-treated wind tower steel makes it difficult to control the warping during rolling and remove surface iron oxide. This leads to the need to flatten subsequent waves and hard bends, and to grind the surface iron oxide after it is pressed in, which increases the workload. At the same time, the first-pass yield is low, which seriously affects production efficiency. Summary of the Invention

[0003] In view of this, it is necessary to provide a method for rolling heat-treated wind tower steel to improve the surface quality and shape of the steel plate.

[0004] A method for rolling heat-treated wind tower steel, comprising the following steps: The steel billet is heated; Preliminary descaling of the steel billet; Fine descaling of the steel billet; The steel billet is rolled into a steel plate. A roll diameter of 1160mm or above is selected for the mill, wherein the upper roll diameter is 1.5-5mm larger than the lower roll diameter. The last pass is a leveling pass with a roll gap 3-5mm larger than the set thickness of the steel plate. The rolling speed of the last pass is not greater than 3.5m / s. Cool the steel plate; The steel plate is hot-straightened, with the straightening roller gap set to be 5mm larger than the set thickness of the steel plate, and straightened in only one pass. The steel plate is cut into sections after being cooled on a cooling bed.

[0005] Furthermore, the heating process for the steel billet includes, in sequence, a heat recovery section, a preheating section, a first heating section, a second heating section, and a soaking section; wherein, the temperature of the heat recovery section is ≤950℃, the temperature of the preheating section is 1000-1150℃, the temperature of the first heating section is 1100-1200℃, the temperature of the second heating section is 1150-1200℃, the temperature of the soaking section is 1110-1180℃, and the steel plate is in the furnace for ≥360 minutes.

[0006] Furthermore, in the initial descaling step of the steel billet, after exiting the furnace, the steel billet automatically enters the descaling box through the steel tapping roller conveyor, with the roller conveyor speed set at 1.0 m / s.

[0007] Furthermore, in the fine descaling step of the steel billet, the steel billet is water-sprayed once before the start of rolling, once before the second rolling, and water-sprayed twice consecutively during the second rolling. After the last rolling, the billet is water-sprayed once at the exit for fine descaling, in order to reduce the surface temperature of the rolled piece and refine the thickness of the surface iron oxide.

[0008] Furthermore, in the step of rolling the billet into a steel plate, a normalizing rolling process is adopted, and the rolling is completed directly and continuously without waiting for the intermediate temperature. The finished product is exited at the inlet, and the last pass uses a roll gap 3-5mm larger than the set thickness to pass through empty, and the tail end is smoothed by using the rolls.

[0009] Furthermore, in the step of rolling the steel billet into a steel plate, the maximum reduction is limited to 45mm, the reduction of the first two passes is ≥35mm, the reduction of the first two passes after the widening and steel transfer is ≥35mm, and the reduction of the remaining passes is ≥25mm.

[0010] Furthermore, in the step of rolling steel billets into steel plates, when the thickness of the finished steel plate is set to be 80mm or more, the rolling shall not exceed 9 passes; when the thickness of the finished steel plate is set to be less than 80mm, the rolling shall not exceed 13 passes.

[0011] Furthermore, after the steel plate is cooled on the cooling bed and then cut into sections, the process also includes: surface inspection, printing, and warehousing.

[0012] Furthermore, after cooling the steel plate on the cooling bed, it also includes warm straightening, with the straightening force limited to a maximum of 3,000 tons. Beneficial effects

[0013] (1) By re-optimizing and redesigning the production mode of heat-treated wind tower steel, and by adopting a variety of methods such as post-rolling fine descaling and water spraying, slow-down rolling in the last pass, finished product exit at the inlet, preheating straightening, straightening with the hot straightening roll gap greater than the contract thickness by 5mm, and limiting the straightening force of the temperature straightening, the surface quality and plate shape of the steel plate have been improved, the labor intensity of employees has been reduced, and the product qualification rate has been increased, so as to achieve the purpose of cost reduction and efficiency improvement. Attached Figure Description

[0014] Figure 1 This is a flowchart of a heat-treated wind tower steel rolling method according to an embodiment of the present invention. Implementation

[0015] The embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0016] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or may also have an intervening component. When a component is considered to be "placed" on another component, it can be directly placed on the other component or may also have an intervening component. The terms "top," "bottom," "upper," "lower," "left," "right," "front," "back," and similar expressions used in this article are for illustrative purposes only.

[0017] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0018] Please see Figure 1 This invention provides a method for rolling heat-treated wind tower steel, comprising the following steps: The steel billet is heated; Preliminary descaling of the steel billet; Fine descaling of the steel billet; The steel billet is rolled into steel plate. Rollers with a diameter of 1160mm or more are selected for the mill. The diameter of the upper roll is 1.5-5mm larger than that of the lower roll, so as to control the waves and hard bends caused by abnormal head lifting of the rolled piece. The last pass is a leveling pass with a roll gap 3-5mm larger than the set thickness. The rolling speed of the last pass is not greater than 3.5m / s. Cool the steel plate; The steel plate is hot-straightened, and the straightening roller gap is set to be 5mm larger than the set thickness of the steel plate. Only one straightening is performed to avoid surface iron oxide being pressed into the base material, which would cause surface pitting. The straightening force is about 300 tons, which improves the phenomenon of large plates curling at the head and tail. The steel plate is cut into sections after being cooled on a cooling bed.

[0019] The set thickness of a steel plate refers to the target thickness of the steel plate in the production design.

[0020] Furthermore, the heating process for the steel billet includes, in sequence, a heat recovery section, a preheating section, a first heating section, a second heating section, and a soaking section; wherein, the temperature of the heat recovery section is ≤950℃, the temperature of the preheating section is 1000-1150℃, the temperature of the first heating section is 1100-1200℃, the temperature of the second heating section is 1150-1200℃, the temperature of the soaking section is 1110-1180℃, and the steel plate is in the furnace for ≥360 minutes.

[0021] Furthermore, in the initial descaling step of the steel billet, after exiting the furnace, the steel billet automatically enters the descaling box through the steel tapping roller conveyor, with the roller conveyor speed set at 1.0 m / s.

[0022] Furthermore, in the fine descaling step of the steel billet, the steel billet is water-sprayed once before the start of rolling, once before the second rolling, and water-sprayed twice consecutively during the second rolling. After the last rolling, the billet is water-sprayed once at the exit for fine descaling, in order to reduce the surface temperature of the rolled piece and refine the thickness of the surface iron oxide.

[0023] The above steps incorporate fine descaling into the rolling process to reduce temperature.

[0024] Furthermore, in the step of rolling the billet into a steel plate, a normalizing rolling process is adopted, and the rolling is completed directly and continuously without waiting for the intermediate temperature. The finished product is exited at the inlet. The last pass uses a roll gap 3-5mm larger than the set thickness to skip the plate and uses the rolls to smooth the tail end. The last pass uses a deceleration rolling process with a rolling speed not exceeding 3.5mm. The reduction rolling procedure adopts a large reduction to improve the core structure and increase the flaw detection pass rate. The reduction per pass is limited to a maximum of 45mm, and at least 35mm is guaranteed in one pass to complete the rolling in the fewest possible passes.

[0025] The rolling reduction is limited to 45mm. The reduction in the first two passes is ≥35mm. After the steel is stretched and transferred, the reduction in the first two passes is ≥35mm, and the reduction in the remaining passes is ≥25mm.

[0026] For finished steel plates with a thickness of 80mm or more, the rolling process shall not exceed 9 passes; for finished steel plates with a thickness of less than 80mm, the rolling process shall not exceed 13 passes.

[0027] Furthermore, after the steel plate is cooled on the cooling bed and then cut into sections, the process also includes: surface inspection, printing, and warehousing.

[0028] After being cooled on a cooling bed, the steel plate is sent to a warm straightening machine for straightening, and then sent to a grinding table.

[0029] Furthermore, the temperature straightening system incorporates an interlocking function to limit the straightening force for steel plates with a thickness of 30mm or more. If the set value is exceeded, the roll gap will automatically rise. The maximum straightening force for temperature straightening is limited to 3000 tons.

[0030] Furthermore, those skilled in the art should recognize that the above embodiments are merely illustrative of this application and are not intended to limit this application. Any appropriate changes and modifications made to the above embodiments within the essential spirit and scope of this application fall within the scope of this application's disclosure.

Claims

1. A method for rolling heat-treated wind tower steel, characterized in that, Including the following steps: The steel billet is heated; Preliminary descaling of the steel billet; The steel billet is descaled. In the descaled steel billet process, the steel billet is sprayed with water once before the start of rolling, once before the second rolling, and sprayed with water twice consecutively during the second rolling. After the last rolling, the steel billet is descaled and sprayed with water once at the exit to reduce the surface temperature of the rolled piece and refine the thickness of the surface iron oxide. To roll steel billets into steel plates, a rolling mill with a roll diameter of 1160mm or larger is selected. The upper roll diameter is 1.5-5mm larger than the lower roll diameter. The final pass uses a roll gap 3-5mm larger than the set thickness of the steel plate for leveling. The rolling speed of the final pass is no more than 3.5m / s. In the process of rolling steel billets into steel plates, a normalizing rolling process is adopted. The rolling is completed continuously without waiting for the intermediate temperature to reach the desired temperature. The finished product exits at the inlet. The final pass uses a roll gap 3-5mm larger than the set thickness for skipping and uses the rolls to level the tail end. In the process of rolling steel billets into steel plates, the maximum reduction is limited to 45mm. The reduction of the first two passes is ≥35mm. After the widening and transfer of the steel, the reduction of the first two passes is ≥35mm, and the reduction of the remaining passes is ≥25mm. In the process of rolling steel billets into steel plates, when the thickness of the finished steel plate is set to be 80 mm or more, the rolling shall not exceed 9 passes; when the thickness of the finished steel plate is set to be less than 80 mm, the rolling shall not exceed 13 passes. Cool the steel plate; The steel plate is hot-straightened, with the straightening roller gap set to be 5mm larger than the set thickness of the steel plate, and straightened in only one pass. The steel plate is cut into sections after being cooled on a cooling bed; The billet heating process includes, in sequence, a heat recovery section, a preheating section, a first heating section, a second heating section, and a soaking section. The temperature in the heat recovery section is ≤950℃, the preheating section temperature is 1000-1150℃, the first heating section temperature is 1100-1200℃, the second heating section temperature is 1150-1200℃, the soaking section temperature is 1110-1180℃, and the billet time in the furnace is ≥360 minutes. After the steel plate is cooled on the cooling bed, it also includes warm straightening, with the straightening force limited to a maximum of 3,000 tons.

2. The method for rolling heat-treated wind tower steel according to claim 1, characterized in that, In the initial descaling step of the steel billet, after exiting the furnace, the steel billet automatically enters the descaling box through the steel tapping roller conveyor, and the roller conveyor speed is set to 1.0 m / s.

3. The rolling method for heat-treated wind tower steel according to claim 1, characterized in that, After the steel plate is cooled on the cooling bed and then cut into sections, the process includes: surface inspection, printing, and warehousing.

Images