ACC cooling method for controlling plate shape of head of medium-thickness plate

Abstract

An ACC cooling method for controlling the plate shape of the head of a medium-thickness plate comprises the specific steps that firstly, an ACC cooling mode is set to be an intermittent water spraying cooling mode, that is, at least two sets of collecting pipes in the middle of the ACC are set not to spray water, that is, the first set of collecting pipes, the second set of collecting pipes, the third set of collecting pipes, the sixth set of collecting pipes, the seventh set of collecting pipes, the eighth set of collecting pipes, the ninth set of collecting pipes and the tenth set of collecting pipes are put into water spraying; when the head of the steel plate passes through the fourth group and the fifth group of the ACC, the steel plate is subjected to air cooling and re-reddening; secondly, ACC hot head control parameters are adjusted, the opening time of first and second groups of upper and lower headers of ACC is staggered, the upper header delays boiling water, and the lower header conducts boiling water in advance, so that the temperature difference of the upper and lower surfaces of the head of the steel plate is reduced, the problem of steel plate blackhead is solved, and flatness of the finished steel plate is guaranteed. Steel plate air cooling re-reddening is additionally arranged on the ACC middle section, the temperature difference between the upper portion and the lower portion of the steel plate head is effectively reduced, and therefore the problem of inverted-U-shaped fluttering of the steel plate head is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel plate shape control, and particularly relates to an ACC cooling method for controlling the head shape of a medium plate. BACKGROUND

[0002] The TMCP process is widely applied to improve the comprehensive mechanical properties of the medium plate, save valuable alloy elements, and improve the weldability of the steel material. Meanwhile, the internal stress level of the steel plate is also increased, which poses a more serious challenge to the plate shape control. At present, medium plate enterprises develop and produce a large number of low-alloy high-strength steels, and the head shape control of medium-sized steel plates becomes a focus problem. Due to the limitation of equipment conditions, some steel plants only use the basic means such as the finishing rolling load and the ACC laminar cooling water ratio to adjust and control the finished plate shape.

[0003] The commonly used process method for ACC laminar cooling to control the uniformity of the steel plate temperature includes: 1. Hot head and hot tail, that is, the ACC header water spraying time is accurately controlled to ensure that the steel plate head or tail is not sprayed or less sprayed. Under normal circumstances, the participating control header is simultaneously reduced or closed when the steel plate passes through the ACC; 2. Roll acceleration, that is, when the steel plate passes through the ACC, the roll is given a constant acceleration to compensate for the steel plate entering the ACC. Therefore, the head shape of the 25-30mm thick steel plate in the low-alloy steel plate production process becomes a problem to be solved. SUMMARY

[0004] The technical problem solved by the present application is to provide an ACC cooling method for controlling the head shape of a medium plate to solve the problems in the above background.

[0005] The technical problem solved by the present application is solved by the following technical scheme: An ACC cooling method for controlling the head shape of a medium plate, and the specific steps are as follows: 1) Set the ACC cooling mode There are ten groups of headers in the ACC, including upper headers and lower headers. The ACC cooling mode is set to an intermittent water spraying cooling mode, and at least two groups of headers in the middle of the ACC are set not to spray water to ensure that the steel plate is air-cooled and red. That is, the first group, the second group, the third group, the sixth group, the seventh group, the eighth group, the ninth group, and the tenth group of headers spray water. When the head of the steel plate passes through the fourth group and the fifth group of the ACC, the steel plate is air-cooled and red to reduce the temperature difference between the top and bottom of the steel plate head and solve the serious inverted U warping problem of the steel plate head. 2) Adjust the ACC hot head control parameters The ACC hot head control parameter is set to the first group and the second group of upper header and lower header staggered delay opening, and specifically includes the following steps: adjusting the hot head function delay parameter of the first group and the second group of upper header and lower header, the lower header of the first group and the second group opens water in advance before the steel plate head enters, and the upper header of the first group and the second group opens water after the steel plate head passes about 1 meter in length, so as to reduce the temperature difference between the upper surface and the lower surface of the steel plate head, solve the problem of black head of the steel plate, and ensure the flatness of the finished steel plate.

[0006] In the application, the steel plate head is provided with a signal detector.

[0007] In the application, the staggered delay parameters of the upper header and the lower header of the first group and the second group of ACC are set separately, specifically: according to the speed set by the ACC roller and the distance from the steel plate head to the header of the first group and the second group of ACC, the signal detector arranged at the steel plate head is used for heat signal detection, and the upper header and the lower header of the first group and the second group of ACC are automatically triggered to open in staggered delay mode after the heat signal is detected.

[0008] In the application, the upper header is a U-shaped header.

[0009] In the application, the lower header is a straight header. Beneficial effects

[0010] 1) The ACC cooling mode is adjusted in the application, and the operation method is simple; 2) The ACC cooling mode is set to an intermittent water spraying cooling mode in the application, and the delay control parameters of the upper header and the lower header of the first group and the second group of ACC are adjusted, so that the upper header and the lower header of the first group and the second group can be opened in staggered mode, and the problem that when the 25-30mm thick steel plate head continuously passes through the ACC header, the cooling water of the lower header falls back to the upper surface of the steel plate head, causing the temperature of the upper surface of the steel plate head to be too low, the metallographic structure difference between the upper surface and the lower surface to be large, and the internal stress caused by the straightening machine being unable to eliminate the metallographic structure difference, and the steel plate being bent due to the release of internal stress, is effectively solved. Specific embodiments

[0011] In order to make the technical means, creative features, purposes and effects realized by the application easy to understand, the application will be further described below in combination with specific embodiments.

[0012] An ACC cooling method for controlling the head shape of a medium plate, and the specific steps are as follows: 1) Set the ACC cooling mode The ACC cooling mode is set to intermittent water spraying cooling mode, and there are ten groups of headers in the ACC, including upper headers and lower headers. At least two groups of headers in the middle of the ACC are set not to spray water to ensure air cooling and red return of the steel plate; that is, the first group, the second group, the third group, the sixth group, the seventh group, the eighth group, the ninth group and the tenth group of headers spray water, and when the head of the steel plate passes through the fourth group and the fifth group of the ACC, the steel plate is air cooled and red returned to reduce the temperature difference between the top and bottom of the head of the steel plate and solve the problem of serious inverted U buckling of the head of the steel plate; 2) Adjust the ACC hot head control parameters The ACC hot head control parameters are set to staggered delay opening of the upper and lower headers of the first group and the second group, which specifically includes the following steps: adjusting the hot head function delay parameters of the upper and lower headers of the first group and the second group, the lower headers of the first group and the second group are opened in advance before the head of the steel plate enters, and the upper headers of the first group and the second group are opened after the head of the steel plate passes through about 1 meter in length, so as to reduce the temperature difference between the upper and lower surfaces of the head of the steel plate and solve the problem of black head of the steel plate, thereby ensuring the flatness of the finished steel plate. If the head of the steel plate passes through less than 1 meter, the actual length of the black head of the steel plate can be kept basically the same.

[0013] In this embodiment, the staggered delay parameters of the upper and lower headers of the first group and the second group of the ACC are separately set as follows: according to the speed set by the ACC roller and the distance from the head of the steel plate to the first group and the second group of headers of the ACC, the hot signal is detected by the signal detector arranged at the head of the steel plate, and when the hot signal is detected, the staggered delay opening of the upper and lower headers of the first group and the second group of the ACC is automatically triggered.

[0014] In this embodiment, the ACC parameters are as follows: Cooling mode: laminar cooling with separate control of upper U-shaped headers and lower straight headers; Total length of cooling section: 30000mm; Number of cooling headers: originally designed as 15 groups of upper headers + 15 groups of lower headers; currently only 10 groups of upper headers + 10 groups of lower headers are retained Maximum flow of upper headers: 280m 3 / h; Maximum flow of lower headers: 800m 3 / h; Maximum total flow of water supply: 9000m 3 / h; Shielding and width adjustment range of upper headers: 1500-3500mm; Flow and pressure of side spraying nozzles: 80 m3 / h, 0.6-1.0Mpa; Tail blowing mode: high-pressure counterattack gas blowing; ACC functions: The ACC is responsible for controlling the cooling temperature, cooling speed, longitudinal temperature uniformity and transverse temperature uniformity of the steel plate, according to the original data of the rolled piece, cooling strategy and other basic data, by controlling the running speed of the rolled piece, the configuration, flow, edge shielding amount and upper and lower flow ratio of the water spraying and other parameters, the target temperature and uniformity of the steel plate are achieved.

[0015] Although the above embodiments make a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiments without creativity, which belong to the protection scope of the present application.

Claims

1. An ACC cooling method of controlling a head shape of a medium-thickness plate, characterized by, The specific steps are as follows: 1) Set the ACC cooling mode There are ten groups of headers in the ACC, including upper headers and lower headers. The ACC cooling mode is set to intermittent water spraying cooling mode, and at least two groups of headers in the middle of the ACC are set not to spray water, that is, the first group, the second group, the third group, the sixth group, the seventh group, the eighth group, the ninth group and the tenth group of headers spray water. When the head of the steel plate passes through the fourth group and the fifth group of the ACC, the steel plate is air-cooled to red; 2) Adjust the ACC hot head control parameters The ACC hot head control parameters are set to staggered delay opening of the upper headers and the lower headers of the first group and the second group, which specifically includes the following steps: adjusting the hot head function delay parameters of the upper headers and the lower headers of the first group and the second group, the lower headers of the first group and the second group open water in advance before the head of the steel plate enters, and the upper headers of the first group and the second group open water again after the head of the steel plate passes through about 1 meter in length; at the same time, a signal detector is arranged at the head of the steel plate.

2. The ACC cooling method of controlling the head shape of a medium-thickness plate according to claim 1, characterized by, The staggered delay parameters of the upper headers and the lower headers of the first group and the second group of the ACC are set separately, which are specifically: according to the speed set by the ACC roller and the distance from the head of the steel plate to the first group and the second group of headers of the ACC, the hot signal is detected by the signal detector arranged at the head of the steel plate, and when the hot signal is detected, the staggered delay opening of the upper headers and the lower headers of the first group and the second group of the ACC is automatically triggered.

3. The ACC cooling method of controlling the head shape of a medium plate according to claim 1, characterized by, The upper headers are U-shaped headers.

4. The ACC cooling method of controlling the head shape of a medium plate according to claim 1, characterized by, The lower headers are straight headers.