Automatic steel charging control method for pusher-type heating furnace

Abstract

The embodiment of the invention provides an automatic steel charging control method for a pusher-type heating furnace, which comprises the following steps of: determining an incident angle of a first laser range finder in advance according to the minimum width and the maximum length of all slabs which need to be pushed into the heating furnace in sequence in production, and mounting the first laser range finder on the side surface of a furnace front roller way according to the incident angle; a first laser range finder monitors the position of the head end face of the to-be-fed plate blank on the furnace front roller way in real time to obtain laser ranging data; according to the laser ranging data and the length of the to-be-fed plate blank, a furnace front roller way is controlled to decelerate and position the to-be-fed plate blank, so that when the to-be-fed plate blank stops in front of the furnace, the center of the to-be-fed plate blank is aligned with the center of a furnace door; and the actual steel pushing distance and steel pushing pressure data of the steel pushing machine are monitored in real time, and according to the actual steel pushing distance, the steel pushing pressure data, the width of the first plate blank on the steel tapping side and the width of the last steel tapping plate blank on the steel tapping side, the step sequence of the steel pushing machine is controlled to complete automatic steel charging of the plate blanks to be fed into the furnace.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgical machinery, and particularly to an automatic steel loading control method for a pusher-type reheating furnace. Background Art

[0002] There are mainly the following several modes for realizing automatic steel loading in today's hot rolling reheating furnaces: (1) realizing automatic positioning of slabs through the speed matching between a laser rangefinder and the speed of the furnace inlet roller table; (2) realizing automatic positioning of slabs through the speed matching between a single or multiple metal detectors or photoelectric sensors and the speed of the furnace inlet roller table; (3) realizing automatic positioning of slabs through the speed matching between limit switches and the speed of the furnace inlet roller table. After the above slab positioning is completed, the displacement of the walking beam is used to calculate whether there is a steel loading vacancy, and then the width of the slab is associated to complete the calculation of the final pusher stroke. For a pusher-type reheating furnace with weak equipment foundation, manual operation is frequent, the automation efficiency of steel loading and unloading is not high, the control accuracy is lacking, the positioning of the slabs entering the furnace and pushing the steel mainly rely on manual operation, the control process is cumbersome, the functions are scattered, the efficiency is low, the proficiency requirement for operators is high, and there is a risk of over-pushing the slabs, which may cause production safety accidents and affect the tapping plan time and production rhythm.

[0003] In the process of realizing the present invention, the applicant found that there are at least the following problems in the prior art:

[0004] The traditional technology does not completely cover the method for accurately positioning the slabs entering the furnace and the pusher, and cannot realize automatic steel loading in the case of mixed loading of slabs with different widths. Summary of the Invention

[0005] The embodiment of the present invention provides an automatic steel loading control method for a pusher-type reheating furnace, so as to solve the technical problem that the traditional technology does not completely cover the method for accurately positioning the slabs entering the furnace and the pusher, and cannot realize automatic steel loading in the case of mixed loading of slabs with different widths.

[0006] To achieve the above object, on the one hand, the embodiment of the present invention provides an automatic steel loading control method for a pusher-type reheating furnace, including the following steps:

[0007] Step S1: Determine the incident angle of the first laser rangefinder in advance according to the minimum width and maximum length of all slabs that need to be pushed into the reheating furnace in sequence during production, and install the first laser rangefinder on the side of the furnace inlet roller table according to the incident angle;

[0008] Step S2: Obtain laser ranging data by using the first laser rangefinder to monitor the position of the head end face of the slab to be put into the furnace on the furnace inlet roller table in real time; wherein, the slab to be put into the furnace is one of a plurality of slabs with different or the same widths that need to be pushed into the reheating furnace in sequence;

[0009] Step S3: According to the laser ranging data and the length of the slab to be charged into the furnace, control the front-of-furnace roller table to decelerate and position the slab to be charged into the furnace, so that when the slab to be charged into the furnace stops in front of the furnace, the center of the slab to be charged into the furnace is aligned with the center of the furnace door;

[0010] Step S4: Real-time monitor the actual pushing distance and pushing pressure data of the pusher. According to the actual pushing distance, pushing pressure data, the width of the first slab on the tapping side, and the width of the last tapped slab on the tapping side, control the pusher's sequence to complete the automatic charging of the slab to be charged into the furnace;

[0011] Wherein, the incident angle is the acute angle formed between the laser ray of the first laser rangefinder and the running direction of the front-of-furnace roller table.

[0012] Further, the step S1 includes:

[0013] Step S11: When the upper edge of the slab with the minimum width and maximum length is aligned with the upper edge of the front-of-furnace roller table, and the head end face of the slab with the minimum width and maximum length is located at the head deceleration position of the slab with the minimum width and maximum length, determine the position of the lower endpoint of the head end face of the slab with the minimum width and maximum length as the first limit steel detection point;

[0014] Step S12: When the lower edge of the slab with the minimum width and maximum length is aligned with the lower edge of the front-of-furnace roller table, and the center line of the slab with the minimum width and maximum length is aligned with the center line of the furnace door, determine the position of the upper endpoint of the head end face of the slab with the minimum width and maximum length as the second limit steel detection point;

[0015] Step S13: Determine the maximum incident angle of the first laser rangefinder according to the following formula:

[0016]

[0017] Wherein, θ max is the maximum incident angle, in degrees, which is the acute angle between the virtual straight line formed by connecting the first limit steel detection point and the second limit steel detection point and the advancing direction of the front-of-furnace roller table; W0 is the minimum width of the slab, in millimeters; W R is the width of the front-of-furnace roller table, in millimeters; L B is the slab deceleration distance, in millimeters;

[0018] Step S14: According to the installation space on the production line site, with the center point of the line connecting the first extreme steel inspection point and the second extreme steel inspection point as the axis, rotate the virtual straight line to obtain a new virtual straight line, and determine the incident angle of the first laser rangefinder, where the incident angle of the first laser rangefinder is less than or equal to the maximum incident angle of the first laser rangefinder, and the incident angle of the first laser rangefinder is the acute angle between the ray path of the first laser rangefinder and the advancing direction of the front-of-furnace roller table;

[0019] Step S15: Under the constraint that the straight-line distance from the first laser rangefinder to the first extreme steel inspection point is less than the measurement range of the first laser rangefinder, set the first laser rangefinder on the installation space on one side of the upper edge of the front-of-furnace roller table along the new virtual straight line according to the incident angle.

[0020] Among them, the lower edge of the slab is the edge of the slab on the furnace door side, and the lower edge of the front-of-furnace roller table is the edge of the front-of-furnace roller table on the furnace door side; the upper edge of the slab is the edge of the slab on the pusher side, and the upper edge of the front-of-furnace roller table is the edge of the front-of-furnace roller table on the pusher side; the head deceleration position of the slab with the minimum width and maximum length is on the incoming side of the slab at the second extreme steel inspection point, and the distance to the second extreme steel inspection point is the position of the slab deceleration distance; the slab deceleration distance is the distance obtained by integrating the speed of the front-of-furnace roller table during the period when the speed of the front-of-furnace roller table decelerates to 0 under the condition that there is no relative sliding between the slab and the surface of the front-of-furnace roller table.

[0021] Further, the step S2 includes:

[0022] Calculate the laser ranging data according to the following formula:

[0023] S0 = L1 * cosθ (2)

[0024] Among them, S0 is the laser ranging data, with the unit of millimeters; L1 is the straight-line distance from the head of the slab to be charged into the furnace directly measured by the first laser rangefinder to the first laser rangefinder, with the unit of millimeters; θ is the incident angle of the first laser rangefinder, with the unit of degrees.

[0025] Further, the step S3 includes:

[0026] Step S31: Determine the head stop position distance of the slab to be charged into the furnace according to the following formula:

[0027]

[0028] Among them, S1 is the distance of the head stop position, which is the vertical distance from the center of the slab to be charged into the furnace to the first laser rangefinder when the head of the slab stops on the front roller table of the furnace in a way that aligns with the center of the furnace door, with the unit of millimeters; L2 is the vertical distance from the center line of the furnace door of the heating furnace to the first laser rangefinder, with the unit of millimeters; L0 is the length of the slab to be charged into the furnace obtained from the production operation plan, with the unit of millimeters; l1 is a preset offset used to compensate for measurement errors, with the unit of millimeters;

[0029] Step S32: Add the head stop position distance of the slab to be charged into the furnace to the slab deceleration distance to obtain the head deceleration position distance of the slab to be charged into the furnace;

[0030] Step S33: During the process of the slab to be charged into the furnace running on the front roller table of the furnace, compare the laser ranging data with the head deceleration position distance and the laser ranging data with the head stop position distance in real time;

[0031] Step S34: If the laser ranging data is less than the head deceleration position distance, reduce the running speed of the front roller table to 10% of the original speed to convey the slab to be charged into the furnace at a low speed; among them, the original speed is the speed of the front roller table during the period when the laser ranging data is greater than the head deceleration position distance;

[0032] Step S35: If the absolute value of the difference between the laser ranging data and the head stop position distance is less than 10 millimeters, control the front roller table to stop running and set the slab positioning completion flag; among them, the slab positioning completion flag will be reset after the pusher steel step is completed;

[0033] Among them, the slab deceleration distance is the distance obtained by integrating the speed of the front roller table during the period when the speed of the front roller table decelerates to 0 while ensuring that there is no relative sliding between the slab and the surface of the front roller table.

[0034] Further, the step S4 includes:

[0035] Step S41: During the period when the pusher pushes the steel, compare the size of the real-time monitored pusher pressure data and the preset pressure processing limit value;

[0036] Step S42: If the pusher pressure data is greater than or equal to the preset pressure processing limit value, use the actual pusher distance obtained by the current real-time monitoring as the first pusher distance;

[0037] Step S43: Subtract the first pusher distance from the rated maximum stroke of the pusher to obtain the pusher stroke margin;

[0038] Step S44: Determine the center line distance between the first slab on the tapping side and the last tapped slab on the tapping side according to the widths of the first slab on the tapping side and the last tapped slab on the tapping side.

[0039] Step S45: Determine the expected pushing stroke of the pusher during the pushing of the slab to be charged into the furnace according to the pusher stroke margin and the center line distance.

[0040] Step S46: During the process of the pusher continuing to push the slab, continuously judge whether the deviation between the actual pushing distance and the expected pushing stroke is within the preset pushing-in-place deviation range.

[0041] Step S47: If it is judged that the deviation between the actual pushing distance and the expected pushing stroke is within the preset pushing-in-place deviation range, set the given value of the pusher proportional valve to zero, stop the pusher from pushing, and retract it to the initial position.

[0042] Further, the step S45 includes:

[0043] Compare the pusher stroke margin with the center line distance;

[0044] In the case where the pusher stroke margin is greater than or equal to the center line distance, reset the pusher stroke shortage flag bit, and set the expected pushing stroke of the pusher during the pushing of the slab to be charged into the furnace to the sum of the first pushing distance and the center line distance;

[0045] In the case where the pusher stroke margin is less than the center line distance, set the pusher stroke shortage flag bit, and set the maximum pushing stroke of the pusher during the pushing of the slab to be charged into the furnace to the minimum safe pushing stroke;

[0046] Wherein, the minimum safe pushing stroke is the stroke for the pusher to just push the slab out of the front furnace roller table.

[0047] Further, the step S4 further includes:

[0048] In response to the pushing pressure data being less than the preset pressure processing limit value, use the actual pushing distance of the pusher obtained by current real-time monitoring as the second pushing distance;

[0049] Judge whether the second pushing distance is greater than the minimum safe pushing stroke;

[0050] If it is judged that the second pushing distance is greater than the minimum safe pushing stroke, reset the front furnace roller table steel feeding prohibition flag bit, otherwise set the front furnace roller table steel feeding prohibition flag bit;

[0051] Wherein, the minimum safe pushing stroke is the stroke for the pusher to just push the slab out of the front furnace roller table.

[0052] Further, step S4 further includes:

[0053] When the pusher returns to the initial position, set the pusher completion signal for 5 seconds, and at the same time send this signal to the rolling line L2 system, and reset the pusher completion signal after 5 seconds.

[0054] Further, the method further includes:

[0055] The actual pusher distance of the pusher is monitored in real time by a second laser rangefinder provided at the rear end of the pusher arm of the pusher, and the irradiation point is the rear end head of the pusher arm.

[0056] The above technical solution has the following beneficial effects: Determine the incident angle of the first laser rangefinder according to the minimum width and maximum length of all slabs, so that the first laser rangefinder provided on the side of the front furnace roller table can monitor the real-time positions of all slabs with a width greater than the minimum width and less than the width of the front furnace roller table on the front furnace roller table, thereby realizing the automatic positioning in front of the furnace for different-width slabs appearing on the same production line. Improve the degree of automatic control of slab charging into the furnace, reduce manual operation, reduce the requirements for the proficiency of operators, improve the charging efficiency, make the heating furnace area operate more stably and efficiently, reduce the risk of over-pushing of slabs, and reduce the occurrence of production safety accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0058] Figure 1 is a flowchart of a method for automatically controlling the charging of a pusher-type heating furnace according to one embodiment of the present invention;

[0059] Figure 2 is a schematic diagram of the incident angle of the first laser rangefinder according to one embodiment of the present invention;

[0060] Figure 3 is a flowchart of the positioning control of the front furnace roller table of the slab to be charged into the furnace according to one embodiment of the present invention;

[0061] Figure 4 is a schematic diagram of the pusher pushing the slab according to one embodiment of the present invention;

[0062] Figure 5 is a flowchart of the automatic pusher control of the pusher according to one embodiment of the present invention;

[0063] Figure 6It is the sequence diagram of the pushing pressure of the pusher in one of the embodiments of the present invention. Detailed implementation manners

[0064] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0065] On the one hand, as Figure 1 shown, an automatic steel loading control method for a pusher-type reheating furnace provided by an embodiment of the present invention includes the following steps:

[0066] Step S1: Determine the incident angle of the first laser rangefinder in advance according to the minimum width and maximum length of all slabs to be pushed into the reheating furnace in production, and install the first laser rangefinder on the side of the front furnace roller table according to the incident angle;

[0067] Step S2: Real-time monitor the position of the head end face of the slab to be charged on the front furnace roller table by the first laser rangefinder to obtain laser ranging data; wherein, the slab to be charged is one of a variety of slabs with different or the same widths that need to be pushed into the reheating furnace in sequence;

[0068] Step S3: Control the front furnace roller table to decelerate and position the slab to be charged according to the laser ranging data and the length of the slab to be charged, so that when the slab to be charged stops in front of the furnace, the center of the slab to be charged is aligned with the center of the furnace door;

[0069] Step S4: Real-time monitor the actual pushing distance and pushing pressure data of the pusher, and control the pusher sequence according to the actual pushing distance, pushing pressure data, the width of the first slab on the discharging side, and the width of the last discharged slab on the discharging side to complete the automatic steel loading of the slab to be charged;

[0070] Wherein, the incident angle is an acute angle formed between the laser ray of the first laser rangefinder and the running direction of the front furnace roller table.

[0071] In some embodiments, the first laser rangefinder for positioning the slab on the front furnace roller table cannot be installed at a position directly facing the running direction of the front furnace roller table and can only be installed on the side of the front furnace roller table. At this time, the first laser rangefinder needs to irradiate the slab on the front furnace roller table at an angle of incidence with the running direction of the front furnace roller table. In order to ensure that the first laser rangefinder can correctly monitor slabs of different widths, it is necessary to determine the angle of incidence of the first laser rangefinder in advance according to the minimum width and maximum length of all slabs that need to be successively pushed into the heating furnace during production, and install the first laser rangefinder on the side of the front furnace roller table according to the angle of incidence. The laser ranging data is the distance along the direction of the front furnace roller table between the head end face of the slab to be charged into the furnace and the first laser rangefinder, that is, the vertical distance between the head end face of the slab to be charged into the furnace and the first laser rangefinder. This distance can be calculated based on the straight-line distance measured by the first laser rangefinder from the first laser rangefinder to the head end face of the slab to be charged into the furnace and the angle of incidence.

[0072] According to the laser ranging data and the length of the slab to be charged into the furnace, control the front furnace roller table to decelerate and position the slab to be charged into the furnace, so that when the slab to be charged into the furnace stops in front of the furnace, the center of the slab to be charged into the furnace is aligned with the center of the furnace door. Real-time monitor the actual pushing distance and pushing pressure data of the pusher. According to the actual pushing distance, pushing pressure data, the width of the first slab on the tapping side (current) (the slab about to be discharged from the tapping side) and the width of the last slab discharged from the tapping side, control the pusher's steps to complete the automatic charging of the slab to be charged into the furnace. The pushing pressure data can be measured by a pressure sensor set on the pusher. According to the pushing pressure data (hydraulic pusher pressure), it can be detected whether the pusher is pushing all the slabs in the heating furnace, whether the pusher starts to retract, etc.; the actual pushing distance when the pusher is pushing all the slabs in the heating furnace can be controlled by the width of the first slab on the tapping side and the width of the last slab discharged from the tapping side, as well as by the pushing pressure data to complete the charging operation by controlling the pusher's steps.

[0073] The embodiments of the present invention have the following technical effects: Determine the angle of incidence of the first laser rangefinder according to the minimum width and maximum length of all slabs, so that the first laser rangefinder set on the side of the front furnace roller table can monitor the real-time positions of all slabs with a width greater than the minimum width and less than the width of the front furnace roller table on the front furnace roller table, thereby realizing the automatic positioning in front of the furnace of slabs of different widths appearing on the same production line. Improve the degree of automatic control of slab charging into the furnace, reduce manual operations, reduce the requirements for the proficiency of operators, improve the charging efficiency, make the heating furnace area operate more stably and efficiently, reduce the risk of over-pushing slabs, and reduce the occurrence of production safety accidents.

[0074] Further, the step S1 includes:

[0075] Step S11: When the upper edge of the slab with the minimum width and maximum length is aligned with the upper edge of the front-of-furnace roller table, and the head end face of the slab with the minimum width and maximum length is located at the head deceleration position of the slab with the minimum width and maximum length, determine the position of the lower endpoint of the head end face of the slab with the minimum width and maximum length as the first limit steel detection point;

[0076] Step S12: When the lower edge of the slab with the minimum width and maximum length is aligned with the lower edge of the front-of-furnace roller table, and the center line of the slab with the minimum width and maximum length is aligned with the center line of the furnace door, determine the position of the upper endpoint of the head end face of the slab with the minimum width and maximum length as the second limit steel detection point;

[0077] Step S13: Determine the maximum incident angle of the first laser rangefinder according to formula (1):

[0078]

[0079] where θ max is the maximum incident angle, in degrees, which is the acute angle between the virtual straight line formed by connecting the first limit steel detection point and the second limit steel detection point and the advancing direction of the front-of-furnace roller table; W0 is the minimum width of the slab, in millimeters; W R is the width of the front-of-furnace roller table, in millimeters; L B is the slab deceleration distance, in millimeters;

[0080] Step S14: According to the installation space at the production line site, with the center point of the connection line between the first limit steel detection point and the second limit steel detection point as the axis, rotate the virtual straight line to obtain a new virtual straight line, and determine the incident angle of the first laser rangefinder; wherein, the incident angle of the first laser rangefinder is less than or equal to the maximum incident angle of the first laser rangefinder, which is the acute angle formed between the laser ray of the first laser rangefinder and the running direction of the front-of-furnace roller table;

[0081] Step S15: Under the constraint that the straight-line distance from the first laser rangefinder to the first limit steel detection point is less than the measurement range of the first laser rangefinder, set the first laser rangefinder along the new virtual straight line at the installation space on one side of the upper edge of the front-of-furnace roller table according to the incident angle.

[0082] Among them, the lower edge of the slab is the edge of the slab on the side of the furnace door, and the lower edge of the front furnace roller table is the edge of the front furnace roller table on the side of the furnace door; the upper edge of the slab is the edge of the slab on the side of the pusher, and the upper edge of the front furnace roller table is the edge of the front furnace roller table on the side of the pusher; the head deceleration position of the slab with the minimum width and the maximum length is on the incoming side of the slab at the second limit steel detection point, and the position with a distance to the second limit steel detection point equal to the slab deceleration distance; the slab deceleration distance is the distance obtained by integrating the speed of the front furnace roller table during the period when the speed of the front furnace roller table decelerates to 0 under the condition that no relative sliding occurs between the slab and the surface of the front furnace roller table.

[0083] In some embodiments, before starting production, the first laser rangefinder needs to be set on the side of the front furnace roller table, specifically on the side of the pusher of the front furnace roller table and on the downstream side of the pusher. The forward direction of the front furnace roller table is defined as the downstream, and the incoming direction of the front furnace roller table is defined as the upstream. In order for the positioned first laser rangefinder to perform front furnace positioning for slabs with various different widths and lengths, the embodiment of the present invention determines the maximum incident angle θ of the first laser rangefinder with a hypothetical slab having the minimum width and the maximum length as a reference. max . The second limit steel detection point is the Figure 2 point B in Figure 2 , and the first limit steel detection point is the

[0084] point A in max . The virtual straight line connecting point A and point B is used as the laser ray path of the first laser rangefinder.

[0084] The maximum incident angle θ of the first laser rangefinder max needs to be determined according to relevant parameters such as the measurement range of the first laser rangefinder, the width (width of the slab) W0 of the slab cross-section, the attitude of the slab during positioning, and the slab deceleration distance. Now consider the positioning situation when the incoming width of the slab is the narrowest. When the slab enters the incoming roller table (front furnace roller table) in the limit attitude, it is divided into two cases:

[0085] One case is when the edge of the slab is close to the edge of the roller table on the pusher side, the ray of the first laser rangefinder first irradiates the edge of the head end face of the slab on the side of the furnace door. At this time, the detection position is the first limit steel detection point A of the first laser rangefinder, and the distance from the first limit steel detection point A of the first laser rangefinder to the head stop position should be greater than or equal to the slab deceleration distance, otherwise the slab positioning cannot be accurately completed;

[0086] The other case is when the edge of the slab is close to the edge of the roller table on the furnace door side, before the slab positioning stops, the irradiation point of the ray of the first laser rangefinder should always be on the cross-section of the slab, and when the slab positioning is completed, the edge of the head end face of the slab on the side of the pusher is the second limit steel detection point B.

[0087] Given the extreme irradiation positions of the first laser rangefinder when feeding steel in two extreme postures, combining the two to analyze the maximum irradiation angle of the laser rangefinder, the maximum incident angle θ for ensuring the normal positioning of the slab can be calculated using formula (1) when the width of the slab is greater than or equal to the minimum width defined by W0. max . Among them, W0 is the minimum width of the slab, in millimeters; W R is the width of the front-of-furnace roller table, in millimeters; L B is the deceleration distance of the slab, in millimeters. The calculation method of L B is as follows: First, without relative sliding between the slab and the roller table surface, during the period when the roller table speed is decelerated to 0, the deceleration distance is calculated by integrating the roller table speed. In practice, if the roller table speed drops too fast, relative displacement will occur between the slab and the roller table. In practical applications, some calculation errors can also be added to the obtained deceleration distance. After obtaining the maximum incident angle, when actually deploying the first laser rangefinder in the production line, the available installation space near the production line also needs to be considered. Preferably, when the installation space permits, the first laser rangefinder is deployed along the straight line connecting points A and B on the outside of the edge of the front-of-furnace roller table close to the pusher side, and the incident angle is set to the maximum incident angle. In some cases, due to the limitation of the installation space near the production line, it is impossible to deploy the first laser rangefinder along the straight line connecting points A and B. Then, the virtual straight line of points A and B can be rotated around the center point of line segment AB to obtain a new virtual straight line. The incident angle corresponding to the new virtual straight line is less than the maximum incident angle. The first laser rangefinder is deployed along the new virtual straight line, with the incident angle corresponding to the new virtual straight line (i.e., the angle between the new virtual straight line and the advancing direction of the front-of-furnace roller table), in the available installation space on the outside of the edge of the front-of-furnace roller table close to the pusher side.

[0088] The embodiments of the present invention have the following technical effects: Determine the incident angle of the first laser rangefinder according to the minimum width and maximum length of all slabs, so that the first laser rangefinder arranged on the side of the front-of-furnace roller table can monitor the real-time positions of all slabs with a width greater than the minimum width and less than the width of the front-of-furnace roller table on the front-of-furnace roller table, thereby realizing the automatic positioning in front of the furnace for different-width slabs appearing on the same production line. Moreover, for slabs with a width greater than the minimum width, they can be irradiated by the first laser rangefinder at any offset position in the width direction of the front-of-furnace roller table. Improve the degree of automatic control of slab charging into the furnace, reduce manual operations, lower the requirements for the proficiency of operators, improve the steel charging efficiency, make the heating furnace area operate more stably and efficiently, reduce the risk of over-pushing the slab, and reduce the occurrence of production safety accidents.

[0089] Further, the step S2 includes:

[0090] Calculate the laser ranging data according to formula (2):

[0091] S0 = L1 * cosθ (2)

[0092] Wherein, S0 is the laser ranging data, in millimeters; L1 is the straight-line distance from the head of the slab to be charged into the furnace to the first laser rangefinder directly measured by the first laser rangefinder, in millimeters; θ is the incident angle of the first laser rangefinder, in degrees.

[0093] In some embodiments, as Figure 2 shown, S0 is the laser ranging data, in millimeters, which is the vertical distance from the first laser rangefinder to the head end face of the slab to be charged into the furnace; L1 is the straight-line distance from the head of the slab to be charged into the furnace to the first laser rangefinder directly measured by the first laser rangefinder, in millimeters; θ is the incident angle of the first laser rangefinder, in degrees; L1 is directly and real-time measured by the first laser rangefinder. The incident angle of the first laser rangefinder has been determined and known when the first laser rangefinder is installed before the start of production. According to the trigonometric function relationship, the laser ranging data can be determined.

[0094] Further, the step S3 includes:

[0095] Step S31: Determine the head stop position distance of the slab to be charged into the furnace according to formula (3):

[0096]

[0097] Wherein, S1 is the head stop position distance, which is the vertical distance from the head of the slab to the first laser rangefinder when the center of the slab to be charged into the furnace stops on the front furnace roller table in a manner that aligns with the center of the furnace door, in millimeters; L2 is the vertical distance from the center line of the furnace door of the heating furnace to the first laser rangefinder, in millimeters; L0 is the length of the slab to be charged into the furnace obtained from the production operation plan, in millimeters; l1 is a preset offset for compensating for measurement errors, in millimeters.

[0098] Step S32: Add the head stop position distance of the slab to be charged into the furnace to the slab deceleration distance to obtain the head deceleration position distance of the slab to be charged into the furnace;

[0099] Step S33: During the process of the slab to be charged into the furnace running on the front furnace roller table, compare the laser ranging data with the head deceleration position distance and the laser ranging data with the head stop position distance in real time;

[0100] Step S34: If the laser ranging data is less than the head deceleration position distance, reduce the running speed of the front furnace roller table to 10% of the original speed to convey the slab to be charged into the furnace at a low speed; wherein, the original speed is the speed of the front furnace roller table during the period when the laser ranging data is greater than the head deceleration position distance;

[0101] Step S35: If the absolute value of the difference between the laser ranging data and the distance to the head stop position is less than 10 millimeters, control the front furnace roller table to stop running, and set the slab positioning completion flag; wherein, the slab positioning completion flag will be reset after the steel pushing step sequence is completed.

[0102] Wherein, the slab deceleration distance is the distance obtained by integrating the speed of the front furnace roller table during the period when the speed of the front furnace roller table decelerates to 0 under the condition that there is no relative sliding between the slab and the surface of the front furnace roller table.

[0103] In some embodiments, as Figure 2 shown, L2 is the vertical distance from the center line of the furnace door of the heating furnace to the first laser rangefinder, in millimeters, which is known as a production line parameter when the first laser rangefinder is installed; L0 is the length of the slab to be charged into the furnace obtained from the production operation plan, in millimeters; l1 is a preset offset for compensating for measurement errors, in millimeters. S1 in formula (3) is the distance to the head stop position, which is the vertical distance from the head of the slab to the first laser rangefinder when the center of the slab to be charged into the furnace stops on the front furnace roller table in alignment with the center of the furnace door, in millimeters; as Figure 3 shown, it is a flowchart of a method for realizing automatic positioning of the slab. To realize the automatic positioning of the charged slab, it is necessary to request the length of the charged slab from the MES system (or production work plan) before positioning the charging roller table. After determining the slab length, select the slab positioning method, including head positioning, middle positioning, and tail positioning. The embodiment of the present invention adopts middle positioning. Calculate the head stop position according to the slab length and the positioning method. During the high-speed transportation of the slab, continuously compare the value of S0 (laser ranging data) with the value of S1 (distance to the head stop position) plus L B (slab deceleration distance) (i.e., the head deceleration position distance): When the laser ranging data S0 is less than the head deceleration position distance, the roller table speed is set to 10% of the low-speed steel feeding speed; when the difference between the laser ranging data S0 and the distance to the head stop position S1 is within 10 millimeters, the roller table stops running and the slab positioning completion flag is set. After the steel pushing step sequence is completed, the slab positioning completion flag is reset.

[0104] The embodiment of the present invention has the following technical effects: By real-time monitoring the laser ranging data with the first laser rangefinder and comparing it with the head deceleration position distance, early deceleration is realized, avoiding the problem that the speed of the slab to be charged into the furnace is too high when it reaches the corresponding head stop position and suddenly stops and slides, thereby avoiding the problem of inaccurate positioning and improving the positioning accuracy.

[0105] Further, the step S4 includes:

[0106] Step S41: During the period when the pusher pushes the steel, compare the size of the real-time monitored steel pushing pressure data and the preset pressure processing limit value.

[0107] Step S42: If the pushing pressure data is greater than or equal to the preset pressure processing limit value, take the actual pushing distance of the pusher obtained by current real-time monitoring as the first pushing distance;

[0108] Step S43: Subtract the first pushing distance from the rated maximum stroke of the pusher to obtain the pusher stroke margin;

[0109] Step S44: Determine the center line distance between the first slab on the tapping side and the previous slab tapped on the tapping side according to the width of the first slab on the tapping side and the width of the previous slab tapped on the tapping side;

[0110] Step S45: Determine the expected pushing stroke of the pusher during the pushing of the slab to be charged into the furnace according to the pusher stroke margin and the center line distance;

[0111] Step S46: During the process of the pusher continuing to push, determine in real time whether the deviation between the actual pushing distance and the expected pushing stroke is within the preset pushing-in-place deviation range;

[0112] Step S47: If it is determined that the deviation between the actual pushing distance and the expected pushing stroke is within the preset pushing-in-place deviation range, set the given value of the pusher proportional valve to zero, stop the pusher from pushing, and retract it to the initial position.

[0113] In some embodiments, during the pushing process, first the pusher will push the slab to be charged into the furnace to move from the front furnace roller table into the heating furnace. At this time, the pusher only pushes this one slab to be charged into the furnace, and the pushing pressure data is relatively small, and the pushing pressure data is less than the preset pressure processing limit value. When the pusher continues to push, the slab to be charged into the furnace enters the heating furnace and contacts the original slabs in the heating furnace, and then the pusher starts to push all the slabs in the heating furnace including the slab to be charged into the furnace to move towards the tapping side of the heating furnace. At this time, the pushing pressure data is greater than or equal to the preset pressure processing limit value. Since the widths of the slabs entering the heating furnace may be the same or different, it is necessary to set the expected pushing stroke according to the width of the first slab on the tapping side and the width of the previous slab tapped on the tapping side. When setting the expected pushing stroke, it is also necessary to consider the limitation of the rated maximum stroke that the pusher can reach, and the expected pushing stroke cannot be greater than the rated maximum stroke of the pusher. By comparing the actual pushing distance with the expected pushing stroke in real time, if the actual pushing distance is equal to the expected pushing stroke, it means that the pushing is in place. In practical applications, it is very difficult to achieve complete equality, so a preset pushing-in-place deviation range is set to improve the success rate of identifying the pushing in place. The minimum value of the preset pushing-in-place deviation range that can ensure the success rate of identifying the pushing in place can be obtained through multiple tests.

[0114] The embodiments of the present invention have the following technical effects: When determining the desired pusher travel, the width of the first slab on the tapping side and the width of the last tapped slab on the tapping side are taken into account, so as to adapt to the tapping of slabs with different widths mixed in the furnace. By real-time monitoring the relationship between the actual pusher distance and the desired pusher travel, automatic pusher operation is realized. The degree of automatic control of slab charging and discharging is improved, manual operation is reduced, and the requirement for the proficiency of operators is lowered. The charging and discharging efficiency is improved, and the heating furnace area operates more stably and efficiently. The risk of over-pushing the slab is reduced, and the occurrence of production safety accidents is decreased. It is ensured that the slab discharged on the tapping side is within the normal tapping area, and the furnace condition is guaranteed to be stable and smooth.

[0115] Further, the step S45 includes:

[0116] Compare the pusher travel margin with the center line distance;

[0117] When the pusher travel margin is greater than or equal to the center line distance, reset the pusher travel shortage flag bit, and set the desired pusher travel of the pusher during the pushing of the slab to be charged into the furnace to the sum of the first pusher distance and the center line distance;

[0118] When the pusher travel margin is less than the center line distance, set the pusher travel shortage flag bit, and set the maximum pusher travel of the pusher during the pushing of the slab to be charged into the furnace to the minimum safe pusher travel;

[0119] Wherein, the minimum safe pusher travel is the travel when the pusher just pushes the slab out of the front roller table of the furnace.

[0120] In some embodiments, when the pusher pressure data is greater than or equal to the preset pressure processing limit value, it indicates that at this time the pusher starts to push all the slabs in the heating furnace to move together towards the tapping side. At this time, the pusher already has a travel of the first pusher distance. At this time, according to the width of the first slab on the tapping side and the width of the last tapped slab on the tapping side, the center line distance between the first slab on the tapping side and the last tapped slab on the tapping side is determined. This center line distance is the distance that the pusher needs to continue pushing, but the total pusher distance of the pusher cannot exceed the rated maximum pusher travel. Therefore, subtract the first pusher distance from the rated maximum pusher travel to obtain the pusher travel margin, and it is necessary to compare the pusher travel margin with the center line distance. When the pusher travel margin is greater than or equal to the center line distance, the pusher can still continue to push for a travel length of the center line distance. Therefore, set the desired pusher travel of the pusher to the sum of the first pusher distance and the center line distance;

[0121] Such as Figure 4As shown, L3 is the limit stroke of the pusher or the rated maximum stroke of the pusher; L4 is the stroke of the pusher head to the inner edge of the roller table; W2 is the width of the previous slab out of the furnace; W3 is the width of the next slab out of the furnace; when the stroke margin of the pusher is less than the center line distance, the pusher can no longer push the stroke of the center line distance. At this time, the maximum pushing stroke of the pusher during the pushing of the slab to be charged into the furnace is set as the minimum safe pushing stroke, so that the pusher can just push the slab to be charged into the furnace out of the front roller table of the furnace, thereby vacating the front roller table of the furnace and avoiding affecting the entry of the next slab into the front roller table of the furnace.

[0122] As Figure 4 shown, calculate the stroke margin of the pusher by using ΔS = L3 - S2, where ΔS is the stroke margin of the pusher, L3 is the rated maximum stroke of pushing, and S2 is the first pushing distance. Compare the stroke margin with the distance that needs to be advanced when pushing the slab to be discharged from the furnace to the tapping position. The distance from the slab out of the furnace to the tapping position is the distance between the center lines of the previous slab and the slab about to be discharged from the furnace. If the remaining distance of the pusher is greater than the distance to push the slab to the tapping position, reset the pusher stroke shortage flag bit, and set the expected pushing stroke of this pushing as S2 + (W2 + W3) / 2. Otherwise, set the pusher stroke shortage flag bit, and set the expected pushing stroke of the pusher this time as the minimum safe pushing stroke L4, so as not to affect the advancing distance of the pusher for the next slab to be pushed. Until the next pushing, judge the pusher stroke again. If the pusher stroke meets the normal pushing distance, reset the flag bit of the pusher stroke shortage. When using the minimum safe distance to push, when a sharp increase in pressure is detected during the advancing of the pusher, it indicates that the pusher is about to push the entire furnace of slabs. If the pusher stroke is greater than the safe stroke at this time, the pusher retracting sequence will be directly triggered in the program. During this period, the slabs on the side of the tapping will not be displaced, nor will it affect the judgment of the next pushing distance.

[0123] The embodiment of the present invention has the following technical effects: when the stroke margin of the pusher is insufficient, the slab to be charged into the furnace is pushed out of the front roller table of the furnace, so as not to affect the entry of the next slab into the front roller table of the furnace and maintain the continuity of production.

[0124] Further, the step S4 further includes:

[0125] In response to the pushing pressure data being less than the preset pressure processing limit value, use the actual pushing distance of the pusher obtained by current real-time monitoring as the second pushing distance;

[0126] Judge whether the second pushing distance is greater than the minimum safe pushing stroke of the pusher;

[0127] If it is judged that the second pushing distance is greater than the minimum safe pushing stroke of the pusher, reset the flag bit of the prohibition of steel entry for the front roller table, otherwise set the flag bit of the prohibition of steel entry for the front roller table;

[0128] Among them, the minimum safe stroke of pushing steel is the stroke when the pusher just pushes the slab out of the front furnace roller table.

[0129] In some embodiments, when the pushing-steel pressure data is less than the preset pressure processing limit value, the pusher is just about to retract. Record the actual pushing-steel distance at this time as the second pushing-steel distance. If the second pushing-steel distance is greater than the minimum safe stroke of pushing steel, it indicates that the front furnace roller table is idle. Reset the steel-inhibition flag of the front furnace roller table and allow the next slab to enter the front furnace roller table. Otherwise, it indicates that there is still a slab on the front furnace roller table that has not been completely pushed out of the front furnace roller table. At this time, set the steel-inhibition flag of the front furnace roller table and prohibit the next slab from entering the front furnace roller table.

[0130] The embodiments of the present invention have the following technical effects: By recording the actual pushing-steel distance as the second pushing-steel distance when the pusher is just about to retract, and comparing the second pushing-steel distance with the minimum safe stroke of pushing steel, it is possible to automatically identify whether the front furnace roller table is idle, so as to control whether the next slab can enter the front furnace roller table, automatically control the timing of the next slab entering the front furnace roller table, and avoid the steel-piling accident on the front furnace roller table.

[0131] Further, the step S4 further includes:

[0132] When the pusher retracts to the initial position, set the pushing-steel completion signal for 5 seconds, and at the same time send this signal to the rolling line L2 system, and reset the pushing-steel completion signal after 5 seconds.

[0133] In some embodiments, after the pusher retracts to the initial position, it is necessary to set the pushing-steel completion signal for 5 s, and at the same time send this signal to the rolling line secondary (L2) system for tracking the slab information in the furnace. The width of the slab discharged on the tapping side this time can be recorded and used as the width of the slab discharged on the tapping side in the previous time for the calculation of the pushing-steel distance of the pusher next time.

[0134] Further, the method further includes:

[0135] The actual pushing-steel distance of the pusher is monitored in real time by a second laser rangefinder provided at the rear end of the pushing arm of the pusher and with the irradiation point being the rear end head of the pushing arm.

[0136] In some embodiments, for the second laser rangefinder, to prevent the instrument from being interfered due to the complex environment it is in, its installation position needs to be at the rear end of the pushing arm of the pusher, and the irradiation point is the rear end head of the pushing arm.

[0137] The above technical solutions of the embodiments of the present invention are described in detail below in combination with specific application examples. For technical details not introduced during the implementation process, reference can be made to the relevant descriptions above.

[0138] An embodiment of the present invention is a control method that uses a detection device to accurately position the slab entering the furnace and the pusher, and can realize automatic steel charging in a pusher-type reheating furnace under the condition of mixed charging of slabs with different widths.

[0139] An embodiment of the present invention is based on a pusher-type reheating furnace with a direct-push type for slab charging into the furnace and a side-push type for steel discharging, where one slab is charged into the furnace at a time, and the specifications of the slab entering the furnace are a length of 9 - 10 m (meters) and a width range of 600 mm - 770 mm (millimeters). In this embodiment of the present invention, first, a suitable positioning method is selected according to the slab length, and the head position of the slab during positioning is calculated by a first laser rangefinder, so as to realize the positioning of the slab entering the furnace on the front roller table of the furnace; after the slab positioning is completed, the pushing distance is automatically calculated based on the slab width scheduled by the linked MES system, and then combined with the second laser rangefinder on the pusher and the pressure mutation of the pressure sensor during pushing, the judgment of the automatic pushing sequence is completed, and finally the complete process of automatic steel charging is realized.

[0140] Detect the relevant data of the first laser rangefinder during the actual positioning of the slab entering the furnace: For the positioning of the slab on the front roller table of the furnace, due to the limitations of the position of the roller table for charging into the furnace and the mechanical structure of the pusher head, and the complexity of the slab conditions during actual production, it is necessary to use the first laser rangefinder to monitor the head section position of the slab in real time and compare it with the preset stop position to control the deceleration and stop of the roller table, so as to realize the positioning of the slab. The installation position of the detection instrument is as Figure 2 shown. Figure 2 In which, L0 is the length of the slab entering the furnace; L1 is the actually measured distance by the laser rangefinder; L2 is the distance between the laser rangefinder and the center line of the furnace door; S0 is the distance obtained by converting the laser rangefinder data into the distance in the same direction as the roller table direction; θ max is the maximum incident angle of the laser rangefinder; W0 is the width of the slab entering the furnace; W R is the width of the roller table; A is the limit irradiation point when the laser rangefinder detects the steel, that is, the first limit steel detection point; B is the limit irradiation point when the laser rangefinder stops, that is, the second limit steel detection point;

[0141] Determine the vertical distance from the head of the slab to the first laser rangefinder according to formula (2), where S0 is the laser rangefinder data, which is the vertical distance from the head of the slab to the first laser rangefinder, in millimeters; L1 is the straight-line distance from the head of the slab to the first laser rangefinder, in millimeters; θ is the incident angle of the first laser rangefinder, in degrees.

[0142] According to formula (3), with the aim of aligning the center of the slab with the center of the furnace mouth when the slab stops in front of the furnace, the head stop position is determined. Among them, S1 is the head stop position distance, which is the vertical distance from the head of the slab to the first laser rangefinder when the head of the slab stops at the head stop position, in millimeters; L2 is the vertical distance from the center line of the furnace door of the heating furnace to the first laser rangefinder, in millimeters; L0 is the slab length, in millimeters, which can be obtained from the production operation plan; l1 is the preset offset, in millimeters, used to compensate for measurement errors.

[0143] The incident angle of the first laser rangefinder is related to the measurement range of the first laser rangefinder, the slab cross-section width W0, the attitude of the slab during positioning, and the slab deceleration distance, etc. Now consider the positioning situation when the slab enters the furnace with the narrowest width. When the slab enters the charging roller table in the extreme attitude, it is divided into two cases: one is when the edge of the slab is close to the edge of the roller table pusher side, the ray of the first laser rangefinder first irradiates the edge of the head cross-section of the slab close to the furnace door side. At this time, the detection position is the first limit steel detection point A of the first laser rangefinder, and the distance from the first limit steel detection point A of the first laser rangefinder to the head stop position should be greater than or equal to the slab deceleration distance, otherwise the slab positioning cannot be accurately completed; the other is when the edge of the slab is close to the edge of the roller table furnace door side, before the slab positioning stops, the irradiation point of the ray of the first laser rangefinder should always be on the slab cross-section, and when the slab positioning is completed, the edge of the head cross-section of the slab close to the pusher side is the second limit steel detection point B. Given the limit irradiation positions of the first laser rangefinder for feeding steel in two extreme attitudes, by combining the two and analyzing, the maximum irradiation angle of the laser rangefinder can be obtained. The maximum incident angle θ that can ensure the normal positioning of the slab in the case where the width of the slab is greater than or equal to the minimum width defined by W0 can be calculated using the following formula max , determine θ according to formula (1) max , preferably, the maximum incident angle can be used as the incident angle of the first laser rangefinder. Among them, W0 is the minimum width of the slab, in millimeters; W R is the width of the roller table in front of the furnace, in millimeters; L B is the slab deceleration distance, in millimeters, and the calculation method of L B is as follows: First, without relative sliding between the slab and the roller table surface, during the period when the roller table speed is decelerated to 0, the deceleration distance is calculated by integrating the roller table speed. In practice, if the roller table decelerates too fast, relative displacement will occur between the slab and the roller table. In practical applications, some calculation errors can also be added to the obtained deceleration distance.

[0144] Such as Figure 3As shown in the figure, the logical judgment of the automatic slab positioning program is realized: to achieve the automatic positioning of the slab entering the furnace, it is necessary to request the length of the slab entering the furnace from the MES system (or production work plan) before positioning on the roller table. After determining the slab length, select the slab positioning method for entering the furnace, including head positioning, middle positioning, and tail positioning. Calculate the head stop position according to the slab length and positioning method. During the high-speed transportation of the slab, continuously compare the value obtained by adding S0 (laser ranging data) and S1 (distance to the head stop position) plus L B (the deceleration distance of the slab) with the laser ranging data S0: when the laser ranging data S0 is less than the head deceleration distance, the roller table speed is set to 10% of the low-speed steel feeding speed; when the difference between the laser ranging data S0 and the head stop position S1 is within 10 mm, the roller table stops running and the slab positioning completion flag is set. After the steel pushing step is completed, the slab positioning completion flag is reset. The automatic positioning control flow chart of the slab entering the furnace is as Figure 3 shown.

[0145] Description of slab mixed loading: When slab mixed loading occurs, with the change of the width of the slab to be fed into the furnace, it will have different effects on the steel pushing distance of the pusher. For different situations of the width of the slab entering the furnace and the width of the slab leaving the furnace, there are the following several effects on the steel pushing distance of the pusher:

[0146] (1) The width of the slab entering the furnace is equal to the width of the slab leaving the furnace

[0147] When the width of the slab entering the furnace is equal to the width of the slab leaving the furnace, it belongs to equal-distance steel pushing. After each steel tapping is completed, a fixed distance equal to the width of the steel slab will be left on the tapping side. When each slab enters the furnace, the pusher only needs to move forward a fixed distance so that the next slab on the tapping side can reach the designated tapping position.

[0148] (2) The width of the slab entering the furnace is less than the width of the slab leaving the furnace

[0149] When the width of the slab entering the furnace is less than the width of the slab leaving the furnace, it belongs to increased-distance steel pushing. Since the slab entering the furnace is narrower than the slab being tapped, after the slab leaves the furnace, the remaining distance on the tapping side will be greater than the width of the slab entering the furnace. When each slab enters the furnace, the pusher needs to increase the stroke to make up for the difference in width between the slab entering and leaving the furnace. After that, the stroke needs to be increased every time a narrow slab is pushed into the furnace.

[0150] (3) The width of the slab entering the furnace is greater than the width of the slab leaving the furnace

[0151] When the width of the slab entering the furnace is greater than the width of the slab leaving the furnace, it belongs to reduced-distance steel pushing. Since the slab entering the furnace is wider than the slab being tapped, after the slab leaves the furnace, the remaining distance on the tapping side will be less than the width of the slab entering the furnace. When each slab enters the furnace, the pusher needs to reduce the stroke to make up for the difference in width between the slab entering and leaving the furnace. After that, the stroke needs to be reduced every time a wide slab is pushed into the furnace.

[0152] Implementation of automatic slab pushing: Some necessary detection components need to be added, including a second laser rangefinder for detecting the real-time position of the slab pusher and a pressure sensor for detecting the oil pressure change in the hydraulic cylinder of the slab pusher. By using the second laser rangefinder to monitor the actual slab pushing distance in real time and the pressure sensor to automatically identify the pressure change from only pushing the slab to be charged into the furnace to pushing all the slabs in the furnace and the pressure change when the slab pusher just starts to retract, and then combining the width of the first slab on the tapping side and the last tapped slab, the influence involved in the slab mixed charging description is solved, and the automatic slab pushing for slabs with different widths in mixed charging is realized.

[0153] Among them, for the second laser rangefinder, to prevent the instrument from being interfered by the complex environment it is in, its installation position needs to be at the rear end of the pushing arm of the slab pusher, and the irradiation point is the rear end head of the pushing arm. The second laser rangefinder needs to convert the position information of the slab pusher into a 4 - 20 mA (milliampere) current signal, and then transmit it to the PLC controller, which quantifies it into the distance between the pusher head of the slab pusher and the preset logical zero position (the extreme retraction limit position of the slab pusher) through program logic; for the pressure sensor, taking advantage of the characteristic that the pressure in the hydraulic cylinder of the slab pusher will change suddenly when pushing all the slabs in the furnace, and combining with the data of the second laser rangefinder to judge the position of the slab pusher and its forward distance at the moment of sudden pressure increase. The pressure sensor also needs to connect the current signal to the PLC controller. To prevent the pressure fluctuation from affecting the program logic judgment, it is necessary to filter the pressure signal.

[0154] The initial stroke of the slab pusher is the maximum stroke when the slab pusher pushes the slab in place, which is measured by the second laser rangefinder when the first slab pushing is completed manually. During the automatic slab pushing process, when there is no slab in the heating furnace, the slab pusher will push the slab with the maximum stroke. When the furnace is about to be filled with slabs, since there is no detection device at the furnace door position on the tapping side and the program logic cannot judge the position of the first slab on the tapping side, the first slab on the tapping side needs to be pushed to the tapping position in manual mode. After manually judging that the slab pushing is in place, the slab pusher retracts manually to the initial position, and the program will automatically latch the maximum stroke when the slab pusher pushes the slab in place according to the signal change of the pressure sensor, which is used for calculating the slab pushing distance in the next slab pushing, so as to realize the automatic slab pushing of the next slab to be charged into the furnace.

[0155] As Figure 5 shown, the logical judgment for realizing automatic slab pushing: When the slab to be charged is positioned on the charging roller table, the program logic sets the signal of the slab positioning completion in front of the furnace. After selecting the automatic mode of the slab pusher in the operation panel, if the furnace meets the slab charging condition, the slab pusher automatically starts the slab pushing and charging sequence.

[0156] (1) First, when the automatic slab pushing starts, it is necessary to request the width of the tapped slab from the MES system first for calculating the maximum stroke of the slab pusher for this slab pushing. After the request is completed, the slab pusher automatically advances to push the slab.

[0157] (2) As Figure 6 shown, when the pressure value of the pressure sensor (pushing steel pressure data) is greater than or equal to the preset pressure processing limit value P5 in the program, the travel of the pusher is latched using the rising edge of this signal. At this time, the travel S2 of the pusher is the travel when the pusher is about to push all the slabs in the furnace. At the same time, the given value of the proportional valve of the pusher is changed, and the pusher slows down to push the steel, which is beneficial to the accurate positioning of the slabs and can also effectively avoid the resonance of the slabs in the furnace during pushing. Figure 6 In it, the horizontal axis is time in seconds, and the vertical axis is pressure in pascals; t1 is the period when the pusher advances without load at startup; p1 is the no-load pressure; t2 is the period when the pusher advances the slab on the front roller table of the furnace; p2 is the pressure for the pusher to push one slab; t3 is the period when the pusher advances all the slabs in the furnace; p3 is the pressure for the pusher to push all the slabs in the furnace; t4 is the period from when the pusher finishes pushing the steel to when it returns to the initial position; p4 is the pressure when the pusher retracts; p5 is the pressure processing critical value (preset pressure processing limit value) in the program.

[0158] (3) As Figure 4 shown, calculate the travel margin of the pusher using ΔS = L3 - S2, and compare the travel margin with the distance that needs to be advanced when pushing the slab to be discharged to the tapping position. The distance from the slab to be discharged to the tapping position is the distance between the centerlines of the last tapped slab and the slab to be discharged. If the remaining distance of the pusher is greater than the distance to push the slab to the tapping position, reset the pusher travel insufficient flag bit, and set the maximum travel of this steel pushing to S2 + (W2 + W3) / 2. Otherwise, set the pusher travel insufficient flag bit, and set the maximum travel of this steel pushing of the pusher to the minimum safe travel L4, so as not to affect the advancing distance of the pusher for the next slab to be pushed. Until the next steel pushing, judge the travel of the pusher again. If the travel of the pusher meets the normal steel pushing distance, reset the flag bit of insufficient pusher travel. When using the minimum safe distance to push the steel, when a sharp increase in pressure is detected during the advancement of the pusher, it indicates that the pusher is about to push the entire furnace of slabs. If the travel of the pusher is greater than the safe travel at this time, the pusher retracting sequence will be directly triggered in the program. During this period, the slabs on the tapping side will not be displaced and will not affect the judgment of the next steel pushing distance.

[0159] (4) The pusher continues to advance to push the steel, and at the same time judge whether the actual travel (actual steel pushing distance) of the pusher and the preset travel (desired steel pushing travel) are within the deviation range, that is, whether the tapped slab has reached the set travel. When the pusher advances to the position, set the given value of the proportional valve of the pusher to zero, and the pusher stops. Otherwise, continue to push the steel at a low speed.

[0160] (5) As Figure 6As shown, it is detected whether the pressure of the pressure sensor is less than the pressure processing limit value P5 in the program. When it is less than the limit value, the falling edge of the signal latches the current stroke S3 of the pusher. The current stroke of the pusher is the stroke when the pusher pushes the slab on the side plate of the steel discharging to the steel discharging position.

[0161] (6) As Figure 4 shown, the program logic judges whether the final stroke S3 of the pusher is greater than L4, that is, whether the pusher has pushed the slab on the front furnace roller table out of the edge of the roller table. If the condition is met, the steel feeding prohibition flag bit of the front furnace roller table is reset, and steel can be pushed normally; otherwise, the flag bit is set, and the next slab is prohibited from entering the front furnace roller table. When the pusher condition is met again, the pusher needs to complete a steel pushing without a newly entered slab, and then judge the pusher stroke again. After the condition is met, the steel feeding prohibition flag bit of the front furnace roller table is reset. After this steel pushing action is completed, the steel loading completion signal sent to the rolling line L2 system needs to be shielded to prevent the furnace internal tracking information from being disordered.

[0162] (7) After the pusher returns to the initial position, the width of W3 is assigned to W2 for calculating the steel pushing distance of the next pusher. The steel pushing completion signal needs to be set for 5s, and at the same time, this signal is sent to the rolling line L2 system for tracking the slab information in the furnace.

[0163] The embodiment of the present invention has the following technical effects: By linking the length of the scheduled slab in the MES system and detecting the actual position of the slab entering the furnace, and comparing it with the preset stop position, the roller table is controlled to decelerate and stop, so as to realize slab positioning and complete automatic slab positioning. A second laser rangefinder for detecting the real-time position of the pusher and a pressure sensor for detecting the oil pressure change in the pusher hydraulic cylinder are added. The displacement and pressure changes are used to judge the steel pushing action and complete the steel pushing sequence. The degree of automatic control of slab charging is improved, manual operation is reduced, and the requirement for the proficiency of operators is lowered; the steel charging and discharging efficiency is improved, and the heating furnace area operates more stably and efficiently; the risk of over-pushing the slab is reduced, and the occurrence of production safety accidents is reduced; it is ensured that the slab discharged on the steel discharging side is in the normal steel discharging area, and the furnace condition is ensured to be stable and smooth.

[0164] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the protection scope of the present disclosure. The appended method claims present the elements of various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy.

[0165] In the foregoing detailed description, various features are combined in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are expressly recited in each claim. On the contrary, as reflected in the appended claims, the invention lies in less than all of the features of the single disclosed embodiment. Accordingly, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0166] The above-described disclosed embodiments are described to enable any person skilled in the art to make or use the present invention. For those skilled in the art, various modifications to these embodiments are obvious, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of the disclosure. Therefore, the disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0167] The foregoing description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but those of ordinary skill in the art should recognize that the various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the manner in which this term is encompassed is similar to the term "including". In addition, any use of the term "or" in the specification or claims is to mean "non-exclusive or".

[0168] Those skilled in the art can also understand that the various illustrative logical blocks, units, and steps listed in the embodiments of the present invention can be implemented by electronic hardware, computer software, or a combination of the two. To clearly show the interchangeability of hardware and software, the above-described various illustrative components, units, and steps have been generally described in terms of their functions. Whether such functions are implemented by hardware or software depends on the specific application and the design requirements of the overall system. Those skilled in the art can use various methods to implement the described functions for each specific application, but such implementation should not be construed as exceeding the scope of protection of the embodiments of the present invention.

[0169] In the embodiments of the present invention, the various illustrative logical blocks or units described can be implemented or operate the described functions through a general-purpose processor, a digital signal processor, an application specific integrated circuit (ASIC), a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of the above designs. The general-purpose processor can be a microprocessor, and optionally, the general-purpose processor can also be any conventional processor, controller, microcontroller or state machine. The processor can also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors combined with a digital signal processor core, or any other similar configuration.

[0170] The steps of the methods or algorithms described in the embodiments of the present invention can be directly embedded in hardware, software modules executed by the processor, or a combination of the two. The software modules can be stored in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM or any other form of storage medium in the art. Exemplarily, the storage medium can be connected to the processor so that the processor can read information from the storage medium and write information to the storage medium. Optionally, the storage medium can also be integrated into the processor. The processor and the storage medium can be provided in an ASIC, and the ASIC can be provided in a user terminal. Optionally, the processor and the storage medium can also be provided in different components of the user terminal.

[0171] In one or more exemplary designs, the functions described in embodiments of the present invention may be implemented in hardware, software, firmware, or any combination of the three. If implemented in software, these functions may be stored on a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. A computer-readable medium includes both computer storage media and communication media that facilitate transfer of a computer program from one place to another. The storage media may be any available media that can be accessed by a general or special purpose computer. For example, such computer-readable media may include, but are not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store program code in the form of instructions or data structures and that can be read by a general or special purpose computer, or a general or special purpose processor. In addition, any connection may be properly defined as a computer-readable medium, for example, if software is transmitted from a website, server, or other remote source via a coaxial cable, fiber optic cable, twisted pair, DSL, or wireless means such as infrared, radio, and microwave, it is also included within the defined computer-readable medium. The disks and discs include compact disks, laser disks, optical disks, DVDs, floppy disks, and Blu-ray disks, disks typically reproduce data magnetically, while discs typically reproduce data optically with a laser. Combinations of the above may also be included within the computer-readable medium.

[0172] The specific embodiments described above have further elaborated on the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An automatic steel charging control method for a pusher-type reheating furnace, characterized in that, including the following steps: Step S1: Determine the incident angle of the first laser rangefinder in advance according to the minimum width and maximum length of all slabs to be pushed into the heating furnace in sequence during production, and install the first laser rangefinder on the side of the front furnace roller table according to the incident angle; Step S2: Monitor the position of the head end face of the slab to be charged into the furnace on the front furnace roller table in real time through the first laser rangefinder to obtain laser ranging data; wherein, the slab to be charged into the furnace is one of multiple slabs with different or the same widths that need to be pushed into the heating furnace in sequence; Step S3: Control the front furnace roller table to decelerate and position the slab to be charged into the furnace according to the laser ranging data and the length of the slab to be charged into the furnace, so that when the slab to be charged into the furnace stops in front of the furnace, the center of the slab to be charged into the furnace is aligned with the center of the furnace door; Step S4: Monitor the actual pushing distance and pushing pressure data of the pusher in real time, and control the sequence of the pusher to complete the automatic charging of the slab to be charged into the furnace according to the actual pushing distance, pushing pressure data, the width of the first slab on the discharging side, and the width of the last discharged slab on the discharging side.

2. The automatic steel charging control method of the pusher-type reheating furnace according to claim 1, characterized in that, The said Step S1 includes: Step S11: When the upper edge of the slab with the minimum width and maximum length is aligned with the upper edge of the front furnace roller table, and the head end face of the slab with the minimum width and maximum length is located at the head deceleration position of the slab with the minimum width and maximum length, determine the position of the lower endpoint of the head end face of the slab with the minimum width and maximum length as the first limit steel detection point; Step S12: When the lower edge of the slab with the minimum width and maximum length is aligned with the lower edge of the front furnace roller table, and the center line of the slab with the minimum width and maximum length is aligned with the center line of the furnace door, determine the position of the upper endpoint of the head end face of the slab with the minimum width and maximum length as the second limit steel detection point; Step S13: Determine the maximum incident angle of the first laser rangefinder according to the following formula: where θ max is the maximum incident angle, in degrees, and is the acute angle between the virtual straight line formed by connecting the first limit steel detection point and the second limit steel detection point and the forward direction of the front furnace roller table; W0 is the minimum width of the slab, in millimeters; W R is the width of the front furnace roller table, in millimeters; L B is the deceleration distance of the slab, in millimeters; Step S14: According to the installation space at the production line site, rotate the virtual straight line with the center point of the connection line between the first limit steel detection point and the second limit steel detection point as the axis to obtain a new virtual straight line, and determine the incident angle of the first laser rangefinder; wherein, the incident angle of the first laser rangefinder is less than or equal to the maximum incident angle of the first laser rangefinder, and is the acute angle formed between the laser ray of the first laser rangefinder and the running direction of the front furnace roller table; Step S15: Under the constraint that the straight-line distance from the first laser rangefinder to the first limit steel detection point is less than the measurement range of the first laser rangefinder, set the first laser rangefinder on the installation space on one side of the upper edge of the front furnace roller table along the new virtual straight line according to the incident angle.

3. The automatic steel charging control method of the pusher-type reheating furnace according to claim 1, wherein, The said Step S2 includes: Calculate the laser ranging data according to the following formula: S0 = L1 * cosθ wherein, S0 is the laser ranging data, in millimeters; L1 is the straight-line distance from the head of the slab to be charged into the furnace directly measured by the first laser rangefinder to the first laser rangefinder, in millimeters; θ is the incident angle of the first laser rangefinder, in degrees.

4. The automatic steel charging control method of the pusher-type reheating furnace according to claim 1, characterized in that, The said Step S3 includes: Step S31: Determine the head stop position distance of the slab to be charged into the furnace according to the following formula: where S1 is the head stop position distance, which is the vertical distance from the head of the slab to the first laser rangefinder when the center of the slab to be charged into the furnace stops on the front furnace roller table in a way that aligns with the center of the furnace door, with the unit of millimeters; L2 is the vertical distance from the center line of the furnace door of the heating furnace to the first laser rangefinder, with the unit of millimeters; L0 is the length of the slab to be charged into the furnace obtained from the production operation plan, with the unit of millimeters; l1 is a preset offset used to compensate for measurement errors, with the unit of millimeters; Step S32: Add the head stop position distance of the slab to be charged into the furnace to the slab deceleration distance to obtain the head deceleration position distance of the slab to be charged into the furnace; Step S33: During the process of the slab to be charged into the furnace running on the front furnace roller table, compare the laser ranging data with the head deceleration position distance and compare the laser ranging data with the head stop position distance in real time; Step S34: If the laser ranging data is less than the head deceleration position distance, reduce the running speed of the front furnace roller table to 10% of the original speed to convey the slab to be charged into the furnace at a low speed; where the original speed is the speed of the front furnace roller table during the period when the laser ranging data is greater than the head deceleration position distance; Step S35: If the absolute value of the difference between the laser ranging data and the head stop position distance is less than 10 millimeters, control the front furnace roller table to stop running and set the slab positioning completion flag; where the slab positioning completion flag will be reset after the pusher steel step is completed; where the slab deceleration distance is the distance obtained by integrating the speed of the front furnace roller table during the period when the speed of the front furnace roller table decelerates to 0 under the condition that there is no relative sliding between the slab and the surface of the front furnace roller table.

5. The automatic steel charging control method for the pusher-type reheating furnace according to claim 1, characterized in that, The said Step S4 includes: Step S41: During the process of the pusher steel machine pushing steel, compare the size of the real-time monitored pusher steel pressure data and the preset pressure processing limit value; Step S42: If the pusher steel pressure data is greater than or equal to the preset pressure processing limit value, take the actual pusher steel distance of the pusher steel machine obtained by the current real-time monitoring as the first pusher steel distance; Step S43: Subtract the first pusher steel distance from the rated maximum stroke of the pusher steel machine to obtain the pusher steel machine stroke margin; Step S44: Determine the center line distance between the first slab on the tapping side and the previous slab on the tapping side according to the width of the first slab on the tapping side and the width of the previous slab on the tapping side; Step S45: Determine the expected pusher steel stroke of the pusher steel machine during the pusher steel process of the slab to be charged into the furnace according to the pusher steel machine stroke margin and the center line distance; Step S46: During the process of the pusher steel machine continuing to push steel, judge in real time whether the deviation between the actual pusher steel distance and the expected pusher steel stroke is within the preset pusher steel in-place deviation range; Step S47: If it is judged that the deviation between the actual pusher steel distance and the expected pusher steel stroke is within the preset pusher steel in-place deviation range, set the pusher steel machine proportional valve setting to zero, stop the pusher steel machine from pushing steel, and retract it to the initial position.

6. The automatic steel charging control method for the pusher-type reheating furnace according to claim 5, characterized in that, The said Step S45 includes: Compare the pusher steel machine stroke margin with the center line distance; When the stroke margin of the pusher is greater than or equal to the center line distance, reset the pusher stroke insufficient flag bit, and set the expected pusher stroke during the pusher of the slab to be charged into the furnace as the sum of the first pusher distance and the center line distance; When the stroke margin of the pusher is less than the center line distance, set the pusher stroke insufficient flag bit, and set the maximum pusher stroke during the pusher of the slab to be charged into the furnace as the minimum safe pusher stroke; Among them, the minimum safe pusher stroke is the stroke when the pusher just pushes the slab out of the front furnace roller table.

7. The automatic steel charging control method for the pusher-type reheating furnace according to claim 5, characterized in that, The step S4 further includes: In response to the pusher pressure data being less than the preset pressure processing limit value, use the actual pusher distance of the pusher obtained by real-time monitoring as the second pusher distance; Judge whether the second pusher distance is greater than the minimum safe pusher stroke; If it is judged that the second pusher distance is greater than the minimum safe pusher stroke, reset the front furnace roller table steel feeding prohibition flag bit, otherwise set the front furnace roller table steel feeding prohibition flag bit; Among them, the minimum safe pusher stroke is the stroke when the pusher just pushes the slab out of the front furnace roller table.

8. The automatic steel charging control method for the pusher-type reheating furnace according to claim 5, characterized in that, The step S4 further includes: When the pusher returns to the initial position, set the pusher completion signal for 5 seconds, and at the same time send this signal to the rolling line L2 system, and reset the pusher completion signal after 5 seconds.

9. The automatic steel charging control method for a pusher-type reheating furnace according to claim 1, wherein The method further includes: Real-time monitor the actual pusher distance of the pusher through a second laser rangefinder set at the rear end of the pusher arm of the pusher and with the irradiation point being the rear end head of the pusher arm.

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