Heating furnace tapping rolling rhythm control method

Abstract

The invention belongs to the technical field of steel smelting, and particularly relates to a heating furnace tapping rolling rhythm control method. Comprising the following steps that (1) a hot metal detector B2 is installed at an inlet of a first rolling mill, the head and the tail of adjacent steel billets are detected in real time, and the actual gap time delta T between the adjacent steel billets is calculated; (2) setting a reference tapping period T0 to be 38.2 seconds and a steel billet gap standard value delta Ts to be 24 seconds; and (3) correcting the tapping period Tn + 1 of the next steel billet according to a linear correction algorithm when the deviation between the actual gap time deltaT and the deltaTs is detected. Through a linear dynamic correction algorithm, 80%-100% of gap deviation can be offset through single correction, the accumulated error is smaller than + / -1 second after continuous operation for 2 hours, the fluctuation of the tapping period is reduced to 37.9-38.5 seconds (the fluctuation amplitude is 0.6 second) from 3.8-6.8 seconds (the fluctuation amplitude is 3.0 seconds) of a traditional mode, and the stability is improved by 80%.

Description

Technical Field

[0001] The invention belongs to the technical field of steel smelting, and in particular relates to a method for controlling the steel tapping and rolling rhythm of a heating furnace. Background Art

[0002] The steel-tapping rhythm of a traditional heating furnace is triggered and started by the hot metal detector H2 at the furnace mouth of the heating furnace according to the steel-tapping cycle set on the screen. Due to the influence of factors such as the shape of the steel billet, the mechanical properties of the steel billet, the friction coefficient of the roller, the weight and length of the steel billet, and the change in friction when biting into the rolling mill, the actual steel-tapping rhythm has errors. With continuous rolling, the accumulated errors become larger and larger, resulting in the instability of the steel-tapping rhythm. The interval time has been fluctuating between 3.8 seconds and 6.8 seconds, which seriously affects the rolling rhythm and reduces production.

[0003] In addition, due to the different gaps and lengths of billets, the speed reduction signal is unstable, resulting in the No. 1 and No. 2 rolling mills not reducing speed or reducing speed in advance, both of which have the risk of steel accumulation. Summary of the invention

[0004] The purpose of the present invention is to provide a method for controlling the steel rolling rhythm of a heating furnace to solve the problems existing in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A method for controlling the steel-rolling rhythm of a heating furnace comprises the following steps:

[0007] (1) Install a hot metal detector B2 at the entrance of the No. 1 rolling mill to detect the heads and tails of adjacent billets in real time and calculate the actual gap time ΔT between adjacent billets;

[0008] (2) The benchmark steel tapping cycle T0 is set to 38.2 seconds and the standard value of the billet gap ΔTs is set to 24 seconds;

[0009] (3) When a deviation between the actual gap time ΔT and ΔTs is detected, the next billet tapping cycle T is corrected according to the linear correction algorithm. n+1 ;

[0010] (4) Based on the revised steel-making cycle T n+1 , control the steel tapping triggering time of the heating furnace discharge roller;

[0011] (5) When the cantilever roller starts to discharge steel and the furnace mouth hot metal detector H2 detects the tail of the billet, the stepping beam is triggered to move, causing the next billet to fall into the cantilever roller 3 seconds in advance.

[0012] Furthermore, the linear correction algorithm is:

[0013] T n+1= Tn + k×(ΔTs - ΔTn)

[0014] Wherein, T n+1 is the corrected next tapping cycle, Tn is the current tapping cycle, k is the correction coefficient, 0.5 ≤ k ≤ 1, ΔTn is the actual gap deviation value detected at the nth time, and ΔTs is the standard billet gap time.

[0015] Furthermore, the correction coefficient k is dynamically adjusted according to the billet length L:

[0016] When the billet length L ≤ 10m, k = 0.5;

[0017] When 10m < L ≤ 15m, k = 0.7;

[0018] When L > 15m, k = 1.0.

[0019] Furthermore, the triggering conditions for the walking beam movement include:

[0020] After the cantilever roller table starts tapping, the delay time detected by H2 at the tail of the billet is (T n+1 - 3) seconds;

[0021] The positioning error of the walking beam transferring the billet to the cantilever roller table is controlled within ±0.2 seconds.

[0022] Furthermore, it also includes:

[0023] According to the deviation value between the billet gap ΔT detected by B2 and ΔTs, generate a hierarchical speed reduction signal for the No. 1 rolling mill and the No. 2 rolling mill:

[0024] When ΔT < ΔTs, send an early speed reduction instruction to the No. 1 rolling mill, and the early amount of speed reduction time is (ΔTs - ΔT) × 0.5 seconds;

[0025] When ΔT > ΔTs, send a delayed speed reduction instruction to the No. 1 rolling mill, and the delayed amount of speed reduction time is (ΔT - ΔTs) × 0.3 seconds;

[0026] The time interval between the speed reduction signals of the No. 2 rolling mill and the No. 1 rolling mill is fixed at 2.5 seconds.

[0027] Furthermore, the calculation method of the actual gap time ΔT is: when the end moment of the tail signal of the previous billet detected by B2 is T1 and the start moment of the head signal of the next billet is T2, ΔT = T2 - T1;

[0028] Calculation accuracy requirement: The measurement error of ΔT ≤ 0.05 seconds.

[0029] The present invention has the following beneficial effects:

[0030] 1. The present invention uses a linear dynamic correction algorithm, and a single correction can offset 80%-100% of the gap deviation. The cumulative error after continuous operation for 2 hours is <±1 second. The fluctuation of the steel-making cycle is reduced from 3.8 to 6.8 seconds (fluctuation range 3.0 seconds) in the traditional mode to 37.9 to 38.5 seconds (fluctuation range 0.6 seconds), and the stability is improved by 80%.

[0031] 2. After the steel-making cycle is precisely controlled, the idling waiting time of the rolling mill is reduced, the effective operating rate is increased from 72% to 89%, and the hourly output is increased by 18% to 22% (taking a production line with an annual output of 1 million tons as an example, the annual output of steel is increased by 160,000 to 200,000 tons).

[0032] 3. The accident rate of steel piling dropped from 2.5 times / month to 0.1 times / month, the fault handling time was reduced by 90%, and the annual production benefit was approximately 12 million yuan (calculated based on a profit of 600 yuan per ton of steel).

[0033] 4. The trigger time error of the walking beam action is reduced from ±1.5 seconds to ±0.2 seconds, and the cantilever roller breakage rate is reduced from 8% to 0.5%, reducing the annual scrap steel loss by about 500 tons (based on the cost of 3,000 yuan per ton of steel, saving 1.5 million yuan).

[0034] 5. The synchronization error of the speed reduction signal between rolling mill No. 1 and rolling mill No. 2 is ≤0.1 second (±0.8 second in the traditional mode), the rolling speed matching degree is improved by 87%, and the success rate of the head biting of the rolled piece is increased from 92% to 99.8%.

[0035] 6. The adaptability range of billet length is 6m to 25m (the traditional method only supports 8m to 18m); through dynamic adjustment of the correction coefficient k (short billet k = 0.5, long billet k = 1.0), the gap control error of billets of different lengths is ≤ ± 0.5 seconds.

[0036] 7. In response to interferences such as roller slippage and temperature fluctuations, the system automatically completes cycle correction within 10 seconds, and the anti-disturbance response speed is 20 times faster than the manual intervention mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the installation of the hot metal detector B2 of the present invention.

[0038] Figure 2 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] Example 1

[0041] Installation of hot metal detector B2: The hot metal detector H2 at the outlet of the heating furnace is retained. The detection range covers the full width of the roller table, with an accuracy of ±0.05 seconds, and communicates with the PLC controller via Profibus-DP. The hot metal detector B2 is installed 5 meters from the entrance side of the No. 1 rolling mill. It uses an infrared scanning detection head with a sampling frequency of 100Hz, which can identify the minimum interval between the head and tail of the billet of 0.1 seconds.

[0042] The actuators include: a stepping beam drive system, driven by a servo motor, with a positioning accuracy of ±1mm, a response time of ≤0.2 seconds, and synchronous control with the PLC through ETherCAT. The frequency converter for the furnace roller table has a power of 55kW, a speed control range of 0.1-2.5m / s, and a speed fluctuation rate of <0.5%. In the control system architecture: the main controller is a Siemens S7-1500PLC, which integrates a PID control module to process the detection signals of B2 and H2 in real time; the human-machine interface (HMI) is a WinCC host computer, which displays real-time steelmaking cycle, gap deviation, rolling mill speed curve and alarm information.

[0043] Embodiment 2:

[0044] Taking the rolling control of a standard steel billet (length 12m, weight 20 tons) as an example, the following steps are performed:

[0045] 2.1 Initial parameter settings: standard steel tapping cycle T0 = 38.2 seconds, standard gap ΔTs = 24 seconds, correction coefficient k = 0.7 (k = 0.7 for a length of 12m). The initial speed of the No. 1 rolling mill is set to 1.8m / s, and the initial speed of the No. 2 rolling mill is set to 2.0m / s.

[0046] The correction factor k is defined as a proportional coefficient between 0 and 1 (usually 0.5≤k≤1), which is used to control the correction amplitude. When k=1, the current deviation is fully compensated (aggressive correction, which may cause system oscillation); when k=0.5, partial compensation (conservative correction, suitable for high fluctuation conditions); it can be adaptively adjusted according to the length of the billet or the working condition (for example, k=1 for long billets and k=0.5 for short billets).

[0047] 2.2 Billet gap detection and periodic correction

[0048] Billet 1: B2 detects that the billet head arrives at time T1 = 10:00:00 and the tail leaves at time T2 = 10:00:24.5 (actual gap ΔT1 = 24.5 seconds). Deviation calculation: ΔT1-ΔTs = +0.5 seconds.

[0049] Corrected steel-making cycle: T1=38.2+0.7×(24-24.5)=38.2-0.35=37.85 seconds.

[0050] The second billet: the tapping was triggered at T1 = 37.85 seconds, and B2 detected ΔT2 = 23.8 seconds (deviation -0.2 seconds).

[0051] Correction period: T2 = 37.85 + 0.7 × (24-23.8) = 37.85 + 0.14 = 37.99 seconds.

[0052] 2.3 Timing control of stepping beam motion

[0053] When H2 detects the tail of the first billet (time stamp 10:00:25.0), the walking beam is started after a delay of (T1-3)=37.85-3=34.85 seconds to transfer the second billet to the cantilever roller, with a placement time error of ≤±0.2 seconds.

[0054] 2.4 Rolling mill graded speed reduction control

[0055] The first billet enters the No. 1 rolling mill: ΔT1 = 24.5 seconds (> ΔT s ), the speed reduction delay of No. 1 rolling mill = (24.5-24) × 0.3 = 0.15 seconds, that is, the original speed reduction time is delayed by 0.15 seconds. The speed reduction signal of No. 2 rolling mill is triggered 2.5 seconds after the speed reduction of No. 1 rolling mill to ensure speed matching.

[0056] In the prior art, the steel-out cycle fluctuates in the range of 3.8-6.8 seconds, and the cumulative error after 30 minutes reaches ±15 seconds; after the present invention is corrected, the cycle fluctuation range is 37.8-38.6 seconds (±0.4 seconds), and the cumulative error after running for 2 hours is less than ±1 second. The steel pile accident rate is reduced from 2.5% to 0.1%; after the rolling rhythm is stabilized, the hourly output is increased by 18% (from 120 tons / hour to 142 tons / hour).

[0057] Embodiment 3:

[0058] This embodiment is a control example when an abnormal working condition occurs, including control when the length of the steel billet changes suddenly and an emergency response example for detector failure.

[0059] 3.1 The length of the billet changes suddenly, taking the control of alternating 15m long billets and 10m short billets as an example.

[0060] Long billet (15m) control: correction coefficient k = 1.0 (aggressive correction when length > 15m). If ΔT = 25 seconds, the correction amount = 1.0 × (24-25) = -1 second, and the steel-making cycle is shortened by 1 second.

[0061] The advance amount of speed reduction of No. 1 rolling mill = (24-25) × 0.5 = -0.5 seconds (i.e. a delay of 0.5 seconds).

[0062] Short billet (10m) control: k = 0.5 (conservative correction), if ΔT = 23 seconds, correction amount = 0.5 × (24-23) = + 0.5 seconds, the steel-out cycle is extended by 0.5 seconds. The speed of the No. 1 rolling mill is reduced by 0.5 seconds in advance to avoid short billets from piling up due to excessive speed.

[0063] 3.2 Emergency response to detector failure

[0064] B2 signal loss: Automatically switch to H2 signal to estimate the gap time (ΔT≈T n -Fixed transmission time 14 seconds), and trigger an alarm to prompt manual intervention. 3 consecutive times of ΔT deviation > 2 seconds: The system automatically resets to T0 = 38.2 seconds, and displays "Cycle abnormality, it is recommended to check roller wear" on the HMI.

[0065] The above-described embodiments are merely descriptions of preferred implementations of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solution of the present invention should all fall within the scope of protection of the present invention.

[0066] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. A method for controlling the steel rolling rhythm of a heating furnace, characterized in that: It includes the following steps: (1) Install a hot metal detector B2 at the entrance of No. 1 rolling mill to detect the head and tail of adjacent billets in real time, and calculate the actual gap time ΔT between adjacent billets; (2) Set the reference tapping cycle T0 to 38.2 seconds and the standard value of billet gap ΔTs to 24 seconds; (3) When a deviation between the actual gap time ΔT and ΔTs is detected, the next billet tapping cycle T is corrected according to the linear correction algorithm. n+1 ; (4) Based on the revised steel-making cycle T n+1 , control the steel tapping triggering time of the heating furnace discharge roller; (5) When the cantilever roller table starts tapping and the hot metal detector H2 at the furnace mouth detects the tail of the billet, trigger the walking beam action to make the next billet fall onto the cantilever roller table 3 seconds in advance.

2. The method for controlling the steel-tapping rolling rhythm of a heating furnace according to claim 1, characterized in that: The formula of the linear correction algorithm is: T n+1 =Tn+k×(ΔTs-ΔTn) Among them, T n+1 is the next steel-making cycle after correction, Tn is the current steel-making cycle, k is the correction coefficient, 0.5≤k≤1, ΔTn is the actual gap deviation value detected for the nth time, and ΔTs is the standard billet gap time.

3. The method for controlling the steel-tapping rolling rhythm of a heating furnace according to claim 2, characterized in that: The correction coefficient k is dynamically adjusted according to the billet length L: When the billet length L ≤ 10m, k = 0.5; When 10m < L ≤ 15m, k = 0.7; When L > 15m, k = 1.

0.

4. The method for controlling the steel-tapping rolling rhythm of a heating furnace according to claim 2, characterized in that: The triggering conditions of the walking beam action include: After the cantilever roller starts to tap steel, the delay time for H2 to detect the tail of the billet is T n+1 -3 seconds; The positioning error of the walking beam transferring the billet to the cantilever roller table is controlled within ±0.2 seconds.

5. The method for controlling the steel-tapping rolling rhythm of a heating furnace according to claim 2, characterized in that: It also includes: Generate a hierarchical speed reduction signal for No. 1 rolling mill and No. 2 rolling mill according to the deviation value between the billet gap ΔT detected by B2 and ΔTs: When ΔT < ΔTs, send an early speed reduction instruction to No. 1 rolling mill, and the early amount of speed reduction time is (ΔTs - ΔT) × 0.5 seconds; When ΔT > ΔTs, send a delayed speed reduction instruction to No. 1 rolling mill, and the delayed amount of speed reduction time is (ΔT - ΔTs) × 0.3 seconds; The time interval between the speed reduction signals of No. 2 rolling mill and No. 1 rolling mill is fixed at 2.5 seconds.

6. The method for controlling the steel-tapping and rolling rhythm of a heating furnace according to claim 2, characterized in that: The calculation method of the actual gap time ΔT is: when the end time of the tail signal of the previous billet detected by B2 is T1 and the start time of the head signal of the next billet is T2, ΔT = T2 - T1; Calculation accuracy requirement: the measurement error of ΔT ≤ 0.05 seconds.

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