Control type cooling method for three-way valves between finishing mill groups

Abstract

The invention discloses a three-way valve control type cooling method among finishing mill groups, which is characterized in that inter-machine cooling water paths independent of roller box panel cooling water paths are arranged among the finishing mill groups, and three-way valves are mounted on the inter-machine cooling water paths; the starting action triggering logic of the three-way valve comprises the following steps: receiving a rolled piece steel signal detected by an upstream pre-finish rolling last frame; and in combination with the speed v of the rolled piece, the distance L from the steel signal detection point to the cooling water injection point and the compensation length D of the head of the rolled piece, according to the formula T = (L / v) + delta t and delta t = D / v, the set delay T is calculated, and the three-way valve is opened after the set delay T. In this way, the three-way valve is driven to be opened by setting time delay, cooling water is opened after the tip end of the head of a rolled piece passes through a cooling injection point and when a head body reaches the cooling injection point, an inter-machine cooling water channel independent of a roller box panel cooling water channel is arranged between finishing mill groups, and the cooling effect of original roller box panel cooling water on a roller ring rolling groove cannot be affected; and the temperature rise of the rolled piece during high-speed finish rolling is better controlled.

Description

Technical Field

[0001] The invention relates to the technical field of steel rolling production, in particular to a three-way valve controlled cooling method between finishing mill groups. Background Art

[0002] Modern industrial production is gradually becoming faster and faster. In particular, the production of wire rods has been increased from 40m / s in the past to 120m / s through the finishing mill. However, high-speed rolling will cause the temperature of the rolled piece to rise (generally, the temperature rise is above 100°C). In order to reasonably control the phase change range of the metal and reduce the cooling pressure after rolling, inter-machine cooling water is added between the finishing mills to control the rolling temperature rise of the finishing mills.

[0003] The original inter-machine cooling water was directly connected to the cooling water of the roll box panel for the sake of design simplicity. The advantage of this solution is that it effectively reduces the complexity of the equipment and reduces equipment costs. The disadvantage is that the inter-machine cooling water is directly connected in series with the cooling water circuit of the roll box panel, which ultimately leads to an increase in the end water use points, which can easily cause the water pressure of the roll ring cooling water to drop, resulting in increased wear of the rolling groove; and the unit panel cooling water must be in a long-open state, which can easily cause the head of the rolled piece to pass through the high-pressure water flow and produce blackheads. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a three-way valve controlled cooling method between finishing mill groups, which changes the cooling form that has always relied on taking water from the unit panel and keeping it open for a long time, and solves the problem that the cooling water between the finishing mill groups strengthens the cooling of the rolled piece head and easily causes slagging of the rolled piece, resulting in abnormal damage to the guide and guard, steel piling, and equipment abnormality caused by increased rolling load.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a three-way valve controlled cooling method between finishing mill groups, comprising:

[0006] An inter-machine cooling water circuit independent of the roll box panel cooling water circuit is set between each finishing rolling unit, and a three-way valve is installed on the inter-machine cooling water circuit;

[0007] The opening action triggering logic of the three-way valve:

[0008] Receive the steel signal from the upstream pre-finishing rolling stand;

[0009] Combined with the workpiece speed v, the distance L from the steel signal detection point to the cooling water injection point, and the workpiece head compensation length D, the set delay T is calculated according to the formula T=(L / v)+Δt, Δt=D / v, and the three-way valve is opened after the set delay T.

[0010] As a further improvement of the present invention: further comprising:

[0011] Combined with the water pressure fluctuation data, the delay T is set.

[0012] The correction formula is: T = (L / v) + Δt-k, where k is the water pressure fluctuation compensation coefficient, which is used to compensate for the water path response delay. k>0, an increase in the k value reduces T, and the valve opens earlier.

[0013] As a further improvement of the present invention: the dynamic adjustment rule of the k value is:

[0014] A pressure sensor is installed at the inlet of the cooling water channel between machines to collect P1 in real time;

[0015] Dynamically adjust the water pressure P0 according to the specifications of the rolled piece: P0 for small-sized rolled pieces> P0 for large-sized rolled pieces, and calculate the water pressure deviation P=|P0-P1|;

[0016] When the water pressure deviation P is greater than the set pressure threshold, the k value increases, which reduces the set delay T and opens the valve in advance to compensate for the response delay caused by insufficient water pressure.

[0017] When the water pressure deviation P is less than the set pressure threshold, the k value is reset to the reference value.

[0018] As a further improvement of the present invention: the compensation length D of the rolled piece head ≥ the length of the high-temperature zone of the rolled piece head + the cooling water spray coverage error tolerance.

[0019] As a further improvement of the present invention: the water inlet of the valve body of the three-way valve is connected to an independent high-pressure water source pipe through a flange, the first water outlet of the three-way valve is connected to the machine room cooling nozzle through a quick-release joint, and the second water outlet of the three-way valve is connected to the cooling water return main through a pressure reducing valve; an electromagnetic drive module is integrated on the top of the valve body and is directly connected to the signal line of the control unit.

[0020] As a further improvement of the present invention: the three-way valve closing control includes:

[0021] Upon receiving a signal that the tail of the workpiece has left the final stand of the pre-finishing rolling mill, the closing delay Tc = (L0 / v) + ΔT is calculated based on the workpiece length L0 and the workpiece speed v;

[0022] Wherein, L0 is the distance from the tail detection point to the injection point, ΔT is the safety cooling margin time, and ΔT ≥ 50ms.

[0023] As a further improvement of the present invention: when the speed of the rolled piece suddenly exceeds a threshold value, the emergency control mode is activated:

[0024] If the speed drops suddenly, immediately close the three-way valve and enable roll gap air cooling compensation;

[0025] If the speed suddenly increases, the delay T is dynamically shortened based on the speed change rate Δv / v:

[0026] T'=T×(1-β·Δv / v), where β is the emergency correction coefficient (0.5≤β≤0.8).

[0027] As a further improvement of the present invention: further comprising:

[0028] Different head compensation length D reference values ​​are set for different steel grades, where:

[0029] The D reference value of high carbon steel is greater than the D reference value of low carbon steel;

[0030] The D reference value of alloy steel is greater than the D reference value of ordinary carbon steel.

[0031] As a further improvement of the present invention: the reference value setting rule of the water pressure fluctuation compensation coefficient k is:

[0032] When the rolling speed v ≥ 100m / s, the k reference value = 0.05s;

[0033] When 50m / s≤v<100m / s, k reference value = 0.03s;

[0034] When v is less than 50 m / s, the k reference value is 0.01 s.

[0035] As a further improvement of the present invention, a temperature feedback signal of the rolled piece at the final stand of the pre-finishing rolling mill is also received. If it is detected that the real-time temperature rise exceeds a temperature rise threshold, the water pressure is increased or the cooling time is extended.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention sets up an inter-machine cooling water circuit between the finishing mill groups that is independent of the roll box panel cooling water circuit, which does not affect the cooling effect of the original roll box panel cooling water on the roll ring rolling groove. Combined with the speed of the rolled piece, the distance from the steel signal detection point to the cooling water injection point and the compensation length of the rolled piece head, the set delay time for the opening of the three-way valve is calculated, and the cooling form of taking water from the unit panel for a long time is cancelled, so as to better control the temperature rise of the rolled piece during high-speed finishing rolling, and solve the problem that the rolled piece is prone to slagging after the cooling water between the finishing mills strengthens the cooling of the rolled piece head. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the process of the present invention.

[0039] Figure 2 It is a logical schematic diagram of the present invention.

[0040] Figure 3 It is a structural schematic diagram of the inter-machine cooling water circuit of the present invention.

[0041] Figure 4 Programming for the three-way cooling water in the machine room. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] It should be noted that relational terms such as "first" and "second" in the specification and claims of this application and the above-mentioned drawings are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0044] In order to solve the technical problems in the prior art, the present invention is further described with reference to the accompanying drawings and embodiments:

[0045] like Figure 1 and Figure 2 As shown, the present invention discloses a three-way valve controlled cooling method between finishing rolling mill groups, including: connecting independent inter-machine cooling water circuits between each finishing rolling mill group, the inter-machine cooling water circuit is separated from the roll box panel cooling water circuit, a three-way valve is installed on the inter-machine cooling water circuit, and the inter-machine cooling water circuit connects the cooling units between each unit.

[0046] By setting up an inter-machine cooling water circuit between the finishing mills, independent of the roll box panel cooling water circuit, and controlling it with a three-way valve, the three-way valve receives a steel signal from an upstream stand (the last stand in the pre-finishing rolling mill, where the main control room can adjust the water supply speed through delay settings) and then sends water to the cooling unit between the mills. This effectively reduces the temperature rise during high-speed rolling while effectively avoiding a sharp drop in the head. Ultimately, it reduces the water cooling pressure after rolling, achieving speed increases and improving head performance.

[0047] The opening action trigger logic of the three-way valve:

[0048] Receive the steel signal from the upstream pre-finishing rolling stand;

[0049] Combined with the workpiece speed v, the distance L from the steel signal detection point to the cooling water injection point, and the workpiece head compensation length D, the set delay T is calculated according to the formula T=(L / v)+Δt, Δt=D / v, and the three-way valve is opened after the set delay T.

[0050] The set delay time of the three-way valve opening is T = (L / v) + (D / v), where:

[0051] L / v: The theoretical time for the steel signal to be transmitted to the injection point;

[0052] D / v: Compensates for the extra time required for the tip of the head to pass;

[0053] Define the head compensation length D to avoid defects caused by insufficient cooling or excessive coverage in the high-temperature area. Set different head compensation length D reference values ​​for different steel grades, where:

[0054] The D reference value of high carbon steel is greater than the D reference value of low carbon steel;

[0055] The D reference value of alloy steel is greater than the D reference value of ordinary carbon steel.

[0056] The three-way valve opening delay is dynamically calculated based on real-time upstream position signals from the workpiece, combined with the workpiece linear speed, the distance from the steel signal detection point to the cooling water injection point, and the compensation length of the workpiece head. After the set delay T, the three-way valve opens, allowing the tip of the workpiece head to pass through the cooling water injection point and the main body of the workpiece head to reach the cooling water injection point, thus completing the water flow coverage and preventing the tip from directly impacting the high-pressure water flow.

[0057] Furthermore, the water inlet of the three-way valve body is connected to an independent high-pressure water source pipe through a flange, the first water outlet of the three-way valve is connected to the inter-machine cooling nozzle through a quick-release joint, and the second water outlet of the three-way valve is connected to the cooling water return main through a pressure reducing valve; the electromagnetic drive module is integrated on the top of the valve body and is directly connected to the control unit signal line.

[0058] In some embodiments, the method further includes: correcting and setting the delay T in combination with the water pressure fluctuation data,

[0059] The correction formula is: T = (L / v) + Δt-k, where k is the water pressure fluctuation compensation coefficient, which is used to compensate for the water path response delay. k>0, an increase in the k value reduces T, and the valve opens earlier.

[0060] The opening and closing of the inter-machine cooling water circuit is dynamically controlled by a three-way valve. Specifically, the three-way valve is triggered by a steel signal from the final stand of the pre-finishing mill. After a set delay, T, the valve is driven open, allowing cooling water to flow after the tip of the rolled piece passes the cooling spray point and the main body of the head reaches the cooling spray point. A water pressure fluctuation compensation coefficient, k (k>0), is introduced to offset valve response delays and ensure stable water flow when the main body of the head arrives.

[0061] The k value is dynamically adjusted and optimized in real time based on water pressure fluctuations to resolve control failures caused by traditional valve response delays and avoid incorrect cooling of the head tip due to water pressure fluctuations.

[0062] The control logic is refined into the timing goal of "opening after the head tip passes + covering when the head body arrives", and the dynamic algorithm (D, k) is bound to the physical parameters of water pressure to solve the problem of premature water opening → rapid cooling and chipping of the head, and delayed water opening → uncontrolled temperature rise.

[0063] Specifically, through T=(L / v)+(D / v)-k, the timing of water boiling is accurately controlled between the tip of the head and the main body of the head; D is defined as a physical compensation parameter (non-fixed value) to meet the condition that the compensation length of the rolled piece head D ≥ the length of the high-temperature zone of the rolled piece head + the cooling water spray coverage error tolerance.

[0064] Furthermore, the dynamic adjustment rule of the k value is:

[0065] A pressure sensor is installed at the inlet of the cooling water channel between machines to collect P1 in real time;

[0066] Dynamically adjust the water pressure P0 according to the specifications of the rolled piece: P0 for small-sized rolled pieces> P0 for large-sized rolled pieces, and calculate the water pressure deviation P=|P0-P1|;

[0067] When the water pressure deviation P is greater than the set pressure threshold, the k value increases, which reduces the set delay T and opens the valve in advance to compensate for the response delay caused by insufficient water pressure.

[0068] When the water pressure deviation P is less than the set pressure threshold, the k value is reset to the reference value.

[0069] Furthermore, the benchmark value setting rule of the water pressure fluctuation compensation coefficient k is:

[0070] When the rolling speed v ≥ 100m / s, the k reference value = 0.05s;

[0071] When 50m / s≤v<100m / s, k reference value = 0.03s;

[0072] When v is less than 50 m / s, the k reference value is 0.01 s.

[0073] Dynamically adjust the k value to meet the water pressure requirements of rolled products of different specifications, ensure stability under high-speed rolling, set the speed-graded k value, and optimize the control accuracy in different speed ranges.

[0074] In some embodiments, a temperature feedback signal of the rolled piece at the final stand of the pre-finishing rolling mill is also received. If it is detected that the real-time temperature rise exceeds a temperature rise threshold, the water pressure is increased or the cooling time is extended.

[0075] In some embodiments, the closing sequence of the three-way valve satisfies:

[0076] Based on the signal that the tail of the rolled piece leaves the pre-finishing rolling stand, based on the rolled piece length L0 and the rolled piece speed v, the closing delay time Tc=(L0 / v)+ΔT is calculated;

[0077] Among them, L0 is the distance from the tail detection point to the injection point, ΔT is the safe cooling margin time, ΔT ≥ 50ms, which is used to ensure that the three-way valve is closed after the tail of the rolled piece has completely passed through the cooling area.

[0078] Add the timing control of tail signal → Tc calculation → valve closing, and the tail delayed closing mechanism ensures uniform cooling of the entire length of the rolled piece, and ΔT prevents premature water shut-off.

[0079] The three-way valve adopts two-stage opening control:

[0080] Before the head of the rolled piece arrives: open the preheating pipeline at 30-40% flow rate;

[0081] Arrival of the main body of the rolled piece: fully open the valve after the set delay T.

[0082] When the three-way valve is closed, gradual pressure reduction is performed: the flow rate is reduced from 100% to 30% and maintained for 2 seconds before closing. The closing time is earlier than the time when the tail of the rolled piece leaves the cooling zone.

[0083] In some embodiments, a speed mutation emergency treatment is provided to prevent steel accumulation or insufficient cooling accidents. When the speed of the rolled piece suddenly exceeds a threshold, an emergency control mode is activated:

[0084] If the speed drops suddenly, immediately close the three-way valve and enable roll gap air cooling compensation;

[0085] If the speed suddenly increases, the delay T is dynamically shortened based on the speed change rate Δv / v:

[0086] T'=T×(1-β·Δv / v), where β is the emergency correction coefficient (0.5≤β≤0.8).

[0087] In practical applications, such as Figure 3 and Figure 4 As shown, a separate high-pressure water line is now connected between each finishing mill unit and controlled by a three-way valve. The principle is: the three-way valve receives a steel signal from an upstream stand (the last stand in pre-finishing rolling, where the main control room can adjust the water supply speed through delay settings) and then sends water to the cooling unit between the mill units. This effectively reduces the temperature rise during high-speed rolling while effectively avoiding a sharp drop in the head. Ultimately, this reduces the water cooling pressure after rolling, achieving higher speeds and improving head performance.

[0088] Implementation Case 1:

[0089] Since the inter-machine cooling water is directly taken from the unit panel and is in a long-term open state, the original finishing mill inter-machine cooling is prone to cause rapid cooling of the head of the rolled piece, resulting in falling blocks and steel accumulation, and abnormal increase in the load on the roll box, causing equipment failure; it also diverts the cooling water of the rolling groove, affecting the cooling effect of the rolling groove, aggravating the wear of the rolling groove and even causing roll ring explosion accidents.

[0090] The present invention discloses a three-way valve-controlled cooling method between finishing mill units. This method connects a separate high-pressure water supply between each finishing mill unit and controls it using a three-way valve. The principle is as follows: the three-way valve receives a steel signal from an upstream stand (the last stand in pre-finishing rolling, where the main control room can adjust the water supply speed via a time delay setting) and then delivers water to the cooling unit between the mill units. This effectively reduces the temperature rise during high-speed rolling while avoiding a sharp drop in the head. Ultimately, this reduces the water cooling pressure after rolling, achieving increased speed and improved head performance.

[0091] Setting up an inter-machine cooling water circuit independent of the roll box panel cooling water circuit between the finishing mill groups will not affect the cooling effect of the original roll box panel cooling water on the roll ring groove, thereby increasing the service life of the roll ring and reducing consumption costs. A separate water circuit can increase the water pressure of the inter-machine cooling, thereby better controlling the temperature rise of the rolled piece during high-speed finishing rolling. After reasonably controlling the finishing rolling temperature of the rolled piece, it can effectively avoid the black head caused by the rolled piece head passing through the high-pressure water flow, and ultimately put an end to the accidents of falling steel and piling steel and equipment accidents caused by abnormal pressure on the roll box, and can effectively reduce the water cooling pressure of the rolled piece after rolling (especially for small-sized wire rods and coils), and ultimately achieve an increase in the final rolling speed.

[0092] The main functions of the present invention are:

[0093] 1. Establish an independent inter-machine cooling water circuit + three-way valve delay control infrastructure to achieve the dual goals of head avoidance cooling and precise temperature control of the main body, and solve the problems of insufficient water pressure in the traditional series connection of inter-machine cooling water circuit and unit panel cooling water circuit, resulting in insufficient cooling of the rolling groove and blackheads caused by long-term cooling water flow.

[0094] 2. It will not affect the cooling effect of the original roll box panel cooling water on the roll ring groove, thereby increasing the service life of the roll ring and reducing consumption costs. It can effectively avoid the blackhead caused by the head of the rolled piece passing through the high-pressure water flow, and ultimately put an end to the accidents of falling steel and piling steel and equipment accidents caused by abnormal pressure on the roll box.

[0095] 3. A separate water channel can increase the water pressure for inter-machine cooling, thereby better controlling the temperature rise of the rolled piece during high-speed finishing rolling. By rationally controlling the finishing temperature of the rolled piece, the water cooling pressure after rolling can be effectively reduced (especially for small-sized wire rods and coils), ultimately achieving an increase in the final rolling speed.

[0096] The foregoing description is intended only to provide specific embodiments of the present invention, intended to enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

[0097] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical solutions and technical concepts of the present invention without creative mental work, and all of them fall within the scope of protection of the present invention.

Claims

1. A three-way valve controlled cooling method between finishing mill groups, characterized in that: include: An inter-machine cooling water circuit independent of the roll box panel cooling water circuit is set between each finishing rolling unit, and a three-way valve is installed on the inter-machine cooling water circuit; The opening action triggering logic of the three-way valve: Receive the steel signal from the upstream pre-finishing rolling stand; Combined with the workpiece speed v, the distance L from the steel signal detection point to the cooling water injection point, and the workpiece head compensation length D, the set delay T is calculated according to the formula T=(L / v)+Δt, Δt=D / v, and the three-way valve is opened after the set delay T.

2. A three-way valve controlled cooling method between finishing mill groups according to claim 1, characterized in that: Also includes: Combined with the water pressure fluctuation data, the delay T is set. The correction formula is: T = (L / v) + Δt-k, where k is the water pressure fluctuation compensation coefficient, which is used to compensate for the water path response delay. k>0, an increase in the k value reduces T, and the valve opens earlier.

3. The three-way valve controlled cooling method between finishing mill groups according to claim 2, characterized in that: The dynamic adjustment rule of k value is: A pressure sensor is installed at the inlet of the cooling water channel between machines to collect P1 in real time; Dynamically adjust the water pressure P0 according to the specifications of the rolled piece: P0 for small-sized rolled pieces> P0 for large-sized rolled pieces, and calculate the water pressure deviation P=|P0-P1|; When the water pressure deviation P is greater than the set pressure threshold, the k value increases, which reduces the set delay T and opens the valve in advance to compensate for the response delay caused by insufficient water pressure. When the water pressure deviation P is less than the set pressure threshold, the k value is reset to the reference value.

4. The three-way valve controlled cooling method between finishing mill groups according to claim 1, characterized in that: The compensation length D of the rolled piece head ≥ the length of the high-temperature zone of the rolled piece head + the cooling water spray coverage error tolerance.

5. The three-way valve controlled cooling method between finishing mill groups according to claim 1, characterized in that: The water inlet of the valve body of the three-way valve is connected to an independent high-pressure water source pipe through a flange, the first water outlet of the three-way valve is connected to the machine room cooling nozzle through a quick-release joint, and the second water outlet of the three-way valve is connected to the cooling water return main through a pressure reducing valve; the electromagnetic drive module is integrated on the top of the valve body and is directly connected to the signal line of the control unit.

6. The three-way valve controlled cooling method between finishing mill groups according to claim 1, characterized in that: Three-way valve closing control includes: Upon receiving a signal that the tail of the workpiece has left the final stand of the pre-finishing rolling mill, the closing delay Tc = (L0 / v) + ΔT is calculated based on the workpiece length L0 and the workpiece speed v; Wherein, L0 is the distance from the tail detection point to the injection point, ΔT is the safety cooling margin time, and ΔT ≥ 50ms.

7. The three-way valve controlled cooling method between finishing mill groups according to claim 1, characterized in that: When the rolling speed suddenly exceeds the threshold, the emergency control mode is activated: If the speed drops suddenly, immediately close the three-way valve and enable roll gap air cooling compensation; If the speed suddenly increases, the delay T is dynamically shortened based on the speed change rate Δv / v: T'=T×(1-β·Δv / v), where β is the emergency correction coefficient (0.5≤β≤0.8).

8. The three-way valve controlled cooling method between finishing mill groups according to claim 1, characterized in that: Also includes: Different head compensation length D reference values ​​are set for different steel grades, where: The D reference value of high carbon steel is greater than the D reference value of low carbon steel; The D reference value of alloy steel is greater than the D reference value of ordinary carbon steel.

9. The three-way valve controlled cooling method between finishing mill groups according to claim 1, characterized in that: The reference value setting rule of the water pressure fluctuation compensation coefficient k is: When the rolling speed v ≥ 100m / s, the k reference value = 0.05s; When 50m / s≤v<100m / s, k reference value = 0.03s; When v is less than 50 m / s, the k reference value is 0.01 s.

10. The three-way valve controlled cooling method between finishing mill groups according to claim 1, characterized in that: It also receives the temperature feedback signal of the rolled piece at the final stand of the pre-finishing rolling mill. If it detects that the real-time temperature rise exceeds the temperature rise threshold, it increases the water pressure or extends the cooling time.

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