Heater capable of reducing brittle fracture of steel coil

Abstract

The utility model discloses a heater for reducing brittle fracture of a steel coil, which belongs to the technical field of steel production and comprises a cover body, a plurality of burners and a supply pipeline. The burners are arranged on the side wall of the cover body. The supply pipeline is used for supplying gas. The cover body forms a closed or semi-closed heating chamber, so that heat loss is reduced, and radiation energy is concentrated. Burners are evenly distributed on the side wall, a uniform heating radiation field is generated through multi-point distributed combustion, and local overheating of the strip steel is avoided. The gas supply pipeline provides fuel gas and combustion-supporting gas for the burner, and stable combustion is supported. Heat radiation is transmitted through gas combustion, and the problems that a traditional heating mode is poor in combustion stability and large in temperature gradient are solved. The internal stress of the strip steel is reduced by strengthening radiation uniformity, and the crimping brittle failure risk is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of steel production, and specifically relates to a heater for reducing brittle fracture of a steel coil. BACKGROUND

[0002] In the steel industry production, the strip steel after cold rolling or hot rolling needs to be treated by tempering or preheating to optimize the material performance. Such a process aims to eliminate the internal stress generated in the processing process, improve the plasticity, toughness and forming performance of the strip steel, and at the same time, provide good substrate conditions for subsequent coating, stamping and other processes. The current mainstream preheating methods include resistance wire heating, electromagnetic induction heating and gas radiation heating.

[0003] The resistance wire heating generates heat energy by the current flowing through the resistance element, and its device structure is simple but has obvious defects: limited by the resistance wire arrangement density and the heat conduction efficiency, a temperature gradient is easily formed on the surface of the strip steel, leading to local overheating or underheating phenomenon; at the same time, the resistance wire has large thermal inertia, and it is difficult to realize rapid and accurate temperature control adjustment, leading to the brittle fracture phenomenon of the strip steel plate in the coiling process.

[0004] The gas radiation heating pre-mixes the gas and the air required for combustion of the gas, and under certain conditions, flameless combustion can be carried out to directly generate infrared radiation for heating. Although the temperature uniformity of this heating method is improved, it is limited by the wavelength matching of the radiation, and it is difficult to meet the wide-spectrum heating demand of different material strip steels. And its combustion process is significantly affected by the purity of the gas, the air ratio and the structure of the combustion chamber, and the flame stability is poor.

[0005] The electromagnetic induction heating can improve the heating rate, but it is sensitive to the thickness change of the strip steel, and the thin plate is easy to produce magnetic saturation effect. UTILITY MODEL CONTENTS

[0006] The utility model aims to provide a heater for reducing brittle fracture of a steel coil to solve the problems in the prior art.

[0007] A heater for reducing brittle fracture of a steel coil is provided, comprising:

[0008] A cover body;

[0009] A plurality of burners are arranged on the side wall of the cover body;

[0010] A supply pipeline for supplying gas.

[0011] Further, the supply pipeline includes a gas pipe and an air pipe. The gas and the air are transported through independent pipelines to realize accurate control of the pre-mixed ratio. The separation design avoids the risk of deflagration caused by backflow or uneven mixing of the gas, and the problem of unstable combustion caused by air ratio fluctuation, improves the combustion efficiency, reduces the emission of unburned gas, and reduces energy consumption.

[0012] Further, the burner is in communication with a gas pipe, and the air pipe is in communication with the inside of the cover. The gas is directly input into the burner for combustion, and the air is circulated through the inside of the cover to supplement the combustion-supporting gas. The secondary air supply is formed to support the completeness of combustion. The closed cover design reduces the interference of the external environment on the combustion process, the combustion exhaust gas is layered with fresh air, the oxygen concentration fluctuation in the cover is reduced, and the excessive oxidation of the strip steel is inhibited.

[0013] Further, the air pipe comprises a combustion-supporting gas pipeline and an inert gas pipeline in communication with each other. The combustion-supporting gas (such as oxygen) is used for normal combustion stage, and the inert gas (such as nitrogen) is used for cooling stage or oxygen replacement in emergency shutdown. Explosion caused by accumulation of residual fuel gas in the cover during shutdown is prevented by inert gas replacement, and growth of the oxidation layer on the surface of the strip steel is reduced by the inert gas during the cooling stage.

[0014] Further, the combustion-supporting gas pipeline is provided with a first shut-off valve, and the inert gas pipeline is provided with a second shut-off valve. The first shut-off valve and the second shut-off valve are independent valve doors for controlling gas switching, realizing flexible control of the combustion-supporting gas and the inert gas. In emergency, the combustion-supporting gas supply is quickly cut off, and the inert gas is injected, realizing seamless switching of the heating and cooling processes, and improving the production continuity.

[0015] Further, the air pipe is provided with a combustion-supporting fan at the output section of the communication port between the combustion-supporting gas pipeline and the inert gas pipeline. The fan pressurization ensures the stability of the flow rate of the combustion-supporting gas or the inert gas, overcomes the pipeline resistance, dynamically adjusts the air volume to match the combustion demand, and solves the problem of combustion efficiency reduction caused by gas pressure fluctuation.

[0016] Further, the gas pipe is provided with a gas control valve. The gas flow is adjusted by the opening degree of the valve, the combustion intensity is controlled, and the closed-loop control is realized in linkage with the temperature sensor. The problem of large thermal inertia of the resistance wire heating and temperature control lag is solved, the strip steel heating temperature is accurately adjusted, and overheating and embrittlement are avoided.

[0017] Further, the output end of the burner is provided with an igniter, and the communication end of the burner with the gas pipe is located outside the cover, and the output end of the burner extends into the inside of the cover. The external gas interface reduces the thermal damage of high temperature to the pipeline seal. The built-in design of the cover of the igniter ensures that the spark directly ignites the gas mixture.

[0018] Further, the inside of the cover is provided with a plurality of supporting rollers. The supporting rollers are passively rotated after contacting with the strip steel to reduce friction, prevent the strip steel from sagging and deforming, and ensure the constant distance from the radiation field.

[0019] Further, the outside of the cover is provided with a driving roller, the driving roller controls the conveying speed of the strip steel, matches the heating time, and is arranged outside the cover to avoid the influence of the high temperature inside the cover on the driving assembly.

[0020] Further, the top of the cover body is provided with a smoke exhaust pipe, and a smoke exhaust fan is arranged in the smoke exhaust pipe.

[0021] Compared with the prior art, the utility model has the advantages that:

[0022] The cover body forms a closed or semi-closed heating chamber, reduces heat loss and concentrates radiation energy. The gas supply pipeline supplies gas and combustion-supporting gas to the burners, and supports stable combustion. The gas combustion heat radiation transmission solves the problems of poor combustion stability and large temperature gradient in the conventional heating mode. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description.

[0024] Fig. 1 is the side view internal structure diagram of the heater provided by the utility model;

[0025] Fig. 2 is the arrangement structure diagram of the heater provided by the utility model.

[0026] In the figure: 1, cover body; 11, supporting roller; 12, smoke exhaust pipe; 13, smoke exhaust fan; 2, burner; 21, igniter; 3, supply pipeline; 31, gas pipe; 311, gas control valve; 32, air pipe; 321, combustion-supporting gas pipeline; 322, inert gas pipeline; 323, first cut-off valve; 324, second cut-off valve; 325, combustion-supporting fan. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the utility model more clear, the following will combine the drawings and embodiments to describe and explain the utility model.

[0028] It is obvious that the drawings in the following description are only some examples or embodiments of the present application, and for those skilled in the art, the present application can be applied to other similar situations without creative labor on the basis of these drawings. In addition, it can be understood that although the efforts made in this development process can be complex and lengthy, some design, manufacture or production changes based on the technical content disclosed in the present application are only conventional technical means for those skilled in the art related to the disclosed content of the present application, and should not be understood as insufficient disclosure of the present application.

[0029] However, unnecessary detailed description can be omitted. For example, there are cases where detailed description of well-known matters, repeated description of actually identical structures is omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0030] Please refer to Figs. 1-2 As shown in the figure, the heater for reducing brittle fracture of steel coil in the embodiment of the present application comprises a cover body 1, a plurality of burners 2 and a supply pipeline 3. The plurality of burners 2 are arranged on the side wall of the cover body 1. The supply pipeline 3 is used for supplying gas.

[0031] The cover body 1 forms a closed or semi-closed heating chamber, and the burners 2 distributed on the side wall release heat generated by the combustion of the gas to the inside. The burners 2 can be arranged along the side wall or in multiple layers, enhancing the coverage of the heat field. The supply pipeline 3 continuously delivers gas and air, maintaining the stability of combustion. The closed heating of the cover body 1 reduces heat loss, improves radiation uniformity, and avoids brittle fracture of the steel strip grain boundary caused by local overheating.

[0032] In one embodiment, the gas and air are uniformly mixed by a Venturi tube, a static mixer or other device before entering the burner, and after forming a combustible mixed gas, it is delivered to the cover body 1 and ignited and burned through the burners 2. This mixing method has high premixed gas mixing rate, fast flame propagation speed, full combustion and high thermal efficiency. The flow rate of the mixed gas matches the combustion rate, which can avoid misfire or backfire. However, the premixed gas in the pipeline is prone to deflagration due to static electricity, high temperature or mechanical spark, and the air-fuel ratio is fixed, which is difficult to adapt to the fluctuation of fuel heat value.

[0033] In one embodiment, the gas and air are independently delivered through the gas pipe 31 and the air pipe 32 respectively, and mixed and burned in the cover body 1 according to the preset ratio. The separate delivery of gas and air can eliminate the explosion risk of premixed gas in the pipeline. Independent control of gas and air flow can respond to load changes in real time and adjust according to load changes.

[0034] Specifically, the burner 2 is in communication with the gas pipe 31, and the air pipe 32 is in communication with the inside of the cover body 1. The gas is mixed with the circulating air in the cover to combust. The air pipe 32 can be connected to different areas of the cover body 1 to form a uniform air flow distribution.

[0035] The air pipe 32 comprises a combustion-supporting gas pipe 321 and an inert gas pipe 322 in communication with each other. The inert gas can be nitrogen, argon or carbon dioxide. The combustion-supporting gas pipe 321 is opened to introduce the combustion-supporting gas to mix with the gas to combust under normal heating, and the combustion-supporting gas pipe 321 is closed and the inert gas pipe 322 is opened to switch the inert gas to purge the residual gas when the machine is stopped, so that the machine can be quickly stopped and the temperature can be quickly adjusted.

[0036] The combustion-supporting gas pipe 321 is provided with a first shut-off valve 323, and the inert gas pipe 322 is provided with a second shut-off valve 324. The first shut-off valve 323 is used to adjust the flow of the combustion-supporting gas, and the second shut-off valve 324 is used to control the timing of the inert gas injection. The valves can be selected from solenoid valves, pneumatic valves or electrically adjustable valves.

[0037] The combustion-supporting fan 325 is arranged at the output section of the communication port between the combustion-supporting gas pipe 321 and the inert gas pipe 322 in the air pipe 32. The combustion-supporting fan 325 provides a constant air pressure for the gas to overcome the pipe resistance, can adjust the air volume in real time to match the change of the gas flow, reduces the fluctuation range of the air and gas ratio, and makes the combustion temperature stability rise and fall.

[0038] The gas pipe 31 is provided with a gas control valve 311, which dynamically adjusts the opening of the valve according to the feedback of the strip surface temperature to close-loop adjust the gas flow.

[0039] The output end of the burner 2 is provided with an igniter 21, which is selected from an electric ignition device and is embedded in the outlet of the burner 2. The igniter 21 ignites the gas-air mixture by electric spark to achieve combustion. The communication end of the burner 2 with the gas pipe 31 is located outside the cover body 1, and the output end of the burner 2 extends into the inside of the cover body 1. The gas pipe 31 interface is external to avoid high-temperature deterioration. A flame detector can be added to the burner 2 to achieve flameout protection.

[0040] The outside of the cover body 1 is provided with a driving roller. The driving roller is driven to rotate by hydraulic pressure or motor, which is used to drive the strip to move and control the linear speed of the strip. The driving roller is external to avoid the influence of high temperature in the inside of the cover body 1 on the driving part. A plurality of support rollers 11 are arranged in the inside of the cover body 1, which are distributed at intervals to prevent the strip from sagging.

[0041] The top of the cover body 1 is provided with a smoke exhaust pipe 12, and the smoke exhaust pipe 12 is provided with a smoke exhaust fan 13. The smoke exhaust fan 13 is used to form a negative pressure in the smoke exhaust pipe 12 to suck the combustion waste gas, prevent the smoke from staying to affect the radiation efficiency, reduce the deposition of smoke dust on the surface of the strip, and improve the coating quality.

[0042] Note that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having the same configuration as the technical idea and achieving the same effects within the scope of the technical idea of the present application are included in the technical scope of the present application. Furthermore, various modifications that can be thought of by those skilled in the art, and other modes of embodiment constructed by combining some of the constituent elements of the embodiments within the scope of the gist of the present application are also included in the scope of the present application.

Claims

1. A heater for reducing brittle fracture of steel coils, characterized in that, include: Cover (1); A plurality of burners (2) are disposed on the side wall of the cover (1); Supply pipe (3), which is used to supply gas.

2. A heater for reducing brittle fracture of steel coils according to claim 1, characterized in that, The supply pipeline (3) includes a gas pipe (31) and an air pipe (32).

3. A heater for reducing brittle fracture of steel coils according to claim 2, characterized in that, The burner (2) is connected to the gas pipe (31), and the air pipe (32) is connected to the inside of the cover (1).

4. A heater for reducing brittle fracture of steel coils according to claim 3, characterized in that, The air pipe (32) includes an interconnected combustion-supporting gas pipe (321) and an inert gas pipe (322).

5. A heater for reducing brittle fracture of steel coils according to claim 4, characterized in that, The combustion-supporting gas pipeline (321) is equipped with a first shut-off valve (323), and the inert gas pipeline (322) is equipped with a second shut-off valve (324).

6. A heater for reducing brittle fracture of steel coils according to claim 4, characterized in that, A combustion-supporting fan (325) is provided in the output section of the air pipe (32) at the connection port between the combustion-supporting gas pipe (321) and the inert gas pipe (322).

7. A heater for reducing brittle fracture of steel coils according to claim 2, characterized in that, The gas pipe (31) is equipped with a gas control valve (311).

8. A heater for reducing brittle fracture of steel coils according to claim 2, characterized in that, The output end of the burner (2) is provided with an igniter (21), and the connection end of the burner (2) and the gas pipe (31) is located outside the cover (1) and the output end of the burner (2) extends into the interior of the cover (1).

9. A heater for reducing brittle fracture of steel coils according to claim 1, characterized in that, The cover (1) is provided with several support rollers (11).

10. A heater for reducing brittle fracture of steel coils according to claim 1, characterized in that, The top of the cover (1) is provided with a smoke exhaust pipe (12), and a smoke exhaust fan (13) is provided inside the smoke exhaust pipe (12).

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