阅读说明：本技术 一种辐射管热处理炉炉内保护性气氛控制的方法 (Method for controlling protective atmosphere in radiant tube heat treatment furnace ) 是由 崔磊 李纪唐 孟宪华 李珂 李伟超 张飞 于 2021-08-31 设计创作，主要内容包括：本发明提供一种辐射管热处理炉炉内保护性气氛控制的方法,属于冶金自动化技术领域。该方法通过PLC控制系统采集入炉侧、出炉侧炉膛压力值及氧含量值,由操作人员在人机交互界面输入适合生产范围的炉压上、下限值,氧含量上、下限值,并选中需要控制保护性气氛的气体阀组,当启用气氛自动控制时,程序根据当前炉况及实时采集的炉膛压力值与氧含量,与输入的限制值对比,通过不同对比结果对保护性气氛气体阀开闭状态进行控制,进而实现对辐射管炉内保护性气氛的控制,该方法解决了辐射管炉内保护性气氛分布不均的问题,减少了炉内保护性气氛的浪费,同时减少了装出钢动作时对气体阀门的使用,并且提高了产品质量。(The invention provides a method for controlling protective atmosphere in a radiant tube heat treatment furnace, belonging to the technical field of metallurgy automation. The method includes the steps that a PLC control system is used for collecting furnace inlet side and furnace outlet side furnace pressure values and oxygen content values, an operator inputs furnace upper limit values and furnace lower limit values suitable for a production range and oxygen content upper limit values and oxygen content lower limit values on a human-computer interaction interface, a gas valve group needing to control protective atmosphere is selected, when atmosphere automatic control is started, a program compares the furnace upper limit values and the furnace lower limit values with the input limit values according to current furnace conditions and the furnace pressure values and the oxygen content which are collected in real time, the opening and closing states of the protective atmosphere gas valve are controlled through different comparison results, and then the control of the protective atmosphere in the radiant tube furnace is achieved.)

1. A method for controlling protective atmosphere in a radiant tube heat treatment furnace is characterized by comprising the following steps: the method comprises the following steps:

s1: collecting furnace inlet side and furnace outlet side furnace pressure values and furnace oxygen content values through a PLC control system;

s2: the distribution of the gas valves of the whole furnace is divided into two parts according to the charging direction of the steel plate, the gas valve close to the charging furnace door is divided into a gas valve at the furnace inlet side, and the gas valve close to the furnace outlet furnace door is divided into a gas valve at the furnace outlet side;

s3: judging whether the heat treatment furnace is in a steel charging state or a steel tapping state, wherein when the heat treatment furnace is in the steel charging state, all gas valves on the furnace inlet side are opened, and when the heat treatment furnace is in the steel tapping state, all gas valves on the furnace outlet side are opened;

s4: judging whether the oxygen content of the furnace inlet side or the furnace outlet side is in a set range,

s41: if the oxygen content is larger than the upper limit value of the input oxygen content, in the gas valves manually selected and controlled according to production experience on the HMI picture, the gas valves close to the furnace inlet side or the furnace outlet side are sequentially opened according to the interval time from the gas valve close to the middle part of the furnace body, wherein the opening interval time is N seconds;

s42: if the oxygen content is less than the lower limit value of the input oxygen content, in the gas valves manually selected and controlled according to production experience on the HMI picture, the gas valves close to the furnace inlet side or the furnace outlet side are sequentially closed to the gas valve close to the middle position of the furnace body according to the interval time, wherein the closing interval time is N seconds;

s5: judging whether the furnace pressure at the furnace inlet side or the furnace outlet side is in a set range,

s51: if the furnace pressure is larger than the input furnace pressure upper limit value, in the gas valves manually selected and controlled according to production experience on the HMI picture, the gas valves close to the furnace inlet side or the furnace outlet side are closed to the gas valves close to the middle position of the furnace body in sequence according to the interval time, wherein the closing interval time is N seconds;

s52: if the furnace pressure is less than the input furnace pressure lower limit value, in the HMI picture, according to the production experience, the nitrogen valves close to the middle part of the furnace body are opened to the nitrogen valve close to the furnace inlet side or the furnace outlet side in turn according to the interval time, wherein the opening interval time is N seconds;

s6: if the heat treatment furnace is not in a steel charging or tapping state at this time, and the oxygen content and the furnace pressure on the furnace inlet side and the furnace outlet side are in the set ranges at this time, in the gas valves manually selected and controlled according to production experience on the HMI picture, the circulation is opened in each group, and the opening time of each gas valve is the circulation time input in the HMI picture.

2. The method of claim 1, further comprising the step of: the gas valve comprises a nitrogen gas valve and an argon gas valve.

3. The method of claim 1, further comprising the step of: and N is 1-10.

Technical Field

The invention relates to the technical field of metallurgy automation, in particular to a method for controlling protective atmosphere in a radiant tube heat treatment furnace.

Background

The heat treatment process of steel generally means that the internal structure of steel is changed through the process steps of heating, heat preservation, cooling and the like, so that the performance of the steel is better. In order to prevent oxidation of the steel during heating, a protective atmosphere, such as nitrogen or argon, is generally introduced into the radiant tube heat treatment furnace, and in view of economy, nitrogen is often used as the protective atmosphere in the heat treatment step.

General subregion of nitrogen gas valve arranges at furnace roof and stove bottom in the radiant tube heat treatment furnace stove, blow off nitrogen gas towards the furnace inside, in actual production, experienced operating personnel can be according to furnace pressure, select the quantity of opening the nitrogen gas valve, and the overwhelming majority all opens the nitrogen gas valve of fixed quantity and keeps unchangeable, lead to in the stove protective atmosphere maldistribution, no matter adorn steel or steel simultaneously, open for preventing the furnace gate and cause a large amount of air to gush into the stove, all nitrogen gas valves all can all open automatically, thereby the serious waste of the energy has been caused, and because protective atmosphere distributes inequality, the interior oxygen content control precision variation of stove, thereby product quality also has the space of further promotion.

Based on the above, the invention designs a method for controlling protective atmosphere in a radiant tube heat treatment furnace to solve the problems.

Disclosure of Invention

The invention aims to provide a method for controlling protective atmosphere in a radiant tube heat treatment furnace.

The method comprises the following steps:

s1: collecting furnace inlet side and furnace outlet side furnace pressure values and furnace oxygen content values through a PLC control system;

s2: the distribution of the gas valves of the whole furnace is divided into two parts according to the charging direction of the steel plate, the gas valve close to the charging furnace door is divided into a gas valve at the furnace inlet side, and the gas valve close to the furnace outlet furnace door is divided into a gas valve at the furnace outlet side;

s3: judging whether the heat treatment furnace is in a steel charging state or a steel tapping state, wherein when the heat treatment furnace is in the steel charging state, all gas valves on the furnace inlet side are opened, and when the heat treatment furnace is in the steel tapping state, all gas valves on the furnace outlet side are opened;

s4: judging whether the oxygen content of the furnace inlet side or the furnace outlet side is in a set range,

s41: if the oxygen content is larger than the upper limit value of the input oxygen content, in the HMI picture, according to the production experience, manually selecting the gas valve to control (generally, the gas valve close to the furnace door is not selected, only the gas valve of the heating section is selected), and the gas valve close to the middle part of the furnace body is opened to the gas valve close to the furnace inlet side or the furnace outlet side according to the interval time, wherein the opening interval time is N seconds;

s42: if the oxygen content is less than the lower limit value of the input oxygen content, in the gas valves manually selected and controlled according to production experience on the HMI picture, the gas valves close to the furnace inlet side or the furnace outlet side are sequentially closed to the gas valve close to the middle position of the furnace body according to the interval time, wherein the closing interval time is N seconds;

s5: judging whether the furnace pressure at the furnace inlet side or the furnace outlet side is in a set range,

s51: if the furnace pressure is larger than the input furnace pressure upper limit value, in the gas valves manually selected and controlled according to production experience on the HMI picture, the gas valves close to the furnace inlet side or the furnace outlet side are closed to the gas valves close to the middle position of the furnace body in sequence according to the interval time, wherein the closing interval time is N seconds;

s52: if the furnace pressure is less than the input furnace pressure lower limit value, in the HMI picture, according to the production experience, the nitrogen valves close to the middle part of the furnace body are opened to the nitrogen valve close to the furnace inlet side or the furnace outlet side in turn according to the interval time, wherein the opening interval time is N seconds;

s6: if the heat treatment furnace is not in a steel charging or tapping state at this time, and the oxygen content and the furnace pressure on the furnace inlet side and the furnace outlet side are in the set ranges at this time, in the gas valves manually selected and controlled according to production experience on the HMI picture, the circulation is opened in each group, and the opening time of each gas valve is the circulation time input in the HMI picture.

Wherein, the gas valve comprises a nitrogen gas valve and an argon gas valve.

N is 1 to 10.

The technical scheme of the invention has the following beneficial effects:

according to the scheme, the problem that protective atmosphere in the radiant tube furnace is not uniformly distributed is solved, waste of protective atmosphere in the furnace is reduced, the use of a gas valve during steel loading and discharging actions is reduced, and the product quality is improved.

Drawings

FIG. 1 is a control flow diagram according to an embodiment of the present invention;

FIG. 2 is a nitrogen gas valve floor plan in an embodiment of the present invention;

FIG. 3 is a diagram illustrating an operation of a human-computer interface according to an embodiment of the present invention.

Wherein: 1-a furnace-entering side oxygen measuring instrument; 2-furnace-entering side pressure instrument; 3-nitrogen gas valve; 4-furnace side.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

The invention provides a method for controlling protective atmosphere in a radiant tube heat treatment furnace.

The method comprises the following steps:

s1: collecting furnace inlet side and furnace outlet side furnace pressure values and furnace oxygen content values through a PLC control system;

s2: dividing the distribution of the gas valve of the whole furnace into a furnace inlet side and a furnace outlet side;

s3: judging whether the heat treatment furnace is in a steel charging state or a steel tapping state, wherein when the heat treatment furnace is in the steel charging state, all gas valves on the furnace inlet side are opened, and when the heat treatment furnace is in the steel tapping state, all gas valves on the furnace outlet side are opened;

s4: judging whether the oxygen content of the furnace inlet side or the furnace outlet side is in a set range,

s41: if the oxygen content is larger than the upper limit value of the input oxygen content, in the selected and controlled gas valves, the gas valves close to the furnace inlet side or the furnace outlet side are sequentially opened according to the interval time from the gas valve close to the middle part of the furnace body, wherein the opening interval time is N seconds;

s42: if the oxygen content is less than the lower limit value of the input oxygen content, the gas valves close to the furnace inlet side or the furnace outlet side to the gas valve close to the middle part of the furnace body in the selected and controlled gas valves are closed in sequence according to the interval time, wherein the closing interval time is N seconds;

s5: judging whether the furnace pressure at the furnace inlet side or the furnace outlet side is in a set range,

s51: if the furnace pressure is larger than the input furnace pressure upper limit value, the gas valves close to the middle position of the furnace body from the gas valve close to the furnace inlet side or the furnace outlet side in the selected controlled gas valves are closed in sequence according to the interval time, wherein the closing interval time is N seconds;

s52: if the furnace pressure is less than the input furnace pressure lower limit value, in the selected and controlled gas valve, a nitrogen valve close to the middle part of the furnace body is opened to a nitrogen valve close to the furnace inlet side or the furnace outlet side in sequence according to the interval time, wherein the opening interval time is N seconds;

s6: if the heat treatment furnace is not in a steel charging or tapping state at this time, and the oxygen content and the furnace pressure on the furnace-in side and the furnace-out side are in the set ranges at this time, in the gas valves selected for control, the circulation is opened in each group, and the opening time of each gas valve is the circulation time input in the HMI picture.

The following description will be given taking the protective atmosphere as nitrogen as an example.

As shown in fig. 1, firstly, the distribution of the nitrogen valves of the whole furnace is divided into a furnace inlet side and a furnace outlet side; collecting furnace inlet side and furnace outlet side furnace pressure values and furnace oxygen content values through a PLC control system; respectively setting a nitrogen automatic control button, a cycle interval time input frame, an oxygen content upper limit input frame, an oxygen content lower limit input frame, a furnace pressure upper limit input frame, a furnace pressure lower limit input frame and a selection button of each group of valves needing to circulate nitrogen (one group of nitrogen valves is one or more pairs of nitrogen valves distributed up and down in a hearth) at the furnace entering side and the furnace exiting side in the HMI picture;

secondly, in practical application, the range of the oxygen content to be controlled, namely the upper limit value and the lower limit value of the oxygen content, is input on an HMI picture, the range of the furnace pressure to be controlled, namely the upper limit value and the lower limit value of the furnace pressure, is input on the picture, the cycle interval time is input in the picture, and a nitrogen valve to be controlled is selected.

Specifically, as shown in fig. 2, the distribution of the nitrogen valves of the whole furnace is divided into a furnace inlet side 4 and a furnace outlet side, and a furnace inlet side oxygen meter 1 and a furnace inlet side pressure meter 2 are provided, wherein 1Zone1 is a nitrogen valve No. 1 in 1Zone, 1Zone2 is a nitrogen valve No. 1 in 1Zone, and 2Zone1 is a nitrogen valve No. 1 in 2 Zone. There may be many zones for 1 heat treatment furnace, and here, assuming 2N zones, a nitrogen valve No. 1Zone (1Zone1) to a nitrogen valve No. 2N Zone (NZone2) are divided into a nitrogen valve on the furnace inlet side, and a nitrogen valve No. 1N Zone (N +1Zone1) to a nitrogen valve No. 2N Zone2 (2NZone2) are divided into a nitrogen valve on the furnace outlet side;

collecting furnace inlet side and furnace outlet side furnace pressure values and furnace oxygen content values through a PLC control system;

as shown in fig. 3, an automatic nitrogen control button, a cycle interval time input box, an upper oxygen content limit input box, a lower oxygen content limit input box, an upper furnace pressure limit input box, a lower furnace pressure limit input box, and a selection button of each group of required cycle nitrogen valves (one group of nitrogen valves is one or more pairs of nitrogen valves distributed vertically in the furnace) are respectively set on the furnace entering side and the furnace exiting side in the HMI screen, and a group of nitrogen valves is taken as an example in fig. 3 as a pair of nitrogen valves distributed vertically in the furnace. That is, in fig. 3, the 1Znoe selection button represents that the 1Zone No. 1 nitrogen valve (1Zone1) and the 1Zone No. 2 nitrogen valve (1Zone2) are selected;

in practical application, inputting an oxygen content range to be controlled on a picture, namely inputting an oxygen content upper limit value and an oxygen content lower limit value, inputting a furnace pressure range to be controlled on the picture, namely inputting a furnace pressure upper limit value and a furnace pressure lower limit value, inputting cycle interval time in the picture, and selecting a nitrogen valve bank to be controlled;

when the automatic nitrogen control button is selected, the specific control method of the nitrogen of the heat treatment furnace hearth comprises the following steps:

s1, judging whether the heat treatment furnace is in a steel charging or steel tapping state, wherein when the heat treatment furnace is in the steel charging state, the nitrogen valves on the furnace entering side are all opened, and when the heat treatment furnace is in the steel tapping state, the nitrogen valves on the furnace exiting side are all opened;

s2, judging whether the oxygen content on the furnace entering side (furnace exiting side) is in a set range, if the oxygen content is larger than the upper limit value of the input oxygen content, opening the nitrogen valves close to the furnace entering side (furnace exiting side) one by one at intervals from the nitrogen valve close to the middle part of the furnace body in the selected controlled nitrogen valves, wherein the opening interval is N seconds;

if the oxygen content is less than the lower limit value of the input oxygen content, closing the nitrogen valves close to the middle part of the furnace body one by one at intervals from the nitrogen valve close to the furnace inlet side (the furnace outlet side) in the selected controlled nitrogen valves, wherein the closing interval is N seconds;

s3, judging whether the furnace pressure on the furnace entering side (furnace exiting side) is in a set range, if the furnace pressure is larger than the input upper limit value of the furnace pressure, closing the nitrogen valves close to the middle position of the furnace body one by one at intervals from the nitrogen valve close to the furnace entering side (furnace exiting side) in the selected controlled nitrogen valves, wherein the closing interval is N seconds;

if the furnace pressure is smaller than the input furnace pressure lower limit value, opening the nitrogen valves close to the furnace inlet side (furnace outlet side) one by one at intervals from the nitrogen valve close to the middle part of the furnace body in the selected controlled nitrogen valves, wherein the opening interval is N seconds;

and S4, if the heat treatment furnace is not in a steel charging (steel discharging) state at the moment, and the oxygen content and the furnace pressure on the furnace entering side (furnace discharging side) are in the set ranges at the moment, in the nitrogen gas valve selected for control, each group is cyclically opened, and the opening time of each valve is the cycle time input in the HMI picture.

That is, when 1Zone selection and 2Zone selection are selected in FIG. 3, if the heat treatment furnace is not charged (tapped) at this time, and the furnace-entering side oxygen content and furnace pressure are within the set ranges at this time,

then the nitrogen valve 1Zone No. 1 (1Zone1) and the nitrogen valve 1Zone No. 2 (1Zone2) are cyclically opened, the opening time of each valve being the cycle time entered in the HMI picture, and the nitrogen valve 1Zone No. 2 (1Zone1) and the nitrogen valve 2Zone No. 2 (1Zone2) are cyclically opened, the opening time of each valve being the cycle time entered in the HMI picture.

The method is successfully applied to nitrogen valve control in a radiant tube heat treatment furnace of a certain coil plant, reduces nitrogen waste, improves product quality, can adjust furnace pressure and oxygen content through pictures, and is popular to users for convenient operation.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.