阅读说明：本技术 一种高强钢镀锌产线氧化膜厚度检测方法 (Method for detecting thickness of oxide film on high-strength steel galvanizing production line ) 是由 李研 蒋光锐 任新意 吴士才 贾杰 周欢 于 2020-05-11 设计创作，主要内容包括：一种高强钢镀锌产线氧化膜厚度检测方法,利用氧化膜生长对带钢表面辐射率变化的影响规律,通过温度测温值反应出氧化膜厚度变化情况；利用带钢表面氧化膜对辐射波的干涉原理,通过测量温度值的极值点对应的波程差,估算出带钢表面氧化膜的厚度数值。通过该方式,可对预氧化仓出口位置氧化膜厚度进行测量,以保证高强钢表面质量,此方法简单,易于操作,成本低廉。(A method for detecting the thickness of an oxide film on a high-strength steel galvanizing production line is characterized in that the thickness change condition of the oxide film is reflected through a temperature measurement value by utilizing the influence rule of the growth of the oxide film on the surface radiance change of strip steel; and estimating the thickness value of the oxide film on the surface of the strip steel by measuring the wave path difference corresponding to the extreme point of the temperature value by utilizing the interference principle of the oxide film on the surface of the strip steel on the radiation wave. Through the method, the thickness of the oxide film at the outlet of the pre-oxidation bin can be measured to ensure the surface quality of the high-strength steel, and the method is simple, easy to operate and low in cost.)

1. The method for detecting the thickness of the oxide film on the high-strength steel galvanizing production line is characterized by comprising the following steps of:

a wedge-shaped pyrometer is arranged at the inlet of the high-strength steel pre-oxidation bin, and a single-wavelength radiation pyrometer is arranged at the outlet of the high-strength steel pre-oxidation bin;

respectively measuring the temperatures of the inlet of the high-strength steel pre-oxidation bin and the outlet of the high-strength steel pre-oxidation bin by using the wedge pyrometer and the single-wavelength radiation pyrometer;

keeping the movement speed of the strip steel and the inlet temperature of the pre-oxidation bin fixed;

ensuring that the oxidation temperature and the oxidation time are fixed, and gradually increasing the dew point or the oxygen content of the pre-oxidation bin;

recording temperature measurement values of the wedge pyrometer and the single-wavelength radiation pyrometer;

and determining the thickness of the oxide film at the outlet position of the strip steel pre-oxidation bin according to the extreme point of the temperature value of the single-wavelength pyrometer.

2. The method for detecting the thickness of the oxide film on the high-strength steel galvanizing production line according to claim 1, wherein the thickness of the oxide film at the outlet of the strip steel pre-oxidation bin is calculated according to the following formula:

wherein d is the thickness of the oxide film at the outlet of the strip steel pre-oxidation bin, and lambda is the radiation wavelength of the single-wavelength pyrometer.

3. The method for detecting the thickness of the oxide film on the high-strength steel galvanizing production line according to claim 1, wherein the step of arranging a single-wavelength radiation pyrometer at the outlet of the high-strength steel pre-oxidation bin comprises the following steps: and a first single-wavelength radiation pyrometer and a second single-wavelength radiation pyrometer are arranged at the outlet of the high-strength steel pre-oxidation bin.

4. The method for detecting the thickness of the oxide film on the high-strength steel galvanizing production line according to claim 3, wherein the first single-wavelength radiation pyrometer and the second single-wavelength radiation pyrometer adopt different radiation wavelengths.

5. The method for detecting the thickness of the oxide film on the high-strength steel galvanizing production line according to claim 1, wherein the step of gradually increasing the dew point of the pre-oxidation bin comprises the steps of:

determining a unit dew point difference value;

increasing the unit dew point difference over the previous dew point value to obtain an adjacent subsequent dew point value.

6. The method for detecting the thickness of the oxide film on the high-strength steel galvanizing production line according to claim 1, wherein the step of gradually increasing the oxygen content in the pre-oxidation bin comprises the steps of:

determining a unit oxygen content difference value;

increasing the unit oxygen content difference over the previous oxygen content value to obtain an adjacent subsequent oxygen content value.

7. The method for detecting the thickness of the oxide film on the high-strength steel galvanizing production line according to claim 1, wherein the method further comprises the following steps after the thickness of the oxide film at the outlet of the strip steel pre-oxidation bin is determined:

obtaining the thickness of an oxide film at the outlet position of the strip steel pre-oxidation bin;

and determining the thickness of the oxide film at other positions of the strip steel by an interpolation method.

Technical Field

The invention belongs to the technical field of steel rolling, and particularly relates to a method for detecting the thickness of an oxide film on a high-strength steel galvanizing production line.

Background

In recent years, various advanced iron and steel enterprises gradually build hot galvanizing units specially applied to high-strength steel production. The high-strength steel is easy to generate selective oxidation phenomenon due to more alloy elements such as Si, Mn, Cr and the like, so that the wettability of the surface of the strip steel is reduced, and the problem of plating leakage is caused. In order to solve the problem, a pre-oxidation bin is often arranged at the heating section of the high-strength steel production line, air or water vapor is introduced into the pre-oxidation bin during the production process, and the oxidation atmosphere is realized in the pre-oxidation bin, so that the internal oxidation of the alloy elements on the surface of the strip steel is realized. After the strip steel is subjected to preoxidation, the thickness of an oxide film on the surface of the strip steel has an important influence on whether the oxide film can be effectively reduced into sponge iron in the rear section of a furnace area, and at present, no effective means is available for measuring the thickness of the oxide film on the surface of the strip steel at the outlet position of a preoxidation layer.

Disclosure of Invention

The invention provides a method for detecting the thickness of an oxide film on a high-strength steel galvanizing production line, which solves the problem that no effective means is available in the prior art for measuring the thickness of the oxide film on the surface of strip steel at the outlet of a pre-oxidation bin.

In order to solve the technical problem, the invention provides a method for detecting the thickness of an oxide film on a high-strength steel galvanizing production line, which comprises the following steps:

a wedge-shaped pyrometer is arranged at the inlet of the high-strength steel pre-oxidation bin, and a single-wavelength radiation pyrometer is arranged at the outlet of the high-strength steel pre-oxidation bin;

respectively measuring the temperatures of the inlet of the high-strength steel pre-oxidation bin and the outlet of the high-strength steel pre-oxidation bin by using the wedge pyrometer and the single-wavelength radiation pyrometer;

keeping the movement speed of the strip steel and the inlet temperature of the pre-oxidation bin fixed;

ensuring that the oxidation temperature and the oxidation time are fixed, and gradually increasing the dew point or the oxygen content of the pre-oxidation bin;

recording temperature measurement values of the wedge pyrometer and the single-wavelength radiation pyrometer;

and determining the thickness of the oxide film at the outlet position of the strip steel pre-oxidation bin according to the extreme point of the temperature value of the single-wavelength pyrometer.

Preferably, the calculation formula of the thickness of the oxide film at the outlet of the strip steel pre-oxidation bin is as follows:

wherein d is the thickness of the oxide film at the outlet of the strip steel pre-oxidation bin, and lambda is the radiation wavelength of the single-wavelength pyrometer.

Preferably, the step of equipping the high-strength steel pre-oxidation bin with a single-wavelength radiation pyrometer at the outlet comprises the following steps: and a first single-wavelength radiation pyrometer and a second single-wavelength radiation pyrometer are arranged at the outlet of the high-strength steel pre-oxidation bin.

Preferably, the first single-wavelength radiation pyrometer and the second single-wavelength radiation pyrometer use different radiation wavelengths.

Preferably, the step-wise increasing the dew point of the pre-oxidation bin comprises the steps of:

determining a unit dew point difference value;

increasing the unit dew point difference over the previous dew point value to obtain an adjacent subsequent dew point value.

Preferably, the step-by-step increase of the oxygen content of the pre-oxidation bin comprises the steps of:

determining a unit oxygen content difference value;

increasing the unit oxygen content difference over the previous oxygen content value to obtain an adjacent subsequent oxygen content value.

Preferably, the method further comprises the following steps after the oxide film thickness at the outlet position of the strip steel pre-oxidation bin is determined:

obtaining the thickness of an oxide film at the outlet position of the strip steel pre-oxidation bin;

and determining the thickness of the oxide film at other positions of the strip steel by an interpolation method.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

according to the method for detecting the thickness of the oxide film on the high-strength steel galvanizing production line, the thickness change condition of the oxide film is reflected through the temperature measurement value by utilizing the influence rule of the growth of the oxide film on the surface radiance change of the strip steel; and estimating the thickness value of the oxide film on the surface of the strip steel by measuring the wave path difference corresponding to the extreme point of the temperature value by utilizing the interference principle of the oxide film on the surface of the strip steel on the radiation wave. Through the method, the thickness of the oxide film at the outlet of the pre-oxidation bin can be measured to ensure the surface quality of the high-strength steel, and the method is simple, easy to operate and low in cost.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a schematic diagram illustrating the interference of an oxide film on a wave in the prior art;

fig. 2 is a schematic view of an interference effect of an oxide film on a radiation wave in the method for detecting the thickness of the oxide film on a high-strength steel and zinc plating production line provided by the embodiment of the invention.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.

Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Referring to fig. 1 and 2, the invention provides a method for detecting the thickness of an oxide film on a high-strength steel galvanizing production line, which comprises the following steps:

a wedge-shaped pyrometer is arranged at the inlet of the high-strength steel pre-oxidation bin, and a single-wavelength radiation pyrometer is arranged at the outlet of the high-strength steel pre-oxidation bin;

respectively measuring the temperatures of the inlet of the high-strength steel pre-oxidation bin and the outlet of the high-strength steel pre-oxidation bin by using the wedge pyrometer and the single-wavelength radiation pyrometer;

keeping the movement speed of the strip steel and the inlet temperature of the pre-oxidation bin fixed;

ensuring that the oxidation temperature and the oxidation time are fixed, and gradually increasing the dew point or the oxygen content of the pre-oxidation bin;

recording temperature measurement values of the wedge pyrometer and the single-wavelength radiation pyrometer;

and determining the thickness of the oxide film at the outlet position of the strip steel pre-oxidation bin according to the extreme point of the temperature value of the single-wavelength pyrometer.

Referring to fig. 1 and 2, in the embodiment of the present application, it can be considered that 2 times of the thickness of the oxide film is approximately equal to the optical path difference, so that the calculation formula of the thickness of the oxide film at the outlet position of the strip steel pre-oxidation bin can be obtained as follows:

wherein d is the thickness of the oxide film at the outlet of the strip steel pre-oxidation bin, and lambda is the radiation wavelength of the single-wavelength pyrometer.

In the embodiment of the application, the step of equipping the high-strength steel pre-oxidation bin with a single-wavelength radiation pyrometer at the outlet comprises the following steps: and a first single-wavelength radiation pyrometer and a second single-wavelength radiation pyrometer are arranged at the outlet of the high-strength steel pre-oxidation bin.

In the embodiment of the application, in order to improve the calculation accuracy of the thickness of the oxide film at the outlet position of the strip steel pre-oxidation bin, two single-wavelength radiation pyrometers can be used for measuring the temperature at the outlet position of the strip steel pre-oxidation bin, so that the thickness values of the oxide films at the outlet positions of the two strip steel pre-oxidation bins can be calculated respectively, the two data are compared, and if the data are equal or the difference value is within an error range, the calculated thickness of the oxide film is considered to be accurate; if the phase difference value exceeds the error range, the measurement can be carried out again, so that the situation that errors possibly exist in data obtained by adopting only one single-wavelength radiation high-temperature timer is avoided.

In an embodiment of the present application, the first single-wavelength radiation pyrometer and the second single-wavelength radiation pyrometer use different radiation wavelengths. When the first single-wavelength radiation pyrometer and the second single-wavelength radiation pyrometer use different radiation wavelengths lambda₁And λ₂During the process, the thickness of the oxide film at the outlet position of the strip steel pre-oxidation bin can be respectively calculated according to the calculation formula of the thickness of the oxide film at the outlet position of the strip steel pre-oxidation bin, namely:

theoretically, the thickness of the oxide film at the outlet position of the strip steel pre-oxidation bin calculated at the same moment is a unique determined value, namely d₁＝d₂. In practice, d is due to measurement errors₁And d₂The difference value is within the error range, and the calculated thickness of the oxide film is considered to be accurate; if the difference exceeds the error range, the measurement can be carried out again, so that the situation that errors exist in data obtained by adopting single-wavelength radiation high-temperature timing with two radiation wavelengths equal to each other is avoided.

In the embodiment of the present application, the step-by-step increase of the dew point of the pre-oxidation bin comprises the steps of:

determining a unit dew point difference value;

increasing the unit dew point difference over the previous dew point value to obtain an adjacent subsequent dew point value.

Specifically, the unit dew point difference is the change value increased each time the dew point value is increased, and the unit dew point difference can be selected according to actual needs. For example, in order to improve the accuracy of the oxide film thickness calculation and reduce the excessive error caused by the excessive distance between the selected dew points, a smaller unit dew point difference value can be selected, so that a more accurate temperature change curve of the single-wavelength radiation pyrometer can be obtained, the extreme point can be more accurately judged, and the oxide film thickness under the extreme point can be calculated.

In the embodiment of the present application, the step-by-step increasing of the oxygen content in the pre-oxidation bin includes the steps of:

determining a unit oxygen content difference value;

increasing the unit oxygen content difference over the previous oxygen content value to obtain an adjacent subsequent oxygen content value.

Specifically, the unit oxygen content difference is a change value added each time the oxygen content value is increased, and the unit oxygen content difference can be selected according to actual needs. For example, in order to improve the accuracy of the oxide film thickness calculation and reduce the excessive error caused by the excessive distance between the selected oxygen contents, a smaller unit oxygen content difference value can be selected, so that a more accurate temperature change curve of the single-wavelength radiometer pyrometer can be obtained, the extreme point can be more accurately judged, and the oxide film thickness under the extreme point can be calculated.

In the embodiment of the application, after the determining the thickness of the oxide film at the outlet position of the strip steel pre-oxidation bin, the method further comprises the following steps:

obtaining the thickness of an oxide film at the outlet position of the strip steel pre-oxidation bin;

and determining the thickness of the oxide film at other positions of the strip steel by an interpolation method.

In the embodiment of the application, when the thickness of the oxide film at the outlet of the strip steel pre-oxidation bin is calculated, because the thickness of the oxide film at the inlet of the strip steel pre-oxidation bin is 0 (the thickness of the oxide film is approximately equal to 0 because the inlet of the pre-oxidation bin has not yet undergone oxidation reaction), the moving speed of the strip steel is constant, the inlet temperature of the pre-oxidation bin is constant, the oxidation temperature and the oxidation time are constant, and the dew point or the oxygen content is also linearly and uniformly increased, the thickness of the oxide film on the surface of the strip steel is also linearly and uniformly increased, the thickness of the oxide film at the inlet of the strip steel pre-oxidation bin is 0, and the thickness of the oxide film at the outlet of the pre-oxidation bin is d.

The present application is described in detail below with specific examples.

In the embodiment, the thickness of the oxide film on the surface of the strip steel at the outlet of the pre-oxidation bin of the hot-dip galvanizing high-strength steel production line is measured as an example. In an embodiment of the invention, there is provided the production of a hot dip galvanized DP780+ Z dual phase steel product having a thickness of 0.8mm and a width of 0300 mm:

in the production process, the inlet temperature of the pre-oxidation bin is set to be 650 ℃ (namely the temperature measurement value of the wedge-shaped pyrometer is constant to be 650 ℃), the movement speed of the strip steel is 90m/min, and the power of a resistance wire in the pre-oxidation bin is constantly controlled to be 120 KW/h. The initial composition inside the pre-oxidation silo included 4% H2 and 96% N2, after which the content of H2 was gradually reduced to 1%, and the steam generator was turned on to stabilize the internal dew point of the pre-oxidation layer at-50 ℃, -45 ℃, -40 ℃, -35 ℃, -30 ℃, -25 ℃, -20 ℃, -15 ℃, -10 ℃, -5 ℃, 0 ℃, 5 ℃, 10 ℃, respectively, and to record the temperature values respectively displayed by the single-wavelength pyrometer 1 (with a temperature measurement of T1) and the single-wavelength pyrometer 2 (with a temperature measurement of T2), as specified in the following table:

the extreme point corresponding to the measured temperature T1 of the pyrometer No. 1 is-15 ℃, and the thickness of the oxide film at the outlet position of the pre-oxidation bin under the dew point reaches half of the wavelength of the pyrometer, namely

The measured temperature T2 of the No. 2 pyrometer corresponds to an extreme value point of-0 ℃, and the thickness of an oxide film at the outlet position of the pre-oxidation bin under the dew point reaches half of the wavelength of the pyrometer, namely

And when the temperature is minus 60 ℃, the interior of the pre-oxidation bin is approximately considered to be completely reducing atmosphere, the oxide film on the surface of the strip steel is approximately considered to be 0, and then the thickness of the oxide film under each dew point condition is approximately determined by adopting an interpolation method.

According to the method for detecting the thickness of the oxide film on the high-strength steel galvanizing production line, the thickness change condition of the oxide film is reflected through the temperature measurement value by utilizing the influence rule of the growth of the oxide film on the surface radiance change of the strip steel; and estimating the thickness value of the oxide film on the surface of the strip steel by measuring the wave path difference corresponding to the extreme point of the temperature value by utilizing the interference principle of the oxide film on the surface of the strip steel on the radiation wave. Through the method, the thickness of the oxide film at the outlet of the pre-oxidation bin can be measured to ensure the surface quality of the high-strength steel, and the method is simple, easy to operate and low in cost.

Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.