JP3353456B2 - Online management of surface treatment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an undercoating management method for controlling the amount of chromate, primer and the like attached to the surface of a steel material on-line as an undercoating treatment when a steel material is provided with an anticorrosion coating.

[0002]

2. Description of the Related Art When an anticorrosion coating is applied to a steel material, a base treatment such as a chromate treatment for attaching a chromate to the steel material surface or a primer treatment for attaching a primer is performed to improve the adhesion of the anticorrosion coating to the steel material surface. You. It is known that these treatments have a remarkable effect on improvement of water resistance and cathodic electrolytic peeling resistance in combination with cathodic protection, and in particular, heavy coating of about 0.5 to 5 mm with a polyolefin resin or a polyurethane resin. It is widely used as a base treatment when applying an anticorrosion coating. Since the performance of these chromate treatment and primer treatment varies depending on the amount of adhesion, the management of the amount of chromate and primer adhesion is an important point.

[0003] The amount of chromate adhering can be increased or decreased by changing the concentration of chromic acid to be applied. However, there is no suitable method for monitoring the amount of chromate adhering on-line conventionally. Regarding the treatment, although a method for quantifying the amount of chromate adhering using fluorescent X-rays of Cr has been developed,
This method is effective in the case of having a flat and smooth surface such as a thin plate.However, for a target whose steel material has a curvature like a steel pipe and whose surface is rough due to blasting, an error may occur. Had the disadvantage of becoming larger.

On the other hand, for the primer treatment, a method of directly measuring the film thickness by an electromagnetic thickness gauge is known, but this measurement is usually performed off-line, and the measurement is performed continuously after the primer coating. In the case where an anticorrosion coating is applied, a person only measures the film thickness in a spot,
No online measurements have been made. In addition, when a person performs spot measurement, the probe is brought into contact with a continuously moving steel material, and measurement is performed while following the movement of the steel material for several seconds.

As a technique in the same technical field, Japanese Patent Laid-Open No.
There is a technique disclosed in Japanese Patent No. 172762. This method is a technique of differentiating a clean portion and a non-clean portion by binarized image processing, and determining the cleanliness of the steel material based on the area ratio of the clean portion. However, when this method is applied to the management of chromate treatment or primer treatment, it is difficult to quantitatively detect the amount of adherence, although it is possible to determine whether or not it is adhered.

[0006]

DISCLOSURE OF THE INVENTION The present invention quantitatively grasps and manages the amount of chromate and / or primer adhered in a process of successively coating chromate and / or primer as a base treatment of an anticorrosion-coated steel material. An object of the present invention is to provide an online management method of a base treatment.

[0007]

According to the present invention, there is provided an on-line management method for undercoating according to the present invention. In the process of applying undercoating to a surface of a metal while moving the metal, the surface of the metal before and after the undercoating is removed. Photographing and analyzing the image to obtain the color difference and / or gloss change amount of the metal material surface before and after the base treatment, and the previously obtained color difference and / or gloss change amount and the adhesion of the base treatment substance The method is characterized in that the method includes a step of determining the amount of the base treatment substance attached based on the relationship with the amount.

[0008]

According to the present invention, the amount of color difference and gloss change can be obtained by optically grasping the surface properties of the metal material to detect the amount of adhesion of the substrate treatment substance. It is possible to perform detailed management of the undercoating process on the material online.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a block diagram showing a case where the on-line management method of the undercoating treatment according to the present invention is applied to the management of the undercoating treatment on the surface of a steel pipe. In FIG. 2 shows an induction heater arranged at a predetermined interval L along the conveyance path of FIG. After being subjected to blasting, the steel pipe 1 is conveyed to the induction heater 2 from the direction of the arrow while performing a screw motion in which the steel pipe 1 is moved in the axial direction while being rotated about the axial center line by a skew roll or the like (not shown) in the longitudinal direction. It is supposed to be. Between the induction heaters 2 and 3, a chromate coating device 4 is provided at a position closer to the upstream side, a primer spray device 5 is provided at a position closer to the downstream side, and further, a surface of the steel pipe 1 is provided downstream of the induction heater 3. A resin extruder 6 for applying a polyolefin coating to the steel pipe 1 is installed facing the passage area of the steel pipe 1, respectively. In the case of polyurethane coating, the resin extruder 6 is a spray coating device.

The chromate coating device 4 includes a brush 4a that comes into contact with the surface of the steel pipe 1 and a chromate liquid supply system 4b that supplies a chromate liquid to the brush 4a. The chromate liquid is supplied from the chromate liquid supply system 4b to the brush 4a. The brush 4a supplies and transfers the chromate liquid to the surface of the rotating steel pipe 1. An aqueous solution containing chromic acid may be used as the chromate solution. In particular, from the viewpoint of anticorrosion properties, a coating type chromate solution containing colloidal silica and hexavalent and trivalent chromium (for example, Cosmer 100 manufactured by Kansai Paint) is used.

The amount of chromate adhering is generally 50 to 500 mg / m ² in terms of Cr. On the other hand, the primer spray device 5 is provided with a nozzle tip 5a for spraying the primer resin in a spray form, and the primer resin is preferably an epoxy primer from the viewpoint of corrosion protection. The epoxy-based primer may be used alone, but usually contains 0.1% by mass to 10% by mass of a coloring pigment by dry weight. If the color pigment is less than 0.1% by mass, the change in color difference due to the change in film thickness is too small, and the quantitativeness of the amount of primer attached is lacking. If it exceeds 10% by mass, the change in color difference becomes saturated at a stage where the amount of adhesion is relatively small. As well as a lack of quantitativeness.

Since the color difference changes under the influence of both the amount of the pigment added and the film thickness, it is important to select an amount of the pigment so that the change around the target film thickness is sufficiently large. is there. In addition, since the pigment has a different concealing property depending on the type, when a pigment having a high concealing property such as carbon black is used, its addition amount is preferably set to 1 mass% or less, and is commonly used. Inorganic pigments such as graphite, red iron oxide, ocher, cobalt blue, cobalt green, chromium oxide, titanium white, zinc white, etc.
Alternatively, in the case of organic pigments such as phthalocyanine blue, phthalocyanine green, and azo pigments, the addition of 1 mass% or more is preferable.

It is desirable that the color tone be different from the color tone of the base. For example, when the chromate treatment is not performed, a silver-white color pigment is avoided. When the chromate treatment is performed, a brown color pigment is used. Good to avoid. Here, the coloring pigment includes a white pigment and a black pigment, but does not include an extender. The extender is a pigment having a refractive index of about 1.5 to 1.6 and poor concealing property, such as calcium carbonate, clay, barium sulfate, silica, mica, and talc. Regarding the extender pigment, its addition is free,
The pigment weight, which is the sum of the coloring pigment and extender pigment, is 60 mass%
It is preferable to set the following.

If it exceeds 60% by mass, the primer coating tends to be brittle, and the adhesion to the top coat is reduced. The color difference is usually displayed in a Lab system. When the color is black or white, the L value (brightness) difference is ΔL. When the color is blue or yellow, it is Δa (difference in yellow-blue). When the color is red or green, Δb is Δb.
When (difference in red-green color) is used as an index, the rate of change with respect to the film thickness increases, and the error decreases. The primer coating is performed in a range of 5 to 100 μm, preferably 10 to 50 μm, in consideration of corrosion resistance and economy.

The video cameras 7 and 8 are located in the conveying area of the steel pipe 1 above and downstream of the chromate coating apparatus 4, and are further downstream of the induction heater 3, and are extruded with resin. Video cameras 9 are arranged upstream of the machine 6. Each video camera 7,
Image analyzers 10, 11, and 12 are connected to the image analyzers 8 and 9, respectively.
Computers 13 and 14 are connected to 1,12, respectively. The video camera 7 shows the surface of the steel tube 1 before the chromate treatment, in other words, the state after the blast treatment, the video camera 8 shows the surface of the steel tube 1 after the chromate treatment, and the video camera 9 shows the surface of the steel tube 1 after the primer treatment. Each surface is photographed, and the image is output to the image analyzers 10, 11, and 12.

Each of the image analyzers 10, 11, and 12 analyzes the image for each predetermined unit area to determine, for example, the lightness, yellowish-blueness, red-greenness, etc., or the glossiness of the surface of the steel pipe 1. 14 is output. The computer 13 determines the color difference ΔE (or ΔL, Δa, Δb) for the same surface of the steel pipe 1 based on the data from the image analyzers 10 and 11.
And / or the glossiness, and the computer 14 also uses the data from the image analyzers 11 and 12 to similarly calculate the color difference ΔE (or ΔL, Δa, Δb) for the same surface of the steel pipe 1.
And / or glossiness, respectively, and color difference and / or glossiness and chromate adhesion amount (C
r conversion amount), based on the relationship between the primer adhesion amount (film thickness), specifically, the calibration curve,
Calculate the amount of primer attached, compare it with the respective target values and eliminate the deviation by using the chromate coating device 4,
The primer spray device 5 is feedback-controlled.

In the narrow sense, the color difference is ΔE = √ [(ΔL)
² + (Δa) ² + (Δb) ² ], but in a broad sense, also includes a lightness difference ΔL, a yellow-blue difference Δa, and a red-green difference Δb.

The computers 13 and 14 are programmed so as to be able to measure a change value in the same part. In the embodiment according to the present invention, the image analysis is performed every 12 seconds. In consideration of the time t ₁ during which the steel pipe 1 moves between the positions 8, the calculation processing is performed using the data t
Processing is performed on the data of the video camera 8 measured after _one . Similarly between the video camera 8 and 9 steel pipe 1 by considering the time to move t _2, and data of the video camera 8 is processing the data of the video camera 9 after the t _2. The value automatically determined by the peripheral speed and the moving speed is programmed in advance, but the peripheral speed and the moving speed of the tube are continuously measured, and the speeds are fed back to automatically calculate the data in the same part. It can also be processed.

The plast surface has an average surface roughness of 30 °.
In a state of 70 μm and a rust removal degree of Sa2.5 or more, the video camera 7 may be omitted by using a pre-measured eigenvalue because it has a substantially constant color tone and gloss. Next, a base treatment process using such a base treatment facility and a management facility will be described. The steel pipe 1 is adjusted to an average surface roughness of 50 μm with a rust removal degree of Sa2.5 or more by blasting, and is conveyed in the axial direction while being rotated around the axis at a predetermined peripheral speed and axial moving speed. , And heated to a predetermined temperature, then the chromate treatment device is supplied quantitatively to the brush 4a in contact with the steel pipe 1 by a pump in the chromate coating device 4, and the chromate solution a Is transferred and applied to the surface of the steel pipe.

Next, an epoxy-based primer b containing a predetermined coloring pigment is spray-coated with a primer spraying device 5 and then heated by an induction heater 3 to be thermally cured and subjected to a primer treatment. Further, after that, the polyethylene resin film is extruded onto the surface of the steel pipe by the resin extruder 6 and is coated with the same, and a heavy corrosion protection coating treatment is performed. On the other hand, before and after such chromate treatment and after the primer coating treatment, the entire peripheral surface of the steel pipe 1 is photographed by the video cameras 7, 8, and 9, respectively, and the images are analyzed by the image analyzers 10, 11, and 1.
Output to 2.

Each of the image analyzers 10, 11, 12 performs an image analysis process for each predetermined unit area, and outputs this to the computers 13, 14. The computer 13 operates on image data input from the image analyzers 10 and 11, and the computer 14 operates on image data input from the image analyzers 11 and 12 on image data obtained from the same surface of the steel pipe 1 with respect to color difference or gloss. Find the change in degree,
The amount of chromate adhering or the amount of primer adhering is determined based on a calibration curve indicating the relationship between the film thickness and the color difference, or the relationship between the film thickness and the amount of change in gloss, which has been obtained in advance.

(Examples of Numerical Values) Hereinafter, specific numerical values will be described. While rotating at a peripheral speed of 1.5 m / min, the steel pipe adjusted to a rust removal degree of Sa2.5 or more and an average surface roughness of 50 μm by blasting is moved at a speed of 1.5 m / min in the axial direction,
The chromate liquid (liquid obtained by diluting Cosmer 100 manufactured by Kansai Paint Co., Ltd. with water) was transferred with a brush, and then an epoxy-based primer containing a different coloring pigment was spray-coated, and then heated and cured by the induction heater 3.

On the other hand, the images captured by the video cameras 7, 8, 9 are converted by the image analyzers 10, 11, 12 into 30 every 12 seconds.
Analyze and process in an area unit of × 30 cm, computer 1
The color difference and the gloss difference were determined in 3 and 14. Here, the color differences are ΔE, Δa, and Δb, all according to JIS Z 873.
Means defined as 0. Next, the results are shown in FIGS.
This will be described with reference to FIG.

(Test Example 1) In Test Example 1, the computer 13 shown in FIG. 1 calculates the color difference ΔE, and calculates the color difference ΔE and the previously obtained color difference ΔE and the value obtained by converting the amount of chromate adhesion to the amount of Cr adhesion. FIG. 2 shows the result of obtaining the Cr adhesion amount based on the calibration curve indicating the relationship.

FIG. 2 is a graph showing the relationship between the value obtained by converting the amount of chromate adhering to the amount of Cr adhering and the color difference ΔE. The horizontal axis represents the amount of Cr adhering (mg / m ² ), and the vertical axis represents the color difference ΔE. It is shown. In the graph, the solid line is the calibration curve, and the x mark is the plot value. As is clear from FIG. 2, the plot value has a small deviation from the calibration curve, and the change in the color difference ΔE with respect to the change in the Cr adhesion amount is large.
It turns out that sufficient quantitativeness is obtained in the range of 0 to 500 mg / m ² .

(Test 2) Table 1 under the conditions shown in Test 1
For samples A to H shown in FIG.
, Color differences ΔE, Δa, Δb were detected, and the thickness of the epoxy primer was controlled.

[0027]

[Table 1]

The results were as shown in FIGS. 3 to 5 are graphs showing the relationship between the color differences ΔE, Δa, Δb and the thickness of the epoxy-based primer. FIG. 3, FIG. 4, FIG.
Indicates the epoxy-based primer film thickness (μm) on the horizontal axis and the color differences ΔE, Δa, Δb on the vertical axis. As is clear from FIG.
While the change in H with respect to the film thickness change is small, the sample C, F, and G show a sufficiently large change with respect to the film thickness change, and sufficient quantitativeness in obtaining the film thickness from the change in the color difference ΔE. Is recognized.

As apparent from FIG. 4, in the case of the color difference Δa, the change with respect to the change in the film thickness of the samples B and E is small, while the change with the film thickness of the samples C and D shows a sufficiently large change. Thus, sufficient quantitativeness in obtaining the film thickness from the change in the color difference Δa is recognized. Further, as is apparent from FIG. 5, in the case of the color difference Δb, the change with respect to the change in the film thickness of the sample C is small, while the change with the film thickness of the sample E shows a sufficiently large change. Sufficient quantitativeness for determining the film thickness is recognized.

Further, as apparent from comparison of FIGS. 4 and 5, it is clear that the color difference .DELTA.a and the color difference .DELTA.b are also used for the film thickness change due to the color difference used in the same samples C and E. The amount of change is remarkably different, and it can be said that it is desirable to determine a color difference corresponding to each sample in advance.

Test Example 3 In Test Example 3, the samples A, C, E, F, and G shown in Table 1
The glossiness of the surface of the epoxy-based primer was determined by using the method, and the relationship with the film thickness was examined. The results are as shown in FIG.
Fig. 6 shows the film thickness (μm) of the epoxy primer coating on the horizontal axis.
, And the gloss is plotted on the vertical axis. In the graph, the solid line indicates the calibration curve, the mark x indicates the sample A, the mark Δ indicates the sample C, the mark サ ン プ ル indicates the sample E, the mark ● indicates the sample F, and the mark □ indicates the plot value of the result of the sample G.

As is clear from FIG. 6, the glossiness changes extremely while the film thickness changes from about 0 to 30 μm, and a sufficient quantitative property for obtaining the film thickness from the glossiness can be obtained. On the other hand, when the film thickness exceeds 30 μm, the change in glossiness rapidly decreases, and sufficient quantitativeness cannot be obtained.

(Test Example 4) FIG. 7 is an explanatory diagram showing an example of online management of the primer film thickness.
The vertical axis indicates the film thickness (μm). Detecting a film thickness on the basis of the color difference or the gloss, the film thickness becomes thinner over time, the results reached 4 hours KomakuAtsu 27μm from the spray started, increasing the primer supply pressure for primer spray device 5 at point P ₁ Thus, the thickness of the primer coating film was increased. After another 4 hours, the primer film thickness was again 27
Since decreased to μm or less, the washing was carried out stopping point P ₂ lines is determined that clogging of the filter portion of the nozzle tip. The ejection amount is recovered by the cleaning, the thickness of the primer coating film is increased, and the primer coating film thickness is reduced to 3 as a whole.
It could be within the range of 0 μm ± 2. Although the embodiment has been described with reference to the case where the steel pipe 1 is subjected to the base treatment, the present invention is not limited to this and can be applied to a flat steel material or the like.

[0034]

As described above, according to the present invention, the amount of change in the color difference and / or the gloss of the surface of the metal material before and after the adhesion of the undercoating substance is determined, and the color difference or the gloss previously determined. Based on the calibration curve that gives the relationship between the variation and the amount of the substrate treatment substance attached, the amount of the substrate treatment substance attached can be detected quickly and accurately, so that the amount of the substrate treatment substance attached can be controlled online. The present invention has excellent effects, for example, the ground treatment efficiency is significantly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an online management apparatus for base processing according to the present invention.

FIG. 2 is a graph showing a relationship between a color difference ΔE and a Cr adhesion amount.

FIG. 3 is a graph showing a relationship between a color difference ΔE and a primer coating film thickness.

FIG. 4 is a graph showing a relationship between a color difference Δa and a primer coating film thickness.

FIG. 5 is a graph showing a relationship between a color difference Δb and a primer coating film thickness.

FIG. 6 is a graph showing a relationship between glossiness and primer coating film thickness.

FIG. 7 is an explanatory diagram showing a management example of a primer film thickness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel pipe 2, 3 Induction heater 4 Chromate coating device 5 Primer spray device 6 Resin extruder 7, 8, 9 Video camera 10, 11, 12 Image analysis device 13, 14 Computer

Continuation of front page (56) References JP-A-6-50722 (JP, A) JP-A-56-151343 (JP, A) JP-A-63-81201 (JP, A) JP-A-3-193897 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 21/89 G01N 21/892 G01B 11/06

Claims (4)

(57) [Claims] In the process of applying a surface treatment to a surface of a metal material while moving the metal material, the surface of the metal material before and after the application of the surface treatment is photographed, and an image thereof is analyzed to analyze the metal before and after the surface treatment. The amount of change in color difference and / or gloss on the surface of the material is determined, and the amount of adhesion of the underlayer treatment substance is determined based on the relationship between the previously determined amount of change in color difference and / or gloss and the amount of adhesion of the underlayer treatment substance. An on-line management method for base treatment, comprising a process. 2. The method according to claim 1, wherein the adhesion amount of the undercoating substance is a chromate adhesion amount and / or a primer adhesion amount. 3. The primer has a dry weight of 0.1 mass.
3. The method according to claim 2, further comprising a coloring pigment of from 10% to 10% by mass. 4. The method according to claim 1, wherein the metal material is a steel pipe or a steel pipe pile.