KR20140023693A - Evaluation apparatus for pickling property and evaluation method for pickling property using the same - Google Patents

Abstract

According to an embodiment of the present invention, an apparatus for evaluating pickling properties comprises: a color difference measuring unit which measures a color difference value of a moving material in order to determine the pickling properties thereof by comparing with a set color difference value; and a moving unit which is connected with the color difference measuring unit in order to move the color difference measuring unit by corresponding the proceeding of the material. In addition, according to an embodiment of the present invention, a method for evaluating pickling properties comprises: a measuring step which measures a color difference value of the surface of a material after pickling using the apparatus for evaluating pickling properties; and a comparing step which compares the measured color difference value with a set color difference value in order to determine the degree of removing scale by the pickling.

Description

Pickling property evaluating apparatus and pickling property evaluation method using the same {pickling property for pickling property and evaluation method for pickling property using the same}

The present invention relates to a pickling evaluation device and a pickling evaluation method using the same, and more particularly, to an invention for measuring the degree of pickling by measuring the color difference after pickling.

Stainless steel has a denser scale layer than hot steel in hot and cold annealing. However, this scale layer must be removed to ensure the beautiful surface quality and high corrosion resistance inherent in stainless steel. If the scale is not completely removed and remains, it may cause a loss of beautiful surface quality and a decrease in corrosion resistance.

In general, the pickling process of stainless steel cold rolled steel sheet is usually finished by nitric acid, sulfuric acid or mixed acid solution by chemical or electrochemical methods. The presence of residual scale is determined by the composition of the mixed acid solution at the finishing stage of the pickling process, and the composition management of the mixed acid solution is very important for complete removal of the scale. In addition, for this purpose, it should be possible to determine whether the scale remains in accordance with the mixed acid solution composition during operation.

On the other hand, stainless steel is roughly divided into 300 series based on austenite and 400 series based on ferrite or martensite, and the stainless steels have different thicknesses and properties of scale layers formed according to steel grade characteristics. Therefore, when using the same pickling equipment, it is necessary to repeat the operation of changing the acid concentration in the tank with appropriate pickling conditions every time the steel grade is changed.

Therefore, in order to ensure the excellent surface quality inherent in stainless steel regardless of the work schedule, the pickling process should proceed smoothly, and for this purpose, the concentration value of each component of the pickling composition is managed in an appropriate range, It is necessary to determine if it has been completely removed.

As a method of evaluating the residual scale after pickling, a method of measuring the glossiness of a product after pickling by using a glossmeter and visually discriminating by using a magnifying glass were used.

However, the gloss value obtained from the glossmeter fluctuates greatly depending on the surface of the rolled material before annealing, and it is difficult to distinguish between acid and tax. In addition, there is a problem that it is difficult to present a consistent criterion for visual discrimination through a magnifying glass.

Therefore, in order to adjust the composition for pickling, a study on the invention for determining the degree of removal of the scale by pickling has been required.

An object of the present invention is to provide a pickling evaluation device and a pickling evaluation method using the same to determine the degree of removal of the scale by pickling to adjust the composition for pickling.

An acid pickling evaluation apparatus according to an embodiment of the present invention is connected to a color difference measuring means for measuring a color difference value of a moving material and the color difference measuring means to determine pickling properties by comparing with a set color difference value. It may include a moving means for moving in response to the progress of the material.

In addition, the color difference measuring means of the pickling evaluation apparatus according to an embodiment of the present invention is provided at one end of the color difference meter to closely contact the color difference meter and the color difference meter to measure the color difference value of the material It may include a suction pad in close contact with the material by air pressure.

In addition, the color difference measuring means of the pickling evaluation apparatus according to an embodiment of the present invention may further include a non-contact sensor for detecting whether the adsorption pad is in close contact with the material and an air pump for sucking the air of the adsorption pad. have.

In addition, the moving means of the pickling property evaluation apparatus according to an embodiment of the present invention is connected to the body frame and the color difference measuring means installed on the conveying path of the material, the front and rear rotation inserted into the front and rear guide grooves of the body frame It may include a stand frame to provide a roll to move in response to the feed rate of the material.

In addition, the moving means of the pickling property evaluation apparatus according to an embodiment of the present invention provides a left and right guide groove into which the left and right rotation rolls coupled to the color difference measuring means is inserted into the upper and lower guide grooves formed in the stand frame. It may further include a support frame for providing a vertical rotation roll.

In addition, the pickling evaluation method according to another embodiment of the present invention is a pickling step using the pickling evaluation device, a measurement step of measuring the color difference value of the surface of the material after pickling and the measured color difference value compared with the set color difference value It may include a comparison step of determining the degree of removal of the scale by.

In addition, the measuring step of the pickling property evaluation method according to another embodiment of the present invention is the color difference value ΔE ΔE = {(L-L ₀ ) ² + (a-a ₀ ) ² + (b-b ₀ ) ² } ^1/2 , where L: black and white value, a: red green value, b: cyan value, L ₀ : black and white reference value, a ₀ : red green reference value, b ₀ : cyan reference value, and L, a and b are measured values and may be L ₀ = 93.13 to 93.18, a ₀ = -0.83 to -.077, and b ₀ = 1.34 to 1.63.

In addition, in the comparison step of the pickling property evaluation method according to another embodiment of the present invention, when the color difference value ΔE divided by the set color difference value ΔE ₀ is divided by (ΔE / ΔE ₀ ) 1, the pickling is completely When the material is made of 300 series stainless steel, it is determined that the set color difference value is set to 12.5 to 15.0, and when the material is 400 series stainless steel, the set color difference value may be set to 12.5 to 17.0.

In the pickling evaluation apparatus and pickling evaluation method using the same according to the present invention can measure the pickling properties of the pickled material by measuring the color difference. That is, there is an effect that can accurately determine the presence of a scale and the like remaining after pickling on the online on which the pickling operation is performed.

Thereby, there exists an advantage which can continuously monitor the fluctuation | variation of the surface quality of stainless steel, and can manage the surface quality appropriately responding to the change of steel grade and operating conditions.

In addition, there is an advantage in that, by evaluating pickling properties, it is possible to provide a mixed acid concentration of an optimum composition for pickling depending on the respective materials.

As a result, the work can be promptly performed in the step of mixing the composition for pickling, and the stability of the pickling operation can be ensured and the material surface quality can be greatly improved.

1 is a front view schematically showing a pickling property evaluation apparatus according to an embodiment of the present invention.
Figure 2 is a plan view schematically showing an pickling property evaluation apparatus according to an embodiment of the present invention.
Figure 3 is a plan view schematically showing the color difference measuring means of the pickling property evaluation apparatus according to an embodiment of the present invention.
Figure 4 is a flow chart of the pickling property evaluation method according to another embodiment of the present invention.
5A and 5B are graphs and surface photographs of materials for STS 304 steel for explaining a pickling evaluation method according to another embodiment of the present invention.
6a and 6b are graphs and surface photographs of materials for STS 409L steel for explaining a pickling evaluation method according to another embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventive concept. Other embodiments falling within the scope of the inventive concept may readily be suggested, but are also considered to be within the scope of the present invention.

The same reference numerals are used to designate the same components in the same reference numerals in the drawings of the embodiments.

1 is a front view schematically showing the pickling property evaluating apparatus 1 according to an embodiment of the present invention, Figure 2 is a plan view schematically showing a pickling performance evaluating apparatus 1 according to an embodiment of the present invention to be.

1 and 2, the pickling acid evaluating apparatus 1 according to an embodiment of the present invention compares the set color difference value ΔE ₀ to determine pickling properties and determines the color difference value of the material 2. And a moving means 200 connected to the color difference measuring means 100 for measuring [Delta] E) and the color difference measuring means 100 to move the color difference measuring means 100 in response to the progress of the material 2. Can be.

In addition, the moving means 200 of the pickling property evaluating apparatus 1 according to an embodiment of the present invention and the body frame 210 and the color difference measuring means 100 installed on the transfer path of the material (2) and It is connected, and may include a stand frame 220 to move in correspondence with the feed rate of the material (2) by providing a front and rear rotation roll 222 inserted into the front and rear guide grooves 211 of the body frame (210). have.

In addition, the moving means 200 of the pickling property evaluating apparatus 1 according to an embodiment of the present invention, the left and right guide grooves 231 into which the left and right rotation rolls 150 coupled to the color difference measuring means 100 are inserted. It may further include a support frame 230 for providing a vertical rotation roll 232 inserted into the vertical guide groove 221 formed in the stand frame 220.

The pickling property evaluator 1 of the present invention relates to an invention for evaluating the degree of pickling by measuring a color difference after pickling for removing a scale or the like. The color difference means a sensory difference between two colors and is a numerical value that can be calculated by Equation 1 to be described later.

Thereby, pickling property of the pickled raw material 2 can be evaluated. In other words, it is possible to accurately determine the presence or absence of scale remaining after pickling on the online where the pickling operation is performed, and it is possible to continuously monitor the variation of the surface quality of stainless steel, so that the surface quality management appropriately responds to changes in steel grade or operating conditions. There is a possible advantage.

On the other hand, by evaluating pickling properties, it is possible to provide the mixed acid concentration of the optimum composition for pickling according to the respective materials (2), so that the work can be quickly performed in the mixing step of the composition for pickling, and the stability of pickling operation is ensured. Not only can this be done, but it can also contribute greatly to the improvement of the surface quality of the raw material 2.

The color difference measuring means 100 measures the color difference value ΔE to evaluate pickling property in order to determine the degree of cleaning of the surface such as scale after pickling the material 2. A detailed description thereof will be given later with reference to Fig.

The moving means 200 serves to move the color difference measuring means 100. That is, the color difference measuring means 100 may move to a position for evaluating pickling.

To this end, the moving means 200 may provide a body frame 210, a stand frame 220 and a support frame 230.

The body frame 210 may be fixed to the base of the workshop. In addition, front and rear guide grooves 211 may be formed to guide the stand frame 220 to move back and forth.

The front and rear guide grooves 211 may be formed so that the driving force of the forward and backward rotation roll 222 to be described later is sufficient, the front and rear rotation roll 222 that serves as a friction difference for the simplification of the structure can move back and forth. It may be formed as a common hole.

One side of the front and rear guide groove 211 may be provided with a limit sensor 212 for controlling the position when the stand frame 220 is moved back and forth. That is, by detecting the movement of the stand frame 220, it is possible to control the movement speed of the stand frame 220 or the stand frame 220 so as not to move out of the limit position of the movable frame.

The stand frame 220 serves to move the color difference measuring means 100 linked through the support frame 230 back and forth in the moving direction of the material 2. That is, the front and rear rotation rolls 222 provided in the stand frame 220 may be inserted into the front and rear guide grooves 211 formed in the body frame 210 to be moved back and forth.

The front and rear rotation roll 222 may be connected to a driving device providing a driving force. An example may be a motor M and the like. The motor M is provided inside the stand frame 220 and may be connected to the front and rear rotation roll 222 through a speed reducer for adjusting the speed. On the other hand, the rotating shaft of the motor (M) may be supported by a bearing so as to reduce the frictional force when the front and rear rotation roll 222 is rotated.

The stand frame 220 may move the color difference measuring means 100 in the moving direction of the material 2 at a speed corresponding to the moving speed of the material 2, and the color difference measuring means 100 may be moved. It is preferable to move the same as the moving speed of the material (2).

The stand frame 220 may be formed with a vertical guide groove 221 that can move the support frame 230 to be described later, up and down, the vertical guide groove 221 is rotated vertically of the support frame 230 Chain rolls 223 supporting the chain 224 may be provided at both sides such that the chain 224 associated with the roll 232 may move up and down.

The support frame 230 serves to move the color difference measuring means 100 to the left and right in the width direction of the material (2). To this end, the left and right guide grooves 231 may be formed in the support frame 230 to move the left and right rotation rolls 150 connected to the color difference measuring means 100.

On the other hand, the support frame 230 may be provided with a vertical rotation roll 232 that is inserted into the vertical guide groove 221 of the stand frame 220 to drive the support frame 230 up and down. .

The up and down rotation roll 232 may also be connected to a driving device capable of receiving a driving force, for example, there may be a motor (M). In addition, it may be connected via a speed reducer, and the rotating shaft of the motor M may be supported by a bearing so as to reduce the frictional force during rotation.

3 is a plan view schematically showing the color difference measuring means 100 of the pickling property evaluating apparatus 1 according to an embodiment of the present invention.

Referring to FIG. 3, the color difference measuring means 100 of the pickling property evaluating apparatus 1 according to an embodiment of the present invention includes a color difference meter 110 for measuring a color difference value ΔE of the material 2; It may include an adsorption pad 120 is provided at one end of the color difference meter 110 to be in close contact with the color difference meter 110 to the material 2, and adhered to the material 2 by air pressure. .

In addition, the color difference measuring means 100 of the pickling properties evaluating apparatus 1 according to an embodiment of the present invention is a non-contact sensor 130 for detecting whether the adsorption pad 120 is in close contact with the material (2) and It may further include an air pump 140 for sucking the air of the suction pad 120.

The color difference measuring means 100 measures the color difference of the material 2 to evaluate the removal of scale and the like by pickling. To this end, the color difference measuring means 100 may include a color difference meter 110, the absorption pad 120 and the like.

The color difference meter 110 is a device for measuring the color difference value ΔE of the material 2 and is a kind of photochromic meter for measuring the color difference value ΔE. The measurement is capable of both reflection and transmission, and it is possible to directly measure L, a, and b, which are coordinate values for preparing a chromaticity diagram of the material 2.

The adsorption pad 120 serves to closely adhere the color difference meter 110 to the material 2. This is because the color difference meter 110 is in close contact with the material 2 so as to prevent interference of external light in order to measure a reliable color difference value ΔE.

To this end, the adsorption pad 120 may be formed with an air hole 121 connected to the air pump 140. That is, the air hole 121 is formed on one side in contact with the material 2 and the other side connected to the air pump 140, respectively, by the suction of air by the air pump 140 to the material (2) By maintaining the portion in contact with the low pressure state, the adsorption pad 120 can be in close contact with the material (2).

As a result, the sensing end of the color difference meter 110 provided horizontally with the lower end of the suction pad 120 may be in close contact with the material 2.

The adsorption pad 120 is preferably formed of a rubber material as long as the elastic restoration is in close contact with the material 2 by air pressure. However, the present invention is not limited thereto, and may be a material of the adsorption pad 120 according to the present invention as long as the material is able to be elastically restored to be in close contact with the material 2 by air pressure.

On the other hand, when the adsorption pad 120 is in close contact with the air pressure, the shape of the adsorption pad 120 is deformed into a compressed shape, the adsorption pad 120 is elastic restoration or the color difference meter 110 In order to prevent the detection end of the contact is excessively close to the material (2) and damaged, it may be provided with an internal filler 122 inside the suction pad 120.

The internal filler 122 is preferably provided in a shape through which air can pass. As an example, the shape may be a mesh type or a honeycomb structure.

The color difference measuring means 100 may provide a non-contact sensor 130 to prevent the color difference meter 110 from being in close contact with the material 2 and being damaged.

The non-contact sensor 130 serves to measure the degree of close contact between the color difference measuring means 100 and the contact surface of the material (2). However, the non-contact sensor 130 is preferably provided in contact with the material 2 to prevent damage.

According to the distance value with the material 2 detected by the non-contact sensor 130, it is possible to adjust the degree of adhesion by the adsorption pad 120 by adjusting the driving of the air pump 140.

On the other hand, the color difference measuring means 100 may be provided with a left and right rotation roll 150 that can be inserted into the left and right guide grooves 231 of the support frame 230 to be driven.

The left and right rotation roll 150 may also be connected to a driving device capable of receiving a driving force, for example, the motor (M) may be. In addition, a reducer and a bearing may be provided.

Figure 4 is a flow chart of the pickling property evaluation method according to another embodiment of the present invention, Figures 5a and 5b are graphs and materials for the STS 304 steel for explaining the pickling property evaluation method according to another embodiment of the present invention ( 2) is a surface photograph, and FIGS. 6A and 6B are graphs and surface photographs of the material 2 for STS 409L steel for explaining a pickling evaluation method according to another embodiment of the present invention.

4 to 6B, the pickling property evaluation method according to another embodiment of the present invention measures the color difference value ΔE on the surface of the material 2 after pickling by using the pickling property evaluating apparatus 1. The measurement step S1 and the measured color difference value ΔE may be compared with the set color difference value ΔE ₀ to determine a degree of removal of the scale due to pickling.

In addition, the measuring step (S1) of the pickling property evaluation method according to another embodiment of the present invention is the color difference value ΔE ΔE = {(L-L ₀ ) ² + (a-a ₀ ) ² + (b -b ₀ ) ² } ^1/2 , where L: black and white, a: red and green, b: cyan, L ₀ : black and white, a ₀ : red and green, b ₀ : cyan. L, a, and b are measured values, and L ₀ = 93.13 to 93.18, a ₀ = -0.83 to -.077, and b ₀ = 1.34 to 1.63.

In addition, the comparison step (S2) of the pickling property evaluation method according to another embodiment of the present invention when the color difference value ΔE measured by the set color difference value ΔE ₀ is divided by (ΔE / ΔE ₀ ) 1 It is determined that pickling is completely performed, and when the material 2 is 300 series stainless steel, the set color difference value ΔE ₀ is set to 12.5 to 15.0, and when the material 2 is 400 series stainless steel, The color difference value ΔE ₀ can be set from 12.5 to 17.0.

The pickling property evaluation method of the present invention relates to an invention in which the degree of pickling is evaluated by measuring the color difference value ΔE after pickling for removing the scale or the like.

In the measuring step S1, the color difference measuring means 100 is moved to a position where the color difference of the material 2 is to be measured, and then the color difference value ΔE of the surface of the material 2 is brought into close contact with the material 2. It is a step of measuring.

The measurement of the color difference may be calculated by Equation 1 to be described later by measuring the L, a, b values with the color difference meter 110.

[Equation 1]

ΔE = ((L-L ₀ ) ² + (a-a ₀ ) ² + (b-b ₀ ) ² } ^1/2 ,

L ₀ = 93.13 to 93.18, a ₀ = -0.83 to -.077, b ₀ = 1.34 to 1.63

The L value is a white (plus) value, the black (black) is a negative value (-), the a value is a red (plus), a negative value (green) (green) The value b is measured by using a yellow value as a positive value and a blue value as a negative value.

In addition, the L ₀ , a ₀ and b ₀ The value may be determined as a value for the white material 2 as a reference value for calculating the color difference value ΔE. However, the L ₀ , a ₀ and b ₀ The value can be given differently depending on the measurement conditions of the measuring device.

On the other hand, the set color difference value ΔE ₀ is a color difference value ΔE when the scale is mostly removed, and is a reference value for determining the degree of removal of the scale. The color difference value ΔE ₀ set as described above may be obtained by measuring the surfaces L, a, and b of the material 2 from which the scale is mostly removed, and substituting it into Equation 1 above.

For example, when the material 2 is 300-based stainless steel, the set color difference value ΔE ₀ may be set to 12.5 to 15.0. As a specific application, there may be STS 304 steel.

That is, in order to obtain the surface color difference value ΔE according to the surface residual scale in the mixed acid deposition process, the STS 304 steel was subjected to a conventional annealing process and pretreated by a neutral salt electrolysis process.

After dipping the raw material 2 into a mixed solution of 45 ° C. having a composition of 90 g / l nitric acid and 3 to 15 g / l free hydrofluoric acid, the surface color difference value ΔE was measured and shown graphically in FIG. 5A.

As the free hydrofluoric acid concentration increases to 9 g / L, the color difference value ΔE decreases from 21.5 to 14.3, and the free hydrofluoric acid concentration does not change in the range of 9 to 13 g / L.

That is, as shown in the photograph (a) of FIG. 5B, a large number of gray or black scales are observed at the initial hydrofluoric acid concentration of 3 g / L, and a black scale having a high binding force is shown in the photograph of FIG. 5B (B) of the hydrofluoric acid concentration of 7 g / L. Although only remaining, as shown in the (c) picture of Fig. 5b, it can be seen that most of the gray or black scale is not observed at the hydrofluoric acid concentration of 9 g / L.

In addition, it can be seen that the color difference value ΔE increases to 14.8 when the free hydrofluoric acid concentration is 15 g / L or more. That is, as shown in the photograph (b) of FIG. 5B, the gray or black scale is not observed at the hydrofluoric acid concentration of 15 g / l.

In summary, the initial low concentration of free hydrofluoric acid shows a large color difference value (ΔE) due to the residual scale, and maintains a constant value in the region where the residual scale is removed from 9 to 13 g / l. It can be seen that the color difference value ΔE increases as the grain boundary erosion depth deepens.

Thus, the degree of removal of the scale can be confirmed from the change in the color difference value ΔE, whereby the optimum mixed solution concentration can be confirmed to be 9 to 13 g / l. In this case, the color difference value ΔE may be 14.3, which may be a set color difference value ΔE ₀ that can determine the degree of removal of the scale. That is, the annealing scale of the STS 304 steel can be completely eliminated if the surface color difference is measured online to provide a mixed acid composition capable of maintaining 14.3 or less.

In another embodiment, when the material 2 is 400 series stainless steel, the set color difference value ΔE ₀ may be set to 12.5 to 17.0. As a specific application, there may be STS 409L steel.

In other words, in order to obtain the surface color difference value (ΔE) according to the surface residual scale in the mixed acid deposition step, the STS 409L steel was subjected to a conventional annealing step and pretreated by a neutral salt electrolysis step and a sulfuric acid electrolysis step.

After dipping the raw material 2 into a mixed acid solution at 38 ° C. having a composition of 90 g / l nitric acid and 0.5-5 g / l free hydrofluoric acid, the surface color difference value ΔE was measured and shown graphically in FIG. 6A.

As the free hydrofluoric acid concentration increases to 2 g / l, the color difference value ΔE decreases from 23.18 to 14.2, and the free color hydrofluoric acid concentration does not change significantly in the range of 2 to 4 g / l.

That is, as shown in the photograph of (a) of FIG. 6b, a large number of gray or black scales are observed at the initial concentration of 0.5 g / l, and only the gray scale is shown in the (b) of FIG. 6b of the hydrofluoric acid concentration of 1.5 g / l. Although it remains, it can be seen that the scale is largely removed and not observed at the hydrofluoric acid concentration of 2.5 g / L as shown in the photo (c) of FIG. 6B.

 In addition, it can be seen that when the free hydrofluoric acid concentration is 5 g / L or more, the color difference value ΔE increases to 14.95. That is, although the scale is not observed at the hydrofluoric acid concentration of 5 g / L as shown in the photograph (b) of FIG. 6B, it can be observed that the depth of erosion has been deepened due to superacid wash.

In summary, the initial low concentration of free hydrofluoric acid shows a large color difference value (ΔE) due to the residual scale, and maintains a constant value in the region of 2 to 4 g / l, where the residual scale is removed, but if the free hydrofluoric acid concentration is excessive, As a result, the difference in erosion depth between crystal faces increases the color difference value ΔE.

Thus, the degree of removal of the scale can be confirmed from the change in the color difference value ΔE, whereby the optimum mixed solution concentration can be confirmed to be 2 to 4 g / l. In this case, the color difference value ΔE may be 14.2, which may be a set color difference value ΔE ₀ that can determine the degree of removal of the scale. In other words, the annealing scale of the STS 409L steel can be completely removed if the surface color difference is measured online to provide a mixed acid composition capable of maintaining 14.2 or less.

The comparison step S2 is a step of determining the degree of removal of the scale by comparing the measured color difference value ΔE with the set color difference value ΔE ₀ . The comparison of the color difference values ΔE may be determined by dividing the measured color difference value ΔE by the set color difference value ΔE ₀ (ΔE / ΔE ₀ ).

That is, if the color difference value ΔE is greater than the set color difference value ΔE ₀ , which is a case where ΔE / ΔE ₀ > 1, the scale may be determined to remain. Thereby, it is possible to adjust the concentration of the mixed solution so that the scale is completely removed.

On the other hand, if the color difference value ΔE smaller than the set color difference value ΔE ₀ when ΔE / ΔE ₀ <1, it may be determined that the scale is completely removed, thereby maintaining the concentration of the mixed solution.

1: pickling evaluation device 2: material
100: color difference measuring means 110: color difference meter
120: adsorption pad 121: air hole
122: internal filler 130: non-contact sensor
140: air pump 150: left and right rotating roll
200: moving means 210: body frame
211: Front and rear guide grooves 212: Limit sensor
220: stand frame 221: upper and lower guide groove
222: back and forth rotation roll 223: chain roll
224: chain 230: support frame
231: left and right guide grooves 232: vertical rotation roll

Claims (8)

Color difference measuring means for measuring a color difference value of a moving material to determine pickling properties by comparing with a set color difference value; And
Moving means connected to the color difference measuring means to move the color difference measuring means corresponding to the progress of the material;
Pickling evaluation apparatus comprising a. The method of claim 1,
The color difference measuring means,
A color difference meter for measuring a color difference value of the material; And
An adsorption pad provided at one end of the color difference system to closely adhere the color difference system to the material, and adhered to the material by air pressure;
Pickling evaluation apparatus comprising a. 3. The method of claim 2,
The color difference measuring means,
A non-contact sensor for detecting whether the adsorption pad is in close contact with the material; And
An air pump that sucks air from the suction pad;
Pickling evaluation device further comprising. The method of claim 1,
Wherein,
A body frame installed on the conveyance path of the material; And
A stand frame connected to the color difference measuring means, the front and rear rotation rolls inserted into the front and rear guide grooves of the body frame to move in correspondence with the feed speed of the material;
Pickling evaluation apparatus comprising a. 5. The method of claim 4,
The moving means provides a left and right guide groove into which the left and right rotation rolls coupled to the color difference measuring means are inserted, and a support frame providing an up and down rotation roll inserted into the upper and lower guide grooves formed in the stand frame;
Pickling evaluation apparatus further comprising a. A measurement step of measuring a color difference value of the surface of the raw material after pickling by using the pickling evaluation apparatus according to any one of claims 1 to 5; And
A comparison step of determining the degree of removal of the scale by pickling by comparing the measured color difference value with a set color difference value;
Pickling evaluation method comprising a. The method according to claim 6,
In the measuring step, the color difference value ΔE
Calculated by ΔE = {(L-L ₀ ) ² + (a-a ₀ ) ² + (b-b ₀ ) ² } ^1/2 ,
Where L: black and white value, a: red green value, b: cyan value, L ₀ : black and white reference value, a ₀ : red green reference value, b ₀ : cyan reference value,
L, a, b is a measured value, L ₀ = 93.13 ~ 93.18, a ₀ = -0.83 ~ -.077, b ₀ = 1.34 ~ 1.63 pickling evaluation method. In claim 6,
The comparison step determines that pickling is completely performed when the color difference value ΔE divided by the set color difference value ΔE ₀ is smaller than (ΔE / ΔE ₀ ) 1.
When the material is 300 series stainless steel, the set color difference value is set to 12.5 to 15.0,
Pickling evaluation method for setting the set color difference value from 12.5 to 17.0 when the material is 400 series stainless steel.

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