Method for detecting pulverization of plating layer of electro-galvanized steel plate

Abstract

The invention relates to the technical field of surface testing, in particular to an electro-galvanized steel sheet coating pulverization detection method which comprises the following steps: cutting an electro-galvanized sheet into a square sample; the sample is clamped between the female dies, the male die conducts upward stamping, and stamping is stopped until the sample cracks; the movement displacement of the male die is gradually reduced until the sample does not crack; observing the state of the sample, and marking the sample as an effective sample and an invalid sample; selecting a plurality of samples, measuring the chromatic values of the surfaces of the samples by using a colorimeter, and stamping by using the gradually reduced displacement of the male die; respectively measuring the chromatic values of the outer surfaces of the stamped samples; and calculating the average value of chromatic aberration before and after stamping to reflect the pulverization degree of the galvanized surface of the electro-galvanized steel plate before and after deformation. According to the method, colorimeter analysis and mechanical property testing are combined, and errors caused by manual interpretation of a single detection method are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of surface testing, in particular to a method for detecting the powdering of the coating of a zinc electroplated steel sheet. BACKGROUND

[0002] Currently, the research on the powdering of the coating of a zinc electroplated steel sheet mainly focuses on the detection method and influencing factors. The existing powdering degree detection methods mostly use reference standard patterns to evaluate the powdering grade by manual visual inspection. However, this method has obvious limitations. The manual detection is greatly affected by subjective factors, and the judgment standards of different detection personnel may differ, which makes it difficult to guarantee the accuracy and reliability of the detection results. In addition, when detecting a zinc electroplated steel sheet with a complex curved surface, the traditional method cannot effectively detect the image details on the surface, making it difficult to accurately determine the powdering condition of the metal surface and correctly identify the powdering grade. Therefore, it is of great practical significance and application value to develop an efficient, accurate and objective test method for the powdering of the coating of a zinc electroplated steel sheet. SUMMARY

[0003] In view of the above technical problems, a method for detecting the powdering of the coating of a zinc electroplated steel sheet is provided. The present application mainly uses a concave die to clamp the sample, uses a convex die to stamp the sample, and gradually reduces the displacement of the convex die so that the sample does not crack after stamping. The color difference value before and after the effective sample is stamped is used to judge the powdering degree of the zinc coating surface of the zinc electroplated steel sheet before and after deformation.

[0004] The technical means adopted by the present application are as follows: A method for detecting the powdering of the coating of a zinc electroplated steel sheet, comprising: cutting a zinc electroplated steel sheet into a square sample; clamping the sample between concave dies, and stamping upward with a convex die until the sample cracks and stops stamping; gradually reducing the displacement of the convex die until the sample does not crack; observing the state of the sample and marking the sample as an effective sample and an ineffective sample; selecting multiple samples, measuring the color value of the sample surface using a color difference meter, and stamping using the gradually reduced displacement of the convex die; measuring the color value of the outer surface of the sample after stamping; calculating the average color difference before and after stamping to reflect the powdering degree of the zinc coating surface of the zinc electroplated steel sheet before and after deformation.

[0005] Further, the clamping force of the sample clamped between the concave dies is 100 kN, and the convex die is stamped upward at a speed of 0.5 mm / min to stamp an indentation on the sample until the sample cracks.

[0006] Further, the displacement L of the convex die when the sample cracks is recorded, and the displacement of the convex die is gradually reduced by 0.1 mm as a step until the sample does not crack, and the displacement of the convex die when the sample does not crack is recorded. .

[0007] Furthermore, the valid sample indicates that there are no cracks on the upper and lower surfaces of the sample after stamping; the invalid sample indicates that there are cracks on the upper and lower surfaces of the sample after stamping.

[0008] Furthermore, multiple samples are selected, and the colorimetric values ​​of the sample surfaces are measured using a colorimeter. Set the punch displacement to The sample is stamped, and the stamped sample is the valid sample. The measurements after stamping are then taken. Surface colorimetric values ​​of each sample .

[0009] Further, the average color difference before and after stamping is calculated. :

[0010] Using the average color difference before and after stamping It reflects the degree of change in the galvanized surface of the electro-galvanized steel sheet before and after deformation. The larger the color difference value, the greater the degree of powdering.

[0011] Compared with the prior art, the present invention has the following advantages: The method for detecting powdering of electro-galvanized steel sheet coating provided by this invention combines colorimeter analysis with mechanical property testing, avoiding errors caused by human interpretation in single detection methods (such as cross-cut test or bending test).

[0012] The method for detecting powdering of electro-galvanized steel sheet coating provided by this invention solves the problems of low efficiency, large error, and high destructiveness in traditional detection methods by optimizing the detection process, improving measurement accuracy, and reducing equipment dependence. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a flowchart of the detection method for powdering of the electro-galvanized steel sheet coating in this invention.

[0015] Figure 2 This is a schematic diagram of the sample stamping process in this invention. Detailed Implementation

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0020] like Figure 1 As shown, the present invention provides a method for detecting powdering of the coating on electro-galvanized steel sheets, comprising: cutting the electro-galvanized sheet material into... Square specimen.

[0021] like Figure 2 The sample is clamped between the dies, and the punch presses upward until the sample cracks and the pressing stops. In a preferred embodiment of the present invention, the clamping force of the sample between the dies is 100kN, and the punch presses upward at a speed of 0.5mm / min to punch an indentation on the sample until the sample cracks.

[0022] During implementation, the sample is replaced and stamped under the same conditions, with the punch moving to... Stop at the designated position; observe the specimen's condition. If there are no cracks on either the upper or lower surfaces of the specimen, mark it as a valid specimen and record the punch displacement. If cracks occur on the upper or lower surfaces, repeat the sample replacement process until the punch moves to the desired position. It's time to stop.

[0023] Gradually reduce the displacement of the punch until the sample no longer cracks; in a preferred embodiment of the invention, record the punch displacement when the sample cracks. The punch displacement was gradually reduced in increments of 0.1 mm until the sample did not crack, and the punch displacement at which cracking did not occur was recorded. .

[0024] Observe the state of the sample and mark it as a valid sample and an invalid sample; in a specific implementation, as a preferred embodiment of the present invention, a valid sample means that there are no cracks on the upper and lower surfaces of the sample after stamping; an invalid sample means that there are cracks on the upper and lower surfaces of the sample after stamping.

[0025] Multiple samples are selected, and the surface colorimetric values ​​of the samples are measured using a colorimeter. The samples are then stamped using a progressively decreasing die displacement. The surface colorimetric values ​​of the stamped samples are measured separately. In a preferred embodiment of this invention, the step of selecting multiple samples and measuring their surface colorimetric values ​​using a colorimeter is described. Set the punch displacement to The sample is stamped, and the stamped sample is the valid sample. The measurements after stamping are then taken. Surface colorimetric values ​​of each sample .

[0026] The average color difference before and after stamping is calculated to reflect the degree of powdering on the galvanized surface of the electro-galvanized steel sheet before and after deformation. In a preferred embodiment of this invention, the average color difference before and after stamping is calculated. :

[0027] Using the average color difference before and after stamping It reflects the degree of change in the galvanized surface of the electro-galvanized steel sheet before and after deformation. The larger the color difference value, the greater the degree of powdering.

[0028] In specific implementation, as a preferred embodiment of the present invention Example 1 This embodiment uses an electroplated zinc EGN5 sample as the experimental object to find the sample's fracture limit location. = 11.52 mm; test the color value of the flat sample; take three identical samples for punching, measure the color value of the punched sample. Calculate the average color difference of 6.88.

[0029] Example 2 This example takes electro-galvanized SECC sample as experimental object, and finds the sample rupture limit position = 10.7 mm; test the color value of the flat sample; take three identical samples for punching, measure the color value of the punched sample. Calculate the average color difference of 11.86.

[0030] Through the color change of the sample before and after the limit deformation, the change of the surface zinc layer of the sheet metal under the limit deformation state is fed back. The smaller the change is, the more stable the bonding state of the zinc layer is, and the stronger the anti-powdering ability is. From the experimental results of example 1 and example 2, the zinc layer bonding state of the electro-galvanized EGN5 sample is more stable than that of the electro-galvanized SECC sample, and the anti-powdering ability is stronger.

[0031] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting powdering of the coating on electro-galvanized steel sheets, characterized in that, include: Cut the electro-galvanized sheet into square samples; The sample is clamped between the dies, and the punch is pressed upward until the sample cracks and the pressing is stopped. Gradually reduce the displacement of the punch until the sample no longer cracks; Observe the condition of the samples and mark them as valid and invalid samples; Multiple samples were selected, and the colorimetric values ​​of the sample surfaces were measured using a colorimeter. The samples were then stamped using a progressively decreasing punch displacement. The colorimetric values ​​of the outer surfaces of the stamped samples were measured separately. The average color difference before and after stamping is calculated to reflect the degree of powdering of the galvanized surface of the electro-galvanized steel sheet before and after deformation.

2. The method for detecting powdering of the electro-galvanized steel sheet coating according to claim 1, characterized in that, The clamping force between the die and the sample is 100kN. The punch presses upward at a speed of 0.5mm / min, punching an indentation on the sample until the sample cracks.

3. The method for detecting powdering of the electro-galvanized steel sheet coating according to claim 1, characterized in that, Record the punch displacement L when the sample cracks. Gradually decrease the punch displacement in 0.1 mm increments until the sample no longer cracks, and record the punch displacement when no cracks occur. .

4. The method for detecting powdering of the electro-galvanized steel sheet coating according to claim 1, characterized in that, The term "valid sample" refers to a sample whose upper and lower surfaces are free of cracks after stamping; the term "invalid sample" refers to a sample whose upper and lower surfaces are cracked after stamping.

5. The method for detecting powdering of the electro-galvanized steel sheet coating according to claim 1, characterized in that, Multiple samples are selected, and the colorimetric values ​​of the sample surfaces are measured using a colorimeter. Set the punch displacement to The sample is stamped, and the stamped sample is the valid sample. The measurements after stamping are then taken. Surface colorimetric values ​​of each sample .

6. The method for detecting powdering of the electro-galvanized steel sheet coating according to claim 1, characterized in that, Calculate the average color difference before and after stamping. : Using the average color difference before and after stamping It reflects the degree of change in the galvanized surface of the electro-galvanized steel sheet before and after deformation. The larger the color difference value, the greater the degree of powdering.

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