Testing method for judging adhesion quality of paint film of deep-drawing steel plate

Abstract

The invention discloses a testing method for judging the adhesion quality of a paint film of a deep drawing steel plate, and belongs to the technical field of deep drawing steel paint film testing. The testing method mainly comprises the following steps: taking a coated deep drawing plate to be tested, bending the center of the plate to be tested by using a bending machine and a flattening machine, flattening for multiple times, and observing the adhesion degree of a paint film. The invention belongs to the field, and particularly relates to a test method for judging the adhesion quality of a paint film of a deep-drawing steel plate. The invention aims to provide the test method for judging the adhesion quality of the paint film of the deep-drawing steel plate, and the adhesion of the paint film of the deep-drawing steel plate can be quickly judged.

Description

Technical Field

[0001] The invention belongs to the technical field of deep-drawn steel paint film testing, and in particular relates to a testing method for determining the adhesion quality of a deep-drawn steel plate paint film. Background Art

[0002] The paint film attached to the deep-drawn plate plays the role of protecting the steel plate from corrosion and making the plate surface more beautiful. However, due to the influence of the coating process, coating, steel plate surface, etc., the paint film is prone to insufficient adhesion and poor toughness. However, there are few test methods that can provide graded guidance and are easy to operate.

[0003] Patent "A Method for Testing Adhesion of Electrophoretic Paint Film on Automobile Plates" CN113514390A, the test method for paint film adhesion is mainly to immerse the test plate in a boiling solution and an ice-water mixture alternately, and after drying, use a grid knife to cut and stick tape to check the shedding of the coating in the grid area, so as to test the adhesion of the paint film on the surface of the test plate. This method has a complicated process and requires soaking and standing for more than 24 hours, which takes a long time, and requires the preparation of a NaCl solution with a concentration of 1%-10%, a NaOH solution with a concentration of 1%-10%, and deionized water, which is costly, the test cannot be repeated, and the repeatability is poor. The test method described in this patent takes less than half an hour, takes less time, and only needs to use the common testing equipment bending machines and flattening machines in automobile manufacturers for testing, which does not increase the cost, and the process is simple, easy to understand and operate.

[0004] Patent "A paint film adhesion tester" CN118310955A designs an instrument for paint film adhesion testing. By setting a clamping component and a scratching component, a scratch depth from shallow to deep is formed on the surface of the sample. During the change of the scratch depth, the point or area is determined to just scratch the coating and the substrate, and the most suitable scratching depth is confirmed, and a second scratch is performed. The scratches in the final grid area are just scratching the coating and the substrate, so as to obtain the experimental results. This instrument does not have a clear judgment standard when determining that the coating is just scratched to the substrate, and it is impossible to accurately judge whether the scratch is just scratched to the substrate, and the repeatability is poor. In the process of analyzing the experimental results, there is no clear classification and evaluation of the paint film adhesion, and it is impossible to provide guidance for the production and use process. And the tool needs to be replaced during the experiment, which has certain safety hazards. The test method described in this patent has clear grading rules for paint film adhesion, can be repeated, and the test method is relatively safe.

[0005] In summary, this patent is a test method for determining the adhesion quality of the paint film based on the use of bending machines and flattening machines, which are commonly used inspection equipment in steel plants or automobile plants. It can analyze the adhesion quality of the paint film at low cost, easy to operate, quickly, safely and conveniently. Summary of the invention

[0006] The purpose of the present invention is to provide a test method for determining the adhesion quality of paint film on deep-drawn steel plates, which can quickly determine the adhesion of paint film on deep-drawn plates.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] The present invention provides a testing method for determining the adhesion quality of a paint film on a deep-drawn steel plate, comprising the following steps:

[0009] 1). Bend the board to be tested along the center line with a bending machine, flatten it with a flattening machine, bend it in the opposite direction along the previous crease with a bending machine, flatten it with a flattening machine after bending, so that the paint film on both sides of the crease undergoes a stretching and compression process, use an eraser to apply a load force greater than 5N to wipe it back and forth 3 times, observe whether the paint film falls off and whether there are paint film fragments on the eraser. If there are paint film fragments on the eraser, the positioning level is one;

[0010] 2). If it has not fallen off, repeat the operation in step 1, use a bending machine to bend along the previous crease in the direction of the first bending in step 1), flatten it with a flattening machine, and use a rubber hand to apply a load greater than 5N to rub it back and forth 3 times, observe whether the paint film falls off and whether there are paint film fragments on the rubber. If there are paint film fragments on the rubber, it is positioned at level 2;

[0011] 3). If it has not fallen off, repeat the operation of step 2), use a bending machine to bend along the previous crease in the opposite direction of step 2), flatten it with a flattening machine, and use an eraser to apply a load force greater than 5N to wipe it back and forth 3 times, observe whether the paint film falls off and whether there are paint film fragments on the eraser. If there are paint film fragments on the eraser, it is positioned at level three.

[0012] Furthermore, the eraser is Deli 71070.

[0013] Furthermore, if the level 1 product is seriously unqualified, it is necessary to check the coating and substrate processes and make comprehensive rectifications.

[0014] Furthermore, if level 2 fails, at least one of the coating process or substrate performance must be optimized before verification again.

[0015] Furthermore, if the level 3 is qualified, the corresponding steel plate and coating process that pass the test are considered to have qualified paint film adhesion quality.

[0016] Compared with the prior art, the beneficial technical effects of the present invention are:

[0017] The method of the present invention can quickly determine the adhesion quality of the paint film of the deep-drawn plate, so as to efficiently identify the application scenarios of the deep-drawn plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the first bend;

[0020] Figure 2 Repeat the bending diagram of step 1;

[0021] Figure 3 This is a bending diagram that repeats step 2;

[0022] Figure 4 This is an example diagram of the test process. DETAILED DESCRIPTION

[0023] A test method for determining the adhesion quality of paint film on deep-drawn steel sheets, comprising:

[0024] Take the deep-drawn plate to be tested after painting, use a bending machine and a flattening machine to bend and flatten the center of the plate for multiple times, and observe the adhesion of the paint film; specifically:

[0025] 1. Bend the board to be tested along the center line with a bending machine, flatten it with a flattening machine, bend it in the opposite direction along the previous crease with a bending machine, flatten it with a flattening machine after bending, so that the paint film on both sides of the crease undergoes a stretching and compression process, use an eraser (Deli 71070) to apply a load force greater than 5N to wipe it back and forth (one reciprocating stroke is counted as one stroke) for 3 times, observe whether the paint film falls off and whether there are paint film fragments on the eraser. If there are paint film fragments on the eraser, the positioning level is one; if Figure 1 As shown;

[0026] 2. If it has not fallen off, repeat the operation in step 1, use a bending machine to bend along the previous crease in the direction of the first bending in step 1, and use a flattening machine to flatten it after bending. Use an eraser (Deli 71070) to apply a load force greater than 5N and rub it back and forth (one time for each reciprocating is counted as one time) for 3 times, and observe whether the paint film falls off and whether there are paint film fragments on the eraser. If there are paint film fragments on the eraser, the positioning level is two; if Figure 2 As shown;

[0027] 3. If it has not fallen off, repeat the operation in step 2, use a bending machine to bend along the previous crease in the opposite direction of step 2, flatten it with a flattening machine, and use an eraser (Deli 71070) to apply a load force greater than 5N to wipe it back and forth 3 times (one back and forth is counted as one time) to observe whether the paint film falls off and whether there are paint film fragments on the eraser. If there are paint film fragments on the eraser, the positioning level is three; if Figure 3 As shown;

[0028] Level 1 is seriously unqualified and requires a review of the coating and substrate processes for comprehensive rectification.

[0029] If level 2 is unqualified, the coating process or substrate performance must be optimized and then verified again.

[0030] Level 3: Only the corresponding steel plates and coating processes that pass this test can be considered to have qualified paint film adhesion quality.

[0031] Example

[0032] Take the painted deep-drawn plate to be tested.

[0033] 1. Use a bending machine to bend the board to be tested, and use a flattening machine to flatten the board to be tested.

[0034] 2. Bend the board to be tested in the opposite direction along the crease using a bending machine, and flatten the board to be tested using a flattening machine.

[0035] 3. Use an eraser to apply a load greater than 5N and rub back and forth three times. Observe that the paint film does not fall off and there are no paint film fragments on the eraser.

[0036] 4. Bend the board to be tested along the crease in the direction of the first bend using a bending machine, and flatten the board to be tested using a flattening machine.

[0037] 5. Use an eraser to apply a load greater than 5N and rub back and forth three times. Observe that the paint film falls off and there are paint film fragments stuck to the eraser.

[0038] 6. Set the board to be tested as level 2

[0039] 7. The test process example diagram is as follows Figure 4 shown.

[0040] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A test method for determining the adhesion quality of paint film on deep-drawn steel sheets, characterized in that: The steps include: 1). Bend the board to be tested along the center line with a bending machine, flatten it with a flattening machine, bend it in the opposite direction along the previous crease with a bending machine, flatten it with a flattening machine after bending, so that the paint film on both sides of the crease undergoes a stretching and compression process, use an eraser to apply a load force greater than 5N to wipe it back and forth 3 times, observe whether the paint film falls off and whether there are paint film fragments on the eraser. If there are paint film fragments on the eraser, the positioning level is one; 2). If it has not fallen off, repeat the operation in step 1, use a bending machine to bend along the previous crease in the direction of the first bending in step 1), flatten it with a flattening machine, and use a rubber hand to apply a load greater than 5N to rub it back and forth 3 times, observe whether the paint film falls off and whether there are paint film fragments on the rubber. If there are paint film fragments on the rubber, it is positioned at level 2; 3). If it has not fallen off, repeat the operation of step 2), use a bending machine to bend along the previous crease in the opposite direction of step 2), flatten it with a flattening machine, and use an eraser to apply a load force greater than 5N to wipe it back and forth 3 times, observe whether the paint film falls off and whether there are paint film fragments on the eraser. If there are paint film fragments on the eraser, it is positioned at level three.

2. The test method for determining the paint film adhesion quality of deep-drawn steel sheets according to claim 1, characterized in that: The rubber is Deli 71070.

3. The test method for determining the paint film adhesion quality of deep-drawn steel sheets according to claim 1, characterized in that: Level 1 is seriously unqualified and requires a review of the coating and substrate processes for comprehensive rectification.

4. The test method for determining the paint film adhesion quality of deep-drawn steel sheets according to claim 1, characterized in that: If level 2 is unqualified, the coating process or substrate performance must be optimized and then verified again.

5. The test method for determining the paint film adhesion quality of deep-drawn steel sheets according to claim 1, characterized in that: Level 3 is qualified. The corresponding steel plates and coating processes that pass this test are considered to have qualified paint film adhesion quality.

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