Method for measuring thickness of zinc layer on cross section of hot-dip galvanized plate

Abstract

The invention discloses a method for measuring the thickness of a zinc layer on the cross section of a hot-dip galvanized sheet, and the method comprises the following steps: 1, cutting a hot-dip galvanized sample: cutting a hot-dip galvanized product through a cutter, and obtaining a hot-dip galvanized sheet sample; step 2, sample inlaying: placing the hot-dip galvanized sheet samples obtained in the step 1 in an inlaying device, clamping copper sheets between the hot-dip galvanized sheet samples to separate the hot-dip galvanized sheet samples, placing cushion blocks below the hot-dip galvanized sheet samples, inlaying the samples and the horizontal plane at an angle, grinding, roughly polishing, finely polishing, cleaning, blow-drying, measuring, and calculating to obtain the hot-dip galvanized sheet. According to the method provided by the invention, the problem of difficulty in sample preparation of the zinc layer of the hot-dip galvanized plate can be effectively solved by obliquely embedding the sample to increase the visible thickness of the zinc layer, so that the experiment efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of scanning electron microscope detection, and in particular to a method for measuring the thickness of a zinc layer on a cross section of a hot-dip galvanized sheet. Background Art

[0002] Hot-dip galvanizing is an effective metal corrosion protection process, primarily used on steel structures across various industries. Zinc coating thickness is a critical parameter in many manufacturing processes, particularly in the areas of metal corrosion protection and surface treatment. The zinc layer effectively isolates the substrate from the external environment, thereby preventing corrosion and increasing the product's service life. Beyond functional considerations, zinc coating thickness is also directly related to the product's aesthetic quality. A zinc coating that is too thin may not fully cover the substrate, resulting in surface spots or color variations; while a zinc coating that is too thick may result in a rough surface. Therefore, precise control of zinc coating thickness during the manufacturing process is crucial to ensure the overall performance and sustainability of the product.

[0003] At present, most of the polishing agents for preparing zinc layers in the existing technology are aluminum oxide suspensions. However, due to the large particle size of the aluminum oxide powder, it often leads to heavy scratches on the cross section of the zinc layer and the embedding of aluminum oxide particles in the substrate and the zinc layer. In addition, during the polishing process of the zinc layer of the galvanized sheet, the zinc layer is prone to fall off and wear, and there is a problem of incomplete retention of the zinc layer. In this regard, a method for measuring the thickness of the zinc layer of the cross section of a hot-dip galvanized sheet is provided. The method can measure the thickness of different zinc layers, improve the cross-sectional state of the zinc layer after polishing, and will not cause the problem of zinc layer shedding, so it is universal. Summary of the Invention

[0004] The present invention aims to provide a method for measuring the thickness of the zinc layer of a hot-dip galvanized sheet cross section, so as to improve the experimental efficiency of measuring the thickness of the zinc layer of the hot-dip galvanized sheet.

[0005] In order to solve the problem that the zinc layer sample is easy to fall off, wear and remain incomplete during the grinding process, a method for measuring the thickness of the zinc layer of the hot-dip galvanized sheet cross section is proposed. The method includes the following steps:

[0006] A method for measuring the thickness of the zinc layer on a hot-dip galvanized sheet cross section, characterized in that the method comprises the following steps:

[0007] Step 1, intercepting a hot-dip galvanized sample, intercepting a hot-dip galvanized product to obtain a hot-dip galvanized sheet sample, and measuring the thickness H of the hot-dip galvanized sheet sample;

[0008] Step 2: Sample inlaying: placing the hot-dip galvanized sheet sample obtained in step 1 into an inlaying device, and inserting a copper sheet between the hot-dip galvanized sheet samples to separate the hot-dip galvanized sheet samples (the sample is at least two pieces), and placing a pad under the hot-dip galvanized sheet sample so that the sample is inlaid at an acute angle to the horizontal plane, and polishing to obtain the polished hot-dip galvanized sheet;

[0009] Step 3, measuring, rough polishing, fine polishing, cleaning, and drying the hot-dip galvanized sheet after polishing obtained in step 2, and measuring the upper zinc layer thickness x1, the lower zinc layer thickness x2, and the overall thickness X of the hot-dip galvanized sample after polishing;

[0010] Step 4, calculation, according to x1, x2, X, H, the calculation formula is Calculate the upper zinc layer thickness h1 of the hot-dip galvanized sheet before grinding and the lower zinc layer thickness h2 of the hot-dip galvanized sheet before grinding.

[0011] Optionally, the side length of the hot-dip galvanized sheet sample in step 1 is 10 to 20 mm;

[0012] The thickness H of the hot-dip galvanized sheet sample in step 1 is 0.60 to 2.50 mm;

[0013] In step 2, there shall be no less than two hot-dip galvanized sheet specimens in the specimen inlay.

[0014] Optionally, the thickness of the copper sheet in step 2 is 0.07 to 0.09 mm.

[0015] Optionally, the acute angle in step 2 is 30 to 70°.

[0016] Optionally, the acute angle in step 2 is independently selected from any value among 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, or a range of values ​​between any two of the above points.

[0017] Optionally, the polishing direction described in step 2 is always perpendicular to the mounted hot-dip galvanized sheet sample, and the hot-dip galvanized sheet sample is polished using 180#, 320#, 500#, and 800# grinding wheels in sequence.

[0018] Optionally, the lubricant used for rough polishing in step 3 is a 3.5 μm diamond polishing agent;

[0019] The lubricant used for fine polishing in step 3 is selected from at least one of ethanol and kerosene.

[0020] Optionally, the cleaning agent used in step 3 is at least one of ethanol and acetone.

[0021] Optionally, the measurement in step 3 is performed under a scanning electron microscope.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The method of the present invention is simple and easy to operate. The problems of difficult sample preparation and measurement of the zinc layer of hot-dip galvanized sheet can be effectively solved by obliquely mounting the sample and adding a copper sheet to increase the visible thickness of the zinc layer. The use of a 3.5μm diamond polishing agent to polish the zinc layer can improve the sample preparation quality of the zinc layer cross section, avoid the introduction of foreign matter during the sample preparation process, and thus improve the experimental efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the cross-sectional angles and lengths of the obliquely mounted sample of the present invention;

[0025] Figure 2 This is a schematic diagram of the oblique mounting sample structure of the present invention;

[0026] Figure 3 This is a 1000x morphology image of the zinc layer cross section on the hot-dip galvanized sheet sample prepared in Comparative Example 1 of the present invention;

[0027] Figure 4 This is a 1000x morphology image of the zinc layer cross section on the hot-dip galvanized sheet sample prepared in Comparative Example 2 of the present invention;

[0028] Figure 5 This is a 1000x morphology image of the cross section of the zinc layer on the hot-dip galvanized sheet sample prepared in Example 1 of the present invention;

[0029] Figure 6 This is a 1000x morphology image of the cross section of the zinc layer on the hot-dip galvanized sheet sample prepared in Example 2 of the present invention;

[0030] Figure 7 This is a 1000x morphology image of the cross section of the zinc layer on the hot-dip galvanized sheet sample prepared in Example 3 of the present invention;

[0031] Figure 8 This is a 1000-fold morphology image of the cross section of the zinc layer on the hot-dip galvanized sheet sample prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

[0033] The hot-dip galvanized products in the comparative examples and embodiments of the present invention were all self-produced; unless otherwise specified, the reagents and raw materials were all commercially available products, and the methods used were conventional methods unless otherwise specified.

[0034] A method for measuring the thickness of the zinc layer on a hot-dip galvanized sheet cross section, the method comprising the following steps:

[0035] Step 1, cutting of hot-dip galvanized sample: using a cutting machine to cut a hot-dip galvanized product with a side length of 10 to 20 mm to obtain a hot-dip galvanized sheet sample, and measuring its thickness H;

[0036] Step 2, sample inlay: Place the hot-dip galvanized sheet sample obtained in step 1 in an inlay device, and place a copper sheet with a thickness of 0.09 mm between the hot-dip galvanized sheet samples to separate the hot-dip galvanized sheet samples (at least two samples are shown), and place a pad under the hot-dip galvanized sheet sample so that the sample is inlaid at an angle of 30° to 70° to the horizontal plane to obtain the inlaid hot-dip galvanized sheet sample;

[0037] Step 3, sample polishing: Use 180#, 320#, 500#, and 800# sandpaper to polish the embedded hot-dip galvanized sheet sample obtained in step 2 in sequence. The polishing direction is perpendicular to the embedded hot-dip galvanized sheet sample and is always maintained in the same direction until the cross section of the hot-dip galvanized sheet sample is completely exposed, thereby obtaining the polished hot-dip galvanized sheet sample;

[0038] Step 4, polishing the sample, using polishing agent I to perform rough polishing on the hot-dip galvanized sheet sample after polishing in step 3, and then using polishing agent II to perform fine polishing on the sample after fine polishing to obtain a polished hot-dip galvanized sheet sample;

[0039] Step 5, sample cleaning, immersing the polished hot-dip galvanized sheet sample obtained in step 4 in ethanol, ultrasonically cleaning it, and drying it to obtain a cleaned hot-dip galvanized sheet sample;

[0040] Step 6, thickness measurement, place the hot-dip galvanized sheet sample cleaned in step 5 under a scanning electron microscope for observation, and measure the thickness of the upper zinc layer x1, the thickness of the lower zinc layer x2, and the thickness of the polished hot-dip galvanized sheet sample X;

[0041] Step 7, calculate the thickness of the original zinc layer, according to the above x1, x2, X, H values, the calculation formula is: Calculate the original zinc layer thickness h1, h2;

[0042] Wherein, the polishing agent I in step 4 is 3.5 μm diamond polishing agent; the polishing agent II is ethanol or kerosene.

[0043] Example 1

[0044] Step 1: Cutting of hot-dip galvanized samples: Taking DC56D+Z hot-dip galvanized products as an example, a cutting machine is used to cut hot-dip galvanized samples with a side length of 15×15 mm, and the average thickness H is measured to be 0.78 mm.

[0045] Step 2, sample inlay: Place the hot-dip galvanized sample obtained in step 1 in an inlay device (i.e., an inlay machine) for inlaying. To ensure that there is a field of view where the complete coating can be observed, four hot-dip galvanized samples are inlaid together. A 0.09 mm thick copper sheet is sandwiched between each galvanized plate. A trapezoidal pad is placed on one side of the sample so that the sample is at an angle of 40° (inlay angle) to the horizontal plane to ensure that the sample does not fall over when inlaid obliquely. The inlaid hot-dip galvanized plate sample is obtained.

[0046] Step 3, sample polishing: After the inlay is completed, use 180# coarse sandpaper to completely polish out the zinc layer on both sides of the inlaid hot-dip galvanized sheet sample obtained in step 2, and then grind it according to 320#→500#→600#→800# sandpaper. The grinding direction is perpendicular to the sample and keeps the same direction. During the grinding process, it is forbidden to touch water to prevent oxidation of the zinc layer. Until the cross-section of the hot-dip galvanized sample is completely exposed, the polished hot-dip galvanized sheet sample is obtained.

[0047] Step 4, sample polishing, using 3.5μm diamond polishing agent as a polishing lubricant to rough-polish the polished hot-dip galvanized sheet sample obtained in step 3, and then using ethanol to fine-polish the rough-polished hot-dip galvanized sheet sample on a dry velvet polishing cloth to obtain a polished hot-dip galvanized sheet sample.

[0048] Step 5, sample cleaning, immersing the polished hot-dip galvanized sheet sample obtained in step 4 in ethanol for ultrasonic cleaning, and then fully drying it with a hair dryer to obtain the cleaned hot-dip galvanized sheet sample.

[0049] Step 6, thickness measurement, the hot dip galvanized sheet sample after cleaning in step 5 is placed under a scanning electron microscope for observation, and the morphology of the upper zinc layer is observed under the scanning electron microscope. Figure 5 The average thickness of the upper zinc layer x1 is 10.98 μm, the average thickness of the lower zinc layer x2 is 10.72 μm, and the average thickness of the entire sample after polishing is 1.02 mm.

[0050] Step 7, calculate the thickness of the original zinc layer according to x1, x2, X, H, by the calculation formula The calculated average thickness of the original zinc layer h1 is 8.41 μm, and the average thickness of h2 is 8.20 μm.

[0051] Example 2

[0052] Step 1, cutting of hot-dip galvanized specimens: DC53D+Z was used as the hot-dip galvanized product, and a cutting machine was used to cut hot-dip galvanized specimens with a side length of 15×15 mm. The average thickness H was measured to be 0.66 mm.

[0053] Step 2, sample inlay: Place the hot-dip galvanized sample obtained in step 1 in an inlay device (i.e., an inlay machine) for inlaying. To ensure that there is a field of view where the complete coating can be observed, four hot-dip galvanized samples are inlaid together. A 0.09 mm thick copper sheet is sandwiched between each galvanized plate. A trapezoidal pad is placed on one side of the sample so that the sample is at an angle of 50° (inlay angle) to the horizontal plane to ensure that the sample does not fall over when inlaid obliquely. The inlaid hot-dip galvanized plate sample is obtained.

[0054] Step 3, sample polishing: After the inlay is completed, use 180# coarse sandpaper to completely polish out the zinc layer on both sides of the inlaid hot-dip galvanized sheet sample obtained in step 2, and then grind it according to 320#→500#→600#→800# sandpaper. The grinding direction is perpendicular to the sample and keeps the same direction. During the grinding process, it is forbidden to touch water to prevent oxidation of the zinc layer. Until the cross-section of the hot-dip galvanized sample is completely exposed, the polished hot-dip galvanized sheet sample is obtained.

[0055] Step 4, sample polishing, using 3.5μm diamond polishing agent as a polishing lubricant to rough-polish the polished hot-dip galvanized sheet sample obtained in step 3, and then using ethanol to fine-polish the rough-polished hot-dip galvanized sheet sample on a dry velvet polishing cloth to obtain a polished hot-dip galvanized sheet sample.

[0056] Step 5, sample cleaning, immersing the polished hot-dip galvanized sheet sample obtained in step 4 in ethanol for ultrasonic cleaning, and then fully drying it with a hair dryer to obtain the cleaned hot-dip galvanized sheet sample.

[0057] Step 6, thickness measurement, the hot dip galvanized sheet sample after cleaning in step 5 is placed under a scanning electron microscope for observation, and the morphology of the upper zinc layer is observed under the scanning electron microscope. Figure 6 As shown, the average value of the upper zinc layer thickness x1 is 10.27 μm, the average value of the lower zinc layer thickness x2 is 10.27 μm, and the average value of the overall thickness X of the sample after polishing is 1.03 mm.

[0058] Step 7, calculate the thickness of the original zinc layer according to x1, x2, X, H, by the calculation formula The calculated average thickness of the original zinc layer h1 is 6.59 μm, and the average thickness of h2 is 6.59 μm.

[0059] Example 3

[0060] The difference from Example 1 is that DC06+Z is used as the hot-dip galvanized sample, a cutting machine is used to cut the hot-dip galvanized sample with a side length of 15×15 mm, and the average thickness H is measured to be 0.87 mm. A 0.09 mm thick copper sheet is sandwiched between each galvanized plate, and a trapezoidal pad is placed on one side of the sample so that the sample is at an angle of 30° (inlay angle) to the horizontal plane to ensure that the sample does not fall over when inlaid at an angle.

[0061] The morphology of the zinc layer was observed by scanning electron microscopy. Figure 7 The average thickness of the upper zinc layer x1 is 7.70μm, the average thickness of the lower zinc layer x2 is 7.58μm, and the average thickness of the entire sample after polishing is 1.00mm. The calculated average thickness of the original zinc layer h1 is 8.90 μm, and the average thickness of h2 is 8.74 μm.

[0062] Example 4

[0063] The difference from Example 1 is that Zn-Al-Mg is used as the hot-dip galvanized sample, a cutting machine is used to cut the hot-dip galvanized sample with a side length of 20×20 mm, and the average thickness H is measured to be 2.00 mm, a 0.09 mm thick copper sheet is sandwiched between each galvanized plate, and a trapezoidal pad is placed on one side of the sample so that the sample is at an angle of 30° (inlay angle) to the horizontal plane to ensure that the sample does not fall over when inlaid at an angle.

[0064] The morphology of the zinc layer was observed by scanning electron microscopy. Figure 8 The average thickness of the upper zinc layer x1 is 27.33μm, the average thickness of the lower zinc layer x2 is 26.98μm, and the average thickness of the entire sample after polishing is 2.30mm. The calculated average thickness of the original zinc layer h1 is 31.56 μm, and the average thickness of h2 is 31.04 μm.

[0065] Comparative Example 1

[0066] Using DC56D+Z as the hot-dip galvanized product, a cutting machine was used to cut hot-dip galvanized sheet samples with a side length of 15×15mm. To ensure that there was a field of view where the complete coating could be observed, the obtained hot-dip galvanized sample was placed in a mounting device (i.e., a mounting machine) for mounting. Four hot-dip galvanized samples were mounted together. After mounting, 180#→320#→500#→600#→800# sandpaper was used for grinding. The grinding direction was perpendicular to the sample and maintained in the same direction. Water was prohibited during the grinding process to prevent oxidation of the zinc layer. After grinding, the surface was polished using an aluminum oxide suspension (aluminum oxide to ethanol mass ratio of 1:10) as a polishing lubricant. During the polishing process, the sample was also prevented from coming into contact with water or aqueous preparations. After polishing, the sample was immersed in analytical pure alcohol for ultrasonic cleaning. After cleaning, it was thoroughly dried with a hair dryer. The average thickness of the zinc layer was measured to be 5.80μm. The zinc layer was partially peeled off, indicating that the use of oblique inlay and additional copper sheets can increase the visible area and achieve better edge protection, as well as more accurate thickness measurement.

[0067] Through the above steps, the morphology of the upper zinc layer was observed by scanning electron microscope. Figure 3 shown.

[0068] Comparative Example 2

[0069] The difference from Example 1 is that, taking the DC56D+Z hot-dip galvanized product as an example, a cutting machine is used to cut a hot-dip galvanized sample with a side length of 15×15mm and the average thickness H is measured to be 0.78mm; the sample inlay (inlay angle is α40°) and the sample polishing process are exactly the same as in Example 1, but an aluminum oxide suspension is used as a polishing lubricant during sample polishing, and the sample is cleaned and dried after polishing. The average thickness of the upper zinc layer x1 is 10.96μm, the average thickness of the lower zinc layer x2 is 10.73μm, and the average thickness of the entire sample after polishing is 1.02mm. The calculated original zinc layer thickness h1 average is 8.40μm, h2 average is 8.23μm. Through the above steps, the morphology of the upper zinc layer is observed by scanning electron microscope. Figure 4 As shown in FIG. 1 , it can be seen that there are many aluminum oxide particles in the cross section of the sample, and the sample preparation effect is worse than that of Examples 1, 2, 3, and 4.

[0070] The above descriptions are merely several embodiments of the present invention and do not constitute any form of limitation to the present invention. Although the present invention is disclosed as above in terms of preferred embodiments, they are not intended to limit the present invention. Any technician familiar with the present profession who, without departing from the scope of the technical solution of the present invention, makes slight changes or modifications using the technical contents disclosed above are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for measuring the thickness of the zinc layer on the cross section of a hot-dip galvanized sheet, characterized in that: The method comprises the following steps: Step 1, intercepting a hot-dip galvanized sample, intercepting a hot-dip galvanized product to obtain a hot-dip galvanized sheet sample, and measuring the thickness H of the hot-dip galvanized sheet sample; Step 2: Inlaying the sample. The hot-dip galvanized sheet sample obtained in step 1 is placed in an inlaying device. Copper sheets are sandwiched between the hot-dip galvanized sheet samples to separate the hot-dip galvanized sheet samples. Pads are placed under the hot-dip galvanized sheet samples to make the sample inlay at an acute angle to the horizontal plane. The sample is polished to obtain a polished hot-dip galvanized sheet. Step 3, measuring, rough polishing, fine polishing, cleaning, and drying the hot-dip galvanized sheet after polishing obtained in step 2, and measuring the upper zinc layer thickness x1, the lower zinc layer thickness x2, and the overall thickness X of the hot-dip galvanized sample after polishing; Step 4, calculation, according to x1, x2, X, H, the calculation formula is Calculate the upper zinc layer thickness h1 of the hot-dip galvanized sheet before grinding and the lower zinc layer thickness h2 of the hot-dip galvanized sheet before grinding.

2. The measuring method according to claim 1, wherein The side length of the hot-dip galvanized sheet sample in step 1 is 10 to 20 mm; The thickness H of the hot-dip galvanized sheet sample in step 1 is 0.60 to 2.50 mm.

3. The measuring method according to claim 1, wherein The thickness of the copper sheet in step 2 is 0.07-0.09 mm; In step 2, there shall be no less than two hot-dip galvanized sheet specimens in the specimen inlay.

4. The measuring method according to claim 1, wherein The acute angle in step 2 is 30 to 70 degrees.

5. The measuring method according to claim 1, wherein: The polishing direction described in step 2 is always perpendicular to the mounted hot-dip galvanized sheet sample, and the hot-dip galvanized sheet sample is polished using 180#, 320#, 500#, and 800# in sequence.

6. The measuring method according to claim 1, characterized in that The lubricant used for rough polishing in step 3 is 3.5 μm diamond polishing agent; The lubricant used for fine polishing in step 3 is selected from at least one of ethanol and kerosene.

7. The measuring method according to claim 1, characterized in that The cleaning agent used in step 3 is at least one of ethanol and acetone.

8. The measuring method according to claim 1, wherein: The measurements in step 3 were performed under a scanning electron microscope.

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