Evaluation method for protection effect of high-manganese steel high-temperature anti-oxidation coating

Abstract

The invention discloses a method for evaluating the protection effect of a high-manganese steel high-temperature anti-oxidation coating, and relates to the technical field of coating application, and the method comprises the following steps: preparing two cuboid high-manganese steel samples with the size of a * a * b, and polishing any a * a end face in each high-manganese steel sample to obtain a high-manganese steel sample with the size of a * a * b; coloring the polished end surface by using a coloring agent; spraying a high-temperature anti-oxidation coating on the polished surface of one high-manganese steel sample; after the heating furnace is heated to the preset temperature, the two high-manganese steel samples are placed in the heating furnace, the polished faces of the samples face upwards, the samples are taken out after heat preservation is conducted for preset time, and the polished faces face upwards and are air-cooled to the room temperature; oxide skin on the surface of the sample is removed; and scanning the polished surfaces of the two samples, and calculating the protection effect of the high-temperature anti-oxidation coating. The method can quickly and accurately judge the protection effect of the high-manganese steel coating, and is more comprehensive and accurate than the conventional method for judging the protection effect through the burn-out rate.

Description

Technical Field

[0001] The present invention relates to the technical field of coating application, in particular to a method for evaluating the protective effect of high-manganese steel high-temperature anti-oxidation coating. Background Art

[0002] According to the China Classification Society's "Application Guide for High Manganese Austenitic Low-Temperature Steel", the C content of high manganese steel HMA400 is 0.35~0.55%, the Mn content is 22.50~25.50%, the Si content is 0.10~0.50%, the Cr content is 3.00~4.00%, and the Cu content is 0.30~0.70%. Due to the composition characteristics of the steel, the Mn element is easily enriched at the grain boundaries during continuous casting. Mn and Si have a strong affinity with oxygen, and the ingot is more easily oxidized in the heating furnace. In addition, due to the segregation of Mn elements at the grain boundaries, the Mn content at the grain boundaries is higher, the grain boundary oxidation is more serious, and grain boundary cracks will occur. Therefore, spraying anti-oxidation coating on high manganese steel can effectively reduce grain boundary cracks and improve the yield rate.

[0003] The effectiveness of high-temperature antioxidant coatings is generally evaluated using the weight loss method. However, this method has limitations. If the coating cracks at a certain point on the surface of the blank, causing oxidation at that point, even if the weight loss is small, the coating's protective effect is not good. Therefore, the weight loss method is not suitable for evaluating the protective effect of high-temperature coatings on high-manganese steel. Therefore, a convenient and accurate method for evaluating the protective effect of high-temperature antioxidant coatings on high-manganese steel is urgently needed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for evaluating the protective effect of high-manganese steel high-temperature anti-oxidation coating.

[0005] In order to solve the above technical problems, the technical solutions of the present invention are as follows: A method for evaluating the protective effect of high-temperature anti-oxidation coating on high-manganese steel comprises the following steps: Step S101: preparing two rectangular high-manganese steel specimens, each of which has a*a*b dimensions, and polishing any a*a end face of each high-manganese steel specimen, and coloring the polished end face with a colorant; Step S102: spraying a high-temperature anti-oxidation coating on the polished surface of one of the high-manganese steel samples; Step S103: After heating the heating furnace to a preset temperature, two high manganese steel samples are placed in the heating furnace with the polished surfaces facing upwards. After being kept at the temperature for a preset time, the samples are taken out and air-cooled to room temperature with the polished surfaces facing upwards. Step S104: removing the oxide scale on the surface of the sample; Step S105: Scan the polished surfaces of the two samples and calculate the protective effect of the high-temperature anti-oxidation coating using Formula 1, where Formula 1 is: P=(1-A1 / A2)*100%, where A1 is the average depth of the pits in the sample sprayed with the high-temperature anti-oxidation coating, and A2 is the average depth of the pits in the sample not sprayed with the high-temperature anti-oxidation coating.

[0006] As a preferred embodiment of the method for evaluating the protective effect of high-temperature anti-oxidation coating for high-manganese steel according to the present invention, in step S101, preparing two rectangular high-manganese steel specimens includes: Two high manganese steel specimens were cut from the high manganese steel ingot.

[0007] As a preferred solution of the method for evaluating the protective effect of the high-temperature anti-oxidation coating on high manganese steel of the present invention, the cutting method is sawing or wire cutting.

[0008] As a preferred solution of the method for evaluating the protective effect of the high-temperature anti-oxidation coating for high-manganese steel of the present invention, the size of the high-manganese steel sample is 40*40*10 mm.

[0009] As a preferred embodiment of the method for evaluating the protective effect of the high-manganese steel high-temperature anti-oxidation coating according to the present invention, in step S102, the coating thickness of the high-temperature anti-oxidation coating is 200 μm, and the thickness uniformity of the coating is less than or equal to 50 μm.

[0010] As a preferred solution of the method for evaluating the protective effect of high-temperature anti-oxidation coating for high-manganese steel according to the present invention, in step S103, the preset temperature of the heating furnace is 1250° C., and the preset insulation time is 3 hours.

[0011] As a preferred embodiment of the method for evaluating the protective effect of high-temperature anti-oxidation coating for high-manganese steel according to the present invention, in step S105, scanning the polished surfaces of the two samples includes: The polished surfaces of the two specimens were scanned using a 3D profilometer with a magnification of 160 times.

[0012] The beneficial effects of the present invention are: This method utilizes the grain boundary oxidation characteristics of high-manganese steel. If the coating is ineffective, severe oxidation can occur, leading to cracks propagating along the grain boundaries and causing grains to break and fall off along the boundaries, forming surface defects similar to pits. By using the pit depth to quickly and accurately assess the protective effect of high-manganese steel coatings, the effectiveness is more comprehensive and accurate than the previous method of assessing protective effectiveness based on burnout rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0014] Figure 1 Schematic diagram of the pit defect in the sample sprayed with high-temperature anti-oxidation coating; Figure 2 Schematic diagram of the pit defect in the sample not sprayed with high-temperature anti-oxidation coating. DETAILED DESCRIPTION

[0015] In order to make the contents of the present invention more clearly understood, the present invention is further described below in detail based on specific implementation methods in conjunction with the accompanying drawings.

[0016] The present invention provides a method for evaluating the protective effect of a high-temperature anti-oxidation coating on high-manganese steel. The method specifically comprises the following steps: Step S101: prepare two rectangular high manganese steel samples, and the dimensions of the two high manganese steel samples are: a*a*b, and polish any a*a end face of each high manganese steel sample, and color the polished end face with a colorant.

[0017] Specifically, two high-manganese steel specimens with dimensions of a*a*b were cut from a high-manganese steel ingot. One of the a*a end faces of each specimen was sanded to remove surface oxide scale, giving the specimen a metallic color. The polished specimen end faces were then colored with a colorant to ensure they were free of cracks.

[0018] It should be noted that the cutting method of high manganese steel samples is saw cutting or wire cutting, and flame cutting cannot be used to prevent the high manganese steel samples from being heated and cracked during the cutting process.

[0019] In this embodiment, the size of the high manganese steel sample is 40*40*10 mm.

[0020] Step S102: spraying a high-temperature anti-oxidation coating on the polished surface of one of the high manganese steel samples.

[0021] Specifically, a high-temperature coating based on α-Al2O3 was sprayed on the polished end face of one high-manganese steel sample. The other high-manganese steel sample was used as a blank sample and was not sprayed with the high-temperature anti-oxidation coating.

[0022] It should be noted that the coating thickness of the high-temperature anti-oxidation coating is 200 μm, and the thickness uniformity of the coating is less than or equal to 50 μm.

[0023] Step S103: After heating the heating furnace to a preset temperature, two high manganese steel samples are placed in the heating furnace with the polished surfaces facing upwards. After keeping the temperature for a preset time, the samples are taken out, with the polished surfaces facing upwards, and air-cooled to room temperature.

[0024] Specifically, the heating furnace was heated to 1250°C, the high manganese steel sample sprayed with high-temperature anti-oxidation coating was placed with the coating surface facing up in the heating furnace, and the high manganese steel sample not sprayed with high-temperature anti-oxidation coating was placed with the polished surface facing up in the heating furnace, and kept warm for 3 hours before being taken out, the high manganese steel sample sprayed with high-temperature anti-oxidation coating was placed with the coating surface facing up, and the high manganese steel sample not sprayed with high-temperature anti-oxidation coating was placed in a windproof place with the polished surface facing up, and air-cooled to room temperature.

[0025] Step S104: removing the oxide scale on the surface of the sample.

[0026] Step S105: Scan the polished surfaces of the two samples and calculate the protective effect of the high-temperature anti-oxidation coating using Formula 1, where Formula 1 is: P=(1-A1 / A2)*100%, where A1 is the average depth of the pits in the sample sprayed with the high-temperature anti-oxidation coating, and A2 is the average depth of the pits in the sample not sprayed with the high-temperature anti-oxidation coating.

[0027] Specifically, a 3D profilometer with a magnification of 160x was used to scan the polished surfaces of the two specimens. The number of pits in both the specimens sprayed with high-temperature antioxidant coating and the specimens without the coating was generally over ten. The average depth of the grooves in the two high-manganese steel specimens was calculated, and the protective effect was calculated using the following formula: P = (1-A1 / A2) * 100%, where A1 is the average depth of the pits in the specimens sprayed with high-temperature antioxidant coating, in μm, and A2 is the average depth of the pits in the specimens without the coating, in μm.

[0028] Figure 1 Schematic diagram of the pit defect in the sample sprayed with high-temperature anti-oxidation coating. Figure 2 Schematic diagram of the pit defect in the sample not sprayed with high-temperature anti-oxidation coating.

[0029] The above scheme mainly utilizes the grain boundary oxidation characteristics of high manganese steel. If the coating protection effect is not good, the high manganese steel grain boundary oxidation is serious, the cracks extend along the grain boundaries, causing the grains to break and fall off along the grain boundaries, and pit-like defects are formed on the surface. Therefore, the protective effect of the high manganese steel coating can be judged by the depth of the pit.

[0030] It can be seen from this that the technical solution of the present invention can quickly and accurately determine the protective effect of high manganese steel coatings, which is more comprehensive and accurate than the previous method of determining the protective effect by the burn-out rate.

[0031] In addition to the above embodiments, the present invention may also have other implementation methods; any technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A method for evaluating the protective effect of high-temperature anti-oxidation coatings on high-manganese steel, characterized by: The following steps are involved: Step S101: preparing two rectangular high-manganese steel specimens, each of which has a*a*b dimensions, and polishing any a*a end face of each high-manganese steel specimen, and coloring the polished end face with a colorant; Step S102: spraying a high-temperature anti-oxidation coating on the polished surface of one of the high-manganese steel samples; Step S103: After heating the heating furnace to a preset temperature, two high manganese steel samples are placed in the heating furnace with the polished surfaces facing upwards. After being kept at the temperature for a preset time, the samples are taken out and air-cooled to room temperature with the polished surfaces facing upwards. Step S104: removing the oxide scale on the surface of the sample; Step S105: Scan the polished surfaces of the two samples and calculate the protective effect of the high-temperature anti-oxidation coating using Formula 1, where Formula 1 is: P=(1-A1 / A2)*100%, where A1 is the average depth of the pits in the sample sprayed with the high-temperature anti-oxidation coating, and A2 is the average depth of the pits in the sample not sprayed with the high-temperature anti-oxidation coating.

2. The method for evaluating the protective effect of high-temperature anti-oxidation coating for high manganese steel according to claim 1, characterized in that: In step S101, preparing two rectangular high manganese steel samples includes: Two high manganese steel specimens were cut from the high manganese steel ingot.

3. The method for evaluating the protective effect of high-temperature anti-oxidation coating for high manganese steel according to claim 2, characterized in that: The cutting method is saw cutting or wire cutting.

4. The method for evaluating the protective effect of high-temperature anti-oxidation coating for high manganese steel according to claim 2, characterized in that: The size of the high manganese steel sample is 40*40*10 mm.

5. The method for evaluating the protective effect of high-temperature anti-oxidation coating for high manganese steel according to claim 1, characterized in that: In step S102 , the coating thickness of the high-temperature anti-oxidation coating is 200 μm, and the thickness uniformity of the coating is less than or equal to 50 μm.

6. The method for evaluating the protective effect of high-temperature anti-oxidation coating for high manganese steel according to claim 1, characterized in that: In step S103, the preset temperature of the heating furnace is 1250° C., and the preset insulation time is 3 hours.

7. The method for evaluating the protective effect of high-temperature anti-oxidation coating for high manganese steel according to claim 1, characterized in that: In S105, scanning the polished surfaces of the two samples includes: The polished surfaces of the two specimens were scanned using a 3D profilometer with a magnification of 160 times.

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