CN111781037A - Etching agent for displaying 18Ni martensitic steel original austenite grain boundary and display method - Google Patents
Etching agent for displaying 18Ni martensitic steel original austenite grain boundary and display method Download PDFInfo
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- CN111781037A CN111781037A CN202010506032.4A CN202010506032A CN111781037A CN 111781037 A CN111781037 A CN 111781037A CN 202010506032 A CN202010506032 A CN 202010506032A CN 111781037 A CN111781037 A CN 111781037A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 77
- 239000010959 steel Substances 0.000 title claims abstract description 77
- 229910001566 austenite Inorganic materials 0.000 title claims abstract description 75
- 229910000734 martensite Inorganic materials 0.000 title claims abstract description 72
- 238000005530 etching Methods 0.000 title claims abstract description 43
- 238000000034 method Methods 0.000 title claims abstract description 37
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 54
- 238000005406 washing Methods 0.000 claims abstract description 40
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 37
- 238000005498 polishing Methods 0.000 claims abstract description 30
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 21
- 238000001035 drying Methods 0.000 claims abstract description 21
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 21
- 235000019441 ethanol Nutrition 0.000 claims abstract description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 20
- 238000000227 grinding Methods 0.000 claims abstract description 12
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- 229920000742 Cotton Polymers 0.000 claims description 18
- 230000003628 erosive effect Effects 0.000 claims description 15
- 238000002360 preparation method Methods 0.000 claims description 11
- 229910003460 diamond Inorganic materials 0.000 claims description 9
- 239000010432 diamond Substances 0.000 claims description 9
- 239000004744 fabric Substances 0.000 claims description 9
- 238000005507 spraying Methods 0.000 claims description 9
- 238000005260 corrosion Methods 0.000 claims description 7
- 230000007797 corrosion Effects 0.000 claims description 7
- 239000000853 adhesive Substances 0.000 claims description 2
- 230000001070 adhesive effect Effects 0.000 claims description 2
- 230000001747 exhibiting effect Effects 0.000 claims 4
- 238000001514 detection method Methods 0.000 abstract description 4
- 239000013078 crystal Substances 0.000 abstract description 2
- 230000000694 effects Effects 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 26
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- 238000003756 stirring Methods 0.000 description 8
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- 238000000265 homogenisation Methods 0.000 description 4
- 229910000851 Alloy steel Inorganic materials 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- SNIOPGDIGTZGOP-UHFFFAOYSA-N Nitroglycerin Chemical compound [O-][N+](=O)OCC(O[N+]([O-])=O)CO[N+]([O-])=O SNIOPGDIGTZGOP-UHFFFAOYSA-N 0.000 description 2
- 229910000797 Ultra-high-strength steel Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229940073020 nitrol Drugs 0.000 description 2
- 229910001339 C alloy Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 1
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- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
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- 239000007769 metal material Substances 0.000 description 1
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
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- C23F1/00—Etching metallic material by chemical means
- C23F1/10—Etching compositions
- C23F1/14—Aqueous compositions
- C23F1/16—Acidic compositions
- C23F1/28—Acidic compositions for etching iron group metals
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- G01N15/0205—Investigating particle size or size distribution by optical means
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- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
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Abstract
The invention discloses an etchant for displaying a prior austenite grain boundary of 18Ni martensitic steel and a display method, and belongs to the technical field of physical detection of the prior austenite grain boundary. The etchant consists of 4-4.5 parts of nitric acid and 95.5-96 parts of absolute ethyl alcohol. The display method comprises the following steps: (1) preparing an aggressive agent; (2) cutting an 18Ni martensitic steel sample, grinding and polishing a surface to be detected until the surface to be detected is a mirror surface without scratches, washing with water, washing with alcohol, and then drying; (3) immersing the polished surface of the sample prepared in the step (2) into an etchant, taking out after 1.5-5 min, washing with water, washing with alcohol, and then drying; (4) the prior austenite grain boundary was observed under a microscope. The etchant provided by the invention is simple to prepare, good in etching effect, clear and complete in crystal boundary, free of metallographic structure interference and etching product residue, convenient to operate, and easy to control in the etching process.
Description
Technical Field
The invention belongs to the technical field of metallographic detection, and particularly relates to an etchant for displaying a 18Ni martensitic steel prior austenite grain boundary and a display method.
Background
The grain size is a parameter for measuring the size of grains, the yield strength and the fatigue strength of steel can be improved by refining the grains, meanwhile, the steel has higher plasticity and impact toughness, the brittle transition temperature of the steel is reduced, the grain size is an important consideration factor when research personnel formulate and optimize process parameters, and the grain size belongs to the technical field of common metallographic detection. However, because of the difference in the components, heat treatment process, physical and mechanical properties, and application environment of different steel grades, the prior austenite grain boundary display methods of different metal materials are completely different, and the prior austenite grain boundary display method for exploring each steel grade is difficult to explore, and needs to be tried and searched by testers continuously.
The high-end ultrahigh-strength steel has great demands in the aspects of aerospace, advanced equipment manufacturing, new energy and the like due to excellent performance. The 18Ni martensitic steel is one of ultra-high strength steels, has ultra-high strength and excellent comprehensive performance, takes the Fe-Ni martensite with ultra-low carbon as a matrix structure, generates intermetallic compounds through aging treatment for reinforcement, and has unique high strength and toughness, low hardening index, good formability, simple heat treatment process and good welding performance.
At present, aiming at the fact that the prior austenite grain boundary erosion agent and method data of 18Ni martensitic steel are very limited, it is necessary to search a prior austenite corrosion solution and a display method suitable for the 18Ni martensitic steel, and in view of the fact, long-time research is carried out on the prior austenite corrosion agent and method for displaying the prior austenite of the 18Ni martensitic steel, and a simple, practical and effective erosion agent and erosion method are searched.
Disclosure of Invention
The invention aims to provide an erosion agent and an erosion method for 18Ni martensitic steel prior austenite grain boundary.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
an erosion agent for displaying 18Ni martensitic steel original austenite grain boundary comprises 4-4.5 parts of nitric acid and 95.5-96 parts of absolute ethyl alcohol.
The nitric acid and the absolute ethyl alcohol in the etching agent are analytically pure, wherein the mass fraction of the nitric acid is 69%.
A display method of 18Ni martensitic steel prior austenite grain boundaries comprises the following steps:
(1) preparing an etchant: the etchant consists of 4-4.5 parts of nitric acid and 95.5-96 parts of absolute ethyl alcohol;
(2) sample preparation: cutting an 18Ni martensitic steel sample, grinding and polishing the surface to be detected until the surface to be detected is a mirror surface without scratches, washing with water, washing with alcohol, and then drying to obtain the finished product;
(3) sample erosion: immersing the polished surface of the sample obtained in the step (2) into an etchant, taking out after 1.5-5 min, washing with water, washing with alcohol, and then drying;
(4) the prior austenite grain boundary was observed under a microscope.
Further, the invention relates to a display method of 18Ni martensitic steel prior austenite grain boundary, wherein: in the step (1), the nitric acid and the absolute ethyl alcohol are analytically pure, wherein the mass fraction of the nitric acid is 69%.
Further, the invention relates to a display method of 18Ni martensitic steel prior austenite grain boundary, wherein: and (2) preparing an etching agent in the step (1), namely slowly adding nitric acid into absolute ethyl alcohol, and uniformly stirring.
Further, the invention relates to a display method of 18Ni martensitic steel prior austenite grain boundary, wherein: the sample size in the step (2) is detected to be less than 400mm in surface area2Preferably, the height of the sample is 15 to 20 mm.
Further, the invention relates to a display method of 18Ni martensitic steel prior austenite grain boundary, wherein: and (3) in the sample preparation process of the step (2), grinding the surface to be detected from coarse to fine on 180#, 400#, 800# and 1000# water-mill sandpaper in sequence, and spraying diamond polishing agent with the particle size of 2.5 microns on silk polishing cloth with back adhesive for polishing.
Further, the invention relates to a display method of 18Ni martensitic steel prior austenite grain boundary, wherein: and (4) placing a small amount of absorbent cotton in the etching agent in the step (3), and placing the surface to be detected of the sample on the absorbent cotton for corrosion at room temperature.
The method for displaying the 18Ni martensitic steel prior austenite grain boundary comprises the steps of (2) and (3), wherein a portable blower is used for blowing the steel for drying, the wind direction is horizontal to the surface of a sample, and the air is blown to the surface until the surface is dried.
The 18Ni martensitic steel sample is subjected to solution treatment, and the temperature range of the solution treatment is 800-915 ℃.
The principle of the invention is as follows:
the 18Ni martensitic steel is carbon-free or ultra-low carbon alloy steel, the metallographic structure is martensite, and the 18Ni martensitic steel has certain corrosion resistance, but the corrosion resistance is poorer than that of nickel-based steel, stainless steel and the like. The metallographic etchant used in common use is: the ferric chloride hydrochloride aqueous solution can only display metallographic structures and can not display original grain austenite crystal boundaries.
4% -4.5% of nital is selected as an original austenite etching agent of the 18Ni martensitic steel, and because the corrosivity of the etching agent is just matched with the grain boundary corrosion resistance of the 18Ni martensitic steel, the etching agent has sensitivity to the grain boundary, can clearly display the grain boundary, is insensitive to an intragranular martensitic structure, has good inhibition effect, and cannot display the intragranular martensitic structure, so that a perfect original austenite structure is obtained.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. the invention is developed under the background that the development varieties of ultra-high strength steel are continuously increased and the corresponding original austenite detection technology is required to be matched, and has strong reference and popularization values in the industry. 2. The etching agent adopted by the invention is simple to prepare and easy to popularize and use in a laboratory, breaks through the idea that the nitrol is often applied to metallographic structure display, innovations the display record that the nitrol can be applied to alloy steel proto-austenite, and is beneficial to improving the curing thinking of testers. 3. The method starts from selecting the original austenite etching agent for preparing the 18Ni martensitic steel sample, well inhibits the metallographic structure martensite, only clearly displays the original austenite grain boundary, and thus improves the calculation precision of the average grain size grade number of the 18Ni martensitic steel. 4. The method can be applied to the display of the original austenite structure of alloy steel solution treatment samples with similar components.
Drawings
FIG. 1 shows the prior austenite of an 18Ni martensitic steel in example 1;
FIG. 2 shows the prior austenite of the 18Ni martensitic steel of example 2;
FIG. 3 shows the prior austenite of the 18Ni martensitic steel of example 3;
FIG. 4 shows the prior austenite of the 18Ni martensitic steel of example 4;
FIG. 5 shows the prior austenite of the 18Ni martensitic steel of example 5;
FIG. 6 shows the prior austenite of the 18Ni martensitic steel of example 6;
FIG. 7 shows the prior austenite of the 18Ni martensitic steel of example 7.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples.
Example 1
In this embodiment, taking 18Ni martensitic steel as an example, the method for air cooling the sample after solution treatment at 800 ℃ for 15min to show its original austenite structure includes the following steps:
1) preparing an etching agent: slowly adding 4ml of nitric acid with the mass fraction of 69% into 96ml of absolute ethyl alcohol, and uniformly stirring to prepare the etching agent.
2) Sample preparation: cutting an 18Ni martensitic steel sample subjected to solution treatment, sequentially grinding the surface to be detected of the sample on 180#, 400#, 800# and 1000# water-mill sandpaper from coarse to fine, spraying a diamond polishing agent with the particle size of 2.5 microns on silk polishing cloth with gum for polishing until the polished surface is a mirror surface and has no scratch, washing the polished surface with water, washing the polished surface with alcohol, and drying the polished surface with a blower;
3) sample erosion: pouring the prepared etching agent into a glass dish at room temperature, placing a small amount of absorbent cotton at the bottom of the glass dish, placing the surface to be detected of the sample on the absorbent cotton, immersing the surface to be detected in the etching agent, taking out the surface after 2.5min, washing the surface with water, washing the surface with alcohol, and drying the surface with a blower;
4) prior austenite grain boundaries were observed under a microscope.
In the 18Ni martensitic steel of the embodiment, original austenite is subjected to solution treatment at 800 ℃ as shown in FIG. 1, and as can be seen from FIG. 1, the sample is uniformly corroded, the grain boundary is clear and complete, the intragranular structure is not shown, and the accurate original austenite grain size grade number can be obtained.
Example 2
In this embodiment, taking 18Ni martensitic steel as an example, the method for air cooling the sample after solution treatment at 825 ℃ for 15min to show its original austenite structure includes the following steps:
1) preparing an etching agent: slowly adding 4ml of nitric acid with the mass fraction of 69% into 96ml of absolute ethyl alcohol, and uniformly stirring to prepare the etching agent.
2) Sample preparation: cutting an 18Ni martensitic steel sample subjected to solution treatment, sequentially grinding the surface to be detected of the sample on 180#, 400#, 800# and 1000# water-mill sandpaper from coarse to fine, spraying a diamond polishing agent with the particle size of 2.5 microns on silk polishing cloth with gum for polishing until the polished surface is a mirror surface and has no scratch, washing the polished surface with water, washing the polished surface with alcohol, and drying the polished surface with a blower;
3) sample erosion: pouring the prepared etching agent into a glass dish at room temperature, placing a small amount of absorbent cotton at the bottom of the glass dish, placing the surface to be detected of the sample on the absorbent cotton, immersing the surface to be detected in the etching agent, taking out the surface after 3min, washing the surface with water, washing the surface with alcohol, and drying the surface with a blower;
4) prior austenite grain boundaries were observed under a microscope.
In the 18Ni martensitic steel of the embodiment, original austenite is subjected to solution treatment at 825 ℃ as shown in FIG. 2, and as can be seen from FIG. 2, the sample is uniformly corroded, the grain boundary is clear and complete, the intragranular structure is not shown, and the accurate original austenite grain size grade number can be obtained.
Example 3
In this embodiment, taking an 18Ni martensitic steel sample as an example, the method for air cooling the sample after solution treatment at 850 ℃ for 15min comprises the following steps:
1) preparing an etching agent: slowly adding 4ml of nitric acid with the mass fraction of 69% into 96ml of absolute ethyl alcohol, and uniformly stirring to prepare the etching agent.
2) Sample preparation: cutting an 18Ni martensitic steel sample subjected to solution treatment, sequentially grinding the surface to be detected of the sample on 180#, 400#, 800# and 1000# water-mill sandpaper from coarse to fine, spraying a diamond polishing agent with the particle size of 2.5 microns on silk polishing cloth with gum for polishing until the polished surface is a mirror surface and has no scratch, washing the polished surface with water, washing the polished surface with alcohol, and drying the polished surface with a blower;
3) sample erosion: pouring the prepared etching agent into a glass dish at room temperature, placing a small amount of absorbent cotton at the bottom of the glass dish, placing the surface to be detected of the sample on the absorbent cotton, immersing the surface to be detected in the etching agent, taking out the surface after 3min, washing the surface with water, washing the surface with alcohol, and drying the surface with a blower;
4) prior austenite grain boundaries were observed under a microscope.
In the 18Ni martensitic steel of the embodiment, original austenite is subjected to solution treatment at 850 ℃ as shown in FIG. 3, and as can be seen from FIG. 3, the sample is uniformly corroded, the grain boundary is clear and complete, the intragranular structure is not shown, and the accurate original austenite grain size grade number can be obtained.
Example 4
In this embodiment, taking 18Ni martensitic steel as an example, a sample is subjected to solution treatment at 875 ℃ for 15min, and air-cooled, and the method for displaying its original austenite structure includes the following steps:
1) preparing an etching agent: slowly adding 4ml of nitric acid with the mass fraction of 69% into 96ml of absolute ethyl alcohol, and uniformly stirring to prepare the etching agent.
2) Sample preparation: cutting an 18Ni martensitic steel sample subjected to solution treatment, sequentially grinding the surface to be detected of the sample on 180#, 400#, 800# and 1000# water-mill sandpaper from coarse to fine, spraying a diamond polishing agent with the particle size of 2.5 microns on silk polishing cloth with gum for polishing until the polished surface is a mirror surface and has no scratch, washing the polished surface with water, washing the polished surface with alcohol, and drying the polished surface with a blower;
3) sample erosion: pouring the prepared etching agent into a glass dish at room temperature, placing a small amount of absorbent cotton at the bottom of the glass dish, placing the surface to be detected of the sample on the absorbent cotton, immersing the surface to be detected in the etching agent, taking out the surface after 3.5min, washing the surface with water, washing the surface with alcohol, and drying the surface with a blower;
4) prior austenite grain boundaries were observed under a microscope.
In the 18Ni martensitic steel of the embodiment, original austenite is subjected to solution treatment at 875 ℃ as shown in fig. 4, and it can be seen from fig. 4 that the sample is uniformly corroded, the grain boundary is clear and complete, the intragranular structure is not shown, and the accurate original austenite grain size grade number can be obtained.
Example 5
In this embodiment, taking 18Ni martensitic steel as an example, the method for air cooling the sample after solution treatment at 900 ℃ for 15min to show its original austenite structure includes the following steps:
1) preparing an etching agent: slowly adding 4.5ml of nitric acid with the mass fraction of 69% into 95.5ml of absolute ethyl alcohol, and uniformly stirring to prepare the etching agent.
2) Sample preparation: cutting an 18Ni martensitic steel sample subjected to solution treatment, sequentially grinding the surface to be detected of the sample on 180#, 400#, 800# and 1000# water-mill sandpaper from coarse to fine, spraying a diamond polishing agent with the particle size of 2.5 microns on silk polishing cloth with gum for polishing until the polished surface is a mirror surface and has no scratch, washing the polished surface with water, washing the polished surface with alcohol, and drying the polished surface with a blower;
3) sample erosion: pouring the prepared etching agent into a glass dish at room temperature, placing a small amount of absorbent cotton at the bottom of the glass dish, placing the surface to be detected of the sample on the absorbent cotton, immersing the surface to be detected in the etching agent, taking out the surface to be detected after 4min, washing the surface with water, washing the surface with alcohol, and drying the surface with a blower;
4) prior austenite grain boundaries were observed under a microscope.
In the 18Ni martensitic steel of the embodiment, original austenite is subjected to 900 ℃ solution treatment, as shown in FIG. 5, it can be seen from FIG. 5 that the sample is uniformly corroded, the grain boundary is clear and complete, the intragranular structure is not shown, and the accurate original austenite grain size grade number can be obtained.
Example 6
In this embodiment, taking 18Ni martensitic steel as an example, the method for air cooling the sample after solution treatment at 915 ℃ for 15min to show its original austenite structure includes the following steps:
in this embodiment, taking 18Ni martensitic steel as an example, the method for air cooling the sample after solution treatment at 900 ℃ for 15min to show its original austenite structure includes the following steps:
1) preparing an etching agent: slowly adding 4.5ml of nitric acid with the mass fraction of 69% into 95.5ml of absolute ethyl alcohol, and uniformly stirring to prepare the etching agent.
2) Sample preparation: cutting an 18Ni martensitic steel sample subjected to solution treatment, sequentially grinding the surface to be detected of the sample on 180#, 400#, 800# and 1000# water-mill sandpaper from coarse to fine, spraying a diamond polishing agent with the particle size of 2.5 microns on silk polishing cloth with gum for polishing until the polished surface is a mirror surface and has no scratch, washing the polished surface with water, washing the polished surface with alcohol, and drying the polished surface with a blower;
3) sample erosion: pouring the prepared etching agent into a glass dish at room temperature, placing a small amount of absorbent cotton at the bottom of the glass dish, placing the surface to be detected of the sample on the absorbent cotton, immersing the surface to be detected in the etching agent, taking out the surface after 5min, washing the surface with water, washing the surface with alcohol, and drying the surface with a blower;
4) prior austenite grain boundaries were observed under a microscope.
In the 18Ni martensitic steel of the embodiment, original austenite is subjected to solution treatment at 915 ℃ as shown in FIG. 6, and as can be seen from FIG. 6, the sample is uniformly corroded, the grain boundary is clear and complete, the intragranular structure is not shown, and the accurate original austenite grain size grade number can be obtained.
Example 7
In the embodiment, 18Ni martensitic steel is taken as an example, and a sample is subjected to homogenization and solution treatment, wherein the homogenization temperature is 1000 ℃ and the time is 60 min; the method for displaying the original austenite structure of the steel by air cooling at the solid solution temperature of 850 ℃ for 15min comprises the following steps:
1) preparing an etching agent: slowly adding 4ml of nitric acid with the mass fraction of 69% into 96ml of absolute ethyl alcohol, and uniformly stirring to prepare the etching agent.
2) Sample preparation: cutting an 18Ni martensitic steel sample subjected to homogenization and solution treatment, sequentially grinding the surface to be detected of the sample on 180#, 400#, 800# and 1000# water-mill sandpaper from coarse to fine, spraying a diamond polishing agent with the particle size of 2.5 microns on silk polishing cloth with gum for polishing until the polished surface is a mirror surface and has no scratch, washing the polished surface with water, washing the polished surface with alcohol, and drying the polished surface with a blower;
3) sample erosion: pouring the prepared etching agent into a glass dish at room temperature, placing a small amount of absorbent cotton at the bottom of the glass dish, placing the surface to be detected of the sample on the absorbent cotton, immersing the surface to be detected in the etching agent, taking out the surface after 1.5min, washing the surface with water, washing the surface with alcohol, and drying the surface with a blower;
4) prior austenite grain boundaries were observed under a microscope.
In the 18Ni martensitic steel of the embodiment, the original austenite is subjected to 1000 ℃ homogenization and 850 ℃ solution treatment, as shown in FIG. 7, the sample is uniformly corroded, the grain boundary is clear and complete, the intragranular structure is not shown, and the accurate original austenite grain size grade number can be obtained.
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (9)
1. An etchant exhibiting prior austenite grain boundaries of 18Ni martensitic steel, characterized in that: the etching agent consists of 4-4.5 parts of nitric acid and 95.5-96 parts of absolute ethyl alcohol.
2. The etchant exhibiting austenite grain boundaries of 18Ni martensitic steel as claimed in claim 1 wherein: the nitric acid and the absolute ethyl alcohol are analytically pure.
3. The etchant exhibiting austenite grain boundaries of 18Ni martensitic steel as claimed in claim 1 wherein: the mass fraction of the nitric acid is 69%.
4. An etchant exhibiting austenite grain boundaries of 18Ni martensitic steel as claimed in any one of claims 1 to 3 wherein: the 18Ni martensitic steel sample is subjected to solution treatment, and the treatment temperature range is 800-915 ℃.
5. A display method of 18Ni martensitic steel prior austenite grain boundaries is characterized by comprising the following steps:
preparing an etchant: the etchant consists of 4-4.5 parts of nitric acid and 95.5-96 parts of absolute ethyl alcohol;
sample preparation: cutting an 18Ni martensitic steel sample, grinding and polishing the surface to be detected until the surface to be detected is a mirror surface without scratches, washing with water, washing with alcohol, and then drying to obtain the finished product;
sample erosion: immersing the polished surface of the sample obtained in the step (2) into an etchant, taking out after 1.5-5 min, washing with water, washing with alcohol, and then drying;
the prior austenite grain boundary was observed under a microscope.
6. The method of displaying 18Ni martensitic steel prior austenite grain boundaries of claim 5, wherein: in the step (1), the nitric acid and the absolute ethyl alcohol are analytically pure, wherein the mass fraction of the nitric acid is 69%.
7. The method of displaying 18Ni martensitic steel prior austenite grain boundaries of claim 5, wherein: and (3) in the sample preparation process of the step (2), grinding the surface to be detected from coarse to fine on 180#, 400#, 800# and 1000# water-mill sandpaper in sequence, and then spraying diamond polishing agent with the granularity of 2.5 microns on silk polishing cloth with back adhesive for polishing.
8. The method of displaying 18Ni martensitic steel prior austenite grain boundaries of claim 5, wherein: and (4) placing a small amount of absorbent cotton in the etching agent in the step (3), and placing the surface to be detected of the sample on the absorbent cotton for corrosion at room temperature.
9. The method for displaying 18Ni martensitic steel prior austenite grain boundaries according to any one of claims 5 to 8, wherein: the 18Ni martensitic steel sample is subjected to solution treatment, and the treatment temperature range is 800-915 ℃.
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| CN113916634A (en) * | 2021-10-27 | 2022-01-11 | 中国华能集团有限公司 | Method for rapidly representing grain sizes of nickel-base and nickel-iron-base alloys |
| CN114324081A (en) * | 2021-12-30 | 2022-04-12 | 中国航空工业集团公司金城南京机电液压工程研究中心 | Martensitic stainless steel grain forming and displaying method |
| CN114486461A (en) * | 2022-02-09 | 2022-05-13 | 松山湖材料实验室 | High-chromium steel sample, preparation method thereof, and grain size determination and grain boundary display method thereof |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113670698A (en) * | 2021-07-12 | 2021-11-19 | 包头钢铁（集团）有限责任公司 | Austenite steel metallographic etchant and display method |
| CN113916634A (en) * | 2021-10-27 | 2022-01-11 | 中国华能集团有限公司 | Method for rapidly representing grain sizes of nickel-base and nickel-iron-base alloys |
| CN113916634B (en) * | 2021-10-27 | 2024-01-26 | 中国华能集团有限公司 | Method for rapidly representing grain size of nickel-based and nickel-iron-based alloy |
| CN114324081A (en) * | 2021-12-30 | 2022-04-12 | 中国航空工业集团公司金城南京机电液压工程研究中心 | Martensitic stainless steel grain forming and displaying method |
| CN114324081B (en) * | 2021-12-30 | 2024-04-02 | 中国航空工业集团公司金城南京机电液压工程研究中心 | Martensitic stainless steel grain forming and displaying method |
| CN114486461A (en) * | 2022-02-09 | 2022-05-13 | 松山湖材料实验室 | High-chromium steel sample, preparation method thereof, and grain size determination and grain boundary display method thereof |
| CN114486461B (en) * | 2022-02-09 | 2023-11-21 | 松山湖材料实验室 | Sample of high chromium steel, preparation thereof, determination of grain size and grain boundary display method |
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