CN113549917A - Corrosive agent and corrosion method for displaying prior austenite grain boundary of martensitic stainless steel - Google Patents
Corrosive agent and corrosion method for displaying prior austenite grain boundary of martensitic stainless steel Download PDFInfo
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- 238000005260 corrosion Methods 0.000 title claims abstract description 52
- 230000007797 corrosion Effects 0.000 title claims abstract description 52
- 229910001566 austenite Inorganic materials 0.000 title claims abstract description 50
- 229910001105 martensitic stainless steel Inorganic materials 0.000 title claims abstract description 40
- 239000003518 caustics Substances 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 25
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 57
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 44
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 44
- 239000010959 steel Substances 0.000 claims abstract description 44
- OXNIZHLAWKMVMX-UHFFFAOYSA-N picric acid Chemical class OC1=C([N+]([O-])=O)C=C([N+]([O-])=O)C=C1[N+]([O-])=O OXNIZHLAWKMVMX-UHFFFAOYSA-N 0.000 claims abstract description 43
- 238000005530 etching Methods 0.000 claims abstract description 26
- 238000010438 heat treatment Methods 0.000 claims abstract description 18
- 239000013078 crystal Substances 0.000 claims abstract description 16
- 239000003945 anionic surfactant Substances 0.000 claims abstract description 13
- 230000000694 effects Effects 0.000 claims abstract description 11
- 230000005764 inhibitory process Effects 0.000 claims abstract description 10
- 235000019441 ethanol Nutrition 0.000 claims description 35
- 238000004140 cleaning Methods 0.000 claims description 18
- 238000005498 polishing Methods 0.000 claims description 18
- 238000003756 stirring Methods 0.000 claims description 16
- 239000006228 supernatant Substances 0.000 claims description 14
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical group [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 claims description 10
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 claims description 10
- 229920006395 saturated elastomer Polymers 0.000 claims description 8
- 239000011734 sodium Substances 0.000 claims description 7
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims description 6
- DUXXGJTXFHUORE-UHFFFAOYSA-M sodium;4-tridecylbenzenesulfonate Chemical compound [Na+].CCCCCCCCCCCCCC1=CC=C(S([O-])(=O)=O)C=C1 DUXXGJTXFHUORE-UHFFFAOYSA-M 0.000 claims description 6
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 238000007517 polishing process Methods 0.000 claims description 3
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 claims description 3
- 125000001273 sulfonato group Chemical group [O-]S(*)(=O)=O 0.000 claims description 3
- 230000002401 inhibitory effect Effects 0.000 claims description 2
- 230000001747 exhibiting effect Effects 0.000 claims 1
- 229940083575 sodium dodecyl sulfate Drugs 0.000 claims 1
- 235000019333 sodium laurylsulphate Nutrition 0.000 claims 1
- 239000011651 chromium Substances 0.000 abstract description 11
- 239000002253 acid Substances 0.000 abstract description 10
- 229910052804 chromium Inorganic materials 0.000 abstract description 6
- 239000007788 liquid Substances 0.000 description 18
- 238000002360 preparation method Methods 0.000 description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 16
- 239000000203 mixture Substances 0.000 description 9
- 238000004506 ultrasonic cleaning Methods 0.000 description 8
- 230000032683 aging Effects 0.000 description 7
- 229910045601 alloy Inorganic materials 0.000 description 5
- 239000000956 alloy Substances 0.000 description 5
- 238000005520 cutting process Methods 0.000 description 5
- 238000005507 spraying Methods 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 229910052737 gold Inorganic materials 0.000 description 4
- 238000010587 phase diagram Methods 0.000 description 4
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 description 4
- 238000000861 blow drying Methods 0.000 description 3
- 239000012153 distilled water Substances 0.000 description 3
- 229910000734 martensite Inorganic materials 0.000 description 3
- -1 picric acid saturated alcohol Chemical class 0.000 description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 239000002453 shampoo Substances 0.000 description 2
- DAJSVUQLFFJUSX-UHFFFAOYSA-M sodium;dodecane-1-sulfonate Chemical compound [Na+].CCCCCCCCCCCCS([O-])(=O)=O DAJSVUQLFFJUSX-UHFFFAOYSA-M 0.000 description 2
- 208000010444 Acidosis Diseases 0.000 description 1
- 206010067484 Adverse reaction Diseases 0.000 description 1
- 229910000954 Medium-carbon steel Inorganic materials 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 231100000644 Toxic injury Toxicity 0.000 description 1
- 229910000797 Ultra-high-strength steel Inorganic materials 0.000 description 1
- 229960000583 acetic acid Drugs 0.000 description 1
- 230000007950 acidosis Effects 0.000 description 1
- 208000026545 acidosis disease Diseases 0.000 description 1
- 230000006838 adverse reaction Effects 0.000 description 1
- 230000001476 alcoholic effect Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 239000012362 glacial acetic acid Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
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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
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- 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
- G01N1/32—Polishing; Etching
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- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
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- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
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- Investigating And Analyzing Materials By Characteristic Methods (AREA)
- ing And Chemical Polishing (AREA)
Abstract
The invention provides an etchant and an etching method for displaying the prior austenite grain boundary of martensitic stainless steel, wherein the etchant comprises saturated picric acid alcohol solution, and 2-10g of anionic surfactant with corrosion inhibition effect, not less than 3 drops of hydrochloric acid solution and 0.2-2g of steel sheet are contained in every 100ml of saturated picric acid alcohol solution. And putting the sample into the corrosive, and performing metallographic corrosion at room temperature. The corrosive agent has the advantages of simple formula components, low content of strong acid, low corrosivity, no need of heat treatment or heating etching, short corrosion time, clear crystal boundary display and excellent applicability, and is particularly suitable for high-chromium martensitic stainless steel with the Cr content of 9-12%.
Description
Technical Field
The invention belongs to the field of metal material metallographic structure observation, and particularly relates to a corrosive agent for displaying a martensitic stainless steel original austenite grain boundary, a preparation method and a corrosion method thereof, which are particularly suitable for displaying and observing a high-chromium martensitic stainless steel original austenite grain boundary with chromium content of 9-12%.
Background
The low-carbon high-alloy martensitic stainless steel has excellent comprehensive properties, is widely applied to high-parameter thermal power generating units, fourth-generation nuclear power and aerospace, and is an important material for large-scale casting and forging pieces such as steam turbine rotors, blades, high-temperature steam pipelines, tee joints, valves and the like.
The martensitic stainless steel obtains a martensitic structure after quenching treatment, but the original austenite grain boundary still remains, and because the refined austenite grains can improve the strength and the toughness of the material, the observation and the rating of the original austenite grain size play an extremely important role in evaluating the performance of the steel. However, martensitic stainless steel, especially high-chromium martensitic stainless steel with Cr content of more than 9%, usually contains a large amount of corrosion-resistant components such as chromium, nickel, molybdenum, etc., and corrosion of grain boundaries is difficult, so how to simply and clearly display the prior austenite grain boundaries is one of the research focuses and difficulties in the field. To address this problem, a number of methods have been accumulated, including:
1. the Chinese patent with the application number of CN201510874430.0 discloses an electrolyte for displaying original austenite grain boundary of Co-containing ferrite heat-resistant steel and a preparation method thereof, wherein the corrosion solution comprises 2.5-5% of sulfuric acid, 2.5-5% of alcohol and 90-95% of saturated picric acid solution by volume fraction. The preparation method comprises adding sulfuric acid into saturated picric acid water solution, adding alcohol, and stirring. Then the sample is corroded and observed by adopting an electrolytic corrosion method. The formula of the corrosion liquid is simple, the types and the quantity of the acid are small, and the preparation is simple. However, the method adopts electrolytic corrosion, and the current and voltage parameters of the method are sensitive to the change of precipitated phase types in the sample, and the reproducibility is not high.
2. The Chinese patent with the application number of CN2018106221604.6 discloses a corrosion solution and a corrosion method for a medium-carbon steel original austenite crystal boundary, wherein the corrosion solution consists of 38-42 ml of water, 2-3 ml of hydrochloric acid, 4-5 g of picric acid, 4-5 ml of carbon tetrachloride, 9-11 ml of ethanol and 5-6 ml of Lafang shampoo, and the concentration of the hydrochloric acid is 36-38% (by mass). The preparation method comprises the following steps: firstly, distilled water is put into a beaker, ethanol is added, then hydrochloric acid, picric acid, carbon tetrachloride and Lafang brand shampoo are slowly added in sequence without fixed sequence, and finally, the mixture is stirred and mixed uniformly. The formula of the invention is relatively simple, the content of strong corrosive acid is not high, heating is not needed, and the safety is relatively high. However, the formula is only suitable for alloys with poor corrosion resistance, such as pipeline steel, and the like, is not suitable for stainless steel, particularly martensitic stainless steel with high Cr content and good corrosion resistance, and cannot be applied to corrosion and observation of the prior austenite grain boundary of the martensitic stainless steel.
3. The application numbers are: 201910730796.9 discloses a corrosive liquid for displaying austenite grain boundary, intragranular bainite and martensite of ultra-high strength steel, a preparation method and application thereof, wherein the corrosive liquid comprises the following components in parts by mass: glacial acetic acid: 1 part, 3-8 parts of absolute ethyl alcohol, picric acid: 0.04-0.10 portion. The method has the advantages that the formula and the operation are simple, concentrated strong acid and strong corrosive acid are not generated, the corrosion time is difficult to control, the corrosion time in the embodiment is different from 1 minute, 30 seconds to 40 minutes, and the method is poor in stability in practical application and difficult to accurately grasp by an operator.
4. The application numbers are: 202010972473.3 patent of Chinese invention relates to a corrosive agent for a prior austenite grain boundary of a half martensitic steel and a preparation and corrosion method thereof, wherein the corrosive agent comprises the following components in percentage by mass: 4 to 6 percent of picric acid, 88 to 92 percent of distilled water and 4 to 6 percent of anionic surfactant with corrosion inhibition effect; the etching method comprises the following steps: placing the sample in a water bath for heating and preserving heat; then, repeatedly wiping the corrosive agent on the surface to be measured in a cross shape. The formula does not contain concentrated strong acid and corrosive acid, is simple, but has higher use temperature, needs to be heated and insulated in a water bath at 70-85 ℃, is easy to cause volatilization of the picric acid and failure of a corrosive agent, and is easy to cause adverse reactions such as picric acidosis and the like after long-term use by operators.
Therefore, the corrosive agent capable of displaying the prior austenite grain boundary of the martensitic stainless steel in various states is found, the prior austenite grain boundary of the alloy with various Cr contents in various heat treatment states is clearly reflected, and the corrosive agent plays an extremely important role in accurately evaluating the grain size of the alloy, improving the heat treatment system, improving the performance of the alloy and the like.
Disclosure of Invention
The invention aims to provide a corrosive agent for displaying the prior austenite grain boundary of martensitic stainless steel and a corrosion method, aiming at solving the problems in the prior art, the corrosive agent has the advantages of simple formula components, low strong acid content, low corrosivity, no need of carrying out heat treatment or heating etching on a sample, short corrosion time, clear grain boundary display and excellent applicability, and is particularly suitable for high-chromium martensitic stainless steel with the Cr content of 9-12%.
In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:
an etching agent showing the prior austenite grain boundary of martensitic stainless steel, which comprises a saturated picric acid alcohol solution and contains 2-10g of an anionic surfactant having a corrosion inhibition effect, not less than 3 drops of a hydrochloric acid solution and 0.2-2g of a steel sheet per 100ml of the saturated picric acid alcohol solution.
Preferably, the alcohol is absolute ethyl alcohol.
Preferably, the anionic surfactant with corrosion inhibition effect is sulfonate.
Further, the sulfonate is sodium dodecyl benzene sulfonate, sodium tridecyl benzene sulfonate, sodium dodecyl sulfonate or sodium dodecyl sulfate.
Preferably, the mass fraction of the hydrochloric acid is 36-38%.
The preparation method of the corrosive agent for displaying the prior austenite grain boundary of the martensitic stainless steel comprises the following steps:
adding excessive picric acid into alcohol, heating and stirring until picric acid crystals are completely dissolved, standing and cooling, and taking supernatant when crystals are separated out; adding anionic surfactant with corrosion inhibiting effect and hydrochloric acid solution into the supernatant, stirring, and adding steel sheet.
The corrosion method for displaying the prior austenite grain boundary of the martensitic stainless steel comprises the steps of putting a sample into the corrosive agent, and carrying out metallographic corrosion at room temperature.
Preferably, the method comprises the following steps:
(1) putting the sample into a corrosive agent for etching at room temperature;
(2) taking out the etched sample, and polishing;
(3) repeating the etching and polishing processes described in (1) - (2) above not less than 1 time;
(4) and cleaning the sample subjected to the last etching and observing the sample.
Further, in the step (1), etching time is not less than 5 minutes;
further, in the step (4), the cleaning specifically comprises: saturated Na is adopted for the sample which is etched for the last time2CO3The solution was ultrasonically cleaned, then sprayed with alcohol and blown dry.
The invention has at least the following beneficial technical effects:
the corrosive agent for displaying the prior austenite grain boundary of the martensitic stainless steel is easy to prepare and store for a long time, and contains strong acid and corrosive acid with low concentrations; since picric acid is poorly soluble in cold water (1g picric acid is soluble in 78ml cold water), more soluble in hot water (1g picric acid is soluble in 15ml boiling water), and more soluble in alcohol (1g picric acid is soluble in 12ml alcohol), the substitution of alcohol for distilled water can increase the effective concentration of picric acid in the etchant per unit volume.
The corrosion method for displaying the prior austenite grain boundary of the martensitic stainless steel, provided by the invention, is characterized in that 0.2-2g of steel sheet is added into a corrosion solution, the specific surface area of the small-size steel sheet is larger than that of a sample to be corroded, and the small-size steel sheet can quickly react with picric acid after being added to generate metal salt so as to increase the sensitivity of the corrosion solution. Because the effective concentration of picric acid in the corrosive liquid is higher, and the sensitivity of the corrosive liquid can be improved by adding the steel sheet, a heat treatment step is not required to be additionally added to a sample, the volatilization of alcohol, hydrochloric acid, picric acid and the like in the corrosive liquid at high temperature can be avoided, the toxic injury to operators is reduced, and the use safety of the picric acid is improved. The invention has better applicability to raw materials, can be completed by adopting a conventional grinding, polishing and wiping device in a laboratory, and has low cost and simple use steps.
Drawings
FIG. 1 is a metallographic photograph of prior austenite grain boundaries of a 9Cr0.5Mo1.8WVNb steel (P92 steel) obtained by corrosion in example 1 of the present invention after aging at 600 ℃ for 100 hours.
FIG. 2 is a metallographic photograph of prior austenite grain boundaries of 9Cr0.5Mo1.8WVNb steel (P92 steel) obtained by corrosion in example 2 of the present invention after aging at 600 ℃ for 3000 hours.
FIG. 3 is a metallographic photograph of prior austenite grain boundaries of 11Cr0.3Mo1.5W1.5CoSiVNb steel (VM12 steel) obtained by corrosion in example 3 of the present invention after aging at 600 ℃ for 100 hours.
FIG. 4 is a metallographic photograph of prior austenite grain boundaries of 11Cr0.3Mo1.5W1.5CoSiVNb steel (VM12 steel) obtained by corrosion in example 4 of the present invention after aging at 650 ℃ for 1000 hours.
Detailed Description
In order to further understand the features and technical means of the present invention and achieve specific functions, the present invention is described in detail with specific embodiments below.
The invention discloses a corrosive agent for displaying a martensitic stainless steel original austenite grain boundary, which comprises picric acid, alcohol, an anionic surfactant with a corrosion inhibition effect, a hydrochloric acid solution and a steel sheet, wherein the dosage proportion of the corrosive agent is as follows: adding 2-10g of anionic surfactant with corrosion inhibition effect, not less than 3 drops of hydrochloric acid solution and 0.2-2g of steel sheet into 100ml of saturated picric acid alcohol solution.
The alcohol is absolute ethyl alcohol, the anionic surfactant with the corrosion inhibition effect is sulfonate, and the mass fraction of the hydrochloric acid is 37%.
The sulfonate is sodium dodecyl benzene sulfonate, sodium tridecyl benzene sulfonate, sodium dodecyl sulfonate or sodium dodecyl sulfate.
The preparation method of the corrosive agent for displaying the prior austenite grain boundary of the martensitic stainless steel comprises the following steps:
firstly, putting a slight excess picric acid into a flask filled with absolute ethyl alcohol, slowly heating and slightly stirring until crystals are completely dissolved, preparing saturated picric acid alcohol solution, standing and cooling for more than 2 hours, and taking supernatant liquor for later use when crystals are separated out; adding an anionic surfactant with a corrosion inhibition effect into the supernatant, slightly stirring until the anionic surfactant is fully dissolved, then dropwise adding hydrochloric acid by using a dropper, fully and uniformly stirring, and finally adding the steel sheet.
A corrosion method for displaying a martensitic stainless steel prior austenite grain boundary adopts the corrosive agent for displaying the martensitic stainless steel prior austenite grain boundary to carry out metallographic corrosion, and comprises the following steps:
(1) after the sample is subjected to conventional cutting, inlaying and polishing treatment, the surface of the sample is cleaned by alcohol and dried for later use;
(2) placing a proper corrosive agent in a culture dish, and soaking the sample in the corrosive agent with the front side facing upwards for not less than 5 minutes at room temperature;
(3) the etched sample was removed and treated with 1 μm Al2O3Slightly polishing the polishing paste and clear water for not less than 5 minutes;
(4) repeating the etching and light polishing processes in the steps (2) to (3) for not less than 1 time;
(5) putting the sample subjected to the last etching into a saturated Na solution2CO3Putting the beaker into an ultrasonic cleaning machine, and cleaning for not less than 1 minute;
(6) and cleaning the surface of the sample subjected to ultrasonic cleaning, spraying absolute alcohol and blow-drying, and carrying out metallographic observation and photographing.
Example 1:
the invention provides a corrosive agent for displaying a martensitic stainless steel original austenite grain boundary, which comprises the following components in parts by weight: 100ml of picric acid saturated alcohol solution, 2g of sodium dodecyl benzene sulfonate and 3 drops (about 0.15ml) of HCl solution, and finally adding about 0.2g of a small piece of steel sheet; the sample to be corroded is 9Cr0.5Mo1.8WVNb steel (P92 steel) aged at 600 ℃ for 100 h.
Preparation and cleaning steps:
(1) firstly, 9g of picric acid is put into a flask, 100ml of absolute ethyl alcohol is added, slow heating is carried out by small fire, the mixture is gently stirred until crystals are completely dissolved, a saturated picric acid alcohol solution is prepared, the mixture is kept stand for 1 day, and when crystals are separated out, supernatant liquor is taken and kept stand for later use.
(2) Taking 100ml of supernatant of the saturated picric acid alcohol solution after fully standing, adding 2g of sodium dodecyl benzene sulfonate, slightly stirring until the sodium dodecyl benzene sulfonate is fully dissolved, then dropwise adding 3 drops of hydrochloric acid by using a dropper, fully stirring uniformly, and finally adding about 0.2g of steel sheets; at this time, the preparation of the corrosive liquid is finished.
(3) And after the conventional cutting, inlaying and polishing treatment is carried out on the 9Cr0.5Mo1.8WVNb steel sample, the surface of the sample is cleaned by alcohol and dried for standby.
(4) Placing a proper amount of the corrosive liquid in a culture dish, immersing a sample to be observed into the corrosive liquid with the right side upward at room temperature, and etching for 10 minutes;
(5) the etched sample was removed and 1 μm Al was used2O3Slightly polishing the polishing paste and clear water for about 10 minutes;
(6) repeating the steps (4) to (5) on the polished sample for 3 times;
(7) putting the sample etched for the last time into a saturated Na solution2CO3Putting the beaker into an ultrasonic cleaning machine, and cleaning for 10 minutes;
(8) and cleaning the surface of the sample subjected to ultrasonic cleaning, spraying absolute ethyl alcohol and blow-drying, and carrying out metallographic observation and photographing.
As shown in FIG. 1, the prior austenite grain boundary can be clearly observed in the gold phase diagram obtained by the etching in this example.
Example 2:
the invention provides a corrosive agent for displaying a martensitic stainless steel original austenite grain boundary, which comprises the following components in parts by weight: 100ml of a saturated alcoholic solution of picric acid, 2g of sodium tridecylbenzenesulfonate, 5 drops (about 0.25ml) of HCl solution, and finally about 1g of a small piece of steel plate; the sample to be corroded is 9Cr0.5Mo1.8WVNb steel (P92 steel) after aging for 1000h at 600 ℃.
Preparation and cleaning steps:
(1) firstly, 9g of picric acid is put into a flask, 100ml of absolute ethyl alcohol is added, slow heating is carried out by small fire, the mixture is gently stirred until crystals are completely dissolved, a saturated picric acid alcohol solution is prepared, the mixture is kept stand for 1 day, and when crystals are separated out, supernatant liquor is taken and kept stand for later use.
(2) Taking 100ml of supernatant of the saturated picric acid alcohol solution after fully standing, adding 2g of sodium tridecylbenzenesulfonate, slightly stirring until the sodium tridecylbenzenesulfonate is fully dissolved, then dropwise adding 5 drops of hydrochloric acid by using a dropper, fully stirring uniformly, and finally adding about 1g of steel sheets; at this time, the preparation of the corrosive liquid is finished.
(3) And after the conventional cutting, inlaying and polishing treatment is carried out on the 9Cr0.5Mo1.8WVNb steel sample, the surface of the sample is cleaned by alcohol and dried for standby.
(4) Placing a proper amount of the corrosive liquid in a culture dish, immersing a sample to be observed into the corrosive liquid with the right side upward at room temperature, and etching for 5 minutes;
(5) the etched sample was removed and 1 μm Al was used2O3Slightly polishing the polishing paste and clear water for about 10 minutes;
(6) repeating the steps (4) to (5) on the polished sample for 3 times;
(7) putting the sample etched for the last time into a saturated Na solution2CO3Putting the beaker into an ultrasonic cleaning machine, and cleaning for 10 minutes;
(8) and cleaning the surface of the sample subjected to ultrasonic cleaning, spraying absolute ethyl alcohol and blow-drying, and carrying out metallographic observation and photographing.
As shown in FIG. 2, the prior austenite grain boundary can be clearly observed in the gold phase diagram obtained by the etching in this example.
Example 3:
the invention provides a corrosive agent for displaying a martensitic stainless steel original austenite grain boundary, which comprises the following components in parts by weight: 100ml of picric acid saturated alcohol solution, 10g of sodium dodecyl benzene sulfonate and 8 drops (about 0.4ml) of HCl solution, and finally adding about 2g of a small steel sheet; the sample to be corroded was 11Cr0.3Mo1.5W1.5CoSiVNb steel (VM12 steel) after aging at 600 ℃ for 100 hours.
Preparation and cleaning steps:
(1) firstly, 9g of picric acid is put into a flask, 100ml of absolute ethyl alcohol is added, slow heating is carried out by small fire, the mixture is gently stirred until crystals are completely dissolved, a saturated picric acid alcohol solution is prepared, the mixture is kept stand for 1 day, and when crystals are separated out, supernatant liquor is taken and kept stand for later use.
(2) Taking 100ml of supernatant of the saturated picric acid alcohol solution after fully standing, adding 10g of sodium dodecyl benzene sulfonate, slightly stirring until the sodium dodecyl benzene sulfonate is fully dissolved, then dropwise adding 8 drops of hydrochloric acid by using a dropper, fully stirring uniformly, and finally adding about 2g of steel sheets; at this time, the preparation of the corrosive liquid is finished.
(3) And after the 11Cr0.3Mo1.5W1.5CoSiVNb steel sample is subjected to conventional cutting, inlaying and polishing treatment, cleaning the surface of the sample by using alcohol and drying for later use.
(4) Placing a proper amount of the corrosive liquid in a culture dish, immersing a sample to be observed into the corrosive liquid with the right side upward at room temperature, and etching for 5 minutes;
(5) the etched sample was removed and 1 μm Al was used2O3Slightly polishing the polishing paste and clear water for about 10 minutes;
(6) repeating the steps (4) to (5) on the polished sample for 1 time;
(7) putting the sample etched for the last time into a saturated Na solution2CO3Putting the beaker into an ultrasonic cleaning machine, and cleaning for 10 minutes;
(8) and spraying absolute alcohol on the clean surface of the sample cleaned by the ultrasonic waves and drying the sample by blowing, so that metallographic observation and photographing can be performed.
As shown in FIG. 3, a gold phase diagram obtained by etching in this example clearly shows prior austenite grain boundaries.
Example 4:
the invention provides a corrosive agent for displaying a martensitic stainless steel original austenite grain boundary, which comprises the following components in parts by weight: 100ml of picric acid saturated alcohol solution, 10g of sodium dodecyl sulfate and 6 drops (about 0.6ml) of HCl solution, and finally adding about 2g of a small steel sheet; the sample to be corroded was 11Cr0.3Mo1.5W1.5CoSiVNb steel (VM12 steel) after aging at 650 ℃ for 1000 hours.
Preparation and cleaning steps:
(1) firstly, 9g of picric acid is put into a flask, 100ml of absolute ethyl alcohol is added, slow heating is carried out by small fire, the mixture is gently stirred until crystals are completely dissolved, a saturated picric acid alcohol solution is prepared, the mixture is kept stand for 1 day, and when crystals are separated out, supernatant liquor is taken and kept stand for later use.
(2) Taking 100ml of supernatant of the saturated picric acid alcohol solution after fully standing, adding 10g of sodium dodecyl sulfate, slightly stirring until the sodium dodecyl sulfate is fully dissolved, then dropwise adding 6 drops of hydrochloric acid by using a dropper, fully stirring uniformly, and finally adding about 2g of steel sheets; at this time, the preparation of the corrosive liquid is finished.
(3) And after the 11Cr0.3Mo1.5W1.5CoSiVNb steel sample is subjected to conventional cutting, inlaying and polishing treatment, cleaning the surface of the sample by using alcohol and drying for later use.
(4) Placing a proper amount of the corrosive liquid in a culture dish, immersing a sample to be observed into the corrosive liquid with the right side upward at room temperature, and etching for 5 minutes;
(5) the etched sample was removed and 1 μm Al was used2O3Slightly polishing the polishing paste and clear water for about 10 minutes;
(6) repeating the steps (4) to (5) on the polished sample for 1 time;
(7) putting the sample etched for the last time into a saturated Na solution2CO3Putting the beaker into an ultrasonic cleaning machine, and cleaning for 10 minutes;
(8) and spraying absolute alcohol on the clean surface of the sample cleaned by the ultrasonic waves and drying the sample by blowing, so that metallographic observation and photographing can be performed.
As shown in FIG. 4, a gold phase diagram obtained by etching in this example clearly shows prior austenite grain boundaries.
The invention can effectively solve the problems of strong corrosivity of the formula, complex operation, need of heat treatment on a sample and the like of the existing corrosive agent and the corrosion method, and completes the corrosion on the prior austenite grain boundary of the martensitic stainless steel in different heat treatment states by adopting a room temperature etching method and hydrochloric acid with a small dosage.
Claims (10)
1. An etching agent showing the prior austenite grain boundary of martensitic stainless steel, characterized in that the etching agent comprises a saturated picric acid alcohol solution, and 2-10g of an anionic surfactant having a corrosion inhibition effect, not less than 3 drops of a hydrochloric acid solution and 0.2-2g of a steel sheet are contained in each 100ml of the saturated picric acid alcohol solution.
2. The corrosive agent for displaying the martensitic stainless steel prior austenite grain boundary of claim 1, wherein the alcohol is absolute ethyl alcohol.
3. The corrosive agent for displaying the martensitic stainless steel prior austenite grain boundary of claim 1, wherein the anionic surfactant having corrosion inhibition effect is sulfonate.
4. The corrosive agent for displaying the martensitic stainless steel prior austenite grain boundary of claim 3, wherein the sulfonate is sodium dodecylbenzene sulfonate, sodium tridecylbenzene sulfonate, sodium dodecylbenzene sulfonate or sodium dodecylsulfate.
5. The corrosive agent for displaying the martensitic stainless steel prior austenite grain boundary of claim 1, wherein the mass fraction of the hydrochloric acid is 36-38%.
6. The method for formulating the corrosive agent for displaying the prior austenite grain boundary of the martensitic stainless steel as claimed in any one of claims 1 to 5, is characterized by comprising the following steps:
adding excessive picric acid into alcohol, heating and stirring until picric acid crystals are completely dissolved, standing and cooling, and taking supernatant when crystals are separated out; adding anionic surfactant with corrosion inhibiting effect and hydrochloric acid solution into the supernatant, stirring, and adding steel sheet.
7. The corrosion method for displaying the martensitic stainless steel prior austenite grain boundary is characterized in that a sample is put into the corrosive agent for displaying the martensitic stainless steel prior austenite grain boundary according to any one of claims 1 to 5, and metallographic corrosion is carried out under the condition of room temperature.
8. The corrosion method for exhibiting a martensitic stainless steel prior austenite grain boundary of claim 7, comprising:
(1) putting the sample into a corrosive agent for etching at room temperature;
(2) taking out the etched sample, and polishing;
(3) repeating the etching and polishing processes described in (1) - (2) above not less than 1 time;
(4) and cleaning the sample subjected to the last etching and observing the sample.
9. The corrosion method showing the prior austenite grain boundary of martensitic stainless steel as set forth in claim 8, wherein in the step (1), the etching time is not less than 5 minutes.
10. The corrosion method for displaying the martensitic stainless steel prior austenite grain boundary according to claim 8, wherein in the step (4), the cleaning is specifically as follows: saturated Na is adopted for the sample which is etched for the last time2CO3The solution was ultrasonically cleaned, then sprayed with alcohol and blown dry.
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| CN115613033A (en) * | 2022-10-31 | 2023-01-17 | 宝武特冶航研科技有限公司 | Corrosive for treating grain boundary of 4Cr14Ni14W2Mo heat-resistant steel and application thereof |
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