CN113862677B - GH4220 high-temperature alloy metallographic structure corrosive and corrosion method - Google Patents
GH4220 high-temperature alloy metallographic structure corrosive and corrosion method Download PDFInfo
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- CN113862677B CN113862677B CN202111117926.5A CN202111117926A CN113862677B CN 113862677 B CN113862677 B CN 113862677B CN 202111117926 A CN202111117926 A CN 202111117926A CN 113862677 B CN113862677 B CN 113862677B
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- 238000005260 corrosion Methods 0.000 title claims abstract description 66
- 230000007797 corrosion Effects 0.000 title claims abstract description 64
- 238000000034 method Methods 0.000 title claims abstract description 37
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 28
- 239000000956 alloy Substances 0.000 title claims abstract description 28
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims abstract description 57
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 50
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000003518 caustics Substances 0.000 claims abstract description 24
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 23
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 23
- 229960000583 acetic acid Drugs 0.000 claims abstract description 21
- 239000012362 glacial acetic acid Substances 0.000 claims abstract description 21
- 229910000601 superalloy Inorganic materials 0.000 claims description 41
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 238000005498 polishing Methods 0.000 claims description 15
- 238000005520 cutting process Methods 0.000 claims description 10
- 238000000227 grinding Methods 0.000 claims description 9
- 238000011010 flushing procedure Methods 0.000 claims description 8
- 238000002791 soaking Methods 0.000 claims description 8
- 238000005406 washing Methods 0.000 claims description 8
- 239000003795 chemical substances by application Substances 0.000 claims description 7
- 235000019580 granularity Nutrition 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 6
- 229910003460 diamond Inorganic materials 0.000 claims description 5
- 239000010432 diamond Substances 0.000 claims description 5
- 239000007921 spray Substances 0.000 claims description 5
- 244000137852 Petrea volubilis Species 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 4
- 238000003756 stirring Methods 0.000 claims description 4
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 238000004458 analytical method Methods 0.000 abstract description 9
- 239000000203 mixture Substances 0.000 abstract description 5
- 239000007769 metal material Substances 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 19
- 238000010586 diagram Methods 0.000 description 9
- 239000011159 matrix material Substances 0.000 description 9
- 238000002360 preparation method Methods 0.000 description 7
- 239000003153 chemical reaction reagent Substances 0.000 description 6
- 230000007547 defect Effects 0.000 description 6
- 238000005728 strengthening Methods 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 4
- 229910000423 chromium oxide Inorganic materials 0.000 description 4
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 239000002923 metal particle Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 4
- 229920000742 Cotton Polymers 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 231100000614 poison Toxicity 0.000 description 3
- 239000003440 toxic substance Substances 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910000365 copper sulfate Inorganic materials 0.000 description 2
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 238000003487 electrochemical reaction Methods 0.000 description 2
- 235000019441 ethanol Nutrition 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 238000004881 precipitation hardening Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 101000912561 Bos taurus Fibrinogen gamma-B chain Proteins 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
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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 & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Health & Medical Sciences (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
The invention discloses a GH4220 high-temperature alloy metallographic structure corrosive agent and a corrosion method, belongs to the technical field of metallographic analysis of metal materials, and solves the problem that the existing corrosive agent and corrosion method cannot clearly display the metallographic structure of the GH4220 high-temperature alloy. The metallographic structure corrosive comprises concentrated hydrochloric acid, concentrated nitric acid, glycerol and glacial acetic acid. The mixture ratio of the components is as follows: 35-45 ml of concentrated hydrochloric acid, 25-35 ml of concentrated nitric acid, 8-12 ml of glycerol and 17-23 ml of glacial acetic acid. The corrosive agent and the corrosion method can quickly and clearly corrode the metallographic structure of the GH4220 high-temperature alloy.
Description
Technical Field
The invention belongs to the technical field of metallographic analysis of metal materials, and particularly relates to a GH4220 high-temperature alloy metallographic structure corrosive agent and a corrosion method.
Background
The development of aerospace technology puts higher requirements on the performance of an engine, and the technical level of the aerospace engine is an important mark for measuring the national technological level and the industrial strength. While the performance of the engine is primarily dependent on the properties of the materials used. The common materials in the materials of the engine comprise GH4220 superalloy, GH4220 is Ni-Co-Cr based precipitation hardening deformation superalloy, the service temperature is 900-950 ℃, and more aluminum and titanium elements are added into the GH4220 alloy to form gamma 'precipitation strengthening phase, wherein omega (gamma') can reach more than 40%. Meanwhile, cobalt, chromium, tungsten and molybdenum elements are added into the GH4220 alloy for solid solution strengthening, and trace cerium, boron and magnesium elements are added for grain boundary strengthening. The GH4220 alloy has higher high-temperature strength and high-temperature plasticity and good comprehensive performance. Therefore, the method is suitable for manufacturing gas turbines and rotating parts of aeroengines which work for a long time at 900-950 ℃. Most of the high-temperature parts are processed by adopting a welding forming mode, and the quality of welding seams is directly related to whether the performance of the product can meet the design requirement.
Metallographic analysis is an important means for judging the quality of parts. The configuration of the etchant is critical for clear observation of the tissue.
Therefore, finding a corrosive agent and a corrosion method capable of clearly displaying the metallographic structure of GH4220 has important significance, clearly displaying the metallographic structure of GH4220, identifying phase composition and defects in the structure and accurately analyzing the structure, can provide basis for evaluating the quality of the high-temperature alloy and making a reasonable heat treatment system, and further obtains excellent structure and performance.
Disclosure of Invention
In view of the above analysis, the present invention aims to provide a metallographic structure etchant and a corrosion method for a GH4220 superalloy, which can solve one of the following technical problems: (1) The existing corrosive agent and the corrosion method can not clearly and completely display the metallographic structure of the GH4220 high-temperature alloy; (2) The existing partial corrosive contains toxic substances, and the safety risk exists.
The aim of the invention is mainly realized by the following technical scheme:
in one aspect, the invention provides a GH4220 superalloy metallographic structure corrosive agent, which comprises concentrated hydrochloric acid, concentrated nitric acid, glycerol and glacial acetic acid.
Further, the metallographic structure corrosive comprises the following components in proportion: 35-45 ml of concentrated hydrochloric acid, 25-35 ml of concentrated nitric acid, 8-12 ml of glycerol and 17-23 ml of glacial acetic acid.
Further, the mass percentage of the concentrated nitric acid is 30%.
Furthermore, the metallographic structure corrosive is prepared by the following method:
step 1, adding concentrated hydrochloric acid into a beaker according to the proportion;
step 2, adding concentrated nitric acid into the beaker according to the proportion;
step 3, adding glacial acetic acid into the beaker according to the proportion;
step 4, adding glycerol into the beaker according to the proportion;
and 5, uniformly stirring and standing to obtain the GH4220 high-temperature alloy metallographic structure corrosive agent.
Further, in the step 4, the standing time is 3 to 5 minutes.
The invention also provides a GH4220 superalloy metallographic structure corrosion method, which comprises the following steps:
s1, cutting a sample of GH4220 superalloy;
s2, grinding the sample by using metallographic water sand paper with different granularities;
s3, polishing the sample on a polishing machine;
s4, flushing the polished sample surface by using clear water, and then flushing by using absolute ethyl alcohol;
s5, placing the surface of the washed sample into a prepared GH4220 high-temperature alloy metallographic structure corrosive agent for soaking;
s6, immediately washing the corroded surface of the sample with clear water, and then washing with absolute ethyl alcohol;
s7, drying the corroded surface, and observing the tissue.
Further, in the step S1, the influence on the tissue of the sample is avoided during the process of cutting the sample.
In the step S2, grinding is sequentially performed from coarse to fine according to the granularity of the metallographic coated abrasive.
In the step S3, a diamond spray abrasive is used as a medium.
Further, in the step S5, the mixture is soaked for 10 to 15 seconds.
Compared with the prior art, the invention has the following beneficial effects:
1) The invention takes the mixed solution of the concentrated hydrochloric acid, the concentrated nitric acid, the glycerol and the glacial acetic acid as the corrosive agent, and does not need to use metal salts such as copper chloride, copper sulfate and the like, so that metal particles displaced by electrochemical reaction can not be left on the corrosion surface, thereby avoiding the influence of the metal particles on the observation of metallographic structures.
2) The corrosive agent does not need toxic substances such as chromium oxide and the like, and ensures the personal safety of operators.
3) The corrosion method provided by the invention can quickly and clearly corrode the metallographic structure of the GH4220 high-temperature alloy matrix through normal-temperature corrosion, does not need heating or electrolytic corrosion, improves the operability and ensures the structural uniformity of a corrosion surface; the corroded structure is clear, phase boundaries, grain boundaries and weld boundaries are clear and visible, the structure condition can be well reflected, the metallographic structure, the grain size and the like of the matrix can be accurately measured by using a metallographic microscope, and further, the preparation process parameters are adjusted and optimized, and the quality of GH4220 products is improved.
4) The invention does not need electrolytic corrosion, improves the operability and ensures the structural uniformity of the corrosion surface.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings thereof.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, like reference numerals being used to refer to like parts throughout the several views.
FIG. 1 is a metallographic structure diagram of GH4220 superalloy in example 3 of the invention;
FIG. 2 is a metallographic structure diagram of GH4220 superalloy in comparative example 1 of the present invention;
FIG. 3 is a metallographic structure diagram of GH4220 superalloy in comparative example 2 of the present invention;
FIG. 4 is a metallographic structure diagram of GH4220 superalloy in comparative example 3 of the present invention;
FIG. 5 is a metallographic structure of GH4220 superalloy in comparative example 4 of the present invention.
Detailed Description
Preferred embodiments of the present invention are described in detail below with reference to the attached drawing figures, which form a part of the present invention and are used in conjunction with embodiments of the present invention to illustrate the principles of the present invention.
Metallographic analysis is an important means for judging the quality of parts, and defects such as composition and distribution of each phase, inclusion, air holes and the like can be observed through metallographic structure analysis. The method can also be used for judging whether the production process of the product is perfect or not, such as corrosion of defects, measuring the depth and width of the product, and further helping to seek the cause of the defects of the product and optimizing the production process parameters. The corrosion effect of the metallographic specimen is a key factor of analysis, measurement and grain size of metallographic structure defects. The corrosion effect is mainly dependent on what substances are used and the proportions thereof. If the selected substances are unsuitable, no matter what proportion is, the tissue of the sample cannot be corroded; even if substances are selected, if the configuration proportion is too high, over-corrosion is easy to form, a piece of black paint is organized, and the contrast between phases is not present; on the other hand, if the arrangement ratio is too low, the tissue is corroded to have no desired effect, and the tissue cannot be clearly observed.
At present, the metallographic structure corrosive of the common GH4220 superalloy mainly comprises a Kalling reagent: 40ml of ethanol +40ml of hydrochloric acid +2g of copper chloride. The inventor has found through long-term deep research that the existing Kalling reagent and corrosion method sometimes cannot well display the metallographic structure of GH4220 high-temperature alloy, cannot clearly identify phase composition in the structure, and has the defects that copper particles are separated out by reaction to pollute the corrosion surface in the corrosion process of the Kalling reagent, so that the structure judgment is difficult; the metallographic structure of the GH4220 superalloy cannot be accurately analyzed. The reagent is prepared by hydrochloric acid and chromium oxide, but the corrosion effect is not ideal, and the chromium oxide is toxic and has potential safety hazard in use; the electrolytic method is used for corrosion, the mixed acid prepared from perchloric acid, phosphoric acid and sulfuric acid is used for corrosion, the current voltage and the corrosion time are not well controlled, the control is slightly poor, the surface of the sample is ablated, the corrosion is spent, only the sample can be polished again, and the sample preparation period is greatly prolonged.
The invention provides a GH4220 superalloy metallographic structure corrosive agent which comprises concentrated hydrochloric acid, concentrated nitric acid, glycerol and glacial acetic acid.
Specifically, the GH4220 superalloy of the invention mainly comprises the following chemical components in percentage by mass: less than or equal to 0.08 percent, cr:9.0-12.00%, co:14.0% -15.00%, mo:5.0% -7.0%, W:5.0% -6.50%, al:3.90% -4.80%, ti:2.20% -2.90%, fe: less than or equal to 3.00 percent and the balance of Ni.
Specifically, the GH4220 superalloy of the invention is a Ni-Co-Cr based precipitation hardening deformation superalloy, and the metallographic structure of the matrix is a solid solution and aging structure.
Considering that the concentration of the concentrated hydrochloric acid is too large, over-corrosion is easy to form, a piece of black paint is organized, and the phase is not lined; the density is too small, the tissue corrosion is too shallow, and the tissue cannot be clearly observed. The concentrated nitric acid has too large concentration and deeper corrosion, and the corrosion cannot be shown due to the too small concentration. The concentration of glacial acetic acid is too large to corrode deeply, and the concentration of glacial acetic acid is too small to corrode. Therefore, the proportion of each component in the corrosive is controlled as follows: 35-45 ml of concentrated hydrochloric acid, 25-35 ml of concentrated nitric acid, 8-12 ml of glycerol and 17-23 ml of glacial acetic acid.
Specifically, the mass percentage of the concentrated hydrochloric acid is 40%, and the mass percentage of the concentrated nitric acid is 30%.
Compared with the prior art, the metallographic structure corrosive provided by the invention adopts concentrated hydrochloric acid, concentrated nitric acid, glycerol and glacial acetic acid, so that GH4220 high-temperature alloy can be corroded more clearly.
Specifically, the preparation method of the GH4220 superalloy metallographic structure corrosive agent comprises the following steps:
step 1, adding concentrated hydrochloric acid into a beaker according to the proportion;
step 2, adding concentrated nitric acid into the beaker according to the proportion;
step 3, adding glacial acetic acid into the beaker according to the proportion;
step 4, adding glycerol into the beaker according to the proportion;
and 5, uniformly stirring and standing to obtain the GH4220 high-temperature alloy metallographic structure corrosive agent.
It is noted that in the above step 4, the standing time is controlled to be 3-5 min (e.g., 3min, 3.5min, 4min, 4.5min, 5 min).
The invention also provides a GH4220 superalloy metallographic structure corrosion method, which comprises the following steps:
s1, longitudinally cutting a sample of GH4220 superalloy;
s2, grinding the sample by using metallographic water sand paper with different granularities;
s3, polishing the sample on a polishing machine by using a diamond spray grinding agent;
s4, flushing the polished sample surface by using clear water, and then flushing by using absolute ethyl alcohol;
s5, placing the surface of the washed sample into a prepared GH4220 high-temperature alloy metallographic structure corrosive agent, and soaking for 10-15S;
s6, immediately washing the corroded surface of the sample with clear water, and then washing with absolute ethyl alcohol;
s7, drying the corroded surface by using a blower, and observing the structure by using a metallographic microscope.
Specifically, in S1, the sample may be cut by various methods (preferably, wire cutting is used), and during the cutting of the sample, the influence on the tissue of the sample (for example, overheating or the like) should be avoided, and precautions (for example, water cooling) may be taken during the cutting, or these influences may be removed after the cutting.
In the above S1, the length of the cut sample is controlled to 10 to 30mm and the height is controlled to 10 to 15mm, considering that the sample is too large or too small to facilitate polishing.
Specifically, in the above step S2, the samples cut in step S1 may be inlaid into regular round samples by an inlaid machine, and then the samples may be polished by using metallographic coated abrasive with different granularities, in consideration of irregular shapes of the samples, which is not easy to handle during polishing.
Specifically, in S2, the metallographic coated abrasive is sequentially ground from coarse to fine in order of particle size of 280 mesh, 400 mesh, 500 mesh, 600 mesh, 800 mesh, 1000 mesh, 1200 mesh.
Specifically, in the step S3, the diamond spray polishing agent is used as a medium, the polished sample is polished on a polishing machine with a speed of 4000r/min until the surface of the sample is bright, and when no scratch exists, clean water is used as a polishing medium, so that the etched surface is polished (polishing refers to the surface being bright, no abrasive residue exists, and no polishing woolen cloth chips remain).
Specifically, in the above step S5, the tissue is too dark due to too long soaking time, and cannot be clearly observed; the soaking time is too short and the corrosion is too shallow, so the soaking time is controlled to be 10-15 s.
Specifically, in the above step S6, after the sample obtained in step S5 is rinsed with clear water until no liquid remains on the surface, in order to prevent water stains on the surface, the surface of the sample is rinsed with absolute ethyl alcohol, the volatility of the absolute ethyl alcohol is good, and no residual watermark mark is ensured on the surface of the sample after rinsing, thereby being more beneficial to observing tissues.
Specifically, in S7, the corroded surface may be dried by a blower while wiping the surface of the sample with absorbent cotton dipped in absolute ethyl alcohol. This is because the wiping with absorbent cotton on the one hand cleans out corrosion products that affect subsequent observations, and on the other hand avoids the carry-over of grease and scratches, while enabling an increase in the air drying speed.
Compared with the prior art, the metallographic structure corrosive and the corrosion method provided by the invention can quickly and clearly corrode the metallographic structure of the GH4220 high-temperature alloy through normal-temperature corrosion, heating and electrolytic corrosion are not needed, the operability is improved, and the structural uniformity of a corrosion surface is ensured; the corroded structure is clear, the phase boundary and the grain boundary are clear and visible, the structure condition can be reflected well, the metallographic structure, the grain size, the grain boundary and the like of the matrix can be measured accurately by using a metallographic microscope, and further, the preparation process parameters are adjusted and optimized, and the quality of GH4220 products is improved.
The invention takes the mixed solution of the concentrated hydrochloric acid, the concentrated nitric acid, the glycerol and the glacial acetic acid as the corrosive agent, and does not need to use metal salts such as copper chloride, copper sulfate and the like, so that metal particles displaced by electrochemical reaction can not be left on the corrosion surface, thereby avoiding the influence of the metal particles on the observation of metallographic structures.
The corrosive agent does not need toxic substances such as chromium oxide and the like, and ensures the personal safety of operators.
The invention does not need electrolytic corrosion, improves the operability and ensures the structural uniformity of the corrosion surface.
Example 1
The embodiment provides a GH4220 superalloy metallographic structure corrosive, which comprises the following components of 40ml of concentrated hydrochloric acid, 30ml of concentrated nitric acid, 10ml of glycerol and 20ml of glacial acetic acid.
The preparation method of the corrosive agent comprises the following steps:
step 1, adding 40ml of concentrated hydrochloric acid into a beaker;
step 2, sequentially adding 30ml of concentrated nitric acid, 20ml of glacial acetic acid and 10ml of glycerol into a beaker;
and step 3, stirring and dissolving the alloy by using a glass rod, and uniformly standing for 4min to obtain the GH4220 high-temperature alloy metallographic structure corrosive agent.
Example 2
The embodiment provides a GH4220 superalloy metallographic structure corrosive, which comprises the following components of 35ml of concentrated hydrochloric acid, 30ml of concentrated nitric acid, 10ml of glycerol and 18ml of glacial acetic acid.
The preparation method of the corrosive agent is the same as that of the example 1, and is not repeated here.
Example 3
This example was used to etch a GH4220 superalloy sample using the etchant of example 1 above. The etching method comprises the following steps:
s1, longitudinally cutting a sample of GH4220 superalloy; the sample is rectangular, and the size is 20mm multiplied by 15mm; embedding the sample into a regular circular sample;
s2, grinding the sample by adopting 280-mesh, 400-mesh, 500-mesh, 600-mesh, 800-mesh, 1000-mesh and 1200-mesh metallographic water sand paper in sequence;
s3, polishing the sample on a 4000r/min polishing machine by using a diamond spray grinding agent until the surface of the sample is bright, and when no scratch exists, using clear water as a grinding medium to make the corrosion surface light;
s4, flushing the polished sample surface by using clear water, and then flushing by using absolute ethyl alcohol;
s5, placing the surface of the washed sample into a prepared GH4220 high-temperature alloy metallographic structure corrosive agent, and soaking for 10S;
s6, immediately washing the corroded surface of the sample with clear water, and then washing with absolute ethyl alcohol;
s7, wiping the surface of the sample by using absorbent cotton dipped with absolute ethyl alcohol, drying the corroded surface by using a blower, and observing the tissue by using a metallographic microscope.
Fig. 1 is a metallographic structure diagram of a GH4220 superalloy sample of the present embodiment after corrosion, and it can be seen from fig. 1 that the corrosive agent and the corrosion method of the present invention can clearly show a matrix structure.
Example 4
This example was used to etch a GH4220 superalloy sample using the etchant of example 2 above. The etching method was the same as that of example 3 above, except that in S5, the etching was performed for 15 seconds. Other steps are not described in detail herein.
The sample of this example clearly showed the matrix structure after corrosion.
Comparative example 1
The present comparative example provides an existing Kalling reagent: 40ml of ethanol +40ml of hydrochloric acid +2g of copper chloride.
The comparative example uses the above-mentioned Kalling reagent to corrode GH4220 superalloy samples.
Fig. 2 is a diagram showing a metallographic structure of a sample of the comparative example after corrosion, and it can be seen from fig. 2 that the use of the etchant can corrode the grain boundary and the strengthening phase of the matrix, but at the same time, cu particles (for example, cu particles in dot-like substances which are scattered and concentrated in circles in the figure) are reacted by substitution, and adhere to the matrix, which is easily confused with the strengthening phase, affects analysis, and has a shallow structure, which is unfavorable for analysis.
Comparative example 2
The comparative example uses: the GH4220 superalloy sample was corroded by an electrolytic corrosion solution of a mixed acid prepared from 20ml perchloric acid, 20ml phosphoric acid, 20ml sulfuric acid and 50ml distilled water.
FIG. 3 is a metallographic structure diagram of the sample of the comparative example after corrosion, and as can be seen from FIG. 3, the structure developed by the corrosion method is darker and cannot be seen clearly.
Comparative example 3
The comparative example provides a GH4220 superalloy metallographic structure corrosive, wherein each component of the corrosive comprises 30ml of concentrated hydrochloric acid, 37ml of concentrated nitric acid, 7ml of glycerol and 25ml of glacial acetic acid.
The etchant was prepared in the same manner as in example 1.
The corrosion agent is adopted to corrode GH4220 high-temperature alloy samples for 3min.
FIG. 4 is a metallographic structure diagram of the sample of the comparative example after corrosion, and as can be seen from FIG. 4, the structure is shallow and the boundary of the structure is not visible by the corrosion method.
Comparative example 4
The comparative example provides a GH4220 superalloy metallographic structure corrosive, wherein each component of the corrosive comprises 48ml of concentrated hydrochloric acid, 40ml of concentrated nitric acid, 10ml of glycerol and 15ml of glacial acetic acid.
The etchant was prepared in the same manner as in example 1.
The corrosion agent is adopted to corrode GH4220 high-temperature alloy samples for 7min.
FIG. 5 is a metallographic structure diagram of the sample of the comparative example after corrosion, and as can be seen from FIG. 5, the structure boundary is too deep to be revealed by the corrosion method.
Comparative examples 3-4 and comparative examples 1-4 show that the metallographic structure etchant and the corrosion method for the GH4220 high-temperature alloy can quickly and clearly corrode the metallographic structure of the GH4220 high-temperature alloy, do not need heating or electrolytic corrosion, improve the operability and ensure the structural uniformity of a corrosion surface; the corroded structure is clear, the phase boundary is clear and visible, the structure condition can be reflected well, the metallographic structure, the grain size and the like of the matrix can be measured accurately by using a metallographic microscope, the preparation process parameters are adjusted and optimized, and the quality of GH4220 superalloy products is improved.
The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.
Claims (7)
1. A method for corroding a metallographic structure of a GH4220 superalloy, which is characterized by comprising the following steps:
s1, cutting a sample of GH4220 superalloy;
s2, grinding the sample by using metallographic water sand paper with different granularities;
s3, polishing the sample on a polishing machine;
s4, flushing the polished sample surface by using clear water, and then flushing by using absolute ethyl alcohol;
s5, placing the surface of the washed sample into a prepared GH4220 high-temperature alloy metallographic structure corrosive agent for soaking;
s6, immediately washing the corroded surface of the sample with clear water, and then washing with absolute ethyl alcohol;
s7, drying the corroded surface, and observing the tissue;
the GH4220 superalloy has the chemical components of C: less than or equal to 0.08 percent, cr:9.0-12.00%, co:14.0% -15.00%, mo:5.0% -7.0%, W:5.0% -6.50%, al:3.90% -4.80%, ti:2.20% -2.90%, fe: less than or equal to 3.00 percent, and the balance being Ni;
the GH4220 superalloy metallographic structure corrosive comprises the following components in proportion: 35-45 ml of concentrated hydrochloric acid, 25-35 ml of concentrated nitric acid, 8-12 ml of glycerol and 17-23 ml of glacial acetic acid;
the mass percentage of the concentrated hydrochloric acid is 40%, and the mass percentage of the concentrated nitric acid is 30%;
and in the step S5, soaking for 10-15S.
2. The GH4220 superalloy metallographic structure corrosion method according to claim 1, wherein the metallographic structure corrosion agent comprises the following components in proportion: 35-40 ml of concentrated hydrochloric acid, 25-30 ml of concentrated nitric acid, 8-10 ml of glycerol and 17-20 ml of glacial acetic acid.
3. The method for corroding the metallographic structure of the GH4220 superalloy according to claim 1 or 2, wherein the metallographic structure corroding agent is prepared by the following method:
step 1, adding concentrated hydrochloric acid into a beaker according to the proportion;
step 2, adding concentrated nitric acid into the beaker according to the proportion;
step 3, adding glacial acetic acid into the beaker according to the proportion;
step 4, adding glycerol into the beaker according to the proportion;
and 5, uniformly stirring and standing to obtain the GH4220 high-temperature alloy metallographic structure corrosive agent.
4. The method for corrosion of a metallographic structure of a GH4220 superalloy according to claim 3, wherein in step 4, the time for standing is 3 to 5 minutes.
5. The method for corrosion of metallographic structure of GH4220 superalloy according to claim 1, wherein in S1, the influence on the structure of the specimen is avoided during the process of cutting the specimen.
6. The method for corrosion of metallographic structure of GH4220 superalloy according to claim 1, wherein in S2, grinding is performed sequentially from coarse to fine according to granularity of metallographic coated abrasive.
7. The method of corrosion of the metallographic structure of the GH4220 superalloy according to claim 1, wherein in S3, diamond spray abrasive is used as a medium.
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