CN112304733A - Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method - Google Patents
Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method Download PDFInfo
- Publication number
- CN112304733A CN112304733A CN202011162845.2A CN202011162845A CN112304733A CN 112304733 A CN112304733 A CN 112304733A CN 202011162845 A CN202011162845 A CN 202011162845A CN 112304733 A CN112304733 A CN 112304733A
- Authority
- CN
- China
- Prior art keywords
- sample
- stainless steel
- martensitic stainless
- corrosive agent
- grinding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 63
- 239000003518 caustics Substances 0.000 title claims abstract description 48
- 229910001566 austenite Inorganic materials 0.000 title claims abstract description 38
- 229910001105 martensitic stainless steel Inorganic materials 0.000 title claims abstract description 37
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 40
- 239000012286 potassium permanganate Substances 0.000 claims abstract description 30
- 238000010438 heat treatment Methods 0.000 claims abstract description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 27
- 230000007797 corrosion Effects 0.000 claims abstract description 26
- 238000005260 corrosion Methods 0.000 claims abstract description 26
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 14
- 238000000227 grinding Methods 0.000 claims description 99
- 238000005498 polishing Methods 0.000 claims description 29
- 238000001035 drying Methods 0.000 claims description 18
- 238000003756 stirring Methods 0.000 claims description 18
- 238000005406 washing Methods 0.000 claims description 18
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 15
- 238000010791 quenching Methods 0.000 claims description 12
- 230000000171 quenching effect Effects 0.000 claims description 12
- 229910001220 stainless steel Inorganic materials 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 6
- 239000010935 stainless steel Substances 0.000 claims description 6
- 229910000831 Steel Inorganic materials 0.000 abstract description 18
- 239000010959 steel Substances 0.000 abstract description 18
- 229910052799 carbon Inorganic materials 0.000 abstract description 14
- 239000013078 crystal Substances 0.000 abstract description 11
- 229910045601 alloy Inorganic materials 0.000 abstract description 9
- 239000000956 alloy Substances 0.000 abstract description 9
- 238000002360 preparation method Methods 0.000 abstract description 8
- 239000000126 substance Substances 0.000 abstract description 7
- 239000000463 material Substances 0.000 abstract description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 3
- 231100000956 nontoxicity Toxicity 0.000 abstract description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 12
- 229910010271 silicon carbide Inorganic materials 0.000 description 12
- 239000000243 solution Substances 0.000 description 9
- 238000005520 cutting process Methods 0.000 description 8
- 238000005303 weighing Methods 0.000 description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 7
- 229910000851 Alloy steel Inorganic materials 0.000 description 6
- 239000011651 chromium Substances 0.000 description 6
- 239000000306 component Substances 0.000 description 6
- 229910052804 chromium Inorganic materials 0.000 description 5
- 229910052750 molybdenum Inorganic materials 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 5
- OXNIZHLAWKMVMX-UHFFFAOYSA-N picric acid Chemical compound OC1=C([N+]([O-])=O)C=C([N+]([O-])=O)C=C1[N+]([O-])=O OXNIZHLAWKMVMX-UHFFFAOYSA-N 0.000 description 5
- 238000004506 ultrasonic cleaning Methods 0.000 description 5
- 244000137852 Petrea volubilis Species 0.000 description 4
- 239000008367 deionised water Substances 0.000 description 4
- 229910021641 deionized water Inorganic materials 0.000 description 4
- 229910003460 diamond Inorganic materials 0.000 description 4
- 239000010432 diamond Substances 0.000 description 4
- 239000004744 fabric Substances 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 239000000314 lubricant Substances 0.000 description 4
- 229910052748 manganese Inorganic materials 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000008399 tap water Substances 0.000 description 4
- 235000020679 tap water Nutrition 0.000 description 4
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
Images
Classifications
-
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means
- G01N15/0227—Investigating particle size or size distribution by optical means using imaging; using holography
Landscapes
- Chemical & Material Sciences (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Dispersion Chemistry (AREA)
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
- ing And Chemical Polishing (AREA)
Abstract
The invention relates to a corrosive agent for displaying austenite grain boundary of martensitic stainless steel and a display method, wherein the corrosive agent comprises potassium permanganate, concentrated sulfuric acid and water, and the dosage ratio of the potassium permanganate, the concentrated sulfuric acid and the water is (0.5-2) g, (5-15) mL (85-95) mL; the display method comprises the steps of preparation of a metallographic sample, ultrasonic corrosion of a test sample, sample observation and grain size statistics. Compared with the prior art, the corrosive agent has the advantages of few chemical varieties, safety, no toxicity, convenience in operation, good display effect and the like, can clearly display the prior austenite crystal grains of the martensitic stainless steel sample by adopting the display method, solves the problem that the austenite crystal boundary of the martensitic stainless steel is difficult to corrode, is suitable for displaying the prior austenite boundaries of various low-carbon high-alloy martensitic steel which is difficult to corrode, has high success rate of corrosion of the crystal boundary of the sample, is safe and convenient with the corrosion method, effectively assists in grading the crystal grains of materials in the actual production process, and provides a basis for optimizing the heat treatment process.
Description
Technical Field
The invention belongs to the technical field of steel material metallographic structure observation, and relates to a corrosive agent for displaying martensite stainless steel austenite grain boundary and a display method.
Background
The low-carbon high-alloy martensitic steel has higher strength, hardness and wear resistance, and is widely applied to modern industry, particularly large-scale casting and forging pieces in the nuclear power field, such as supercritical rotors and nuclear turbine blades, and core components in the aerospace field, such as engine blades and the like.
The refined austenite grain is the only method which can improve the strength and the toughness of the material, so the grain size of the prior austenite is one of the important indexes for evaluating and testing the performance of the low-carbon high-alloy steel. In order to discuss the refinement of austenite grains, a suitable method is firstly required to observe and evaluate the size of the austenite grains. The low-carbon high-alloy martensitic steel usually contains a large amount of alloy elements such as chromium, nickel, molybdenum and the like, so that the corrosion resistance is relatively high, and the corrosion of a grain boundary is difficult.
Chinese invention patent CN103018141A introduces a high-alloy low-carbon martensitic steel original crystal grain display agent and a display method, wherein the display agent comprises 5-10ml of concentrated nitric acid, 10-30ml of concentrated hydrochloric acid, 50-100ml of alcohol, 0.5-4 g of picric acid and 1.0-6.0 g of sodium dodecyl benzene sulfonate. The required reagents are various, and the picric acid contained in the picric acid belongs to dangerous chemicals and can explode when being heated, exposed to open fire, high in heat or subjected to friction vibration and impact, so that the picric acid is strictly controlled, the acquisition channel is limited, and the picric acid also has strong toxicity and can possibly cause various diseases. Therefore, the display agent and the display method are not safe to be operated manually.
The Chinese invention patent CN110926912A introduces a method for manufacturing and corroding an etchant for displaying a super martensitic stainless steel crystal boundary, wherein the etchant comprises potassium permanganate, sulfuric acid and water in a mass ratio of 1: 23-30: 83-87. When the method is used, a preparation sample is required to be placed in an erosion liquid for 2-4 min before a formal sample is eroded, then the preparation sample is taken out, after the formal sample is eroded, 10% -15% oxalic acid aqueous solution is required to be used for cleaning and removing dirt on the surface of the sample, the steps are complicated, and finally a large amount of dirt remains on the surface of the sample. The invention uses ultrasonic vibration to corrode, so that only one step is needed for etching, dirt is not attached to the surface of the sample, the sample is directly taken out and washed by alcohol, the steps are simple and convenient, and the sample is clean.
In summary, the existing methods are complicated or dangerous to operate. Therefore, it is important to develop a simple, efficient and safe corrosive agent and a corresponding corrosion method to display the prior austenite grain boundary of the low-carbon high-alloy martensitic steel.
Disclosure of Invention
The invention aims to provide a corrosive agent for displaying austenite grain boundaries of martensitic stainless steel and a display method, the corrosion operation is simple and convenient, the grain boundary display effect is clear, and the problems that low-carbon high-alloy steel does not have a proper corrosive agent and the corrosion method is unreasonable are solved.
The purpose of the invention can be realized by the following technical scheme:
the corrosive agent comprises potassium permanganate, concentrated sulfuric acid and water, wherein the dosage ratio of the potassium permanganate to the concentrated sulfuric acid to the water is (0.5-2) g, (5-15) mL, (85-95) mL.
Further, in the concentrated sulfuric acid, H2SO4The mass percentage of the components is 97-99%.
A preparation method of a corrosive agent for displaying austenite grain boundary of martensitic stainless steel comprises the following steps: and (3) adding concentrated sulfuric acid into water under the stirring state, then adding potassium permanganate, and uniformly stirring to obtain the corrosive agent.
An application of corrosive in displaying austenite grain boundary of martensitic stainless steel.
The method is based on the corrosive and mainly comprises preparation of a metallographic sample, ultrasonic corrosion of a sample, sample observation and grain size statistics. The method comprises the following steps:
1) carrying out austenitizing heat treatment on a martensitic stainless steel sample, polishing and polishing the quenched martensitic stainless steel sample until the surface is bright and has no scratch, and then washing and drying the martensitic stainless steel sample to obtain a sample to be corroded;
2) heating the corrosive agent to 50-80 ℃, then placing a sample to be corroded in the corrosive agent, carrying out ultrasonic vibration corrosion for 10-30 minutes to obtain a corroded sample, taking out the corroded sample, washing and drying;
3) the samples were observed with a metallographic microscope. And observing the obtained sample under a metallographic microscope, clearly observing the original austenite grain boundary of the low-carbon high-alloy martensite steel, respectively shooting metallographic pictures with different magnification factors, and counting the original austenite grain diameter and grain size by using image analysis software.
Further, in the step 1), the temperature is 900-1200 ℃ in the austenitizing heat treatment process, and the time is 10 minutes-6 hours. The quenched low-carbon high-alloy martensitic stainless steel sample can be obtained by adopting a conventional austenitizing heat treatment process.
Further, in the step 1), the grinding comprises coarse grinding and fine grinding which are sequentially carried out; the coarse grinding process comprises the following steps: sequentially grinding martensite stainless steel samples by 180#, 320#, and 600# abrasive paper; the fine grinding process comprises the following steps: the roughly ground martensitic stainless steel coupon was ground on 1200# sandpaper.
Further, in step 2), the polished surface of the sample to be etched is placed in the etchant upward. And (3) putting the beaker filled with the corrosive agent into an ultrasonic cleaning machine with a heating function, heating the beaker to 50-80 ℃ in a water bath, putting the polished surface of a sample to be corroded into the beaker in an upward mode after the temperature is constant, and starting an ultrasonic vibration function during corrosion.
Further, in step 2), the surface of the corroded sample is rinsed with alcohol.
Further, the martensitic stainless steel comprises the following components in percentage by weight: 0.01-0.14% of C, 9.00-16.00% of Cr, 0.80-10.10% of Ni, 0.65-1.60% of Mo, 0-0.8% of Si, 0-0.9% of Mn, 0-0.01% of P, 0-0.01% of S, 0-1.15% of Co, 0-0.21% of Ti, 0-1.03% of W, 0-0.20% of V, 0-0.066% of Al, 0-0.03% of Sn, 0-0.06% of N, 0-0.049% of Nb, 0-0.04% of Cu, 0-0.01% of B, and the balance of Fe and inevitable impurity elements.
Compared with the prior art, the invention has the following characteristics:
1) the corrosive disclosed by the invention needs few chemical drugs, has the advantages of safety, no toxicity, convenience in operation, good display effect and the like, and provides convenience for grading material crystal grains in the actual production process.
2) The display method can clearly display the prior austenite crystal grains of the martensitic stainless steel sample, solves the problem that the austenite crystal boundary of the martensitic stainless steel is difficult to corrode, is suitable for displaying various low-carbon high-alloy martensitic steel prior austenite boundaries which are difficult to corrode, has high success rate of corrosion of the crystal boundary of the sample, is safe and convenient for a corrosive agent and a corrosion method, effectively assists in grading of the crystal grains of the material in the actual production process, and provides a basis for optimizing a heat treatment process.
Drawings
FIG. 1 is a metallographic photograph of prior austenite grains of 0Cr16Ni5Mo1 steel obtained by 12-minute austenitizing and then quenching in example l using the method of the present invention at 1100 ℃;
FIG. 2 is a metallographic photograph of prior austenite grains of a steel X12CrMoWVNbN10-1-1 obtained by 30-minute austenitizing and quenching in example 2 using the method of the present invention at 1150 ℃;
FIG. 3 is a metallographic photograph of prior austenite grains of COST-FB2 rotor steel obtained by 5-hour austenitizing and then quenching in example 3 using the method of the present invention at 950 ℃;
FIG. 4 is a metallographic photograph of prior austenite grains of a 00Cr12Ni10MoTi steel obtained by 1 hour austenitizing and then quenching at 1100 ℃ as shown in example 4 by the method of the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
Example 1:
in the embodiment, the low-carbon high-alloy steel is 0Cr16Ni5Mo1, and the specific chemical components and mass percentage content are as follows: c: 0.055%, Cr: 15.32%, Ni: 4.82%, Mo: 0.87%, Si: 0.35%, Mn: 0.88%, P: 0.005%, S: 0.002%, Sn: 0.028%, Cu: 0.04% and the balance of Fe and inevitable impurity elements.
Preparing a metallographic sample:
a. cutting a 10mm multiplied by 5mm block sample by a linear cutting method, austenitizing at 1100 ℃ for 12 minutes, and then quenching to prepare for subsequent grinding and polishing;
b. coarse grinding of the sample: grinding a sample by sequentially using silicon carbide waterproof abrasive paper with the speed of rotation of a grinding disc set to 600rpm and the next-pass abrasive paper, rotating the sample by 90 degrees along a grinding surface every time to enable a new-pass grinding mark to be vertical or approximately vertical to a previous-pass grinding mark, and grinding until the new-pass grinding mark covers the previous-pass grinding mark, wherein tap water is used as a lubricant during grinding;
c. and (3) fine grinding of the sample: grinding the rough-ground sample on 1200# silicon carbide waterproof abrasive paper, setting the rotating speed of a grinding disc at 400rpm, and grinding the sample along the direction vertical to the previous primary grinding mark until the previous primary grinding mark cannot be seen;
d. polishing of the sample: polishing the sample polished by the 1200# silicon carbide waterproof sand paper on a rough polishing cloth, sequentially using 9 mu m → 3 mu m → 0.05 mu m diamond polishing solution at the rotating speed of 200rpm to obtain a bright polished surface, sequentially washing with water and alcohol and drying by using a blower.
Preparing a corrosive agent: weighing 5mL of concentrated sulfuric acid, slowly pouring the concentrated sulfuric acid into 95mL of deionized water, continuously stirring by using a glass rod, then weighing 1.5g of potassium permanganate, pouring the potassium permanganate into a sulfuric acid solution, and fully stirring to dissolve the potassium permanganate;
③ ultrasonic corrosion of the sample: putting the beaker containing the corrosive prepared in the second step into an ultrasonic cleaning machine with a heating function, heating to 60-70 ℃, putting the sample prepared in the first step into the beaker with the polished surface facing upwards after the temperature is constant, starting ultrasonic vibration, taking out after corroding for 15-20 minutes, washing the surface of the sample with alcohol and drying;
and fourthly, observing a sample: the samples obtained through the steps from the first step to the third step are observed under a metallographic microscope with a field of view of 100 times, and as shown in figure 1, by adopting the corrosive agent and the corrosion method, the original austenite grain boundary of the 0Cr16Ni5Mo1 steel sample is complete and clearly visible, and completely meets the metallographic photograph standard required by grain size rating.
Example 2:
in the embodiment, the low-carbon high-alloy steel is X12CrMoWVNbN10-1-1, and the specific chemical components and mass percentage content are as follows: c: 0.11%, Cr: 10.35%, Ni: 0.80%, Mo: 1.00%, Si: 0.08%, Mn: 0.41%, P: 0.008%, S: 0.004%, W: 1.03%, V: 0.18%, Al: 0.02%, N: 0.05%, Nb: 0.04% and the balance of Fe and inevitable impurity elements.
Preparing a metallographic sample:
a. cutting a 10mm multiplied by 5mm block sample by a linear cutting method, austenitizing at 1150 ℃ for 30 minutes, and then quenching to prepare for subsequent grinding and polishing;
b. coarse grinding of the sample: grinding a sample by sequentially using silicon carbide waterproof abrasive paper with the speed of rotation of a grinding disc set to 600rpm and the next-pass abrasive paper, rotating the sample by 90 degrees along a grinding surface every time to enable a new-pass grinding mark to be vertical or approximately vertical to a previous-pass grinding mark, and grinding until the new-pass grinding mark covers the previous-pass grinding mark, wherein tap water is used as a lubricant during grinding;
c. and (3) fine grinding of the sample: grinding the rough-ground sample on 1200# silicon carbide waterproof abrasive paper, setting the rotating speed of a grinding disc at 400rpm, and grinding the sample along the direction vertical to the previous primary grinding mark until the previous primary grinding mark cannot be seen;
d. polishing of the sample: polishing the sample polished by the 1200# silicon carbide waterproof sand paper on a rough polishing cloth, sequentially using 9 mu m → 3 mu m → 0.05 mu m diamond polishing solution at the rotating speed of 200rpm to obtain a bright polished surface, sequentially washing with water and alcohol and drying by using a blower.
Preparing a corrosive agent: weighing 12mL of concentrated sulfuric acid, slowly pouring the concentrated sulfuric acid into 88mL of deionized water, continuously stirring by using a glass rod, then weighing 1g of potassium permanganate, pouring the potassium permanganate into a sulfuric acid solution, and fully stirring to dissolve the potassium permanganate;
③ ultrasonic corrosion of the sample: putting the beaker containing the corrosive prepared in the second step into an ultrasonic cleaning machine with a heating function, heating to 70 ℃, putting the sample prepared in the first step into the beaker with the polished surface facing upwards after the temperature is constant, starting ultrasonic vibration, taking out the sample after corroding for 20 minutes, washing the surface of the sample with alcohol and drying the sample;
and fourthly, observing a sample: observing the sample obtained through the steps from the first step to the third step under a metallographic microscope with a field of view of 100 times, and as shown in figure 2, by adopting the corrosive agent and the corrosion method, the original austenite grain boundary of the X12CrMoWVNbN10-1-1 steel sample is clear and complete, and although a little tissue appears in the inside of the grain, the grain also meets the metallographic standard required by grain size rating.
Example 3:
in the embodiment, the low-carbon high-alloy steel is COST-FB2 rotor steel, and comprises the following specific chemical components in percentage by mass: c: 0.14%, Cr: 9.06%, Co: 1.15%, Mo: 1.51%, Ni: 0.17%, Si: 0.06%, Mn: 0.42%, V: 0.20%, N: 0.06%, Nb: 0.049%, B: 0.008% and the balance of Fe and inevitable impurity elements.
Preparing a metallographic sample:
a. cutting a 10mm multiplied by 5mm massive sample by a linear cutting method, austenitizing the sample at 950 ℃ for 5 hours, and then quenching the sample to prepare for subsequent grinding and polishing;
b. coarse grinding of the sample: grinding a sample by sequentially using silicon carbide waterproof abrasive paper with the speed of rotation of a grinding disc set to 600rpm and the next-pass abrasive paper, rotating the sample by 90 degrees along a grinding surface every time to enable a new-pass grinding mark to be vertical or approximately vertical to a previous-pass grinding mark, and grinding until the new-pass grinding mark covers the previous-pass grinding mark, wherein tap water is used as a lubricant during grinding;
c. and (3) fine grinding of the sample: grinding the rough-ground sample on 1200# silicon carbide waterproof abrasive paper, setting the rotating speed of a grinding disc at 400rpm, and grinding the sample along the direction vertical to the previous primary grinding mark until the previous primary grinding mark cannot be seen;
d. polishing of the sample: polishing the sample polished by the 1200# silicon carbide waterproof sand paper on a rough polishing cloth, sequentially using 9 mu m → 3 mu m → 0.05 mu m diamond polishing solution at the rotating speed of 200rpm to obtain a bright polished surface, sequentially washing with water and alcohol and drying by using a blower.
Preparing a corrosive agent: weighing 13mL of concentrated sulfuric acid, slowly pouring the concentrated sulfuric acid into 87mL of deionized water, continuously stirring by using a glass rod, then weighing 1.2g of potassium permanganate, pouring the potassium permanganate into a sulfuric acid solution, and fully stirring to dissolve the potassium permanganate;
③ ultrasonic corrosion of the sample: putting the beaker containing the corrosive prepared by the second step into an ultrasonic cleaning machine with a heating function, heating to 65 ℃, putting the sample prepared by the first step into the beaker with the polished surface facing upwards after the temperature is constant, starting ultrasonic vibration, taking out the sample after corroding for 22 minutes, washing the surface of the sample by alcohol and drying the sample;
and fourthly, observing a sample: the samples obtained through the steps from the first step to the third step are observed under a metallographic microscope with a field of view of 100 times, and as shown in figure 3, by adopting the corrosive and the corrosion method, the prior austenite grain boundary of the COST-FB2 rotor steel sample is clear and complete and meets the metallographic photograph standard required by grain size rating.
Example 4:
in the embodiment, the low-carbon high-alloy steel is 00Cr12Ni10MoTi steel, and the specific chemical components and mass percentage content are as follows: c: 0.017%, Cr: 11.88%, Ni: 10.1%, Mo: 0.65%, Ti: 0.21%, Si: 0.78%, Mn: 0.0075%, Al: 0.066%, S: 0.001%, P: 0.004%, and the balance of Fe and inevitable impurity elements.
Preparing a metallographic sample:
a. cutting a 10mm multiplied by 5mm block sample by a linear cutting method, austenitizing at 1100 ℃ for 1 hour, and then quenching to prepare for subsequent grinding and polishing;
b. coarse grinding of the sample: grinding a sample by sequentially using silicon carbide waterproof abrasive paper with the speed of rotation of a grinding disc set to 600rpm and the next-pass abrasive paper, rotating the sample by 90 degrees along a grinding surface every time to enable a new-pass grinding mark to be vertical or approximately vertical to a previous-pass grinding mark, and grinding until the new-pass grinding mark covers the previous-pass grinding mark, wherein tap water is used as a lubricant during grinding;
c. and (3) fine grinding of the sample: grinding the rough-ground sample on 1200# silicon carbide waterproof abrasive paper, setting the rotating speed of a grinding disc at 400rpm, and grinding the sample along the direction vertical to the previous primary grinding mark until the previous primary grinding mark cannot be seen;
d. polishing of the sample: polishing the sample polished by the 1200# silicon carbide waterproof sand paper on a rough polishing cloth, sequentially using 9 mu m → 3 mu m → 0.05 mu m diamond polishing solution at the rotating speed of 200rpm to obtain a bright polished surface, sequentially washing with water and alcohol and drying by using a blower.
Preparing a corrosive agent: weighing 15mL of concentrated sulfuric acid, slowly pouring the concentrated sulfuric acid into 85mL of deionized water, continuously stirring by using a glass rod, then weighing 0.8g of potassium permanganate, pouring the potassium permanganate into a sulfuric acid solution, and fully stirring to dissolve the potassium permanganate;
③ ultrasonic corrosion of the sample: putting the beaker containing the corrosive prepared in the second step into an ultrasonic cleaning machine with a heating function, heating to 75 ℃, putting the sample prepared in the first step into the beaker with the polished surface facing upwards after the temperature is constant, starting ultrasonic vibration, taking out the sample after corroding for 18 minutes, washing the surface of the sample with alcohol and drying the sample;
and fourthly, observing a sample: the samples obtained through the steps from the first step to the third step are observed under a metallographic microscope with a field of view of 100 times, and as shown in figure 4, by adopting the corrosive agent and the corrosion method, the original austenite grain boundary of the 00Cr12Ni10MoTi steel sample is clear and complete and completely meets the metallographic photograph standard required by grain size rating.
Example 5:
the corrosive agent comprises potassium permanganate, concentrated sulfuric acid and water, wherein the dosage ratio of the potassium permanganate to the concentrated sulfuric acid to the water is 0.5g to 15mL to 85 mL.
In concentrated sulfuric acid, H2SO4The mass percentage of (B) is 99%.
The preparation method of the corrosive comprises the following steps: and (3) adding concentrated sulfuric acid into water under the stirring state, then adding potassium permanganate, and uniformly stirring to obtain the corrosive agent.
A method for displaying austenite grain boundary of martensitic stainless steel is based on the corrosive agent and comprises the following steps:
1) carrying out austenitizing heat treatment on a martensitic stainless steel sample, grinding and polishing after quenching, and then washing and drying to obtain a sample to be corroded;
2) heating the corrosive agent to 80 ℃, then placing a sample to be corroded in the corrosive agent, carrying out ultrasonic vibration corrosion for 10 minutes to obtain a corroded sample, taking out the corroded sample, washing and drying;
3) the samples were observed with a metallographic microscope.
In the step 1), the temperature is 1200 ℃ and the time is 10 minutes in the austenitizing heat treatment process. The polishing comprises coarse grinding and fine grinding which are sequentially carried out; the coarse grinding process comprises the following steps: sequentially grinding martensite stainless steel samples by 180#, 320#, and 600# abrasive paper; the fine grinding process comprises the following steps: the roughly ground martensitic stainless steel coupon was ground on 1200# sandpaper.
In step 2), the polished surface of the sample to be corroded is placed upwards in the corrosive agent. The surface of the corroded sample is rinsed with alcohol.
Example 6:
the corrosive agent comprises potassium permanganate, concentrated sulfuric acid and water, wherein the dosage ratio of the potassium permanganate to the concentrated sulfuric acid to the water is 2g:5mL:95 mL.
In concentrated sulfuric acid, H2SO4The mass percentage of (B) is 98%.
The preparation method of the corrosive comprises the following steps: and (3) adding concentrated sulfuric acid into water under the stirring state, then adding potassium permanganate, and uniformly stirring to obtain the corrosive agent.
A method for displaying austenite grain boundary of martensitic stainless steel is based on the corrosive agent and comprises the following steps:
1) carrying out austenitizing heat treatment on a martensitic stainless steel sample, grinding and polishing after quenching, and then washing and drying to obtain a sample to be corroded;
2) heating the corrosive agent to 50 ℃, then placing a sample to be corroded in the corrosive agent, carrying out ultrasonic vibration corrosion for 30 minutes to obtain a corroded sample, taking out the corroded sample, washing and drying;
3) the samples were observed with a metallographic microscope.
In the step 1), the temperature is 900 ℃ and the time is 6 hours in the austenitizing heat treatment process. The polishing comprises coarse grinding and fine grinding which are sequentially carried out; the coarse grinding process comprises the following steps: sequentially grinding martensite stainless steel samples by 180#, 320#, and 600# abrasive paper; the fine grinding process comprises the following steps: the roughly ground martensitic stainless steel coupon was ground on 1200# sandpaper.
In step 2), the polished surface of the sample to be corroded is placed upwards in the corrosive agent. The surface of the corroded sample is rinsed with alcohol.
Example 7:
the corrosive agent comprises potassium permanganate, concentrated sulfuric acid and water, wherein the dosage ratio of the potassium permanganate to the concentrated sulfuric acid to the water is 1g:10mL:90 mL.
In concentrated sulfuric acid, H2SO4The mass percentage of (B) is 97%.
The preparation method of the corrosive comprises the following steps: and (3) adding concentrated sulfuric acid into water under the stirring state, then adding potassium permanganate, and uniformly stirring to obtain the corrosive agent.
A method for displaying austenite grain boundary of martensitic stainless steel is based on the corrosive agent and comprises the following steps:
1) carrying out austenitizing heat treatment on a martensitic stainless steel sample, grinding and polishing after quenching, and then washing and drying to obtain a sample to be corroded;
2) heating the corrosive agent to 60 ℃, then placing a sample to be corroded in the corrosive agent, carrying out ultrasonic vibration corrosion for 20 minutes to obtain a corroded sample, taking out the corroded sample, washing and drying;
3) the samples were observed with a metallographic microscope.
In the step 1), the temperature is 1100 ℃ and the time is 2 hours in the austenitizing heat treatment process. The polishing comprises coarse grinding and fine grinding which are sequentially carried out; the coarse grinding process comprises the following steps: sequentially grinding martensite stainless steel samples by 180#, 320#, and 600# abrasive paper; the fine grinding process comprises the following steps: the roughly ground martensitic stainless steel coupon was ground on 1200# sandpaper.
In step 2), the polished surface of the sample to be corroded is placed upwards in the corrosive agent. The surface of the corroded sample is rinsed with alcohol.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.
Claims (10)
1. The corrosive agent for displaying the austenite grain boundary of the martensitic stainless steel is characterized by comprising potassium permanganate, concentrated sulfuric acid and water, wherein the dosage ratio of the potassium permanganate to the concentrated sulfuric acid to the water is (0.5-2) g, (5-15) mL, (85-95) mL.
2. The corrosive agent for displaying austenite grain boundary of martensitic stainless steel as claimed in claim 1, wherein in said concentrated sulfuric acid, H is2SO4The mass percentage of the components is 97-99%.
3. A method for preparing an etchant for displaying austenite grain boundaries of martensitic stainless steel as claimed in claim 1 or 2, wherein the method comprises: and (3) adding concentrated sulfuric acid into water under the stirring state, then adding potassium permanganate, and uniformly stirring to obtain the corrosive agent.
4. Use of an etchant according to claim 1 or 2 to reveal austenitic grain boundaries of martensitic stainless steel.
5. A method for displaying austenitic grain boundaries of martensitic stainless steels, based on the corrosive agent according to claim 1 or 2, characterized in that it comprises the following steps:
1) carrying out austenitizing heat treatment on a martensitic stainless steel sample, grinding and polishing after quenching, and then washing and drying to obtain a sample to be corroded;
2) heating the corrosive agent to 50-80 ℃, then placing a sample to be corroded in the corrosive agent, carrying out ultrasonic vibration corrosion for 10-30 minutes to obtain a corroded sample, taking out the corroded sample, washing and drying;
3) the samples were observed with a metallographic microscope.
6. The method for showing the austenite grain boundary of the martensitic stainless steel as claimed in claim 5, wherein the temperature in the austenitizing heat treatment process in the step 1) is 900-1200 ℃ for 10 minutes-6 hours.
7. The method for showing austenite grain boundaries of martensitic stainless steel as claimed in claim 5, wherein in the step 1), the grinding comprises a coarse grinding and a fine grinding which are sequentially carried out; the coarse grinding process comprises the following steps: sequentially grinding martensite stainless steel samples by 180#, 320#, and 600# abrasive paper; the fine grinding process comprises the following steps: the roughly ground martensitic stainless steel coupon was ground on 1200# sandpaper.
8. The method for displaying austenite grain boundaries of martensitic stainless steel as claimed in claim 5, wherein in step 2), the polished surface of the sample to be corroded is placed upwards in the corrosive agent.
9. The method for showing austenite grain boundaries of martensitic stainless steel as claimed in claim 5, wherein in the step 2), the surface of the sample after corrosion is washed by alcohol.
10. The method of claim 5, wherein the martensitic stainless steel comprises the following components in percentage by weight: 0.01-0.14% of C, 9.00-16.00% of Cr, 0.80-10.10% of Ni, 0.65-1.60% of Mo, 0-0.8% of Si, 0-0.9% of Mn, 0-0.01% of P, 0-0.01% of S, 0-1.15% of Co, 0-0.21% of Ti, 0-1.03% of W, 0-0.20% of V, 0-0.066% of Al, 0-0.03% of Sn, 0-0.06% of N, 0-0.049% of Nb, 0-0.04% of Cu, 0-0.01% of B, and the balance of Fe and inevitable impurity elements.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011162845.2A CN112304733A (en) | 2020-10-27 | 2020-10-27 | Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011162845.2A CN112304733A (en) | 2020-10-27 | 2020-10-27 | Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112304733A true CN112304733A (en) | 2021-02-02 |
Family
ID=74330373
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011162845.2A Pending CN112304733A (en) | 2020-10-27 | 2020-10-27 | Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112304733A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113125318A (en) * | 2021-05-25 | 2021-07-16 | 西安热工研究院有限公司 | Macroscopic grain size detection method for martensite cast steel test piece containing Mo and Co |
| CN113218736A (en) * | 2021-05-07 | 2021-08-06 | 大唐锅炉压力容器检验中心有限公司 | Original austenite grain boundary corrosion method of martensitic stainless steel for steam turbine bolt |
| CN113358646A (en) * | 2021-05-12 | 2021-09-07 | 东南大学 | Corrosive agent for testing 16MnCr5 steel austenite grain boundary and testing method thereof |
| CN113390911A (en) * | 2021-05-26 | 2021-09-14 | 中国工程物理研究院材料研究所 | Extracting corrosive agent and extracting method for beryllium phase three-dimensional microscopic morphology of beryllium-aluminum alloy |
| CN114002221A (en) * | 2021-11-10 | 2022-02-01 | 中国航发贵州黎阳航空动力有限公司 | GH4169 alloy semi-finished product blade carbonitride display method |
| CN114136746A (en) * | 2021-11-08 | 2022-03-04 | 陕西飞机工业有限责任公司 | Use method of martensite precipitation hardening stainless steel free ferrite corrosive agent |
| CN114397166A (en) * | 2021-12-09 | 2022-04-26 | 阳江合金材料实验室 | Application of potassium permanganate corrosive agent in metallographic corrosion of high-carbon martensitic stainless steel |
| CN115014915A (en) * | 2022-07-06 | 2022-09-06 | 中国科学院金属研究所 | Method for displaying austenite grain boundary of low-carbon bearing steel |
| CN116659982A (en) * | 2023-04-23 | 2023-08-29 | 鞍钢股份有限公司 | Austenitic stainless steel grain display method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102221495A (en) * | 2011-03-31 | 2011-10-19 | 洛阳Lyc轴承有限公司 | Method for displaying original austenite grain boundary of 40Cr15Mo2VN bearing steel |
| CN107014661A (en) * | 2017-04-27 | 2017-08-04 | 东北大学 | A kind of caustic solution for showing high nitrogen martensitic stain less steel original austenite crystal boundary |
| CN109187152A (en) * | 2018-09-05 | 2019-01-11 | 天津重型装备工程研究有限公司 | It is a kind of for showing the corrosive agent and display methods of heat resisting steel original austenite crystal boundary |
| CN110926912A (en) * | 2019-11-04 | 2020-03-27 | 北京科技大学 | Preparation and erosion method of etchant for displaying grain boundary of low-carbon super martensitic stainless steel |
| CN111060384A (en) * | 2019-11-27 | 2020-04-24 | 中国科学院金属研究所 | Corrosion method for rapidly, simply and clearly displaying original austenite grain boundary of pipeline steel |
-
2020
- 2020-10-27 CN CN202011162845.2A patent/CN112304733A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102221495A (en) * | 2011-03-31 | 2011-10-19 | 洛阳Lyc轴承有限公司 | Method for displaying original austenite grain boundary of 40Cr15Mo2VN bearing steel |
| CN107014661A (en) * | 2017-04-27 | 2017-08-04 | 东北大学 | A kind of caustic solution for showing high nitrogen martensitic stain less steel original austenite crystal boundary |
| CN109187152A (en) * | 2018-09-05 | 2019-01-11 | 天津重型装备工程研究有限公司 | It is a kind of for showing the corrosive agent and display methods of heat resisting steel original austenite crystal boundary |
| CN110926912A (en) * | 2019-11-04 | 2020-03-27 | 北京科技大学 | Preparation and erosion method of etchant for displaying grain boundary of low-carbon super martensitic stainless steel |
| CN111060384A (en) * | 2019-11-27 | 2020-04-24 | 中国科学院金属研究所 | Corrosion method for rapidly, simply and clearly displaying original austenite grain boundary of pipeline steel |
Non-Patent Citations (1)
| Title |
|---|
| 于芸等: "含氮不锈轴承钢原始奥氏体晶界显示方法试验", 《轴承》 * |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113218736A (en) * | 2021-05-07 | 2021-08-06 | 大唐锅炉压力容器检验中心有限公司 | Original austenite grain boundary corrosion method of martensitic stainless steel for steam turbine bolt |
| CN113358646A (en) * | 2021-05-12 | 2021-09-07 | 东南大学 | Corrosive agent for testing 16MnCr5 steel austenite grain boundary and testing method thereof |
| CN113358646B (en) * | 2021-05-12 | 2023-01-31 | 东南大学 | Corrosive agent for testing 16MnCr5 steel austenite grain boundary and testing method thereof |
| CN113125318A (en) * | 2021-05-25 | 2021-07-16 | 西安热工研究院有限公司 | Macroscopic grain size detection method for martensite cast steel test piece containing Mo and Co |
| CN113390911A (en) * | 2021-05-26 | 2021-09-14 | 中国工程物理研究院材料研究所 | Extracting corrosive agent and extracting method for beryllium phase three-dimensional microscopic morphology of beryllium-aluminum alloy |
| CN113390911B (en) * | 2021-05-26 | 2023-02-07 | 中国工程物理研究院材料研究所 | Extracting corrosive agent and extracting method for beryllium phase three-dimensional microscopic morphology of beryllium-aluminum alloy |
| CN114136746A (en) * | 2021-11-08 | 2022-03-04 | 陕西飞机工业有限责任公司 | Use method of martensite precipitation hardening stainless steel free ferrite corrosive agent |
| CN114002221A (en) * | 2021-11-10 | 2022-02-01 | 中国航发贵州黎阳航空动力有限公司 | GH4169 alloy semi-finished product blade carbonitride display method |
| CN114397166A (en) * | 2021-12-09 | 2022-04-26 | 阳江合金材料实验室 | Application of potassium permanganate corrosive agent in metallographic corrosion of high-carbon martensitic stainless steel |
| CN115014915A (en) * | 2022-07-06 | 2022-09-06 | 中国科学院金属研究所 | Method for displaying austenite grain boundary of low-carbon bearing steel |
| CN116659982A (en) * | 2023-04-23 | 2023-08-29 | 鞍钢股份有限公司 | Austenitic stainless steel grain display method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112304733A (en) | Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method | |
| CN107014661B (en) | A kind of caustic solution showing high nitrogen martensitic stain less steel original austenite crystal boundary | |
| Di Schino et al. | Effects of the grain size on the corrosion behavior of refined AISI 304 austenitic stainless steels | |
| CN109187152A (en) | It is a kind of for showing the corrosive agent and display methods of heat resisting steel original austenite crystal boundary | |
| CN111041486B (en) | Medium-entropy high-temperature alloy metallographic corrosive agent and corrosion method | |
| CN103792128B (en) | A kind of method of the biphase crystal boundary showing two phase stainless steel | |
| CN104805440B (en) | The corrosive agent and display methods of superstrength alloy structural steel original austenite crystal boundary | |
| CN108426883B (en) | A kind of aggressive agent and corrosion method of two phase stainless steel | |
| CN110926912A (en) | Preparation and erosion method of etchant for displaying grain boundary of low-carbon super martensitic stainless steel | |
| CN113358646B (en) | Corrosive agent for testing 16MnCr5 steel austenite grain boundary and testing method thereof | |
| Vidyarthi et al. | Effect of deep cryogenic treatment on the microstructure and wear performance of Cr–Mn–Cu white cast iron grinding media | |
| Qu et al. | The effects of tempering reactions on temper embrittlement of alloy steels | |
| CN110749718A (en) | Dendritic crystal corrosive agent and corrosion method for maraging stainless steel | |
| CN113218736A (en) | Original austenite grain boundary corrosion method of martensitic stainless steel for steam turbine bolt | |
| CN108396321A (en) | A kind of metallographic etchant for austenitic stainless steel and its prepare caustic solution | |
| CN111638113B (en) | Precipitation strengthening martensite stainless steel prior austenite grain boundary corrosion method | |
| CN105823671A (en) | Display method of austenitic grain boundary of medium-manganese steel for automobile | |
| CN111424279A (en) | Corrosive and corrosion method for displaying metallographic structure of cobalt-chromium-molybdenum alloy | |
| CN116481882A (en) | Original austenite grain boundary showing method for high-temperature bearing steel | |
| CN114113086A (en) | Preparation and application method of high-carbon high-alloy steel isothermal quenching tissue corrosive | |
| CN112504798A (en) | Metallographic corrosive agent and corrosion method for high-alloy ultra-pure ultra-high strength steel | |
| CN114397166B (en) | Application of potassium permanganate etchant in metallographic corrosion of high-carbon martensitic stainless steel | |
| CN110132697A (en) | A kind of caustic solution of bearing steel grain size | |
| CN115323378B (en) | Metallographic corrosive agent for displaying sliding band of austenitic material, and preparation method and use method thereof | |
| Barcik | The process of σ-phase solution in 25 pct Cr-20 pct Ni austenitic steels |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210202 |
|
| RJ01 | Rejection of invention patent application after publication |