CN115537712A - Chemical heat treatment method for improving hydrogen resistance of gamma-alpha double-phase stainless steel - Google Patents
Chemical heat treatment method for improving hydrogen resistance of gamma-alpha double-phase stainless steel Download PDFInfo
- Publication number
- CN115537712A CN115537712A CN202211156311.8A CN202211156311A CN115537712A CN 115537712 A CN115537712 A CN 115537712A CN 202211156311 A CN202211156311 A CN 202211156311A CN 115537712 A CN115537712 A CN 115537712A
- Authority
- CN
- China
- Prior art keywords
- stainless steel
- phase
- duplex stainless
- gamma
- polishing
- 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.)
- Granted
Links
- 239000001257 hydrogen Substances 0.000 title claims abstract description 44
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 44
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 37
- 238000010438 heat treatment Methods 0.000 title claims abstract description 32
- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000000126 substance Substances 0.000 title claims abstract description 15
- 229910001220 stainless steel Inorganic materials 0.000 title abstract description 17
- 239000010935 stainless steel Substances 0.000 title abstract description 17
- 229910001039 duplex stainless steel Inorganic materials 0.000 claims abstract description 49
- 238000005498 polishing Methods 0.000 claims abstract description 46
- 239000000463 material Substances 0.000 claims abstract description 38
- 238000000227 grinding Methods 0.000 claims abstract description 16
- 239000007789 gas Substances 0.000 claims abstract description 7
- 239000011159 matrix material Substances 0.000 claims description 14
- 238000004506 ultrasonic cleaning Methods 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 244000137852 Petrea volubilis Species 0.000 claims description 5
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 5
- 230000003746 surface roughness Effects 0.000 claims description 4
- 230000018199 S phase Effects 0.000 abstract description 15
- 238000009792 diffusion process Methods 0.000 abstract description 8
- 230000007797 corrosion Effects 0.000 abstract description 7
- 238000005260 corrosion Methods 0.000 abstract description 7
- 150000002431 hydrogen Chemical class 0.000 abstract description 7
- 238000004140 cleaning Methods 0.000 abstract description 3
- 230000006378 damage Effects 0.000 abstract description 3
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 239000007769 metal material Substances 0.000 abstract description 2
- 238000004381 surface treatment Methods 0.000 abstract description 2
- 239000010410 layer Substances 0.000 description 20
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 13
- 229910001566 austenite Inorganic materials 0.000 description 12
- 229910000831 Steel Inorganic materials 0.000 description 7
- 239000010959 steel Substances 0.000 description 7
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 6
- 229910000859 α-Fe Inorganic materials 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 239000008367 deionised water Substances 0.000 description 5
- 229910021641 deionized water Inorganic materials 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000009466 transformation Effects 0.000 description 4
- 238000005524 ceramic coating Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 229910003460 diamond Inorganic materials 0.000 description 3
- 239000010432 diamond Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 238000007517 polishing process Methods 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- CXOWYMLTGOFURZ-UHFFFAOYSA-N azanylidynechromium Chemical compound [Cr]#N CXOWYMLTGOFURZ-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 238000005097 cold rolling Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000008595 infiltration Effects 0.000 description 2
- 238000001764 infiltration Methods 0.000 description 2
- 238000005121 nitriding Methods 0.000 description 2
- 125000004433 nitrogen atom Chemical group N* 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 1
- 238000000861 blow drying Methods 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000016507 interphase Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 238000005580 one pot reaction Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- 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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/28—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases more than one element being applied in one step
- C23C8/30—Carbo-nitriding
- C23C8/32—Carbo-nitriding of ferrous surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention relates to the technical field of metal material surface treatment, and provides a chemical heat treatment method for improving the hydrogen resistance of gamma-alpha double-phase stainless steel, which comprises the specific steps of (1) mechanically grinding, polishing and ultrasonically cleaning the double-phase stainless steel material; (2) Carrying out gas nitrocarburizing treatment on the duplex stainless steel material in the step (1); (3) Carrying out centrifugal polishing on the duplex stainless steel material in the step (2); by adopting the above treatment method for nitrocarburizing, a layer of S phase with the thickness of several microns can be formed on the surface of the gamma phase and the alpha phase, the S phase is compact and continuous, no bulge and cavity exist, the CrN phase which can not damage the corrosion resistance of the material is separated out, and the hydrogen diffusion coefficient can be reduced by 2 orders of magnitude, thereby effectively preventing the environmental hydrogen from permeating into the interior, and greatly expanding the application of the duplex stainless steel in a high-pressure hydrogen contacting structure.
Description
Technical Field
The invention relates to the technical field of metal material surface treatment, and provides a chemical heat treatment method for improving the hydrogen resistance of gamma-alpha duplex stainless steel.
Background
Austenitic stainless steel is often used as steel for a hydrogen-contacting structure because the face-centered cubic structure of the austenitic stainless steel is not sensitive to hydrogen, but the common austenitic steel is softer and has lower strength so that the common austenitic steel cannot bear some ultrahigh pressure environments on a hydrogen-adding station system, and the high-strength precipitation-strengthened stainless steel with high nickel and high chromium is expensive. The gamma-alpha duplex stainless steel is stainless steel with gamma phase and alpha phase accounting for about 50% of each other, and has strength 2 times higher than that of common austenitic stainless steel, but the existence of a large amount of alpha phase makes the gamma-alpha duplex stainless steel have high hydrogen brittleness sensitivity under a high-pressure hydrogen environment. If a continuous hydrogen-blocking layer can be prepared on the surface of the duplex stainless steel by a surface engineering means to prevent external hydrogen from permeating into a steel matrix, a way can be provided for the application of the duplex stainless steel in an ultrahigh pressure hydrogen structure.
Most of the hydrogen-resistant layers which are widely researched at present are ceramic coatings prepared by PVD, CVD, spraying and other methods, and because the components and the structure of the ceramic coatings are greatly different from those of stainless steel substrates, the ceramic coatings are easy to damage and fall off under the action of internal stress or load, and the geometric characteristics and the size of a processing object are limited mostly. In addition, chemical nitriding, nitrocarburizing, and the like are used to transform the γ phase of the austenitic stainless steel surface layer into the expanded austenite (S) phase, thereby improving the corrosion resistance, hardness, and wear resistance of the austenitic steel. However, the thermal stability of the S phase is poor, and CrN is easily decomposed at a temperature of more than 450 ℃, so that experts propose a low-temperature nitrocarburizing process of 430 ℃ to 450 ℃ for austenitic stainless steel. However, when nitrocarburizing treatment is performed on a γ - α duplex stainless steel, the inventors have found that the S phase generated by the transformation of the original α phase is thinner than the S phase generated by the transformation of the original γ phase, and that the S phase generated by the transformation of the α phase is inferior in stability, and can be decomposed at 420 ℃ to form CrN. If the uniform S phase with excellent hydrogen resistance can be formed on the surface of the gamma-alpha duplex stainless steel, the penetration of environmental hydrogen into an internal steel matrix can be effectively inhibited, and the application of the expanded duplex steel in an ultrahigh-pressure hydrogen environment is significant for practical engineering application. Therefore, a new nitrocarburizing treatment process must be developed for γ - α duplex stainless steel.
Disclosure of Invention
Aiming at various defects in the prior art, the invention provides a chemical heat treatment method for improving the hydrogen resistance of gamma-alpha double-phase stainless steel, which comprises the following specific steps of (1) mechanically grinding and polishing and ultrasonically cleaning the double-phase stainless steel material; (2) Carrying out gas nitrocarburizing treatment on the duplex stainless steel material in the step (1); (3) Carrying out centrifugal polishing on the duplex stainless steel material in the step (2); by adopting the above treatment method for nitrocarburizing, a layer of S phase with the thickness of several microns can be formed on the surface of the gamma phase and the alpha phase, the S phase is compact and continuous, no bulge and cavity exist, the CrN phase which can not damage the corrosion resistance of the material is separated out, and the hydrogen diffusion coefficient can be reduced by 2 orders of magnitude, thereby effectively preventing the environmental hydrogen from permeating into the interior, and greatly expanding the application of the duplex stainless steel in a high-pressure hydrogen contacting structure.
The specific concept of the invention is as follows:
a large number of nitrogen atoms enter the FCC or BCC crystal structure and reach a supersaturation state, and the resulting compressive strain causes the crystal structure to deform and the lattice parameter to grow, forming an austenite layer in which the nitrogen atoms are dissolved in solid solution (also called an expanded austenite layer, denoted as γ) N Phase or S phase); the austenite is transformed into the expanded austenite only by one-step reaction, and the ferrite is transformed into the expanded ferrite and then transformed into the expanded austenite. However, the expanded austenite has poor thermal stability and is easily decomposed into phases of expanded ferrite and chromium nitride at high temperature. The dispersedly distributed nitride and carbide are beneficial to improving the hydrogen resistance, but when the dissociable phase is changed, the dissociable phase will destroy the integrity of the surface passive film, so that the stainless steel is poor in intercrystalline chromium, the hardness is improved, and the corrosion resistance is deteriorated. This is the main problem of the existing heat treatment, and the present application is the solution provided for this drawback.
The specific technical scheme of the application is as follows:
a chemical heat treatment method for improving the hydrogen resistance of gamma-alpha duplex stainless steel comprises the following steps:
(1) Carrying out mechanical grinding and polishing and ultrasonic cleaning on the surface of the duplex stainless steel material;
(2) Performing gas nitrocarburizing treatment on the duplex stainless steel material treated in the step (1);
(3) And (3) performing centrifugal polishing on the duplex stainless steel material obtained in the step (2).
Wherein the duplex stainless steel material is a cold-rolled material, and the thickness of the material to be treated is preferably 0.5 mm-8 mm.
Further, the step of grinding, polishing and ultrasonically cleaning the duplex stainless steel material in the step (1) comprises the following steps:
the surface of the material is gradually ground by adopting a mechanical grinding method, and the polishing can be mechanical polishing or electrolytic polishing;
the optional mechanical grinding and polishing mode comprises the following steps:
sequentially grinding and polishing the upper part and the lower part of the matrix by adopting SiC sand paper of 150#, 400#, 600#, 800#, 1000#, 1500# and 2000#, wherein the surface roughness of the ground and polished material is less than Ra1.6; no matter what polishing mode is adopted, the surface roughness of the polished material is less than Ra1.6.
The polished stainless steel is cleaned by deionized water and ethanol for 15min by ultrasonic wave;
and drying the cleaned stainless steel by using cold air.
The step (2) of low-temperature nitrocarburizing comprises the following steps:
raising the temperature of the vacuum heating furnace to 380-400 ℃;
introducing NH into the vacuum heating furnace 3 CO and N 2 And the flow control ratio of the three is NH 3 :CO:N 2 ＝2:1:1；
Setting the pressure in the furnace to be 0.07 MPa-0.09 MPa, and carrying out low-temperature nitrocarburizing for 20 h-25 h.
The parameters of centrifugal polishing in the step (3) are time: 10 min-20 min, frequency: 20 Hz-40 Hz, and the oxide layer on the surface of the material after the previous step of shock heat treatment can be removed through centrifugal polishing, so that a high-quality infiltration layer which is smooth, flat, uniform and glossy in infiltration layer can be obtained.
Compared with the prior art, the technical scheme of the invention has the beneficial effects that:
(1) The invention transforms the austenite phase on the surface of the duplex stainless steel and the original ferrite phase sensitive to hydrogen into an expanded austenite phase structure by low-temperature nitrocarburizing treatment with the help of the infiltrated nitrogen and carbon atoms, and has no precipitation of harmful chromium nitride;
(2) Compared with the coating obtained by the PVD technology, the hydrogen-resistant layer obtained by in-situ growth on the surface of the stainless steel has no obvious interface between the coating and the substrate, has a diffusion layer, is strong in binding force and not easy to fall off, and the service life of the coating is greatly prolonged;
(3) The hydrogen diffusion coefficient of the hydrogen-resistant coating prepared by the invention can be reduced by 2 orders of magnitude, and the hydrogen-resistant coating can be applied to the field of hydrogen resistance and widens the application field of the duplex stainless steel.
Drawings
FIG. 1 is a metallographic structure diagram of a 2205 matrix in example 1, and the metallographic structure diagram is composed of a gamma phase and an alpha phase;
FIG. 2 is a metallographic structure of a section of example 1 subjected to nitrocarburizing treatment at 380 ℃ with the γ phase and the α phase on the surface transformed into a uniform continuous S phase;
FIG. 3 is a metallographic structure diagram of a 420 ℃ nitriding-treated cross section in comparative example 1, in which the S phase formed by the alpha phase transformation is relatively thin and the CrN phase is partially decomposed;
FIG. 4 is a graph of electrochemical hydrogen permeation of 2205 stainless steel in example 2;
FIG. 5 is a graph showing the electrochemical hydrogen permeation of 2205 stainless steel treated by nitrocarburizing at 380 ℃ in example 2.
Detailed Description
For better understanding of the present invention, the following examples are provided to further illustrate the present invention, but the present invention is not limited to the following examples. Unless defined otherwise, all technical and scientific terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention in the embodiments below is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used in the following embodiments includes any and all combinations of one or more of the associated listed items.
Example 1
A chemical heat treatment method for improving the hydrogen resistance of gamma-alpha duplex stainless steel comprises the following steps:
(1) Carrying out mechanical grinding and polishing and ultrasonic cleaning on the surface of the duplex stainless steel material;
(2) Performing gas nitrocarburizing treatment on the duplex stainless steel material treated in the step (1);
(3) And (3) performing centrifugal polishing on the duplex stainless steel material obtained in the step (2).
Wherein the duplex stainless steel material is 2205 duplex stainless steel in a cold rolling state;
the method comprises the following more specific steps:
(1) Taking a cold-rolled 2205 duplex stainless steel plate with the thickness of 10mm multiplied by 5mm, and gradually grinding the upper part and the lower part of a matrix by adopting SiC sand paper of 150#, 400#, 600#, 800#, 1000#, 1500# and 2000 #; polishing with diamond polishing paste, and washing the surface with anhydrous ethanol every 1min for observation until no scratch is formed under flesh eyes, and detecting that the surface roughness is less than Ra1.6. Then ultrasonic cleaning is carried out for 15min by using deionized water and ethanol which are completely soaked in the sample respectively to remove residues in the polishing process, and then cold air is used for drying;
(2) Placing the sample treated in the step (1) in a vacuum heating furnace, and raising the temperature to 380-400 ℃; introducing NH into the vacuum heating furnace 3 CO and N 2 And NH 3 At 2L/min, CO at 1L/min, N 2 Introducing the mixture into the vacuum heating furnace at the speed of 1L/min; setting the pressure in the furnace to be 0.085MPa, and carrying out low-temperature nitrocarburizing for 25 hours;
(3) And (3) carrying out centrifugal polishing on the duplex stainless steel material obtained in the step (2) to eliminate a non-seepage layer with the surface being 2-3 microns after heat treatment. The method is carried out by adopting a centrifugal polishing machine, wherein the selected centrifugal polishing machine is purchased from Guanguan Guangsheng polishing materials Co., ltd, the polishing time is 15min, and the frequency is 30Hz.
Through detection, as shown in fig. 1, an untreated original sample is taken, a metal matrix is corroded by corrosive liquid, the metallographic structure of the matrix is observed under an optical microscope, the matrix mainly comprises austenite and ferrite which are distributed in an interphase mode, wherein the ferrite phase is dark gray, and the austenite phase is light gray;
as shown in FIG. 2, the specimen subjected to the nitrocarburizing was sampled, and the metallographic structure of the cross section was observed under an optical microscope by etching the metal matrix with an etchant. The white bright layer (expanded austenite layer) is clearly visible at the part close to the surface, and the thickness of the sample carburized layer subjected to nitrocarburizing treatment at 380 ℃ is 4.1-7.3 mu m.
Comparative example 1
The prior art researches the mature process of nitrocarburizing on the surface of austenitic stainless steel, and according to the chemical heat treatment method in the prior art, the method comprises the following steps:
(1) Carrying out mechanical grinding and polishing and ultrasonic cleaning on the surface of the duplex stainless steel material;
(2) Performing gas nitrocarburizing treatment on the duplex stainless steel material treated in the step (1);
(3) And (3) performing centrifugal polishing on the duplex stainless steel material obtained in the step (2).
The method comprises the following more specific steps:
(1) Taking a cold-rolled 2205 duplex stainless steel plate with the thickness of 10mm multiplied by 5mm, and gradually grinding the upper part and the lower part of a matrix by adopting SiC sand paper of 150#, 400#, 600#, 800#, 1000#, 1500# and 2000 #; polishing with diamond polishing paste, and washing the surface with anhydrous ethanol every 1min for observation until no scratch is formed under flesh eyes. Then ultrasonic cleaning is carried out for 15min by using deionized water and ethanol which are completely soaked in the sample respectively to remove residues in the polishing process, and then the sample is dried by cold air;
(2) Placing the sample treated in the step (1) in a vacuum heating furnace, and raising the temperature to 400-450 ℃; introducing NH into the vacuum heating furnace 3 CO and N 2 And NH 3 At 1-2L/min, CO at 0.5-2L/min, N 2 Introducing the mixture into the vacuum heating furnace at the speed of 1L/min; the pressure in the furnace is set to 0.085MPa, and low-temperature nitrocarburizing is carried out for 25 hours.
(3) And (3) carrying out centrifugal polishing on the duplex stainless steel material obtained in the step (2) to eliminate a non-seepage layer with the surface of 2-3 microns after heat treatment. The method is specifically carried out by adopting a centrifugal polishing machine, wherein the centrifugal polishing machine is purchased from Guanguan Shengyuan polishing materials Co., ltd, the polishing time is 15min, and the frequency is 30Hz.
After the examination, the sample treated as shown in fig. 3 was subjected to corrosion of the metal matrix with an etchant, and the metallographic structure of the cross section was observed under an optical microscope. In the sample treated at 420 ℃, the S phase of the white layer near the surface layer corresponding to the alpha phase begins to decompose into CrN, which indicates that the thermal stability of the S phase converted from the alpha phase is different from that of the S phase converted from the gamma phase.
The white bright layer of the sample treated at 380-400 ℃ shown in FIG. 2 is continuously dense, has no hole defects and does not precipitate CrN. Thus, unexpected technical effect can be achieved by reducing the treatment temperature, and the blank in the field is filled up
In the process, a corrosive agent prepared from 100mL of alcohol, 100mL of hydrochloric acid and 5g of anhydrous copper chloride is selected for corrosion treatment on the cross section of the sample before and after chemical heat treatment in metallographic observation, the corrosive solution on the surface of the sample is washed by deionized water after corrosion for 15 seconds, the surface of the sample is washed by anhydrous ethanol, and blow-drying treatment is carried out.
Example 2
A chemical heat treatment method for improving the hydrogen resistance of gamma-alpha duplex stainless steel comprises the following steps:
(1) Carrying out mechanical grinding and polishing and ultrasonic cleaning on the surface of the duplex stainless steel material;
(2) Performing gas nitrocarburizing treatment on the duplex stainless steel material treated in the step (1);
(3) And (3) performing centrifugal polishing on the duplex stainless steel material obtained in the step (2).
Wherein the duplex stainless steel material is 2205 duplex stainless steel in a cold rolling state,
the method comprises the following more specific steps:
(1) Taking a cold-rolled 2205 double-phase stainless steel plate with the thickness of 24mm multiplied by 0.5mm, and grinding the upper part and the lower part of a matrix step by adopting SiC sand paper of 150#, 400#, 600#, 800#, 1000#, 1500# and 2000 #; polishing with diamond polishing paste, and washing the surface with anhydrous ethanol every 1min for observation until no scratch is formed under flesh eyes. Then ultrasonic cleaning is carried out for 15min by using deionized water and ethanol which are completely soaked in the sample respectively to remove residues in the polishing process, and then the sample is dried by cold air;
(2) Placing the sample treated in the step (1) in a vacuum heating furnace, and raising the temperature to 380-400 ℃; introducing NH into the vacuum heating furnace 3 CO and N 2 And NH 3 At 2L/min, CO at 1L/min, N 2 Introducing the mixture into the vacuum heating furnace at the speed of 1L/min; the pressure in the furnace is set to be 0.085MPa, and low-temperature nitrocarburizing is carried out for 20 hours.
(3) And (3) carrying out centrifugal polishing on the duplex stainless steel material obtained in the step (2) to eliminate a non-seepage layer with the surface of 2-3 microns after heat treatment. The method is carried out by adopting a centrifugal polishing machine, wherein the selected centrifugal polishing machine is purchased from Guanguan Guangsheng polishing materials Co., ltd, the polishing time is 15min, and the frequency is 30Hz.
Through detection, as shown in fig. 4, an untreated original sample is taken, the hydrogen permeation behavior of the original stainless steel material is tested by adopting an electrochemical hydrogen permeation test, and the test result is shown in the figure, and the hydrogen diffusion coefficient D =6.135 × 10 -8 。
As shown in FIG. 5, the samples after the above treatment were taken, and the permeation layer prepared by the present invention was subjected to a hydrogen barrier performance test by an electrochemical hydrogen permeation test, from which it can be seen that the steady-state current value of the hydrogen permeation curve after nitrocarburizing treatment was only one-half of that of the substrate, and the hydrogen diffusion coefficient D =6.7468 × 10 -10 It can be seen that the hydrogen diffusion coefficient is reduced by two orders of magnitude compared with the matrix, which shows that the diffusion layer prepared by the preparation method of the invention has good hydrogen resistance.
The above example is one of the selected embodiments of the present invention, and general changes and substitutions by those skilled in the art within the technical scope of the present invention are included in the protection scope of the present invention.
Claims (4)
1. A chemical heat treatment method for improving the hydrogen resistance of gamma-alpha duplex stainless steel is characterized by comprising the following steps:
(1) Carrying out mechanical grinding and polishing and ultrasonic cleaning on the surface of the duplex stainless steel material;
(2) Performing gas nitrocarburizing treatment on the duplex stainless steel material treated in the step (1);
(3) And (3) performing centrifugal polishing on the duplex stainless steel material obtained in the step (2).
2. The chemical heat treatment method for improving the hydrogen resistance of the gamma-alpha duplex stainless steel according to claim 1, wherein the mechanical grinding and polishing in the step (1) are as follows: and (3) gradually grinding the upper part and the lower part of the matrix by using SiC sand paper of 150#, 400#, 600#, 800#, 1000#, 1500# and 2000#, wherein the surface roughness of the ground and polished material is less than Ra1.6.
3. The chemical heat treatment method for improving the hydrogen resistance of gamma-alpha duplex stainless steel according to claim 1, wherein the step (2) of performing the low temperature nitrocarburizing comprises the steps of:
raising the temperature of the vacuum heating furnace to 380-400 ℃; introducing NH into the vacuum heating furnace 3 CO and N 2 And the flow control ratio of the three is NH 3 :CO:N 2 1; setting the pressure in the furnace to be 0.07 MPa-0.09 MPa, and carrying out low-temperature nitrocarburizing for 20 h-25 h.
4. The chemical heat treatment method for improving the hydrogen resistance of gamma-alpha duplex stainless steel according to claim 1, wherein the centrifugal polishing parameters in step (3) are time: 10 min-20 min, frequency: 20Hz to 40Hz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211156311.8A CN115537712B (en) | 2022-09-22 | 2022-09-22 | Chemical heat treatment method for improving hydrogen resistance of gamma-alpha duplex stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211156311.8A CN115537712B (en) | 2022-09-22 | 2022-09-22 | Chemical heat treatment method for improving hydrogen resistance of gamma-alpha duplex stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115537712A true CN115537712A (en) | 2022-12-30 |
| CN115537712B CN115537712B (en) | 2024-06-11 |
Family
ID=84729644
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211156311.8A Active CN115537712B (en) | 2022-09-22 | 2022-09-22 | Chemical heat treatment method for improving hydrogen resistance of gamma-alpha duplex stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115537712B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004324883A (en) * | 2003-04-08 | 2004-11-18 | Ntn Corp | Motor bearing and its manufacturing method |
| CN105950834A (en) * | 2016-06-13 | 2016-09-21 | 张家港阿斯恩表面工程科技有限公司 | Surface treatment process of stainless steel machined product |
-
2022
- 2022-09-22 CN CN202211156311.8A patent/CN115537712B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004324883A (en) * | 2003-04-08 | 2004-11-18 | Ntn Corp | Motor bearing and its manufacturing method |
| CN105950834A (en) * | 2016-06-13 | 2016-09-21 | 张家港阿斯恩表面工程科技有限公司 | Surface treatment process of stainless steel machined product |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115537712B (en) | 2024-06-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Shen et al. | Plasma nitriding of AISI 304 austenitic stainless steel with pre-shot peening | |
| Ceschini et al. | Fatigue behaviour of low temperature carburised AISI 316L austenitic stainless steel | |
| JP2011032536A (en) | Method of combined heat treatment of quench-hardened steel member, and quench-hardened steel member | |
| Souza et al. | Structure and properties of low temperature plasma carburized austenitic stainless steels | |
| Yi et al. | A study for pre-processing of Nb diffusion in Nb–N layer by double-glow plasma alloying | |
| Zhang et al. | Effect of micro-shot peening on fatigue properties of precipitate strengthened Cu-Ni-Si alloy in air and in salt atmosphere | |
| Zhang et al. | Effects of nitrocarburizing on fatigue property of medium carbon steel in very high cycle regime | |
| Kurelo et al. | Tribo-mechanical features of nitride coatings and diffusion layers produced by cathodic cage technique on martensitic and supermartensitic stainless steels | |
| Stoudt et al. | Suppression of fatigue cracking with nanometer-scale multilayered coatings | |
| Jiang et al. | Effect of oxygen boost diffusion treatment on the mechanical properties of Ti-6Al-4V alloy | |
| CN115537712A (en) | Chemical heat treatment method for improving hydrogen resistance of gamma-alpha double-phase stainless steel | |
| MXPA02010475A (en) | Surface treatments to improve corrosion resistance of austenitic stainless steels. | |
| CN113088978A (en) | Stainless steel surface treatment method | |
| CN114231895B (en) | Austenitic stainless steel high-performance low-temperature high-efficiency ion composite infiltration surface modification method | |
| CN103276349A (en) | Low-carbon steel surface salt bath rare earth vanadium-titanium boronizing agent and treatment process thereof | |
| Mitterer et al. | Optimization of plasma-assisted chemical vapour deposition hard coatings for their application in aluminium die-casting | |
| KR101614259B1 (en) | Method for formation of hardened layer on martensitic precipitation-hardening stainless steel by the application of in-situ combination of aging treatment and plasma nitrocaburizing treatment | |
| Zhang et al. | Stress corrosion behavior of low-temperature liquid-nitrided 316 austenitic stainless steel in a sour environment | |
| CN114182213A (en) | Titanium alloy wear-resistant antioxidant composite coating and preparation method thereof | |
| JPH08158035A (en) | Carburizing treatment for austenitic metal and austenitic metal product using the same | |
| Yasumaru et al. | Mechanical properties of type 304 austenitic stainless steel coated with titanium nitride after ion-nitriding | |
| CN114317898A (en) | Method for improving wear resistance and corrosion resistance of ferritic stainless steel surface | |
| JP3064909B2 (en) | Carburized hardware and its manufacturing method | |
| Wang et al. | Combined effect of rapid nitriding and plastic deformation on the surface strength, toughness and wear resistance of steel 38CrMoAlA | |
| Devaraju et al. | The effect of surface roughness on sursulf, gas and plasma nitride coatings on austenitic stainless steel type AISI 316LN |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |