CN107620031B - Austenitic stainless steel nitriding treatment system and method based on hollow cathode ion source - Google Patents
Austenitic stainless steel nitriding treatment system and method based on hollow cathode ion source Download PDFInfo
- Publication number
- CN107620031B CN107620031B CN201711051778.5A CN201711051778A CN107620031B CN 107620031 B CN107620031 B CN 107620031B CN 201711051778 A CN201711051778 A CN 201711051778A CN 107620031 B CN107620031 B CN 107620031B
- Authority
- CN
- China
- Prior art keywords
- hollow cathode
- nitriding
- furnace
- parts
- stainless steel
- 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.)
- Active
Links
- 238000005121 nitriding Methods 0.000 title claims abstract description 106
- 229910000963 austenitic stainless steel Inorganic materials 0.000 title claims abstract description 31
- 238000000034 method Methods 0.000 title claims abstract description 19
- 239000002184 metal Substances 0.000 claims abstract description 29
- 238000005259 measurement Methods 0.000 claims abstract description 11
- 238000004321 preservation Methods 0.000 claims description 16
- 238000010438 heat treatment Methods 0.000 claims description 9
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 6
- 238000000605 extraction Methods 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 239000000498 cooling water Substances 0.000 claims description 3
- 238000000227 grinding Methods 0.000 claims description 2
- 238000005498 polishing Methods 0.000 claims description 2
- 150000002500 ions Chemical class 0.000 description 22
- 230000007797 corrosion Effects 0.000 description 18
- 238000005260 corrosion Methods 0.000 description 18
- 239000007789 gas Substances 0.000 description 15
- 230000018199 S phase Effects 0.000 description 6
- 230000010287 polarization Effects 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 4
- 150000004767 nitrides Chemical class 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 238000006056 electrooxidation reaction Methods 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 244000137852 Petrea volubilis Species 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- -1 chlorine ions Chemical class 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000011534 incubation Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000005381 potential energy Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Landscapes
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
The invention relates to a nitriding treatment system and a nitriding treatment method for austenitic stainless steel based on a hollow cathode ion source, belonging to the technical field of nitriding treatment of austenitic stainless steel, wherein the nitriding treatment system comprises a power supply system, a vacuum nitriding furnace, a hollow cathode device, an air exhaust system, an air supply system, a measurement and control system, a connecting pipeline and a valve , wherein the hollow cathode device is arranged in the furnace, the hollow cathode device is structurally characterized in that a plurality of metal plates are arranged in the furnace in parallel, each metal plate is provided with a plurality of strip grooves which are arranged at intervals, and each groove is provided with through holes which are arranged at intervals.
Description
Technical Field
The invention belongs to the technical field of austenitic stainless steel nitriding treatment, and particularly relates to austenitic stainless steel nitriding treatment systems and methods based on a hollow cathode ion source.
Background
Due to the presence of passive film (e.g. Cr) on the surface of austenitic stainless steel2O3) In the case of gas nitriding, the process of desmearing the surface of the workpiece becomes indispensable steps, the passive film on the surface is removed by prior heat treatment such as pickling and shot blasting, and the regeneration thereof is suppressed, whereas in the case of direct current ion nitriding, the oxide layer is effectively removed from the surface of stainless steel due to the strong sputtering action of the cathode, and therefore, nitrogen is effectively transmitted at temperatures below 400 ℃.
A large number of experimental researches and theoretical analyses indicate that the key point of the austenitic stainless steel ion nitriding treatment technology is to control the nitriding temperature to be low enough or the nitriding time to be short, so that the formation of CrN is inhibited as much as possible, a single S-phase hardened layer is generated, the single S-phase layer improves the hardness and the wear resistance and simultaneously ensures the original corrosion resistance of austenitic stainless steel, the S-phase is intermediate phases in a metastable state, and the structure and the performance of the austenitic stainless steel nitriding layer change along with the increase of the treatment temperature.
The plasma nitriding technology is widely applied to the field of surface strengthening treatment of austenitic stainless steel materials due to the excellent performance of the austenitic stainless steel materials treatment by , the hollow cathode plasma nitriding is improved by steps of the conventional ion nitriding, ion nitriding based on the hollow cathode structure improves the conventional ion nitriding but also generates -defined limitation, for example, the ion nitriding of two parts, namely, an austenitic stainless steel mold ejector rod and an exhaust valve, is studied by Koch-Dai et al, the two parts are subjected to quenching and tempering pretreatment, a wire mesh with -defined specifications is arranged at a proper distance around the parts to serve as an auxiliary cathode, so that a hollow cathode structure is formed by discharging electricity between the samples of the two parts and the auxiliary cathode, the exhaust valve is nitrided for 1-4h at 550 ℃ and 580 ℃, the mold ejector rod is nitrided for 4h at 520 ℃, the two parts are accelerated in nitriding rate and obtain a uniform hardened layer under the assistance of the hollow cathode, the two parts are provided with a nitriding speed of increasing the nitriding rate and obtain a uniform hardened layer under the assistance of the hollow cathode, the vacuum cathode, the two parts are also used for carrying out nitriding on 316 austenitic stainless steel samples, namely, the vacuum furnace, the two parts, the surface strengthening treatment, the vacuum furnace wall strengthening treatment is carried out a large-400 mm-150 mm-400-0-mm parallel annealing treatment, the three-mm-0-mm-400-mm-0-mm parallel-400-mm-thickness-0-mm-400-mm-0-mm-thickness-mm-0-mm-thickness-0-mm-thickness parallel-mm.
The plasma nitriding methods of the various hollow cathodes have the following defects:
the research of Korotkow et al is that each different austenitic stainless steel part is respectively provided with a hollow cathode structure, the part is also used as part of the hollow cathode structure, the surface of a sample can be over-burnt or form small holes, the nitriding treatment of a large number of workpieces is not facilitated, the preparation work before nitriding treatment is complicated, the utilization rate of hollow cathode equipment is low, waste is easily caused, the coverage area of the hollow cathode used by Zhaohuang et al is small, the gas ionization rate is influenced, the nitriding efficiency is reduced, the sample cannot be heated, a heating plate is required to be additionally arranged, the energy consumption is increased due to the heating plate, the hollow cathode structure of K.Nikolov et al only treats the part with the internal length of 140mm and the height of 150mm, namely the size requirement of the workpiece or the sample is strict, only the plate or the thin sample can be treated, and the gas diffusion is influenced due to the additionally arranged exhaust block, and the efficiency is reduced.
Disclosure of Invention
The invention aims to overcome the defect that the prior art consumes too long time for nitriding austenitic stainless steel at low temperature and has low nitriding rate, and provides austenitic stainless steel nitriding treatment systems and methods based on a hollow cathode ion source, wherein a hollow cathode discharge structure in a nitriding system of the hollow cathode ion source is improved, on the basis, a high-temperature rapid nitriding treatment technology is carried out on austenitic stainless steel workpieces, the method improves the surface hardness and wear resistance of austenitic stainless steel and simultaneously improves the nitriding efficiency on the basis of not influencing the corrosion resistance of the austenitic stainless steel workpieces, the austenitic stainless steel nitriding treatment system based on the hollow cathode ion source comprises a power supply system, a vacuum nitriding furnace, a hollow cathode device, an air exhaust system, an air supply system and a measurement and control system which are arranged in the furnace, connecting pipelines and valves between the hollow cathode device, the power supply system is connected with the vacuum nitriding furnace and the measurement and control system through valves , the air supply system is connected into the vacuum nitriding furnace and the hollow cathode device, the lower part of the vacuum nitriding furnace is connected with the vacuum nitriding furnace through valves , and is characterized in that the hollow cathode device in the vacuum nitriding furnace is of a plurality of metal strips arranged at intervals, and each metal strip is provided with a plurality of metal nitriding plates which are arranged in the arrangement.
A nitriding method based on the hollow cathode device, comprising the steps of:
1) grinding and polishing the surfaces of a plurality of parts to be processed; cleaning the polished surface of the part by using alcohol to wash off oil stains on the surface of the part;
2) placing a plurality of parts between two metal plates provided with hollow cathode devices in a vacuum nitriding furnace, connecting the parts with a power supply cathode, covering a furnace cover, opening an air pump to vacuumize the nitriding furnace, and introducing cooling water; when the vacuum is pumped to 5-15Pa, the working voltage and the duty ratio are adjusted, then the ammonia gas bottle is opened, and the gas pressure supplied by the flow meter is adjusted to be maintained at 400-450 Pa;
3) heating the parts in the vacuum nitriding furnace, and adjusting current and pressure to ensure the discharge stability of the hollow cathode until the temperature is raised to 500-550 ℃;
4) when the temperature is raised to the required temperature, preserving the heat of the part and starting timing, wherein the heat preservation time is 0.5h-1.5h to ensure that the fluctuation range is controlled at 1-2 ℃;
5) after the heat preservation value is reached and the heat preservation is finished, the parts are cooled along with the furnace;
6) and when the part is cooled to below 300 ℃, opening the furnace to take out the part after the cooling stage is finished, and finishing the nitriding treatment.
The invention has the characteristics and beneficial effects that:
the invention realizes hollow cathode discharge by means of the improved hollow cathode electrode, and the austenitic stainless steel part can be rapidly heated in the nitriding medium atmosphere with high activity and high concentration. The rapid nitriding is expected to be carried out at high temperature, and CrN cannot be aggregated and separated out in a short time, so that the high-temperature rapid nitriding treatment technology improves the surface hardness and the wear resistance of austenitic stainless steel without influencing the corrosion resistance, and simultaneously improves the nitriding efficiency.
The plate-shaped hollow cathode in the system is provided with the groove and the hole, the groove increases the area of the cathode plate, so that the discharge area is increased under the same parameter, the temperature and the heating rate of parts are higher, the diffusion rate of nitrogen atoms can be accelerated, the ionization rate of gas ionization can be increased by increasing the area, the nitriding efficiency is improved, and meanwhile, the hole structure is favorable for accelerating the gas ionization by gas diffusion, so that the metal plate can be impacted by a large number of ions, and the nitriding quality is improved; the plate-shaped hollow cathode structure can be flexibly placed in a nitriding furnace, has small requirements on the external dimensions of parts, and improves the utilization rate of the space in the nitriding furnace. These characteristics make the nitriding efficiency of the plate-shaped hollow cathode structure with grooves and holes more than 1.5 times that of the existing hollow cathode structure.
Drawings
FIG. 1 is a schematic structural diagram of an austenitic stainless steel nitriding treatment system based on a hollow cathode ion source.
Wherein, 1.1 is a power supply system, 1.2 is a vacuum nitriding furnace, 1.3 is hollow cathode equipment arranged in the furnace, 1.4 is a measurement and control system, 1.41 is a display system for measuring temperature, pressure and other data in the measurement and control system, 1.5 is an ammonia gas bottle (gas supply system), and 1.6 is a vacuum pump (gas extraction system).
FIG. 2 is a schematic diagram of the structure of a hollow cathode device of the system of the present invention.
Wherein 2.1 is a groove on the hollow cathode plate, and 2.2 is a through hole in the groove on the plate.
FIG. 3 is an SEM image of a nitride layer of a component after nitridation process according to an embodiment of the present invention.
FIG. 4 is a polarization diagram of electrochemical corrosion after nitridation process according to an embodiment of the present invention.
Detailed Description
The invention provides austenitic stainless steel nitriding treatment systems and methods based on a hollow cathode ion source, which are further described in detail in in combination with the attached drawings and specific embodiments.
The invention provides an austenitic stainless steel nitriding treatment system based on a hollow cathode ion source, which is structurally shown in figure 1 and comprises a power supply system 1.1, a vacuum nitriding furnace 1.2, a hollow cathode device 1.3 placed in the furnace, a vacuum pump (air extraction system) 1.6, an ammonia gas bottle (air supply system) 1.5, a measurement and control system 1.4, connecting pipelines and valves among all parts, wherein the power supply system 1.1 is connected with the vacuum nitriding furnace 1.3, the measurement and control system 1.4 is composed of a nitriding furnace device self-carried pressure, temperature, voltage and current gas flow display 1.14 and a computer for detection and control, the ammonia gas bottle (air supply system) 1.5 is connected with the measurement and control system through a valve and then connected with the vacuum nitriding furnace and the hollow cathode device, and the lower part of a vacuum nitriding furnace body is connected with the vacuum pump (air extraction system) 1.6 through a valve .
The austenitic stainless steel nitriding treatment systems based on the hollow cathode ion source of the embodiment except the structure of the hollow cathode device is different from the prior art, and other parts can be realized by adopting a conventional device, which is described as follows:
the power supply system adopts a conventional medium-frequency pulse power supply to ensure that hollow cathode discharge is generated under the condition of different vacuum degrees, the structure of a hollow cathode device in the adopted vacuum nitriding furnace is a plurality of metal plates which are arranged in parallel in the furnace, each metal plate is provided with a plurality of strip grooves 2.1 which are arranged at intervals, and each groove is provided with through holes 2.2 which are arranged at intervals, as shown in figure 2, the length and the width of the metal plate can be determined by a nitriding furnace and parts, the space between the metal plates can be adjusted according to the placing position and the number of the parts each time, the thickness is 15-20mm, the width of the grooves is 7-10mm, the depth is 5-7mm, the space between the grooves can be equal to the width , the through holes are arranged at the bottom of the grooves, the diameter is 1mm or the same as the width of the grooves, the space between the through holes can be equal to the diameter , the size and the space between the metal plates can be determined according to the number of the nitriding parts and the space in the nitriding furnace, the size of the metal plates used in the metal plates and the space between the metal plates can be adjusted according to the size of the metal plates, the size of the metal plates can be placed, the metal plates, the space between the metal plates, the metal plates can be treated, the metal plates can be improved by the metal plate heating structure, and the metal plates can.
The nitriding treatment method based on the hollow cathode device provided by the invention is carried out in hollow cathode ion source nitriding furnace equipment, and comprises the following steps:
1) the treated objects of this example are a plurality of austenitic stainless steel parts (the method of the present invention can be applied to austenitic stainless steel with any composition and shape, this example uses disk-shaped austenite with diameter of 20mm and thickness of 6mm, the two metal plates are 50mm away from the part), and SiC sand paper with the numbers of 240#, 400#, 800#, 1000#, 1500#, 2000# is used to grind and polish the surface of the part; cleaning the polished part surface with alcohol to remove oil stains and the like on the part surface;
2) placing a plurality of parts between two metal plates provided with hollow cathode devices in a vacuum nitriding furnace, connecting the parts with a power supply cathode, covering a furnace cover, opening an air pump to vacuumize the nitriding furnace, and introducing cooling water; when the vacuum is pumped to 5-15Pa (in the embodiment, 10Pa, the value can be seen from the pressure indicator, and the pressure, the temperature, the voltage, the current and the gas flow can be displayed on a computer of the control system), the working voltage (700-;
3) heating the parts in the vacuum nitriding furnace, and adjusting the current and the pressure (the pressure is controlled by adjusting a flowmeter on an ammonia gas bottle, so that the temperature rise speed is 15-25 ℃ per minute under the condition of ensuring the discharge stability of the hollow cathode, the current and the pressure can be increased when the temperature rise speed is slow, and the current and the pressure can be reduced when the discharge is unstable) until the temperature rises to 500-550 ℃ (the parameter of the embodiment is 530 ℃);
4) when the temperature is raised to the required temperature (530 ℃), the parts are kept warm and timing is started, and the heat preservation time can be 0.5h-1.5h (the heat preservation time is 1h in the embodiment). In the heat preservation process, adjusting current, voltage or air pressure (when the temperature continues to rise in the heat preservation stage, the current density is too large and needs to be reduced, and when the temperature drops, the current density is too small and needs to be increased, the voltage or the air pressure can be increased) to ensure that the fluctuation range (the temperature fluctuation range is controlled to be 1-2 ℃) is not too large;
5) after the heat preservation value is reached and the heat preservation is finished, the parts are cooled along with the furnace;
6) and when the part is cooled to below 300 ℃, opening the furnace to take out the part after the cooling stage is finished, and finishing the nitriding treatment. When the equipment is closed, the gas is firstly closed, then the flowmeter is closed, and finally the power supply is closed.
The working principle of the invention is as follows: as known from the mechanism of generating hollow cathode discharge, when the hollow cathode discharge is generated, electrons oscillate at constant amplitude d/2 between two polar plates, and the mean free path of the electrons in the gas filled in the hollow cathode discharge is just larger than but close to that of the electrons, namely
d＝2ke
Wherein d is the distance between the two cathode plates; e is the electron mean free path; k is the intensity coefficient.
The electron mean free path is:
in the formula, K is Boltzmann constant, T is the working temperature, r is the molecular radius of the working gas, and P is the working air pressure.
When the K value is larger than and close to 1/2, namely d is larger than and close to lambdae, the electrons obtain the maximum kinetic energy and potential energy conversion, if the electrons collide with gas atoms in the negative bright area, the probability of ionization is the highest, although the collision is generated because the cathode fall areas of the two poles are closer, a plurality of high-energy electrons can fall from the cathode into the cathode fall area, the swing proportion of d/2 amplitude of the electrons between the two poles is the maximum, so the strongest spacing of the hollow cathode is generated, and when the K value is increased, the spacing is increased, at the moment, if the electrons accelerated from cathode fall generate collision or excitation process in the negative bright area, and the number of high-energy particles entering the cathode fall area of the other pole plate after the energy is consumed is reduced because of the spacing increase, namely, the proportion of the number of the electrons capable of generating oscillation is reduced, and the discharge intensity of the hollow cathode is reduced.
The key to the ignition of a hollow cathode is firstly that a stable plasma sheath (cathode fall region) can be established on the surface of the cathode, otherwise, a self-sustaining discharge cannot be formed. The cathode fall region has the formula
dc＝[(KiVc 2)(1+γ)/(nj0)]1/3
dcThe width of the cathode fall region; kiIs the electron drift rate; vcIs the cathode fall region voltage; gamma is a second ionization coefficient of the decoction; j is a function of0The initial current density. It can be seen that the width of the cathode fall region is monotonically increasing with increasing voltage V. The movement speed of electrons in the cathode space is accelerated by increasing the voltage (the working voltage of the equipment is 700-900V), the generation of the hollow cathode effect is facilitated, the hollow cathode structure can be 3-6 times higher than the traditional ion nitriding ionization rate (10% -20%) under the voltage, and the plasma density is increased.
The results of the nitriding treatment of this example were analyzed and compared as follows:
FIG. 3 is a SEM image of a nitrided layer wherein: (a) stopping heating the part just at 530 ℃, namely keeping the temperature for 0h, (b) keeping the temperature of the part at 530 ℃ for 1h, (c) keeping the temperature of the part at 530 ℃ for 5h, and (d) keeping the temperature of the part at 450 ℃ for 10h by traditional ion nitriding. When the temperature is up to the temperature (namely 0h), a thin 2.6 mu m nitride layer is formed on the surface. The temperature is kept at 530 ℃ for 1h, and the nitrided layer is about 8 mu m and has good corrosion resistance. The conventional ion nitriding heat preservation 10h also had a nitrided layer thickness of about 8 μm, indicating that 1h of ion nitriding based on a hollow cathode produced a nitrided layer having the same thickness as the conventional ion nitriding 10 h. After 5h incubation, the nitride layer had a thickness of 18 μm, but with the precipitation of black phases.
The samples subjected to nitriding treatment by the method of the invention all have new and wider diffraction peaks S (111) and S (200). when the holding time is prolonged to 5h, the XRD pattern mainly comprises CrN and martensite α phases, and the metastable S phase is transformed at high temperature along with the prolonging of the nitriding treatment time, wherein S → CrN + α has nitride precipitates and defects.
The hardness is continuously increased with the extension of the treatment time. The surface hardness value of the nitrided 1h sample is increased to 800-900HV0.1. When the treatment time reaches 5h, the hardness value reaches 1100HV0.1Left and right. The hardness value is 800-900HV0.1And 530 ℃ ofThe hardness at 1h is not different.
As shown in FIG. 4, the electrochemical corrosion test was conducted on untreated and nitrided parts, in which 4.1 is a polarization curve of the parts without treatment, 4.2 is a polarization curve of the parts subjected to heat-preservation at 530 ℃ for 0h, 4.3 is a polarization curve of the parts subjected to heat-preservation at 530 ℃ for 1h, 4.4 is a polarization curve of the parts subjected to heat-preservation at 530 ℃ for 5h, and 4.5 is a polarization curve of the parts subjected to conventional ionic nitriding at 450 ℃ for 10h, the pitting potentials of the parts subjected to short-time treatment at 0h and 1h were increased by 0.2V, and even at a voltage of 0.8V, the corrosion current was lower than that of the untreated parts, which is a S-phase layer prepared on the surface by rapid nitriding and has better corrosion resistance, and is capable of inhibiting the intrusion of corrosive liquid, particularly chlorine ions, the conventional ionic nitriding at 450 ℃ for 10h, the parts subjected to hollow cathodic nitriding at 530 ℃ for 0h and 1h from the corrosion potential lower than that of the hollow cathodic nitriding at 530 ℃ for 0h and 1h, the corrosion resistance of the parts subjected to galvanic nitriding is equal to corrosion resistance deterioration due to the corrosion of a galvanic corrosion formed by a different phase nitriding between 530 ℃ and 355 h, and a corrosion resistance of the corrosion of the nitriding, which is equal corrosion resistance of the corrosion formed by a Crcorrosion.
The surface of a sample nitrided for 0.5 to 1.5 hours has no pitting corrosion phenomenon, which shows that the pitting corrosion resistance of the austenitic stainless steel is improved by the high-temperature rapid nitriding process, AISI304 austenitic stainless steel can be effectively treated by the high-temperature rapid nitriding, nitrided layers with different thicknesses and structures are prepared on the surface, the hardness of a matrix is obviously improved, a single S-phase nitrided layer without CrN precipitation can be prepared within a short treatment time (0.5 to 1.5 hours) at the high temperature of 530 ℃, the thickness of the nitrided layer is not less than that of the conventional ionic nitriding at the temperature of 450 ℃ for 10 hours, and an electrochemical corrosion experiment shows that compared with the conventional ionic nitriding at the temperature of 450 ℃ for 10 hours, a nitrided part at the high temperature for a short time (0.5 to 1.5 hours) improves the pitting corrosion resistance in a NaCl solution.
Claims (2)
- The austenitic stainless steel nitriding treatment system based on the hollow cathode ion source comprises a power supply system, a hollow cathode device, an air extraction system, an air supply system, a measurement and control system, connecting pipelines and valves , wherein the hollow cathode device, the air extraction system, the air supply system and the measurement and control system are arranged in a furnace, the connecting pipelines and the valves are arranged between the hollow cathode device and each part, the power supply system is connected with a vacuum nitriding furnace, the air supply system is connected with the measurement and control system through the valves and then connected into the vacuum nitriding furnace and the hollow cathode device, and the lower part of a vacuum nitriding furnace body is connected with the air extraction system through the valves ;the thickness of the metal plate is 15-20mm, the width of a groove of the metal plate is 7-10mm, the depth of the groove of the metal plate is 5-7mm, the interval of the groove is equal to the width of , a through hole is formed at the bottom of the groove, the diameter of the through hole is 1mm or the same as the width of the groove, and the interval of the through hole is equal to the diameter of .
- A method of nitriding treatment based on the hollow cathode device of claim 1, comprising the steps of:1) grinding and polishing the surfaces of a plurality of parts to be processed; cleaning the polished surface of the part by using alcohol to wash off oil stains on the surface of the part;2) placing a plurality of parts between two metal plates provided with hollow cathode devices in a vacuum nitriding furnace, connecting the parts with a power supply cathode, covering a furnace cover, opening an air pump to vacuumize the nitriding furnace, and introducing cooling water; when the vacuum is pumped to 5-15Pa, the working voltage and the duty ratio are adjusted, then the ammonia gas bottle is opened, and the gas pressure supplied by the flow meter is adjusted to be maintained at 400-450 Pa;3) heating the parts in the vacuum nitriding furnace, and adjusting current and pressure to ensure the discharge stability of the hollow cathode until the temperature is raised to 500-550 ℃;4) when the temperature is raised to the required temperature, preserving the heat of the part and starting timing, wherein the heat preservation time is 0.5h-1.5h to ensure that the fluctuation range is controlled at 1-2 ℃;5) after the heat preservation value is reached and the heat preservation is finished, the parts are cooled along with the furnace;6) and when the part is cooled to below 300 ℃, opening the furnace to take out the part after the cooling stage is finished, and finishing the nitriding treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711051778.5A CN107620031B (en) | 2017-10-30 | 2017-10-30 | Austenitic stainless steel nitriding treatment system and method based on hollow cathode ion source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711051778.5A CN107620031B (en) | 2017-10-30 | 2017-10-30 | Austenitic stainless steel nitriding treatment system and method based on hollow cathode ion source |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107620031A CN107620031A (en) | 2018-01-23 |
| CN107620031B true CN107620031B (en) | 2020-01-31 |
Family
ID=61092494
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711051778.5A Active CN107620031B (en) | 2017-10-30 | 2017-10-30 | Austenitic stainless steel nitriding treatment system and method based on hollow cathode ion source |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107620031B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108411246B (en) * | 2018-06-13 | 2024-03-19 | 深圳市奥美特纳米科技有限公司 | Auxiliary equipment and method for improving ion nitriding efficiency of surface of low-alloy structural steel |
| CN111843407B (en) * | 2020-07-29 | 2021-11-02 | 扬州大学 | Nitriding device and nitriding processing method for 304 stainless steel spiral reamer |
| CN113667924B (en) * | 2021-07-21 | 2022-06-14 | 华南理工大学 | Ion nitriding device and method suitable for strengthening cutting edge of cutter |
| CN114892123B (en) * | 2022-05-23 | 2024-04-16 | 太原理工大学 | Ion nitriding method for eliminating risk of small hole arcing |
| CN116837319B (en) * | 2023-07-06 | 2024-01-05 | 常州富丽康精密机械有限公司 | Screw rod surface machining device with motion state detection function |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101158022B (en) * | 2007-10-31 | 2010-06-02 | 大连海事大学 | Austenitic stainless steel electron beam auxiliary plasma surface modifying method and equipment |
| CN201574191U (en) * | 2009-12-18 | 2010-09-08 | 大连海事大学 | Low-alloy steel surface nitriding-oxidizing composite processing device |
| JP2016197528A (en) * | 2015-04-03 | 2016-11-24 | 株式会社島津製作所 | Plasma processing apparatus |
-
2017
- 2017-10-30 CN CN201711051778.5A patent/CN107620031B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN107620031A (en) | 2018-01-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107620031B (en) | Austenitic stainless steel nitriding treatment system and method based on hollow cathode ion source | |
| Li et al. | Wear and corrosion properties of AISI 420 martensitic stainless steel treated by active screen plasma nitriding | |
| CN101158022B (en) | Austenitic stainless steel electron beam auxiliary plasma surface modifying method and equipment | |
| Zhang et al. | Electrochemical corrosion properties of the surface layer produced by supersonic fine-particles bombarding on low-carbon steel | |
| Fossati et al. | Improvement of corrosion resistance of austenitic stainless steels by means of glow-discharge nitriding | |
| CN103233197A (en) | Low-temperature rapid ion nitriding method of austenitic stainless steel | |
| Cheng et al. | Phosphating process of AZ31 magnesium alloy and corrosion resistance of coatings | |
| CN110983257B (en) | Surface treatment method for improving corrosion resistance and anti-icing performance of titanium alloy surface | |
| CN104911533A (en) | Low-temperature anti-corrosion gas nitriding method for metal workpiece and metal workpiece | |
| CN104630693A (en) | Combined treatment method of surface of austenitic stainless steel | |
| Budilov et al. | Ion nitriding in glow discharge with hollow cathode effect | |
| Roy et al. | Feasibility study of aqueous electrolyte plasma nitriding | |
| CN102943231B (en) | Surface three-step nitridation method of aluminium and aluminium alloy | |
| CN102943230B (en) | The nitriding method on Al and Alalloy surface | |
| Zhao et al. | Active screen plasma nitriding of AISI 316L austenitic stainless steel at different potentials | |
| CN104141104A (en) | Solution for rapid plasma electrolytic carbonitriding on steel surface and carbonitriding method | |
| CN103789722B (en) | One significantly improves the corrosion proof chemical heat treatment method of gear | |
| CN101591784B (en) | Mechanical infiltration method for surface alloying of pure iron-based plate | |
| Sankar et al. | Surface Modification of EN353 Gear Material by Chromium Plating and Plasma Nitriding to Improve Surface Properties, Corrosion and Wear Resistance | |
| Han et al. | Study on the fast nitriding process of active screen plasma nitriding | |
| CN201106063Y (en) | Austenitic stainless steel electron beam auxiliary plasma surface modifying equipment | |
| Zhao et al. | Improvement of corrosion and wear resistances of 300M ultra high strength steel by low temperature cathode assisted plasma nitriding | |
| CN101307441A (en) | Method for enhancing pitting corrosion resistant performance of stainless steel | |
| CN101892449B (en) | Method of using nano-sized iron oxide to induce surface of carbon steel through nitrogen alloying | |
| Zheng et al. | Plasma carburizing and post-treatment of austenitic stainless steel |
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 |