scholarly journals Application of Avinit vacuum plasma technologies Avinit to the manufacture of high-precision full-size gears

2021 ◽  
Vol 5 (1) ◽  
pp. 79-88
Author(s):  
Alexei Sagalovych ◽  
Viktor Popov ◽  
Vladuslav Sagalovych ◽  
Stanislav Dudnik ◽  
Andrew Edinovych
Keyword(s):  
High Precision ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Test Time ◽  
Ring Gear ◽  
Functional Coatings ◽  
Nitriding Time ◽  
Gas Nitriding ◽  
Vacuum Plasma

Avinit duplex technologies have been developed, combining Avinit N plasma nitriding of finished high-precision parts with subsequent application of Avinit superhard antifriction coatings in a single technological process Due to the absence of a brittle layer on the nitrided surface after precision nitriding, the preservation of the original geometric dimensions that do not require further mechanical refinement, and the compatibility of the processes of plasma precision nitriding of Avinit N and the vacuum plasma deposition of functional coatings Avinit C, duplex technologies allow the deposition of strong adhered, high-quality coatings. The effect of the duplex process on the dimensions of parts during plasma nitriding of high-precision gears and the application of Avinit C functional coatings was investigated, the properties of the nitrided layer and the parameters of Avinit coatings were studied. Plasma precision technology Avinit N allows nitriding of finished parts without changing dimensions, including gears of 4 degrees of accuracy. Avinit N nitriding time is 2 ... 4 times less than with gas nitriding. The coating of Avinit C310 parts increases the microhardness of the surfaces of the parts and reduces the coefficient of friction, while it has sufficient adhesion to the working surfaces of the gear teeth and bearing raceways. Manufacturing of high-precision gears with accuracy grade 4 using Avinit duplex technologies was carried out. Analysis of the results shows that, within the measurement accuracy, no changes in the profiles of the teeth, their location on the ring gear, as well as the location of the gear ring relative to the measuring bases are observed. Plasma nitriding makes it possible to reduce the nitriding time by more than two times compared to gas nitriding, while the thickness of the layer of the brittle phase with the maximum surface hardness is ensured within the specified values ​​to ensure the necessary indicators of contact and bending long-term strength in the manufacture of gears according to the degree of accuracy 4 without grinding after nitriding. Measurements of the ring gear after nitriding and coating showed that there were no changes in the geometry of the gear processed by duplex technology. Avinit C310 anti-friction coating 1.5 microns thick does not distort the geometry of the tooth profiles. All parameters of the ring gear manufactured using the Avinit duplex technology correspond to accuracy grade 4 in accordance with the requirements of technical documentation. The gears manufactured using the Avinit duplex technology were tested as part of the AI-450M engine reducer at the Ivchenko-Progress hydraulic brake stand according to the program of equivalent cyclic tests. A pair of experimental gears were installed in the engine reducer instead of the serial wheels of the second stage of the reducer. The total test time of the wheels was 26 hours. After testing, no damage to the gear, including the Avinit coating, was found. Antifriction coating Avinit C310 with a thickness of 1.5 microns does not distort the geometry of the tooth profiles during testing as part of the AI-450M engine reducer. Measurement of the parameters of the teeth showed a complete absence of wear.

scholarly journals Acceleration of Plasma Nitriding at 550 °C with Rare Earth on the Surface of 38CrMoAl Steel

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1122
Author(s):  
Dongjing Liu ◽  
Yuan You ◽  
Mufu Yan ◽  
Hongtao Chen ◽  
Rui Li ◽  
...  
Keyword(s):  
Rare Earth ◽  
Electron Microscope ◽  
Weight Gain ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Optical Microscope ◽  
Steel Microstructure ◽  
Transmission Electron ◽  
Modified Layer

In order to explore the effect of the addition of rare earth (RE) to a steel microstructure and the consequent performance of a nitrided layer, plasma nitriding was carried out on 38CrMoAl steel in an atmosphere of NH3 at 550 °C for 4, 8, and 12 h. The modified layers were characterized using an optical microscope (OM), a microhardness tester, X-ray diffraction (XRD), a scanning electron microscope (SEM), a transmission electron microscope (TEM), and an electrochemical workstation. After 12 h of nitriding without RE, the modified layer thickness was 355.90 μm, the weight gain was 3.75 mg/cm2, and the surface hardness was 882.5 HV0.05. After 12 h of RE nitriding, the thickness of the modified layer was 390.8 μm, the weight gain was 3.87 mg/cm2, and the surface hardness was 1027 HV0.05. Compared with nitriding without RE, the ε-Fe2-3N diffraction peak was enhanced in the RE nitriding layer. After 12 h of RE nitriding, La, LaFeO3, and a trace amount of Fe2O3 appeared. The corrosion rate of the modified layer was at its lowest (15.089 × 10−2 mm/a), as was the current density (1.282 × 10−5 A/cm2); therefore, the corrosion resistance improved.

The Influence of Plasma Nitriding Period on Nitrided Layers Thickness

2016 ◽  
Vol 258 ◽  
pp. 395-398 ◽  
Author(s):  
Ondrej Pilch ◽  
Vojtěch Hruby
Keyword(s):  
Optical Microscopy ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Experimental Methods ◽  
Nitriding Process ◽  
Material Surface ◽  
Hardness Testing ◽  
Surface Layers ◽  
Cross Sectional

The plasma nitriding as a technology for finishing of material surface layers was carried out on selected material. The effect of plasma nitriding conditions on the thickness and hardness of nitrided layer was investigated. The influence of plasma nitriding period on the thickness of the plasma nitrided layers was comprehensively assessed on the C55 steels. Plasma nitriding was carried out on selected material at 500 °C under 280 Pa with a mixture atmosphere of H2 and N2 in the plasma nitriding equipment. The period of the plasma nitriding process was changeable from 5 to 20 hours. Measurements of the properties of nitrided layers of selected material were solved by using experimental methods in accordance with standards. The samples were characterized by GDOES spectrometry, optical microscopy, and hardness testing. The depths of the plasma nitriding layers were also detected using cross-sectional microhardness profiles. Relation between plasma nitriding period and a thickness of a nitrided layer was explained and has shown that microhardness and surface hardness of mentioned samples were significantly increased.

LOW-TEMPERATURE NITRIDING BEHAVIOR OF COMPRESSIVE DEFORMED AISI 316Ti AUSTENITIC STAINLESS STEELS

2019 ◽  
Vol 26 (05) ◽  
pp. 1850188 ◽  
Author(s):  
FATIH KAHRAMAN ◽  
GÖKÇE MEHMET GENÇER ◽  
AYÇA D. KAHRAMAN ◽  
COŞKUN YOLCU ◽  
HAYDAR KAHRAMAN
Keyword(s):  
Low Temperature ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Cold Deformation ◽  
Surface Hardness ◽  
Compound Layer ◽  
Optical Microscope ◽  
Layer Growth ◽  
Nitrogen Diffusion ◽  
Undeformed Sample

The effects of compressive cold deformation under the quasi-static loads on the nitride formation, nitride layer growth and surface hardness properties were researched in this study. Martensite structure did not form in AISI 316Ti stainless steel as a result of quasi-static deformation. Diffusion layer did not form in all nitrided samples. Both the deformed and undeformed samples have only compound layer on the surfaces at the low-temperature nitriding conditions (400∘C, 7[Formula: see text]h). According to the X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS) and electron probe microanalysis (EPMA) results, S-phase and chromium nitride (CrN) were formed in the compound layers of the deformed samples. However, CrN did not form in the compound layer of the undeformed sample. The optical microscope (OM) results showed that the compressive cold deformation increased the nitrogen diffusion rate and led to thicker nitrided layer than the undeformed sample under the same plasma-nitriding conditions. All nitrided layers presented higher microhardness values ([Formula: see text][Formula: see text]HV) when compared with the untreated sample hardness. It was also verified that the deformation amount did not affect significantly the nitrided layer hardness.

Kinetics of nitrided layers formation on low-alloy steels in the gas nitriding process

2020 ◽  
Vol 24 (4) ◽  
pp. 31-36
Author(s):  
Grzegorz Wójcik ◽  
Barbara Kucharska ◽  
Piotr Wach
Keyword(s):  
Diffusion Layer ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Nitriding Process ◽  
Process Time ◽  
Low Alloy Steels ◽  
Two Phase ◽  
Gas Nitriding ◽  
Alloy Steels ◽  
Kinetics Of

The study examined cylindrical samples made of low-alloy structural steel 42CrMo4 (40HM) and 41CrAlMo7 (38HMJ) subjected to the nitriding process at 540oC during 2, 7, 12 and 17 hours. During the first 2 hours of the process, the atmosphere was ammonia, while the rest of the process was carried out in the atmosphere consisting of 50% ammonia and 50% dissociated ammonia. After the process, surface hardness, hardness distribution at the depth of 50 µm from the surface up to the hardness of the core, and microstructure of the nitrided layer produced were examined. It has been shown that along with the extension of the duration of the nitriding process on 40HM steel, the surface thickness of the layer of nitrides increases from 6 µm after 2 hours to 14 µm after 17 hours of the process and this layer has a two-phase structure (+’), while the thickness of the diffusion layer was from 0.15 to 0.44 mm (depending on the process time). In the case of 38HMJ steel, the thickness of the layer of nitrides increased from 1 µm after 2 hours to 9.5 µm after 17 hours. The thickness of the diffusion layer was from 0.08 to 0.35 µm (depending on the process time).

Plasma Ion Nitriding of Low Carbon Stainless Maraging Steel

2015 ◽  
Vol 830-831 ◽  
pp. 675-678
Author(s):  
M. Agilan ◽  
T. Venkateswran ◽  
D. Sivakumar ◽  
Bhanu Pant
Keyword(s):  
Maraging Steel ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Case Depth ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Ion Nitriding ◽  
X Ray ◽  
Stainless Maraging Steel

Low carbon stainless maraging steel (0.03%C-12%Cr-10Ni-0.6Mo-0.2Ti) is being used widely for various components of the aerospace engines. To improve the wear resistance of the steel various surface hardening processes are being utilized to improve the surface hardness above 900HV. In this present research, plasma nitriding was carried out at two different temperatures of 450 °C and 475 °C for the holding duration of 10 hrs. Temperature of the nitrding process was ensured below the ageing temperature (500 °C) of the steel to avoid lowering of mechanical properties. Effect of plasma nitriding parameters on the surface hardness, case depth, microstructure and phases present in the nitrided layer were investigated in detail using microhardness analysis across the nitrided layer, X-ray diffraction (XRD), optical microscopy and scanning electron microscopy (SEM). It was observed that increase in nitriding temperature increased the surface hardness and case depth. In addition, the presence of Fe3N and Fe4N phases in the nitrided layer were observed using X-ray diffraction technique.

Effect of Gas Nitriding on CO2 Corrosion Behavior of 40Cr Steel

2011 ◽  
Vol 66-68 ◽  
pp. 956-959
Author(s):  
Bing Ying Wang ◽  
Zhen Tong Sun ◽  
S.N. Zhou
Keyword(s):  
High Pressure ◽  
Corrosion Behavior ◽  
Nitrided Layer ◽  
Optical Microscope ◽  
Nitriding Time ◽  
Gas Nitriding ◽  
Corrosion Scales ◽  
40Cr Steel ◽  
High Temperature High Pressure ◽  
Microhardness Tester

In this paper, 40Cr steel was gas-nitrided for varying time. The microstructure and microhardness of the nitrided layer were examined by means of optical microscope and microhardness tester. The CO2 corrosion behavior of 40Cr steel influenced by nitriding was studied using high temperature high pressure autoclave. The SEM, EDS and XRD technique were adopted to study the characteristics of CO2 corrosion scales on 40Cr steel. The results show that the pitting is generated for all the un-nitrided and nitrided specimens, however, the corrosion tendency and corrosion rate decreases with nitriding time increasing, mainly due to the compact of FeCO3 formed on the surface.

Nitriding parameters analized by neural network and genetic algorithm

2004 ◽  
Vol 120 ◽  
pp. 355-362
Author(s):  
T. Filetin ◽  
I. Žmak ◽  
D. Novak
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Standard Deviation ◽  
Chemical Composition ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Hardness Profile ◽  
Nitriding Temperature ◽  
Nitriding Time

The surface hardness and hardness profile of a nitrided workpiece depend on the chemical composition of the steel, nitriding temperature and time, and on type of the nitriding process (i.e. atmosphere). An issue in this approach was to test how the statistical analysis, artificial neural network, genetic algorithm and genetic programming may be used for determination of nitriding time and surface hardness, in case when the chemical composition of steel, nitriding temperature and required thickness of nitrided layer are known. In the neural network learning procedure datasets of results were used, after nitriding 5 different steel grades. Different combinations of time, temperature, surface hardness and thickness of plasma and gas nitriding layer are compiled from the experiments and industrial experience and also from the literature. The static multi-layer feed-forward neural network is proposed. To accelerate the convergence of the proposed static error-back propagation learning algorithm, the momentum method is applied. The mean error between experimental data of nitriding time and data predicted using a neural network, and also the standard deviation for both the learning and the testing dataset is found to be small and acceptable. The determination of time by genetic algorithm gives greater standard deviation than by using neural network. Determining surface hardness after nitriding by the use of neural network gives less reliable results due to relatively imprecise input data and a narrow learning dataset. Due to nitriding data insufficiency, the network was tested only with the learning dataset.

IMPROVEMENT OF WEAR RESISTANCE OF SHREDDER BLADES USED IN A REFUSE-DERIVED FUEL (RDF) FACILITY BY PLASMA NITRIDING

2019 ◽  
Vol 27 (04) ◽  
pp. 1950131
Author(s):  
HAKAN AYDIN ◽  
FURKAN BOSTANCI
Keyword(s):  
Wear Resistance ◽  
Working Conditions ◽  
Plasma Nitriding ◽  
Surface Hardness ◽  
Service Condition ◽  
Case Depth ◽  
Nitriding Process ◽  
Nitriding Time ◽  
Refuse Derived Fuel ◽  
Hardness Values

Refuse-derived fuel (RDF) is a kind of renewable energy source to produce energy for replacement of fossil fuels. Aggressive working conditions in RDF facilities cause the shredder blades to wear out quickly. So, the purpose of this paper was to study the effect of plasma-nitriding process on wear resistance of shredder blades made of AISI D2 tool steel in the service condition of RDF facility. Shredder blades were commercially available from two different suppliers (A and B suppliers). These hardened shredder blades were plasma-nitrided in the mixed nitrogen and hydrogen atmosphere at a volume ratio of 3:1 at 450∘C for 12, 18 and 24[Formula: see text]h at a total pressure of 250 Pa. Characterisation of plasma-nitrided layers on the shredder blades was carried out by means of microstructure and microhardness measurements. Wear tests of plasma-nitrided shredder blades were performed under actual working conditions in the RDF facility. Wear analysis of these shredder blades was conducted using three-dimensional (3D) optical measuring instrument GOM ATOS II. The compositional difference of the shredder blades provided by A and B suppliers played an important role on the nitrided layer. The case depth of A-blades significantly increased with increasing plasma-nitriding time. However, the case depth of B-blades was fairly lower at the same nitriding time and only slightly increased with increasing plasma-nitriding time. Plasma-nitriding process significantly improved the surface hardness of the shredder blades. Maximum surface hardness values were achieved at nitriding time of 18 h for both blades. In this case, this increase in surface hardness values was above 100%. At nitriding time of 24[Formula: see text]h, the maximum surface hardness of A-blades significantly decreased, whereas this decrease in surface hardness of B-blades was the negligible value. The wear test results showed that plasma-nitriding process significatly decreased the wear of shredder blades; 18 h nitriding for A-blades and 24[Formula: see text]h nitriding for B-blades had better wear-reducing ability in the service condition of RDF facility. In these cases, the decreases in the total volume wear loss for A- and B-blades were 53% and 60%, respectively.

Research on Gas Nitriding Technology Catalyzed by Rare Earth for 40CrNiMoA Alloy Steel

2019 ◽  
Vol 953 ◽  
pp. 21-25
Author(s):  
Wan Jun Li ◽  
Xiao Xia Li
Keyword(s):  
Rare Earth ◽  
Alloy Steel ◽  
Vickers Hardness ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Effect Of Temperature ◽  
Layer Depth ◽  
Gas Nitriding

A kind of gas nitriding method catalyzed by rare earth for 40CrNiMoA alloy steel was researched in this article. Effect of temperature on surface hardness of gas nitriding method catalyzed by rare earth, change law of layer depth with time at 500 °C were carried out and compared with normal gas nitriding. Based on these researches, gas nitriding method catalyzed by rare earth was optimized. The results show that gas nitriding catalyzed by rare earth can not only increase the nitriding speed, but also enhance the surface hardness of the nitriding layer. Using three - stage gas nitriding method catalyzed by rare earth and after 40 hours, the samples can meet the need of nitrided layer depth no less than 0.5mm, surface vickers hardness no less than 600.

scholarly journals HARDNESS OF NITRIDED LAYERS TREATED BY PLASMA NITRIDING

2020 ◽  
Vol 27 ◽  
pp. 53-56
Author(s):  
Zdeněk Joska ◽  
Zdeněk Pokorný ◽  
Jaromír Kadlec ◽  
Zbyněk Studený ◽  
Emil Svoboda
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Austenitic Stainless Steels ◽  
Aisi 316L ◽  
Aisi 304 ◽  
Measurement Surface

Stainless steels, particularly the austenitic stainless grades are widely used in many industries due to good corrosion resistance, but very poor mechanical properties as surface hardness and wear resistance limit its possible use. Plasma nitriding is one of the few ways to increase the surface hardness of these steels, even though this will affect its corrosion resistance. This paper focuses on the description of the mechanical properties of nitrided layers in the two most widespread austenitic stainless steels AISI 304 and AISI 316L. The microstructure and properties of nitrided layers were evaluated by metallography and microhardness measurement. Surface properties of nitrided steels were characterized by Martens hardness. The results show that plasma nitriding created very hard nitrided layers with thickness about 40 μm and microhardness about 1300 HV0.05. Surface hardness measurements have shown that the maximum values for both steels are about 8.5 GPa, but have different behaviour under higher loads, when the AISI 316L nitrided layer began to crack on the surface and sink.

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