Integral Diffusion Model of the Kinetics of Growth of Nitrided Layer in Gas Nitriding of Armco Iron

2021 ◽  
Author(s):  
Mourad Keddam ◽  
Peter Jurči
Keyword(s):  
Diffusion Model ◽  
Armco Iron ◽  
Nitrided Layer ◽  
Gas Nitriding ◽  
Kinetics Of

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).

SIMULATION MODEL OF THE GROWTH KINETICS OF Fe2B LAYERS WITH CONSIDERATION OF THE BORIDE INCUBATION TIME EFFECT

2019 ◽  
Vol 27 (04) ◽  
pp. 1950127
Author(s):  
BENDAOUD MEBAREK ◽  
MOURAD KEDDAM ◽  
HAMZA BOUSSEBHA
Keyword(s):  
Diffusion Model ◽  
Incubation Time ◽  
Armco Iron ◽  
Time Effect ◽  
Mass Balance Equation ◽  
Parabolic Growth ◽  
Simulation Results ◽  
Growth Constants ◽  
Good Concordance ◽  
Kinetics Of

In this work, a mathematical model for simulating the thermochemical boronizing process is presented. The diffusion model used in this paper is based on Fick’s laws by solving the mass balance equation of the (FeB/Fe2B) interface. In this developed model, the effect of boride incubation times during the formation of Fe2B layers on Armco iron was considered. To demonstrate the validity of our calculations, the simulation results are compared with experimentally obtained data on borided Armco iron, which allowed us to verify the validity of the model. Therefore, a good concordance was observed when comparing the experimental parabolic growth constants taken from the literature with our simulated values of the parabolic growth constants from the present diffusion model. From this study, it has been found that the incubation time has a very important influence on the evolution of the kinetics of the boride layers.

scholarly journals Nitriding of car engine parts using ZeroFlow method

2016 ◽  
Vol 167 (4) ◽  
pp. 3-7
Author(s):  
Jagoda KOWALSKA ◽  
Leszek MAŁDZIŃSKI
Keyword(s):  
Nitrided Layer ◽  
Simulation Models ◽  
Layer Growth ◽  
Nitriding Process ◽  
Hardness Distribution ◽  
Practical Application ◽  
Influence Of Process Parameters ◽  
Gas Nitriding ◽  
And Control ◽  
Kinetics Of

This article presents new method of controlled gas nitriding called ZeroFlow, which is used for nitriding of selected car engine parts. Parts such as crankshafts, camshafts, piston rings, poppet valve springs and discs, piston pins or nozzles for unit injectors was nitrided with ZeroFlow method so far. Through the use of simulation models it was possible to develop the specially dedicated process with specific parameters for each of this parts; it allows forming of nitrided layer with strictly expected properties: required phase structure with thicknesses of each zone occurs in it and required hardness distribution. Moreover, through the use of simulation models this layers were obtained in in the shortest possible time, which is connected with the lowest energy consumption; therefore, nitriding process using ZeroFlow method is both economical and environmentally friendly. This article will discuss the essence of controlled gas nitriding process, with an emphasis on the influence of process parameters on results of nitriding process. This information are the basis to understand the issue of the kinetics of nitrided layer growth, and as it follows – for its practical application in designing, regulation and control of nitriding processes using simulation models (simulator of the kinetics of nitrided layer growth). Designing of ZeroFlow nitriding processes on the basis of the kinetics of nitrided layer will be shown on the example of nitriding of crankshafts for sports car engines.

Determining the Kinetics of Asphaltene Adsorption from Toluene: A New Reaction–Diffusion Model

2017 ◽  
Vol 31 (9) ◽  
pp. 9101-9116 ◽  
Author(s):  
Sophie Campen ◽  
Luca di Mare ◽  
Benjamin Smith ◽  
Janet S. S. Wong
Keyword(s):  
Diffusion Model ◽  
Reaction Diffusion ◽  
Reaction Diffusion Model ◽  
Kinetics Of

Mechanical Behaviour of Gas Nitrided Ti6Al4V Bars Produced by Selective Laser Melting

2016 ◽  
Vol 704 ◽  
pp. 225-234 ◽  
Author(s):  
Peter Franz ◽  
Aamir Mukhtar ◽  
Warwick Downing ◽  
Graeme Smith ◽  
Ben Jackson
Keyword(s):  
Heat Treatment ◽  
Selective Laser Melting ◽  
Nitrided Layer ◽  
Xrd Analysis ◽  
Compound Layer ◽  
Processing Parameters ◽  
Heat Treatments ◽  
Laser Melting ◽  
Gas Nitriding ◽  
Heat Treated

Gas atomized Ti-6Al-4V (Ti64) alloy powder was used to prepare distinct designed geometries with different properties by selective laser melting (SLM). Several heat treatments were investigated to find suitable processing parameters to strengthen (specially to harden) these parts for different applications. The results showed significant differences between tabulated results for heat treated billet Ti64 and SLM produced Ti64 parts, while certain mechanical properties of SLM Ti64 parts could be improved by different heat treatments using different processing parameters. Most heat treatments performed followed the trends of a reduction in tensile strength while improving ductility compared with untreated SLM Ti64 parts.Gas nitriding [GN] (diffusion-based thermo-chemical treatment) has been combined with a selected heat treatment for interstitial hardening. Heat treatment was performed below β-transus temperature using minimum flow of nitrogen gas with a controlled low pressure. The surface of the SLM produced Ti64 parts after gas nitriding showed TiN and Ti2N phases (“compound layer”, XRD analysis) and α (N) – Ti diffusion zones as well as high values of micro-hardness as compared to untreated SLM produced Ti64 parts. The microhardness profiles on cross section of the gas nitrided SLM produced samples gave information about the i) microhardness behaviour of the material, and ii) thickness of the nitrided layer, which was investigated using energy dispersive spectroscopy (EDS) and x-ray elemental analysis. Tensile properties of the gas nitrided Ti64 bars produced by SLM under different conditions were also reported.

Intraparticle diffusion model to determine the intrinsic kinetics of ethyl levulinate synthesis promoted by Amberlyst-15

2020 ◽  
Vol 228 ◽  
pp. 115974 ◽  
Author(s):  
Vincenzo Russo ◽  
Carmelina Rossano ◽  
Emiliano Salucci ◽  
Riccardo Tesser ◽  
Tapio Salmi ◽  
...  
Keyword(s):  
Diffusion Model ◽  
Intraparticle Diffusion ◽  
Amberlyst 15 ◽  
Intraparticle Diffusion Model ◽  
Ethyl Levulinate ◽  
Intrinsic Kinetics ◽  
Kinetics Of

Characterization and growth kinetics of plasma nitrided layer fabricated on Incoloy 901 superalloy

2020 ◽  
Vol 396 ◽  
pp. 125960
Author(s):  
Hongjian Huang ◽  
Xiaowei Wei ◽  
Haiyan He ◽  
Yuhao Wu ◽  
Jianhui Qiu
Keyword(s):  
Growth Kinetics ◽  
Nitrided Layer ◽  
Kinetics Of
Sign in / Sign up

Export Citation Format

Share Document