scholarly journals Influence of hydrogen content in working gas on diffusion processes at ion nitriding of martensitic and austenitic steels

2017 ◽  
Vol 872 ◽  
pp. 012017 ◽  
Author(s):  
U G Khusainov ◽  
K N Ramazanov ◽  
R D Agzamov ◽  
E L Vardanyan ◽  
R S Esipov
Keyword(s):  
Hydrogen Content ◽  
Diffusion Processes ◽  
Austenitic Steels ◽  
Ion Nitriding

Influence of Ultrafine-Grained Structure of Martensitic and Austenitic Steels on Diffusion Processes at Low-Temperature Ion Nitriding

2018 ◽  
Vol 383 ◽  
pp. 167-172
Author(s):  
Uldash Gamirovich Khusainov ◽  
Kamil Nurulaeyevich Ramazanov ◽  
Roman Sergeevich Esipov
Keyword(s):  
Growth Rate ◽  
High Pressure ◽  
Low Temperature ◽  
Diffusion Layer ◽  
Diffusion Processes ◽  
Austenitic Steels ◽  
Ion Nitriding ◽  
Ultrafine Grained Structure ◽  
Ultrafine Grained ◽  
Before And After

The paper discusses the influence of ultrafine-grained structure of martensitic and austenitic steels on diffusion processes at low-temperature ion nitriding. The microstructure of ultrafine-grained steels was analysed before and after nitriding. Depth distributions of microhardness are given depending on the class and structure of steels. The study proves that ultrafine-grained structure of steels obtained by high pressure deformation by torsion allows an increased growth rate of the diffusion layer at nitriding.

scholarly journals Ion nitriding of martensitic and austenitic steels after SPD at different temperatures

2018 ◽  
Vol 1115 ◽  
pp. 032033 ◽  
Author(s):  
Yu G Khusainov ◽  
K N Ramazanov ◽  
R D Agzamov ◽  
I V Zolotov ◽  
R S Esipov
Keyword(s):  
Austenitic Steels ◽  
Ion Nitriding ◽  
Different Temperatures

scholarly journals Influence of hydrogen content on ion nitriding of coarse-grained and ultrafine-grained VT6 titanium alloys

2019 ◽  
Vol 1393 ◽  
pp. 012095
Author(s):  
Yu G Khusainov ◽  
A A Nikolaev ◽  
R D Agzamov ◽  
K N Ramazanov ◽  
A F Tagirov
Keyword(s):  
Titanium Alloys ◽  
Hydrogen Content ◽  
Coarse Grained ◽  
Ion Nitriding ◽  
Ultrafine Grained

Corrosion, Corrosion Barrier Development and Mechanical Properties of Steels Foreseen as Structural Materials in Liquid Lead Alloy Cooled Nuclear Systems

2009 ◽  
Author(s):  
Alfons Weisenburger ◽  
Georg Mu¨ller ◽  
Annette Heinzel ◽  
Adrian Jianu ◽  
Heinrich Muscher ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Diffusion Processes ◽  
Creep Behaviour ◽  
Alumina Scale ◽  
Austenitic Steels ◽  
Liquid Lead ◽  
Oxide Scales ◽  
Martensitic Steels ◽  
Pulsed Electron Beam ◽  
Nuclear Systems

A key problem in development of heavy liquid metal cooled nuclear energy and transmutation reactors is the corrosion of structural and fuel cladding materials in contact with the liquid metal. Lead and lead bismuth attack unprotected steel surfaces by dissolution of the metallic components into the liquid metal. It is common understanding that oxide scales on the surface provide the best protection against dissolution attack. However, at temperatures above 500°C austenitic steels suffer from severe dissolution attack, while martensitic steels form thick oxide scales, which hinder heat transfer from the fuel pins and which may break off and eventually lead to a blocking of the coolant channel. Above 500°C steels have to be protected by stable, thin oxide scales. A well understood measure is alloying of stable oxide formers into the surface. Al has shown its ability to form such oxide scales. In the range of 4–10 wt% Al on the surface a stable thin alumina scale is formed by Al diffusion to the surface and selective oxidation. The alumina scale grows only very slowly and prevents migration of oxygen into the steel as well as migration of steel components onto the surface. A number of corrosion experiments showed the good protective behaviour of Al scales in LBE with 10−6 wt% oxygen up to 650°C and for exposure times up to 10000 h. Alloying Al into the surface was done by diffusion processes and also by pulsed electron beam (GESA) melting of a thin surface layer on which Al or an Al containing alloy was precipitated before. This presentation gives an overview on investigations of the steel behaviour in HLM environment carried out to explore their suitability for systems with Pb/LBE coolants. Results of experiments with static and flowing LBE are discussed. The behaviour of steels examined and their respective application ranges are described. Part of the presentation deals with protective barrier development on the steel surface by alloying of Al and its effect on the corrosion resistance. Furthermore the influence of parameters like stresses in the cladding wall, creep behaviour, different flow velocities of the LBE and changing temperatures and oxygen concentrations in LBE is discussed.

Influence of Ion Nitriding Regimes on Diffusion Processes in Titanium Alloy Ti-6Al-4V

2018 ◽  
Vol 383 ◽  
pp. 161-166 ◽  
Author(s):  
Rashid D. Agzamov ◽  
Ainur F. Tagirov ◽  
Kamil Nurulaeyevich Ramazanov
Keyword(s):  
Titanium Alloy ◽  
Diffusion Processes ◽  
Arc Discharge ◽  
Nitrided Layer ◽  
High Current ◽  
Nitriding Temperature ◽  
Ion Nitriding ◽  
Process Duration ◽  
Working Medium ◽  
Glowing Discharge

The paper reports on the results of two-stage-experiments of low-temperature ion nitriding of the Ti-6Al-4V titanium alloy in a non-self-sustained high-current arc discharge and in a glow discharge under various conditions. The diffusion of nitrogen into the interior of the material was determined by the thickness of the layer being modified. It was established that the depth of the nitrided layer greatly depends on temperature, composition of the working medium, as well as on process duration. When treated in non-self-sustained high-current arc discharge, the depth of the nitrided layer increases from 4 to 17 μm, and in the glowing discharge the depth increases from 9 to 13 μm. The nitriding temperature affects the sign and magnitude of the residual stresses.

scholarly journals Influence of hydrogen content in working gas on growth kinetics of hardened layer at ion nitriding of steels

2018 ◽  
Vol 1115 ◽  
pp. 032034
Author(s):  
Yu G Khusainov ◽  
K N Ramazanov ◽  
R D Agzamov ◽  
I V Zolotov ◽  
R S Esipov
Keyword(s):  
Growth Kinetics ◽  
Hydrogen Content ◽  
Hardened Layer ◽  
Ion Nitriding ◽  
Kinetics Of

scholarly journals NITROGENING HYDRAULIC CYLINDER RODS

2020 ◽  
Vol 17 (2) ◽  
pp. 25-30
Author(s):  
V.M. Yurov ◽  
Keyword(s):  
Diffusion Processes ◽  
Plasma Nitriding ◽  
Classical Case ◽  
Hydraulic Cylinder ◽  
Bulk Sample ◽  
Size Factor ◽  
Nitrogen Diffusion ◽  
Ion Nitriding ◽  
Hydraulic Cylinders ◽  
Factor Α

The paper considers the method of ion-plasma nitriding of polished rods of hydraulic cylinders. With ion nitriding, the surface hardening of parts is most pronounced. This is due to the fact that the surface layer of the part does not exceed 20 nm, that is, it is a nanostructure. In this nanostructure, nitrogen diffusion processes are significantly different from bulk ones. The size effects in the nanostructure lead to the fact that the “classical” Fick equations do not work in the layer, and the diffusion of nitrogen in this layer depends logarithmically on the properties of the steel. It was theoretically found that diffusion in a nanoplate depends both on the material of the plate through the diffusion coefficient of the bulk sample D0 and on the size factor α. In the classical case, there is no such dependence.

scholarly journals Practical and Economical Effects of the Use of Screen Meshes for Steel Nitriding Processes with Glow Plasma

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3808
Author(s):  
Jerzy Pisarek ◽  
Tadeusz Frączek ◽  
Tomasz Popławski ◽  
Michał Szota
Keyword(s):  
Electric Fields ◽  
Diffusion Processes ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Hydrogen Atmosphere ◽  
Austenitic Steels ◽  
Diffusion Layers ◽  
Processed Material ◽  
Glow Plasma ◽  
Screen System

The dynamically developing energy sector forces technologists to create new materials that meet the increasingly higher mechanical, chemical, and electrical requirements. The paper relates to the method of reducing the energy consumption of the plasma nitriding process of austenitic steels. The method proposed by the authors involves the modification of nitriding technology in glow plasma. It consists of introducing perforated screens between the anode and nitrided surface made of a material with a composition similar to the processed material and the use of an HF power supply with controlled mean current generating negative voltage peaks of about 1000 V. Nitriding is carried out in a nitrogen-hydrogen atmosphere. The processed material has a negative potential in relation to the surrounding plasma and strongly negative in relation to the vacuum chamber jacket. The actual treatment is preceded by ionic cleaning of the surface of the detail and heating it to the temperature that activates the diffusion processes. The authors analyse the dynamic distribution of electric fields generated at the surface of the nitrided material with different configurations of the cathode-sample-screen system, trying to find the correlation of treatment parameters with the parameters of the nitrided layer. A significant influence of the screening meshes on the depth of the obtained diffusion layers containing nitrogen was found. The oscilloscopic measurements of the plasma in the boundary layer allowed for the observation of voltage peaks, probably leading to an increase in the peak kinetic energy of nitrogen ions and their easier penetration into the material. The work is of a cognitive nature and is probably one of the first to look for relationships between the dynamic electrical parameters of plasma and the efficiency of nitriding.

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