Influence of Hydrogen on the Plasmas Nitriding Process of 35CrMo Steel

2011 ◽  
Vol 295-297 ◽  
pp. 1004-1009
Author(s):  
Li Zhong ◽  
Xi Han
Keyword(s):  
Plasma Nitriding ◽  
Elastic Collision ◽  
Nitriding Process ◽  
Cathode Voltage ◽  
Active Nitrogen ◽  
Mixture Ratio ◽  
Neutral Particles ◽  
Positive Ions ◽  
Nitrided Case ◽  
Mixture Plasma

The mechanism of the formation of active nitrogen atoms and the function of hydrogen molecules for the dissociation of the mixture of nitrogen and hydrogen in the plasma nitriding process are discussed in this paper. The results show that the nitrided case thickness of nitrided samples become thinner and the surface hardness decreases with the increase of cathode voltage. Active nitrogen atoms mainly result from non-elastic collision between positive ions H2+ and neutral particles N2 for N2-H2 mixture plasma nitriding at 550V cathode voltage, the volume percent of e-Fe3N and the superficial nitrogen concentration of plasma nitrided case decrease with the increase of the mixture ratio of N2/H2. However, active nitrogen atoms mainly result from non-elastic collision between energetic positive ions H2+, N2+and neutral particles N2 for N2-H2 mixture plasma nitriding at 650V cathode voltage. The existence of a few of nitrogen molecules makes critical energy of positive ions H2+ dissociating neutral N2 molecules drop to 26.06eV and the cathode voltage threshold value become 490V.

Fatigue Crack Surface Topography after Plasma Nitriding Process

2016 ◽  
Vol 258 ◽  
pp. 298-301
Author(s):  
Zbynek Studeny ◽  
Zdeněk Pokorný ◽  
David Dobrocky
Keyword(s):  
Fatigue Crack ◽  
Surface Topography ◽  
Fatigue Testing ◽  
Plasma Nitriding ◽  
Fatigue Cracks ◽  
Pulse Length ◽  
Nitriding Process ◽  
Mixture Ratio ◽  
Topography Analysis ◽  
Fish Eye

Fatigue characteristics of steel 41CrAlMo7-10 and topography analysis testing methodology of fish eye were studied. Both sets of samples were heat-treated at the same conditions and subsequently were plasma nitrided. The mixture ratio of these main gases, forming the atmosphere during the plasma nitriding was inverted for both sets of samples. Process parameters such as the duration, the applied voltage and the pulse length were identical for all samples. Following test after heat treatment and surface layer formation by plasma nitriding process for both sets of samples was the <em>rotating bending fatigue testing</em> in the machine R.R.Moore L2568 of Instron Co. The fatigue tests were carried out in accordance with the CSN 42 0363 Fatigue Testing of Metals, Methodology of Testing. Then, tests were evaluated numerically and graphically using Wöhler`s (S-N) curve in a semi-logarithmic form. The testing was stopped after reach the fracture of tested sample or after 107 cycles. The surface topography of fatigue cracks were evaluated on Talysurf CCI. The topography analysis was mainly focused on the initial part of fatigue crack called the fish-eye. The topography analysis was performed only on one selected sample of each series.

Modeling of the Plasma Nitriding Process

1990 ◽  
pp. 155-158
Author(s):  
J. L. Marchand ◽  
H. Michel ◽  
D. Ablitzer ◽  
M. Gantois ◽  
A. Ricard ◽  
...  
Keyword(s):  
Plasma Nitriding ◽  
Nitriding Process

scholarly journals X-Ray Phase Analysis Of Nitrided Layers Of X2CrNiMo17-12-2 Austenitic Steel

2015 ◽  
Vol 60 (3) ◽  
pp. 2005-2012 ◽  
Author(s):  
T. Frączek ◽  
M. Olejnik ◽  
M. Pilarska
Keyword(s):  
Austenitic Steel ◽  
Phase Analysis ◽  
Plasma Nitriding ◽  
Subsurface Layer ◽  
Nitrogen Plasma ◽  
Nitriding Process ◽  
X Ray ◽  
Temperature Range ◽  
Chromium Nitrides

Abstract This work presents the results of diffraction analyses carried out using X-ray phase analyses (XRD and GIXRD) of nitrided layers of X2CrNiMo17-12-2 austenitic steel. Plasma nitriding process was c arried out in the temperature range of 325 ÷ 400 °C and time of 2 ÷ 4 h. Hydrogen-nitrogen plasma was used as reactive atmosphere (H2 75% + N2 25%) with pressure of 150 Pa. On the basis of the X-ray analyses it was stated that the obtained nitrided layers consisted of a subsurface layer of chromium nitrides and a zone of nitrogen saturated austenite.

A fundamental contribution to a study of the active screen plasma nitriding process

2006 ◽  
Vol 151 (11) ◽  
pp. 441-445 ◽  
Author(s):  
P. Hubbard ◽  
D. G. McCulloch ◽  
E. D. Doyle ◽  
S. J. Dowey ◽  
J. N. Georges
Keyword(s):  
Plasma Nitriding ◽  
Nitriding Process ◽  
Active Screen Plasma Nitriding ◽  
Active Screen

The Design of an Automated Plasma Diagnostic System – From Measurement to Signal Processing

MACRo 2015 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Nimród Kutasi ◽  
Lajos Kenéz ◽  
Emőd Filep ◽  
István Szöllösi ◽  
László Jakab Farkas
Keyword(s):  
Signal Processing ◽  
Power Supply ◽  
Plasma Nitriding ◽  
Diagnostic System ◽  
Nitriding Process ◽  
Plasma Diagnostic ◽  
Communication Interface ◽  
Measurement Results ◽  
Processing Program ◽  
Different Temperatures

AbstractThe paper deals with the design of a new plasma diagnostic system consisting of a microcontroller based power supply for automatic control of the measurement using Langmuir probe, the communication interface of the power supply and the signal processing program. The main motivation for the design of the automated plasma diagnostic system was given by our research in different methods of plasma nitriding of steels. During the nitriding process, it is important to achieve information about the plasma, which is the medium where the heat-treatment process is going on. The new diagnostic system is able to perform measurements during the nitriding process, thus we can analyze the plasma at different temperatures and gas mixtures. The obtained voltage-current curves are recorded and transmitted to the computer, where further signal processing is performed. The paper presents the design of the power supply, the measurement results and the developed signal processing software.

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.

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