Kinetics of Low Temperature Nitriding of Precipitation Hardened Stainless Steel

2011 ◽  
Vol 312-315 ◽  
pp. 530-535 ◽  
Author(s):  
Paweł Kochmański ◽  
Jolanta Baranowska
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Chemical Elements ◽  
Nitrided Layer ◽  
Nitriding Time ◽  
Diffusion Layers ◽  
Optical Spectrometry ◽  
Xrd Phase Analysis ◽  
Time Changes ◽  
Kinetics Of

The paper presents results of research on nitrided layers on precipitation hardened stainless steel, known also as 1RK91 (Sandvik NanoflexTM). Samples were subjected to low temperature nitriding. The influence of nitriding parameters on nitriding kinetics was investigated. The nitriding process was carried out in a mixture of NH3 50% and products of its dissociation as well as in 100% ammonia atmosphere at temperature range 425-475°C. To investigate the kinetics of nitrided layer formation, the nitriding time changes between 2 and 8 h. The obtained diffusion layers were examined using the following methods: light and scanning electron microscopy, XRD phase analysis. The distribution profiles of selected chemical elements were acquired using optical spectrometry GDOES.

The Kinetics of Gas Nitrided Layer Growth on Austenitic Stainless Steel

2010 ◽  
Vol 297-301 ◽  
pp. 573-578 ◽  
Author(s):  
Jolanta Baranowska
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Nitrided Layer ◽  
Light And Electron Microscopy ◽  
Layer Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treated Steel ◽  
Optical Spectrometry ◽  
Kinetics Of

This paper presents the results of investigations on gas nitrided austenitic stainless steel. The treatment was conducted at various temperatures (400-515°C), gas compositions of atmospheres used (20-100% NH3) and times (0.5-12h). The layers were investigated by X-ray diffraction, Light and Electron Microscopy and Glow Discharge Optical Spectrometry. The kinetics of layer growth has been analysed in terms of the process parameters and compared with the data presented for plasma treated steel. The specific nitrogen profiles of nitrided layers are discussed in the context of the layers’ microstructure and phase composition.

Low Temperature Fluidized Bed Nitriding of Austenitic Stainless Steel

2006 ◽  
Vol 118 ◽  
pp. 125-130 ◽  
Author(s):  
E. Haruman ◽  
Y. Sun ◽  
H. Malik ◽  
Agus Geter E. Sutjipto ◽  
S. Mridha ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Fluidized Bed ◽  
Corrosion Behaviour ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Temperature Plasma ◽  
316L Austenitic Stainless Steel ◽  
Fluidized Bed Process

In the present investigation, low temperature nitriding has been attempted on AISI 316L austenitic stainless steel by using a laboratory fluidized bed furnace. The nitriding was performed in temperature range between 400°C and 500°C. X-ray diffraction, metallography, and corrosion tests were used to characterize the resultant nitrided surface and layers. The results showed that fluidized bed process can be used to produce a precipitation-free nitrided layer characterized by the S phase or expanded austenite on austenitic stainless steel at temperatures below 500°C. But there exists a critical temperature and an incubation time for effective nitriding, below which nitriding is ineffective. The corrosion behaviour of the as-nitrided surfaces is significantly different from that previously reported for low temperature plasma nitriding. This anomaly is explained by the formation of iron oxide products and surface contamination during the fluidized process.

scholarly journals Combating the Tribo-Corrosion of LDX2404 Lean Duplex Stainless Steel by Low Temperature Plasma Nitriding

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 93 ◽  
Author(s):  
Xiaoying Li ◽  
Wenbo Dou ◽  
Linhai Tian ◽  
Hanshan Dong
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Electrochemical Corrosion ◽  
Treatment Temperature ◽  
Temperature Plasma ◽  
Lean Duplex Stainless Steel

A lean duplex stainless steel, LDX2404, was DC plasma nitrided under a range of treatment conditions. The microstructure characterisation evaluation of the treated samples revealed that a dense, super-hard surface layer can be produced by low-temperature (<450 °C) plasma treatments. The original austenite phase became S-phase and the ferrite phase was supersaturated with nitrogen and ε-Fe3N nitride precipitated from it. When plasma nitriding was carried out at above 450 °C, chromium nitrides precipitated in the surface nitrided layer. Compared to the untreated samples, the surface hardness of the lean duplex stainless steel (DSS) is increased up to four times. The dry wear resistance increased when increasing the treatment temperature. In contrast, the low-temperature treated samples showed the best performance in the electrochemical corrosion and corrosion-wear tests; the performance of the high temperature (>450 °C) plasma nitrided samples was found to be significantly worse than that of the untreated material.

The Effect of Low-Temperature Glow Discharge Nitriding of Duplex Stainless Steel on Absorption and Desorption of Hydrogen

2011 ◽  
Vol 183 ◽  
pp. 71-80 ◽  
Author(s):  
Bartosz Gołębiowski ◽  
Tadeusz Zakroczymski ◽  
Wiesław Świątnicki
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Low Temperature ◽  
Glow Discharge ◽  
Hydrogen Absorption ◽  
Nitrided Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron ◽  
Absorption Of Hydrogen

The effect of the nitrided layers produced on ferritic-austenitic stainless steel to hydrogen absorption and desorption was studied. The layers were formed during low-temperature glow discharge nitriding process. The microstructure of steel after nitriding and cathodic hydrogen charging was investigated by means of X-ray diffraction and by scanning electron microscopy (SEM). One of the objectives was to determine the quantity of hydrogen absorbed by the steel samples with and without the nitrided layer. To determine the quantity of the diffusible and trapped hydrogen, the electrochemical permeation and desorption methods were used. The influence of the nitrided layer on the entry, absorption and desorption of hydrogen was determined. The results revealed that the nitrided layer hinders absorption of hydrogen into and desorption of hydrogen from the membrane.

Effect of Atmosphere Proportion and Nitriding Time on Plasma Nitriding of Duplex Stainless Steel

2014 ◽  
Vol 1061-1062 ◽  
pp. 61-64
Author(s):  
Wei Ye ◽  
Xing Sheng Tong
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Plasma Nitriding ◽  
Analytical Techniques ◽  
Corrosion Properties ◽  
Nitriding Time

Samples of duplex stainless steel were plasma nitrided at different atmosphere proportion and nitriding time. The hardness and the corrosion resistance of the untreated and various plasma treated samples were characterised by a variety of analytical techniques. The results show that plasma nutriding at low temperature can improve hardness of duplex stainless steel and its corrosion properties at the same time. Declining the atmosphere proportion of ammonia and argon can effectively prevent the nonuniformity of hardness of nitriding layers and extension of nitriding time is conducive to enhance the hardness and thickness of nitriding layer. In addition, the corrosion peoporties of duplex stainless steel nitrided increase when the nitriding time improves, but its corrosion resistance rises slowly after nitriding for 9h.

Surface Modification of SS2205 Duplex Stainless Steel by Plasma Nitriding at Anodic Potential

2014 ◽  
Vol 881-883 ◽  
pp. 1263-1267 ◽  
Author(s):  
Shuo Zhao ◽  
Liang Wang ◽  
Jiu Jun Xu ◽  
Y. Shan
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Anodic Potential ◽  
Wear And Corrosion

The duplex stainless steel has better pitting corrosion resistance but lacks of hardness and wear resistance. Therefore, the low temperature nitriding treatment can be used to increase its hardness and wear resistance or to gain more perfect corrosion resistance. The plasma nitriding of SS2205 stainless steel was carried out at temperatures from 693k to 753k for 4 hours at anodic potential. The nitrided samples were analyzed by optical microscopy, X-ray diffraction, SEM-EDX analysis, microhardness testing, wear and corrosion evaluation. The XRD analysis of all treated samples showed that the nitrogen-expanded austenite phase was formed. Both α and γ phase of the substrate were transformed into γNduring plasma nitriding. Observing the nitrided layers formed on α and γ phase, the ones situated in the austenite were thinner than the ones in the ferrite. This phenomenon was more evident at low temperature, which confirmed that the nitrogen has a higher diffusion rate in the ferrite during plasma nitriding treatment. The surface hardness of nitrided layer was increased with the nitriding temperature. The highest hardness value obtained in this experiment was about 1300 HV0.05which was 4 times as the original sample (380 HV0.05). Furthermore, through the wear and corrosion property tests, it was shown that anodic plasma nitriding improved the wear resistance and corrosion resistance of the duplex stainless steel.

Structure and Properties of Gas Nitrided Layers on Nanoflex Stainless Steel

2012 ◽  
Vol 326-328 ◽  
pp. 291-296 ◽  
Author(s):  
Paweł Kochmański ◽  
Jolanta Baranowska
Keyword(s):  
Stainless Steel ◽  
Treatment Temperature ◽  
Structure And Properties ◽  
Influence Of Process Parameters ◽  
Gas Nitriding ◽  
Diffusion Layers ◽  
Treatment Conditions ◽  
Xrd Phase Analysis ◽  
Nitrogen Potential ◽  
Ammonia Atmosphere

The paper presents results of research on nitrided layers on Sandvik NanoflexTMprecipitation hardened stainless steel. The influence of process parameters on nitriding kinetics and structure of the layers was investigated. The gas nitriding process was conducted in a mixture of ammonia 50% and products of its dissociation, as well as in 100% ammonia atmosphere at temperature range 400500°C and time between 2 and 8 h. The obtained diffusion layers were examined using the following methods: light and scanning electron microscopy, XRD phase analysis and EDS chemical analysis. Mechanical properties were tested with hardness measurements. It was found that kinetics depends on treatment temperature and nitrogen potential of the atmosphere. Moreover, treatment conditions affecting Sphase formation and expanded martensite in nitrided layers are discussed.

scholarly journals Controlled thermogasocyclic nitriding processes

2021 ◽  
Vol 13 (S) ◽  
pp. 13-20
Author(s):  
Irina S. BELASHOVA ◽  
Peter S. BIBIKOV ◽  
Alexander A. OREKHOV ◽  
Eduard I. STAROVOITOV
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Diffusion Layer ◽  
Nitrided Layer ◽  
Physical And Mechanical Properties ◽  
New Method ◽  
Control Panel ◽  
Nitriding Time ◽  
Composition And Structure ◽  
Working Volume

The existing basic nitriding methods do not exploit many of the potential opportunities. To intensify it and increase its efficiency, this paper considers and proposes a new method of low-temperature nitriding, which makes it possible to optimise the classical process and reduce the consumption of ammonia from 2 to 10 times, reduce the nitriding time by 4-6.5 times with an increase in the thickness of the diffusion layer by 2-6 times without reducing the physical and mechanical properties. During the experiment, gas-cyclic and thermogasocyclic nitriding of armco iron was carried out on an experimental setup, which included a system for monitoring and maintaining the temperature in the working volume, a gas supply system, monitoring the flow rate and degree of ammonia dissociation, cleaning and drying gas, as well as two electromagnetic gas valves controlled from the control panel, allowing the processes to be carried out automatically. As a result, a new method of low-temperature nitriding has been developed – under the conditions of a thermo-gas cycle. This method consists in periodic alternation of saturation cycles during flow nitriding and resorption of the nitrided layer with the maximum possible decrease in the saturating capacity of the atmosphere. The proposed new method of thermogasocyclic nitriding is a new, effective hardening technology that allows to reduce the consumption of saturating gas and emissions into the atmosphere by up to 10 times, the nitriding time by 4-6.5 times, and also to increase the thickness of the diffusion layer by 2-6 times without reducing the physical and mechanical properties. A new technological parameter has been established – the duration of half-cycles, which allows simply and effectively regulating the phase composition and structure of the layer in order to obtain the required physical and mechanical properties.

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