Effect of vacuum oxy-nitrocarburizing on the microstructure of tool steels: an experimental and modeling study

Nikolova, Maria P.; Nikolov, Danail; Derin, Bora; Yankov, Emil

doi:10.1051/matecconf/20179403011

Cited by 3 publications

(4 citation statements)

References 18 publications

(21 reference statements)

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“…Because the duration of the process is very low (4 to 8 h), oxy-nitrocarburizing is recommended instead of normal nitration in natural gas [10]. At temperatures of 570 -600 ° C in the case of oxynitrocarburizing (Fe -N -C system), the phase domain ε (which confers corrosion resistance) [4] is wider than with * email: gina.sicoe@upit.ro; gina_boicea@yahoo.com, Phone: +40752222303 the usual nitration (Fe -N system) [4], it is possible to obtain this phase in lower temperature conditions and nitrogen concentration as compared to the Fe -N system, the layer obtained may consist of one or more phases [5], depending on the N concentrations and temperature, the chemical composition of steel or cast iron.…”

Section: Experimental Partmentioning

confidence: 99%

“…For this study, 10 samples of grey cast iron with the chemical composition shown in table 1 were used. Parameters of the thermo-chemical treatment of oxynitrocarburizing [5,12] applied are shown in table 2.…”

Section: Experimental Partmentioning

confidence: 99%

“…The Nitrogen diffusion profile (GDOS-S2), as well as the depth of white layer (GDOS-S1) [7] were analyzed with the GD-OES (Glow Discharge -Optical Emission Spectrometry) spectrometer [5,13]. So, each sample was analyzed with the GD-OES spectrometer (JY 5000RF spectral apparatus), using an exposure time of up to 550 s.…”

Section: Experimental Partmentioning

confidence: 99%

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Researches on the Diffusion Phenomena in the Thermo-Chemical Treatment of Oxy-nitrocarburizing of Some Grey Cast Irons

SICOE¹

2019

Rev. Chim.

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The thermo-chemical treatment of oxy-nitrocarburizing consists in the enrichment of materials in C, N and O in order to improve the physico-mechanical properties and the use of the materials. This leads to the increase in exploitation life, the increase of wear resistance, galling, corrosion, and slight erosion. The research presented in this article followed the study of the application of this treatment and the results obtained on pearlitic grey cast iron with different chemical compositions, domain in which there are few experimental results published. The results obtained on a number of 10 samples, presented in the article, highlighted the good compatibility of these materials with the thermo-chemical treatment of oxy-nitrocarburizing, obtaining on the surface some white layers which give good anti-corrosive properties, similar to those obtained on steel. There was no correlation between the depth of the white layer and the chemical composition of the studied cast iron. It was also emphasized that the depth of nitrogen diffusion is influenced by the chemical composition of the studied materials which is directly proportional to carbon equivalent (Ceq) of cast iron.

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Section: Experimental Partmentioning

confidence: 99%

Section: Experimental Partmentioning

confidence: 99%

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Researches on the Diffusion Phenomena in the Thermo-Chemical Treatment of Oxy-nitrocarburizing of Some Grey Cast Irons

SICOE¹

2019

Rev. Chim.

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“…Low‐temperature vacuum carburizing performed in an atmosphere of a mixture of acetylene and hydrogen, [ 19,33 ] a mixture of acetylene and nitrogen, [ 20 ] a mixture of acetylene, ethylene and hydrogen, [ 17 ] as well as vacuum oxy‐nitrocarburizing [ 34 ] are widely described in the literature. However, these are different processes than low‐pressure FNC.…”

Section: Introductionmentioning

confidence: 99%

Low‐Pressure Nitrocarburizing in Standard Vacuum Furnaces—Preliminary Studies

Pawęta,

Galeziewska,

Rewers

et al. 2023

Adv Eng Mater

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For the first time, low‐pressure nitrocarburizing process is performed in a minorly modified standard vacuum furnace on 16MnCr5 alloy steel samples. Ammonia and acetylene are used as a source of nitrogen and carbon, respectively. Lowering the pressure of the process ensures longer and more efficient ammonia dissociation. To prove the safety of the process, exhaust gases are investigated online using residual gas analyzer mass spectrometer, whereas reaction products deposited on the sample's surface are studied by means of time‐of‐flight secondary ion mass spectrometer. Possible reactions taking place in the atmosphere of the chamber are written down. In the results of conducted examinations, it is confirmed that no toxic gases are generated, and no cyanides and polycyclic aromatic hydrocarbons are formed during the process. Additionally, microstructure analysis of the cross sections of nitrocarburized sample is performed using scanning electron microscopy (SEM) and optical microscopy. It confirms the diffusion of nitrogen and carbon into the near surface layer. SEM/energy‐dispersive X‐ray spectroscopy analysis demonstrates precipitation of carbide and carbonitride, what is proved by X‐ray diffractometer and microhardness profile analysis. The presented low‐pressure nitrocarburizing results in an increase in hardness from about 200 to over 500 HV and the formation of an effective case depth of about 20 μm, after only 20 min of the process.

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Morphology of the DIN 100Cr6 Case Hardened Steel after Plasma Nitrocarburizing Process

Fontes¹,

Scheid

Machado

et al. 2019

Mat. Res.

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Nitrocarburizing is considered one of the most important thermochemical treatments for surface modification of metallic materials and involves the simultaneous diffusion of nitrogen and carbon onto the surface. Understanding and controlling the formation of the nitrocarburized layer have considerable industrial interest due to the improvements regarding wear, fatigue, and corrosion resistances. DIN 100Cr6 steel samples were treated by plasma nitrocarburizing for two hours, with two treatment temperatures (550 and 600°C) and four methane concentrations in the gas mixture composition (0, 1.0, 1.5, and 2.0%). SEM and XRD analyses, and wear resistance tests were used to characterize the samples. Results showed that the treatment temperature and atmosphere composition had considerable influence on the compound layer morphology. For nitrided samples the compound layer consists of γ'-Fe 4 N phase, and the presence of carbon in the gas mixture helps stabilize the ɛ-Fe 2-3 N phase. Higher CH 4 concentration in the treatment atmosphere improve the sample superficial wear resistance.

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Effect of vacuum oxy-nitrocarburizing on the microstructure of tool steels: an experimental and modeling study

Cited by 3 publications

References 18 publications

Researches on the Diffusion Phenomena in the Thermo-Chemical Treatment of Oxy-nitrocarburizing of Some Grey Cast Irons

Researches on the Diffusion Phenomena in the Thermo-Chemical Treatment of Oxy-nitrocarburizing of Some Grey Cast Irons

Low‐Pressure Nitrocarburizing in Standard Vacuum Furnaces—Preliminary Studies

Morphology of the DIN 100Cr6 Case Hardened Steel after Plasma Nitrocarburizing Process

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