Growth kinetics of the compound layers: Effect of the nitriding potential

Кеддам, М.; Bouarour, B.; Kouba, R.; Chegroune, R.

doi:10.1016/j.phpro.2009.11.108

Cited by 17 publications

(4 citation statements)

References 4 publications

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“…Nitriding efficiency depends on adsorption properties of N on steel surface (surface roughness, absence of contaminants) and on diffusivity of substrate to assist the inward flow of N from surface to bulk volume. It can be stated that development of Fe 4 N and Fe 2 N compounds in surfacial layers is strongly affected by nitriding potential and by surface condition (Keddam et al, 2004(Keddam et al, , 2009Michalski et al, 2005) whereas development of the diffusion zone mostly depends on material structure and on related diffusion coefficient (Michalski et al, 2005;Calliari et al, 2008). This latter aspect in turn is ruled by mobility of nitrogen atoms through microstructural features such as grain boundaries and dislocations rather than through ordinary interstitials lattice sites (Tong et al, 2008;Ferkel et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

“…In recent decades, detailed information on phase stability, growth kinetics and processing parameters effects have been made available in literature (Hernandez et al, 2008;Keddam et al, 2004Keddam et al, , 2009Ratajski et al, 2010). The effects of nitriding on mechanical behaviour of steels is also well documented, especially considering fatigue strength (Genel et al, 2000;Li et al, 2000;Alsaram et al, 2002) and wear properties (Baranowska et al, 2005;Kamminga et al, 2004;Lin et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Effect of substrate structure on properties of nitrided layers formed on pure iron

Lecis

Vedani

Farè

2012

International Journal of Structural Integrity

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Purpose -This paper aims to investigate the structure and scratch resistance properties of gas nitrided pure iron samples. Design/methodology/approach -The effects of material strain hardening and amount of grain boundaries exposed on nitriding surface were evaluated by cold rolling the starting samples to different reduction levels before gas nitriding. Findings -The study finds that nitriding without any prior cold rolling produced a comparatively wide compound layer with a large fraction of porous zone featuring low scratch hardness values but no evidence of damage. On the contrary, cold rolling before nitriding led to a more irregular and thinner compound layer with reduced amount of porous zone and much finer nitrides in the diffusion zone. Scratch hardness was increased but failure mechanism changed by generation of conformal cracks within the track groove and the appearance of discontinuous spallation at high loads. Originality/value -One of the issues of great industrial importance concerning nitriding of steels is the need to predict the extent of the nitrided layer in products showing small variations in microstructure or in extent of cold working due to complex manufacturing cycles. Despite the practical importance, relatively little information is available in literature about these issues. The present paper is therefore aimed at investigating the structure and mechanical properties of pure iron samples, gas nitrided with different amounts of cold working and microstructural conditions.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of substrate structure on properties of nitrided layers formed on pure iron

Lecis

Vedani

Farè

2012

International Journal of Structural Integrity

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“…During the gas nitriding process, mostly two different nitride layers are formed. On the surface of the material, the compound layer consists of ε-Fe 2−3 N, and γ -Fe 4 N phase should be formed [11,12]. This type of layer is very hard and brittle with good friction and anticorrosion properties [13,14].…”

Section: Introductionmentioning

confidence: 99%

Influence of alloying elements on gas nitriding process of high-stressed machine parts of weapons

Pokorny¹,

Dobrocký²,

Kadlec³

et al. 2018

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The chemical composition of the steel is one of the primary characteristics that influence the mechanical properties of high-stressed machine parts such as barrels of small arms weapon. Heat treatment is the most important technology to reach requested mechanical properties. By a suitable combination of mechanical and tribological properties, it is possible to improve the surface of highly stressed parts as to improve the wear resistance of barrel surface. Thus, surface technology is next step for obtaining new properties as tribological properties or preferable mechanical properties. Due to obtain suitable microstructure and wear resistance the samples of C35, 34Cr4, 37Cr4 and 42CrMo4 were heat-treated with following chemical heat treatment by gas nitriding process, for 6 hours. This paper deals with the influence of alloying elements of structural steels on surface microhardness and depth of diffusion layer. The gas nitriding process caused the creation of a compound layer on the surface of the steel. This layer leads to significant improvement in wear resistance. The concentration of alloying elements was analysed by OES methods. The technology of nitriding was applied to annealed, tempered and quenched steels. After chemical heat treatment, new surface morphology was created. The surface layers of the samples were analysed by microhardness method; surface morphology was evaluated by SEM method. Experimental part concerns structural steels with a concentration of alloying elements to 1 wt.%. In experimental part, the influence of alloying elements on the diffusion process in Fe-C system and the microhardness of the surface was proved.K e y w o r d s : gas nitriding, microhardness, chemical composition, diffusion, barrel

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“…Ainda, segundo o autor, essas mudanças são passivas de alterações bruscas no comportamento do processo como consequência da formação das fases γ' e ɛ [camada branca] que nucleia e cresce internamente nos contornos dos poros abertos e interconectados. Todavia, a natureza microestrutural da camada branca depende do potencial de nitretação para gerar uma configuração monofásica (γ') ou bifásica (ɛ + γ') a uma dada temperatura, ao qual é estritamente dependente da relação entre as pressões parciais de amônia e hidrogênio (KEDDAM et al, 2009).…”

Section: Mecanismos Do Processounclassified

Processamento e caracterização de aços sinterizados contendo dispersão de fases obtidas através de reação in situ.

Almeida¹

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Growth kinetics of the compound layers: Effect of the nitriding potential

Cited by 17 publications

References 4 publications

Effect of substrate structure on properties of nitrided layers formed on pure iron

Effect of substrate structure on properties of nitrided layers formed on pure iron

Influence of alloying elements on gas nitriding process of high-stressed machine parts of weapons

Processamento e caracterização de aços sinterizados contendo dispersão de fases obtidas através de reação in situ.

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