Electrolytic-plasma Nitriding Research Articles

Surface Modification of Chromium–Nickel Steel by Electrolytic Plasma Nitriding Method

Electrolytic plasma nitriding is an attractive chemical heat treatment used to improve the surface properties of steel by implementing nitrogen saturation. This method is widely applied to steel and iron-based alloys operating under various operating conditions. In this work, using liquid-phase plasma nitriding technology, a nitrided layer was obtained on the surface of 40CrNi steel in electrolytes of different concentrations. The microstructure and phase composition of the nitrided layer were investigated and analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), and we performed Vickers hardness and wear resistance tests using the ball-on-disc method. The microhardness and wear resistance of nitrided 40CrNi steel were significantly improved due to the lubricating properties of the ε-Fe2N phase formed on its surface.

PLASMA-ELECTROLYTIC MODIFICATION OF STEEL AND TITANIUM SURFACES BY COMBINING CATHODIC NI-TRIDING AND ANODIC POLISHING

The possibility of increasing the wear resistance of steel 45 surfaces by 19.9 times and titanium alloy VT6 by 3.6 times after cathodic electrolytic plasma nitriding in a solution of ammonium chloride and ammonia and subsequent anodic electrolyte-plasma polishing in a solution of ammonium sulfate. A positive effect on wear resistance was revealed reducing surface roughness and removing the outer part of the oxide layer using anodic electrolytic plasma polishing and increasing the hardness of the surface layer as a result of cathodic nitriding. The wear mechanism is defined as fatigue upon plastic contact and boundary friction.

Interaction model of low-temperature plasma with a steel surface during electrolyte plasma nitriding in an electrolyte on the bases of carbamide

The features of the formation of low-temperature plasma and its interaction with a metal surface were studied in this work. A qualitative model of the interaction of low-temperature plasma with the steel surface during nitriding has been developed by summarizing the available research results and taking into account the specific features of the electrolyte plasma process. In accordance with this model, in the first moments of the interaction of low-temperature plasma with the steel surface in the near-surface layer, which accelerated formation of the Feα(N) solid solution occurs due to the action of directed bombardment of charged particles, which enhances the adsorption and diffusion of nitrogen into the interior of the material, then dispersed particles of nitride of alloying elements are formed as further saturation in places with an increased level of free energy (at lattice defects, at grain boundaries, etc.). Subsequently, transformations occur in the surface zone of the layer when the limiting solubility of nitrogen in iron is exceeded, which leading to the formation of nitrides of the γ′-phase (Fe4N) and ε-phase (Fe2–3N) in it. Thus, electrolyte plasma nitriding opens up many new possibilities, in particular: varying the nitriding temperature over a wide range (400–700 ºC), targeted production of a nitrided layer consisting only of a diffusion layer without a layer of compounds, while obtaining a diffusion layer with particles γ’-phase (Fe4N) of plate form and with finely dispersed nitrides MN (CrN). The use of an electric discharge in an electrolyte (low-temperature plasma) makes it possible to increase the heating rate and diffusion saturation of the material surface. This work is of practical importance, since the studied method of electrolytic-plasma nitriding makes it possible to obtain a modified surface layer on steels with high physical and mechanical properties.

Research of Electrolyte Plasma Treatment Impact on Wear Resistance and Roughness of 18HN3MA-SH Steel

This work provides the results of research of the wear resistance of the surface of samples of low carbon structural of 18HN3MA-SH steel, subjected to electrolytic-plasma treatment by nitriding and carbonitriding. The effect of the structure on the surface wear resistance of steel is shown. Changes in abrasive wear and dry friction characteristics were studied depending on temperature and processing time. The results of studies of tribological tests show that after electrolytic-plasma nitriding, the wear resistance of steel 18HN3MA-SH increases by 1.5–2 times compared with the initial state. The observed effects can be explained by the flowing surface modification - the formation of a modified surface layer with the formation of hardening phases. The nature of changes in the surface roughness Ra of steel samples after cementation, carbonitriding and nitriding was studied.

Changing the structure and phasestates and the microhardness of the R6M5 steel surface layer after electrolytic-plasma nitriding

Changing the structure and phasestates and the microhardness of the R6M5 steel surface layer after electrolytic-plasma nitriding

Influence of electrolytic plasma nitriding mode on structural phase state of pearlitic steel

The paper describes results of studies of phase transitions in structural phase state occurring in the type 0.34C-1Cr-1Ni-1Mo-Fe steel under electrolytic plasma nitriding in nitrogen-containing water solution. The nitriding voltages considered in the given study were 550 and 600 V. The research was conducted by means of X-ray diffraction electron microscopy. The specimens were studied in two states : 1) before modification (original state) and 2) after nitriding in the surface layer of the specimen. The study was conducted on thin foils. It was found that nitriding lead to significant changes in the structure of steel, namely in its phase composition and in the number of existing phases. In the original state the structure of steel was given as lamellar pearlite, ferritic carbide mix and fragmented ferrite. After 550 V nitriding it was lath martensite, plates of α-phase, with colonies of thin parallel plates of γ-phase and coarse grains of α-phase, containing γ-phase grains which were different in size and shape and were various-directional. Increase in nitriding voltage up to 600 V lead to change in the structure given as a lamellar non-fragmented pearlite and fragmented ferrite. The original state was marked by presence of particles of M3C cementite, after nitriding irrespective of the voltage it had the particles of M3C alloyed cementite, Fe3Mo3N nitride and Cr2C0.61N0.39 carbonitride. The sizes, volume fractions and locations of particles were dependent on nitriding voltage.

Influence of electrolytic plasma nitriding mode on structural phase state of pearlitic steel

The paper describes results of studies of phase transitions in structural phase state occurring in the type 0.34C-1Cr-1Ni-1Mo-Fe steel under electrolytic plasma nitriding in nitrogen-containing water solution. The nitriding voltages considered in the given study were 550 and 600 V. The research was conducted by means of X-ray diffraction electron microscopy. The specimens were studied in two states : 1) before modification (original state) and 2) after nitriding in the surface layer of the specimen. The study was conducted on thin foils. It was found that nitriding lead to significant changes in the structure of steel, namely in its phase composition and in the number of existing phases. In the original state the structure of steel was given as lamellar pearlite, ferritic carbide mix and fragmented ferrite. After 550 V nitriding it was lath martensite, plates of α-phase, with colonies of thin parallel plates of γ-phase and coarse grains of α-phase, containing γ-phase grains which were different in size and shape and were various-directional. Increase in nitriding voltage up to 600 V lead to change in the structure given as a lamellar non-fragmented pearlite and fragmented ferrite. The original state was marked by presence of particles of M3C cementite, after nitriding irrespective of the voltage it had the particles of M3C alloyed cementite, Fe3Mo3N nitride and Cr2C0.61N0.39 carbonitride. The sizes, volume fractions and locations of particles were dependent on nitriding voltage.

Microstructure and tribological properties of electrolytic plasma nitrided high-speed steel

In this work, the influence of electrolytic plasma nitriding on the structure and tribological properties of R6M5 high-speed steel were investigated. We found out that after electrolytic plasma nitriding of R6M5 steel a surface modified layer is formed with a thickness of 20 to 40 μm and with increased microhardness of 9000–12 200 MPa. It is established, that after nitriding surface friction coefficient of the sample steel decreased from 0.90 to 0.65, and sample wear rate reduced up to 5 times compared to the original, which indicates considerable wear resistance increase and hardness of R6M5 steel surface layer. It was also determined that abrasive wear resistance of R6M5 steel surface layer increased to 25 % as a result of electrolytic plasma nitriding. Thus, studies have demonstrated the feasibility and applicability of electrolytic plasma nitriding in order to improve the service time of cutting tools working under friction and wear conditions.

Surface Modification of High-Speed Steel by Plasma Nitriding

The article investigates the changing in the structure and phase composition of the R6M5 high-speed steel surface layer after electrolytic-plasma nitriding. It is found that after electrolytic-plasma nitriding on the R6M5 steel surface, modified layer is formed, which consist from a diffusion layer. It was showed phase composition of difysion layer is changing depending on the nitriding. It is found that electrolytic-plasma nitriding lead to accelerated formation of the modified layer. It is determined that after electrolytic-plasma nitriding on the high-speed steel surface, modified layer is formed, consisting only of the diffusion layer.

Impact of Electrolytic-Plasma Nitriding on 34CrNi1Mo Steel Surface Layer Properties

The present work is devoted to the research into the microstructure and microhardness of structural steel 34CrNi1Mo after electrolytic-plasma nitriding in a cathode heating mode. The technology of electrolyte-plasma hardening provides a reliable quality and the required mechanical properties of the products which are often subjected to wear and temperature-force actions.

The Formation of Modified Layers at High-Speed Steels after Electrolytic-Plasma Nitriding

In the article the formation peculiarities of the modified layer at R9, R6M5 R18 high-speed steels (HSS) after electrolytic-plasma nitriding are shown. It is established that in the result of electrolytic-plasma nitriding on the of high-speed steels samples surfaces formed modified layers with higher hardness. Hardness of HSS increased to 11.9-12.8 HPa after electrolytic-plasma nitriding, mainly depends to the formation of a diffusion layer of nitrogen martensite with Fe4N (γ’-phase) monophasic nitride. It is determined that a modified layer consists of nitrogenous martensite with Fe4N monophasic nitride. Perspectivity of use an electrolytic-plasma nitriding method to improve performance cutting tools made of high speed steels is shown.

Change of Structure and Mechanical Properties of R6M5 Steel Surface Layer at Electrolytic-Plasma Nitriding

In the article changes in the structure and mechanical properties of R6M5 steel surface layer after electrolytic-plasma nitriding are shown. The optimal mode of electrolytic-plasma nitriding of R6M5 high-speed steel in electrolyte based on carbamide, which allows saturation of the surface with nitrogen from low-temperature plasma and get the modified layer of high hardness and wear-resistance. It is established, that after electrolytic-plasma nitriding reduced R6M5 steel wear rate and increases its resistance to abrasive wear. Perspectivity of use an electrolytic-plasma nitriding method to improve performance cutting tools made from R6M5 steel is shown.

Wear-Resistance of Nitrided W-Mo-High Speed Steel in Abrasive Wear Conditions

In this work the influence of electrolytic-plasma nitriding on the abrasive wear-resistance of R6M5 high-speed steel were under research. We registered that after electrolytic-plasma nitriding on R6M5 steel surface modified layer is formed with 20-40 μm thickness and with increased microhardness of 9000-12200 MPa. Testing mode for the nitrided samples high-speed steel on abrasive wear developed. It is established, that electrolyte-plasma nitriding allows to increase wear-resistance of R6M5 steel surface layer comparing to original. It was determined that abrasive wear-resistance of R6M5 steel surface layer is increased to 25% as a result of electrolytic plasma nitriding. Thus, studies have demonstrated the feasibility and applicability of electrolytic-plasma nitriding in order to improve cutting tools work resource, working under friction and wear conditions.

Influence of Plasma Carbonitriding and Nitriding on Phase Composition and Mechanical Properties of a X 12 CrNi 18 10 Ti Stainless Steel Surface

Abstract The surface structure of a X 12 CrNi 1810 Ti low-carbon steel after saturation with nitrogen and carbon as a consequence of electrolytic plasma nitriding and carbonitriding was studied in this work. It turned out that the X 12 CrNi 1810 Ti steel surface has a modified martensite structure and high hardness after electrolytic plasma processing. It was determined that carbide and nitride particles are formed in the surface layer during nitriding and carbonitriding followed by tempering. The X 12 CrNi 1810 Ti steel wear resistance after carbonitriding and nitriding was investigated and a decrease of the friction coefficient was observed.

Research of Electrolytic-Plasma Carbonitriding and Nitriding Influence on Phase Composition of the Stainless Steel

In the present work we have studied the phase structure of surface modified layer of austenitic steel 12Cr18Ni10Ti after electrolytic-plasma carbonitriding and nitriding. It was determined that the carbonitriding and nitriding with the subsequent hardening formed carbide and nitride phase. Also it is revealed that steel 12Cr18Ni10Ti after the electrolyte-plasma processing has high hardness. The microstructure of samples surface is presented by martensite and residual austenite. Optimum modes of steel 12Cr18Ni10Ti carbonitriding and nitriding by electrolytic-plasma way have been identified.

Influence Nitriding in the Electrolytic Plasma on the Tribological Properties of Low-Alloy 40Cr Steel

This paper presents the results of research influence nitriding in electrolytic plasma on the tribological properties of low-alloy 40Cr steel. It is shown that the process of electrolytic plasma nitriding can significantly increase the wear resistance of the samples 40Cr steel. Found that after nitriding component adhesive wear mechanism is changed to abrasion.

Microstructure and Microhardness Changes of 40Cr Steel after Treatment in the Electrolytic Plasma

In this work the microstructure and microhardness distribution of modified layers 40Cr (AISI 5140) alloy steel after nitriding by electrolytic plasma have been under research. It is shown that as a result of electrolytic plasma nitriding it becomes possible to increase the surface microhardness of the steel.

Electrolyte Plasma Nitriding of High-Speed Steel

Developed a new method of electrolytic-plasma nitriding, which enable to carry out surface modification of high-speed steels and provide the high kinetic energy efficiency of diffusion saturation process. . Implementation of electrolytic-plasma nitriding of high-speed steel R6M5 in the optimal mode was determined, which leads to a significant increase in hardness and wear-resistance of the high-speed steel surface layer. It is experimentally established, that after nitriding of electrolytic-plasma heating on the surface of high-speed steel R6M5 formed the modified layer, which has high abrasive wear resistance as compared with the source material.

Nitriding and Carbonitriding Influence on Stainless Steels Surface Layers Changes

The structure of low-carbon steels after saturation by nitrogen and carbon in the mode of electrolytic-plasma nitriding and carbonitriding on the surface structure of austenitic stainless steel 12Cr18Ni10Ti has been studied. Optimum modes of electrolytic-plasma nitriding and carbonitriding are determined ensuring the maximum saturation of nitrogen and carbon, the microhardness of the surface. It is established, that after electrolyte-plasma processing microstructure of steel 12Cr18Ni10Ti has martensite structure. As a result of the research it is revealed that steel 12Cr18Ni10Ti after the electrolyte-plasma processing has high hardness.

Modification of Stainless Steels Surface Layers by Nitriding and Carbonitriding

The structure of low-carbon steels after saturation by nitrogen and carbon in the mode of electrolytic-plasma nitriding and carbonitriding on the surface structure of austenitic stainless steel 12Cr18Ni10Ti has been studied. Optimum modes of electrolytic-plasma nitriding and carbonitriding are determined ensuring the maximum saturation of nitrogen and carbon, the microhardness of the surface. It is established, that after electrolyte-plasma processing microstructure of steel 12Cr18Ni10Ti has martensite structure. As a result of the research it is revealed that steel 12Cr18Ni10Ti after the electrolyte-plasma processing has high hardness.