Structure and Phase Composition of Ferriticperlitic Steel Surface after Electrolytic Plasma Quenching

2020 ◽  
Vol 63 (5) ◽  
pp. 791-796
Author(s):  
N. A. Popova ◽  
E. L. Nikonenko ◽  
E. E. Tabieva ◽  
G. K. Uazyrkhanova
Keyword(s):  
Phase Composition ◽  
Steel Surface ◽  
Plasma Quenching

The structure, phase composition, and residual stresses of diffusion boride layers formed by thermal-chemical treatment on the die steel surface

2021 ◽  
Vol 23 (2) ◽  
pp. 147-162
Author(s):  
Undrakh Mishigdorzhiyn ◽  
◽  
Nikolay Ulakhanov ◽  
Aleksandr Tikhonov ◽  
Pavel Gulyashinov ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Low Temperature ◽  
Residual Stresses ◽  
Diffusion Layer ◽  
Chemical Treatment ◽  
Steel Surface ◽  
Boron Content ◽  
Die Steel ◽  
Temperature Mode

Introduction. Control and management of technological residual stresses (TRS) are among the most critical mechanical engineering technology tasks. Boriding can provide high physical and mechanical properties of machine parts and tools with minimal impact on the stress state in the surface layers. The purpose of this work is to determine the temperature modes of diffusion boriding, contributing to a favorable distribution of TRS in the surface layer of die steel 3Kh2V8F. The paper considers the results of studies on the TRS determination by the experimental method on the UDION-2 installation in diffusion layers on the studied steel surface. Boriding was carried out in containers with a powder mixture of boron carbide and sodium fluoride as an activator at a temperature of 950 °C and 1050 °C for 2 hours. The obtained samples of steels with a diffusion layer were examined using an optical microscope and a scanning electron microscope (SEM); determined the layers' microhardness, elemental, and phase composition. The experiments resulted in the following findings: as the boriding temperature rose from 950 °C to 1050 °C, the diffusion layer's thickness increased from 20 to 105 μm. The low-temperature mode of thermal-chemical treatment (TCT) led to the formation of iron boride Fe2B with a maximum boron content of 6 % and a microhardness up to 1250 HV. A high-temperature mode resulted in FeB formation with a top boron content of 11 % and a microhardness up to 1880 HV. Results and Discussions. It is found that boriding at 950 °C led to a more favorable distribution of compression TRS in the diffusion layer. However, significant TRS fluctuations in the diffusion layer and the adjacent (transitional) zone could affect the operational properties after TCT at a given temperature. An increase in the TCT temperature led to tensile TRS's appearance in the layer's upper zone at a depth of up to 50 μm from the surface. Despite tensile stresses on the diffusion layer surface after high-temperature TCT, the distribution of TCT is smoother than low-temperature boriding.

Surface Modification of High-Speed Steel by Plasma Nitriding

2014 ◽  
Vol 709 ◽  
pp. 403-409 ◽  
Author(s):  
Bauyrzhan K. Rakhadilov ◽  
Mazhyn Skakov ◽  
Erlan Batyrbekov ◽  
Michael Scheffler
Keyword(s):  
Surface Layer ◽  
Phase Composition ◽  
Diffusion Layer ◽  
High Speed ◽  
Steel Surface ◽  
Plasma Nitriding ◽  
High Speed Steel ◽  
R6m5 Steel ◽  
Modified Layer ◽  
Surface Modified

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.

scholarly journals EFFECT OF HIGH-INTENSITY ELECTRON-BEAM MACHINING ON THE STRUCTURE AND PHASE COMPOSITION OF STAINLESS STEEL SURFACE

2012 ◽  
Vol 55 (2) ◽  
pp. 57-59
Author(s):  
C. V. Gorbyunov ◽  
C. V. Vorob’ev ◽  
Yu. F. Ivanov ◽  
Yu. A. Kolubaeva ◽  
A. D. Terecov
Keyword(s):  
Stainless Steel ◽  
Electron Beam ◽  
Phase Composition ◽  
High Intensity ◽  
Steel Surface ◽  
Stainless Steel Surface

Microstructure and Property of Novel γ-Fe/ (Cr, Fe)7C3 Lamellar Eutectics Reinforced Composite Coating

2021 ◽  
Vol 871 ◽  
pp. 134-143
Author(s):  
Yin Hua Shi ◽  
Qin Shi
Keyword(s):  
Wear Resistance ◽  
Phase Composition ◽  
Composite Coating ◽  
Carbon Fibers ◽  
Steel Surface ◽  
Surface Hardness ◽  
Lamellar Eutectic ◽  
Reinforced Composite ◽  
Metallurgical Bonding ◽  
16Mn Steel

γ-Fe/(Cr, Fe)7C3 lamellar eutectics reinforced the composite coating was deposited onto the 16Mn steel surface to enhance its surface hardness and wear resistance. The microstructure, phase composition, microhardness as well as wear resistance of the cladding coating were explored. Results indicated that the coating showed the dense and defect-free metallurgical bonding with the substrate and mainly consisted of (Cr, Fe)7C3, γ-Fe/(Cr, Fe)7C3 lamellar eutectic, B4C and carbon fibers. (Cr, Fe)7C3, B4C and carbon fibers were tightly embedded in the γ-Fe/(Cr, Fe)7C3 lamellar eutectics matrix. The microhardness and wear resistance of the coating compared with that of the substrate were highly improved by nearly 5 and 3 times, respectively.

Modeling of the Phase Formation Processes on the Steel Surface Contacting with Water Medium under Conditions of Deep Geological Repository

2021 ◽  
Vol 20 ◽  
pp. 60-72
Author(s):  
О. М. Lavrynenko ◽  
◽  
B. G. Shabalin ◽  
◽  
Keyword(s):  
Phase Composition ◽  
Phase Formation ◽  
Steel Surface ◽  
Spinel Ferrite ◽  
Corrosion Products ◽  
Chemical Mechanism ◽  
Formation Processes ◽  
Deep Geological Repository ◽  
Iron Oxyhydroxides ◽  
Geological Repository

The experimental modeling of the corrosive phase formation processes was performed under conditions approaching the initial and transitional stages of evolution of the deep geological repository (the hydrogen index of the medium lied in the range of 9–12 and a temperature was 50–70 °C). The specificity of the system of rotating disk electrode made it possible to determine the phase composition of corrosion products formed under oxidative conditions (the near surface layer, NSL) and, conditionally, reductive — on the steel surface (SL) covered by NSL, that significantly complicated the access of oxygen into the reaction area. It was determined that phase composition of the corrosion products at the pH0 values 9–11 was identical and it is regulated by the compensative action of cathodic half-reaction of oxygen reducing on the steel surface. Green Rust and magnetite or non-stoichiometric spinel ferrite characterized by coagulative type of the structure and spherical particle shape were determined as the main phases of SL. Iron oxyhydroxides — goethite and lepidocrocite were presented as the phases of NSL. Increase in the pH0 to 12 changes the chemical mechanism of the corrosion process and it leads to the formation of weak crystallized iron oxyhydroxide phases. It was proved the main phase formed under corrosion of steel at 50–70 °C was spinel ferrite. Its morphology is presented as the cubic shaped particles that evidences about condensingcrystallizing mechanism of their formation. Generally, the presence of Co2+ and Mn2+ cations does not influence on the phase formation process and the phase composition as well, whereas the iron oxyhydroxides with admixture of Mn2+ and Mn3+ oxygen compounds are dominant in the sediment compositions when they are formed in the presence of Mn7+.

Phase Composition and Thin Structure of Steel Surface after Plasma Electrolytic Carbonitriding

2020 ◽  
Vol 62 (10) ◽  
pp. 1794-1800
Author(s):  
N. A. Popova ◽  
A. I. Potekaev ◽  
E. L. Nikonenko ◽  
A. A. Klopotov ◽  
L. B. Bayatanova ◽  
...  
Keyword(s):  
Phase Composition ◽  
Steel Surface ◽  
Thin Structure ◽  
Plasma Electrolytic

Plasma immersion N and N+C implantation into high-speed tool steel: surface morphology, phase composition and mechanical properties

2001 ◽  
Vol 142-144 ◽  
pp. 406-411 ◽  
Author(s):  
V.V Uglov ◽  
V.M Anishchik ◽  
A.K Kuleshov ◽  
J.A Fedotova ◽  
N.T Kvasov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Surface Morphology ◽  
Tool Steel ◽  
High Speed ◽  
Steel Surface

scholarly journals Microstructure and Chemical Composition of Fe-Cr Alloy Tempered in High Temperature and Atmosphere Containing Ar-SO2

2016 ◽  
Vol 61 (3) ◽  
pp. 1607-1612 ◽  
Author(s):  
A. Radziszewska ◽  
A. Kranzmann ◽  
I. Dörfel ◽  
M. Mosquera Feijoo ◽  
M. Solecka
Keyword(s):  
Stainless Steel ◽  
Phase Composition ◽  
High Temperature ◽  
Chemical Composition ◽  
Steel Surface ◽  
High Temperature Corrosion ◽  
Corrosion Process ◽  
Gas Atmosphere ◽  
Amorphous Zone ◽  
Scale Surface

AbstractThe paper presents the microstructure, chemical and phase composition of thin scale, obtained as a result of high-temperature corrosion of X20Cr13 stainless steel. Samples were exposed to gas atmosphere of the following composition: 0.25 vol.% of SO2and 99.75 vol.% of Ar at 600 °C for 5 h. As a consequence, thin compact scale was formed on steel surface. This scale consisted of three different zones. An amorphous zone was formed close to steel surface. Then, nanocrystalline zone could be observed. Finally, larger grains were formed during the corrosion process. The analysis of the chemical composition revealed higher concentration of chromium near steel surface. In contrast, to chromium, the content of iron, increased near the scale surface. It was found out that the (Cr, Mn, Fe)5O12phase appeared in the thin scale.

scholarly journals Selective Oxidation during the Austenitic Annealing of a CMnSi Steel

2006 ◽  
Vol 15-17 ◽  
pp. 129-134 ◽  
Author(s):  
Tom van de Putte ◽  
Zinedine Zermout ◽  
Didier Loison ◽  
Serge Claessens ◽  
Jan Penning
Keyword(s):  
Phase Composition ◽  
Water Vapour ◽  
Selective Oxidation ◽  
Steel Surface ◽  
High Strength ◽  
Surface Region ◽  
Protective Atmosphere ◽  
Major Influence ◽  
Residual Water ◽  
Passenger Cars

High strength multiphase CMnSi steel is increasingly used in passenger cars. Si and Mn alloying levels are typically in the range of 1-2% in mass. While Si improves the mechanical properties, it considerably deteriorates the galvanisability of steel. Residual water vapour in the reducing gas atmosphere during the intercritical or austenitic annealing results in the selective oxidation of Si and Mn at the steel surface. Besides Mn and Si, C is oxidized as well at the steel surface, leading to the formation of CO gas and decarburisation of the steel surface. This decarburisation has a major influence on the phase composition in the steel surface region: it shifts the ferrite to austenite transformation to higher annealing temperatures, leading to differences in surface and bulk microstructure. The phase composition influences the solubility and diffusivity of all alloying elements near the surface. The evolution with temperature of the selective oxidation at the steel surface has been studied by interrupted annealing in a protective atmosphere containing residual water vapour. The influence of the annealing temperature on the selective oxidation of Mn and Si is characterized by XPS (X-ray Photo-electron Spectroscopy) analysis.

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