scholarly journals ПІДВИЩЕННЯ СТРУКТУРНОЇ СТАБІЛЬНОСТІ ТА ВЛАСТИВОСТЕЙ ЖАРОМІЦНИХ НІКЕЛЕВИХ СПЛАВІВ ДЛЯ ЛОПАТОК ГТД ОБРОБКОЮ НАНОМАТЕРІАЛАМИ

2018 ◽  
pp. 60-65
Author(s):  
Марина Викторовна Грекова ◽  
Наталия Евграфовна Калинина ◽  
Василий Тимофеевич Калинин ◽  
Михаил Васильевич Гученков ◽  
Евгений Алексеевич Джур ◽  
...  
Keyword(s):  
Heat Resistance ◽  
Nickel Alloys ◽  
Titanium Carbonitride ◽  
Coarse Grained ◽  
Low Alloy Steels ◽  
Initial State ◽  
The Matrix ◽  
Alloy Steels ◽  
Analytical Review ◽  
The Impact

An analytical review of existing views on the problem of increasing the heat resistance, heat resistance, and durability of high-temperature nickel alloys of the ZhC3 group of blades of gas turbine engines is carried out. The effect of alloying elements of alloys on structural transformations, types of hardening and corrosion resistance is analyzed. A complex powder modifier based on titanium carbonitride Ti (CN) is proposed for processing nickel melts. The choice of nanodispersed Ti (CN) carbonitride powders of a fraction of less than 100 nm as modifiers of low-alloy steels is substantiated. It has been established that Ti (CN) titanium carbonitride particles have a face-centered crystal lattice. The necessary criteria for the selection of nanopowder modifiers have been obtained: insolubility in the melt, correspondence of crystal lattices with the matrix of steel, proportionality with the critical radius of the austenite embryo during crystallization. A mechanism for the interaction of a steel melt with a layer of a nanodisperse composition is established. The macro- and microstructure of nickel alloys ZhC3, ZhC3DK was investigated. An analysis of microdiffraction patterns of particles is carried out, the nanopowders are shown to belong to solid crystalline bodies with a metallic bond. The coarse-grained and low-plastic matrix of the nickel alloy is under the influence of a large local loading, which contributes to the premature cracking of grain boundaries. Modification leads to significant changes in the structure of the alloy ZhC3 in comparison with the unmodified state. The structure of ZhC3 after modification is homogeneous, fine-grained. In modified samples, the grinding of grain was achieved 3 ... 5 times and the structure was stabilized in comparison with the initial state. Mechanical studies of samples in a modified state showed an increase in all parameters: tensile strength by 10 %; yield strength - by 13 %; the elongation by 20 % and the impact strength by 40 % compared to the original samples. Tests of samples for heat resistance showed a decrease in the depth of corrosion at a temperature of 1000 °C in the modified state on average by 25 %, which confirms the effect of modifying the alloys with nanodispersed modifiers.

The critical influence of La content on the microstructure-toughness relationship in the simulated coarse-grained heat-affected zone of high-strength low-alloy steels

2021 ◽  
Vol 118 (2) ◽  
pp. 212
Author(s):  
Yuxin Cao ◽  
Xiangliang Wan ◽  
Feng Zhou ◽  
Hangyu Dong ◽  
Kaiming Wu ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Acicular Ferrite ◽  
High Strength ◽  
Coarse Grained ◽  
Low Alloy Steels ◽  
Fine Grained ◽  
Welding Thermal Cycle ◽  
Alloy Steels ◽  
High Fraction ◽  
The Impact

The present study was envisaged to investigate the role of La content on the particle, microstructure and toughness in the simulated coarse-grained heat-affected zone (CGHAZ) of high-strength low-alloy steels. Three steels with La content of 0.016 wt.%, 0.046 wt.% and 0.093 wt.% were prepared and simulated in a 100 kJ/cm heat input welding thermal cycle. Subsequently, the particle and microstructure of selected specimens were characterized and the impact absorb energy was measured at −20 °C. The results indicated that the La2O2S inclusions in 0.016 wt.%-La steel were gradually modified to LaS-LaP in 0.046 wt.%-La steel and to LaP in 0.093 wt.%-La steel. A higher fraction of acicular ferrite was obtained in the simulated CGHAZ of 0.016 wt.%-La steel, since the inclusion of La2O2S was more powerful to induce the formation of acicular ferrite. Furthermore, the fraction of M-A constituents in the simulated CGHAZ increased with increasing La content. The impact toughness in the simulated CGHAZ of 0.016 wt.%-La steel was the highest, owing to the high fraction of the fine-grained acicular ferrite and low fraction of M-A constituent.

scholarly journals Effect of Ce Content on Microstructure-Toughness Relationship in the Simulated Coarse-Grained Heat-Affected Zone of High-Strength Low-Alloy Steels

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2003
Author(s):  
Yuxin Cao ◽  
Xiangliang Wan ◽  
Feng Zhou ◽  
Yong Wang ◽  
Xinbin Liu ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Energy Levels ◽  
High Strength ◽  
Coarse Grained ◽  
Low Alloy Steels ◽  
Moderate Degree ◽  
Treated Steel ◽  
Alloy Steels ◽  
The Impact ◽  
Ce Content

The study aimed to identify a moderate degree of Ce addition to improve the toughness in the simulated coarse-grained heat-affected zone (CGHAZ) of high-strength low-alloy steels, based on the effect of the Ce content on particle characteristics, microstructure and impact toughness. Three steels with 0.012 wt.%, 0.050 wt.% and 0.086 wt.% Ce content were subjected to 100 kJ/cm heat input in their thermal welding cycles. The particles and microstructures in the simulated CGHAZ of each steel were characterized and the impact-absorbance energy levels were measured at −20 °C. The results indicated that Ce2O2S inclusion compounds were gradually modified to CexSy-CeP and CeP with the increasing of the Ce content. A higher fraction of acicular ferrite was formed in the 0.012 wt.%-Ce-treated steel due to the lower mismatch between Ce2O2S and α-Fe. Furthermore, a lower fraction of M-A constituent was obtained in the 0.012 wt.%-Ce-treated steel. As a result, superior toughness and a typical amount of ductile fracture were detected in the simulated CGHAZ of the 0.012 wt.%-Ce-treated steel. Compared with the 0.012 wt.%-Ce-treated steel, a smaller prior austenite grain was observed in the 0.086 wt.%-Ce-treated steel because of the segregation of CeP at the grain boundary. However, the larger size and density of CeP led to poor toughness in the CGHAZ of the 0.086 wt.%-Ce-treated steel.

Study of hydrogenation and corrosion of steel equipment and pipelines at the production facilities of H2S -containing hydrocarbon raw materials

2021 ◽  
pp. 170-181
Author(s):  
R. K. Vagapov
Keyword(s):  
Raw Materials ◽  
Strength Properties ◽  
Point Of View ◽  
Low Alloy Steels ◽  
Safety And Reliability ◽  
Alloy Steels ◽  
Steel Equipment ◽  
Equipment And Pipelines ◽  
Corrosion Of Steel ◽  
The Impact

The impact of hydrogen sulfide raw materials on steel equipment and pipelines is associated not only with corrosion processes, but also with the hydrogenation of used carbon and low-alloy steels. This can lead to the loss of their strength properties and the subsequent destruction of equipment operated under conditions of increased operating pressures. Such corrosive-mechanical effects associated with the penetration of hydrogen into steel are the most dangerous from the point of view of the safety and reliability of the operation of facilities for the production of hydrocarbon fluids. The effect of H2S on the main types of structural steels was investigated according to the results of autoclave tests. The formation of blistering (blistering) and cracks on the surface of steels due to the effect of hydrogen on the steel was recorded. A study of the phase composition of corrosion products and their possible effect on the processes of corrosion and hydrogenation of steel has been carried out.

Digital technologies in detecting inhomogeneous concentration zones in heat-resistant nickel alloys structure, including those obtained by selective laser melting

2021 ◽  
pp. 32-47
Author(s):  
A. N. Raevskikh
Keyword(s):  
Nickel Alloys ◽  
Integrated Approach ◽  
Thermal Study ◽  
Resistant Material ◽  
Initial State ◽  
Electron Microscopic ◽  
Heat Resistant ◽  
Heat Resistant Material ◽  
Nickel Base ◽  
The Impact

This work presents the experimental data obtained using an integrated approach in the study of the chemical, crystallographic and morphological homogeneity of the structure of a heat-resistant material on a nickel base with carbide-intermetallic hardening and an increased content of the γ-phase, synthesized on single-crystal substrates of various compositions with CHO <001> in Z-direction. Using the proposed method for studying the capabilities and certification of different-level structural structures of samples in the initial state and after thermal study of the impact. The analysis was carried out using the system for EBSD analysis integrated into the scanning electron microscope and the software package for the analysis of electron microscopic images. 

Effects of titanium content on the impact wear properties of high-strength low-alloy steels

Wear ◽  
2021 ◽  
pp. 203647
Author(s):  
Shuying Li ◽  
Hao Yu ◽  
Yuan Lu ◽  
Jun Lu ◽  
Wenchao Wang ◽  
...  
Keyword(s):  
High Strength ◽  
Titanium Content ◽  
Low Alloy Steels ◽  
Impact Wear ◽  
Wear Properties ◽  
Alloy Steels ◽  
The Impact

Impact of Mo content on the microstructure– toughness relationship in the coarse-grained heat-affected zone of high-strength low-alloy steels

2021 ◽  
Vol 112 (2) ◽  
pp. 98-107
Author(s):  
Yuxin Cao ◽  
Xiangliang Wan ◽  
Feng Zhou ◽  
Yu Shen ◽  
Yu Liu ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Prior Austenite ◽  
High Strength ◽  
Coarse Grained ◽  
Low Alloy Steels ◽  
Austenite Grain ◽  
Alloy Steels ◽  
Mo Content ◽  
Grain Boundary Pinning ◽  
Prior Austenite Grain

Abstract The present study elucidates the influence of Mo content on the microstructure – toughness relationship in the coarsegrained heat-affected zone of high-strength low-alloy steels. The low-Mo and high-Mo steels were subjected to 100 kJ cm–1 heat input welding thermal cycling. The results indicated that (Ti,Mo)-carbonitrides were formed in high-Mo steel, whereas (Ti,Nb)-carbonitrides were formed in low-Mo steel. The finer and dispersed precipitates in high-Mo steel refined the prior austenite grain in the coarse-grained heat-affected zone based on the grain boundary pinning effect. However, the smaller prior austenite grain and excessive Mo content induced the formation of an entirely bainitic microstructure in high-Mo steel. Furthermore, a higher fraction of martensite –austenite constituents was observed in high-Mo steel. These results could be responsible for the deterioration of the toughness in the coarse-grained heat-affected zone of high-Mo steel.

scholarly journals The Effect of Electrochemical Composite Coatings with LaF3-LaB6 Particles in Nickel–Copper Matrix on the Metallurgical Processes in Arc Welding of Low Alloy Ferrite-Pearlite Steels

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1509
Author(s):  
Sergey G. Parshin ◽  
Victor A. Karkhin ◽  
Peter Mayr ◽  
Alexey S. Maystro
Keyword(s):  
Weld Pool ◽  
Composite Coatings ◽  
Copper Matrix ◽  
Low Alloy Steels ◽  
Electrostatic Deposition ◽  
Insoluble Particles ◽  
Promising Area ◽  
Alloy Steels ◽  
The Impact ◽  
Metallurgical Processes

Development of welding consumables with fluorides and borides of rare earth metals is a promising area for improving the weldability of low alloy steels. As lanthanum fluoride and boride dissociate, lanthanum and boron dissolve in the weld pool and the welding arc plasma is saturated with fluorine. As a result of FeO, MnO, SiO2 deoxidation and FeS, MnS desulfurization, refractory lanthanum sulfides and oxides La2O3, La2S3 are formed in the weld pool, which can be the crystallization nuclei in the weld pool and the origin of acicular ferrite nucleation. The paper proposes a model of metallurgical processes in the arc and weld pool, as well as a model of electrochemical adsorption of Ni2+ cations in colloidal electrolytes during electrostatic deposition of nano-dispersed insoluble particles of LaF3 or LaB6 on the surface of wire. The paper discusses the constructional design of the welding wire and the technology for forming electrochemical composite coatings with copper and nickel matrix. The composite wires applied in the welding of low alloy steels make it possible to refine the microstructure, increase the tensile strength by 4% and the impact toughness of welds by 20%.

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