scholarly journals Comparative Analysis of Laser and Plasma Surfacing by Nickel-Based Superalloy of Heat Resistant Steel

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2367 ◽  
Author(s):  
Artur Czupryński ◽  
Bernard Wyględacz
Keyword(s):  
High Temperature ◽  
Iron Content ◽  
Heat Dissipation ◽  
Dendritic Structure ◽  
Parameters Optimization ◽  
Inconel 625 ◽  
High Quality ◽  
Nickel Based Superalloy ◽  
Outer Area

In this article, the results of surfacing technology development, and structural, and mechanical properties examinations of 16Mo3 steel pipes with an outside coating of Inconel 625 deposited by automated plasma powder transferred arc (PPTA) and automated high power direct diode laser (HPDDL) surfacing were presented. Based on the results of non-destructive, metallographical macro- and microscopic, chemical composition, and thickness and hardness examinations optimal technology for use in high temperature energy or chemical industry applications was selected. The examinations conducted for each of the aforementioned technologies revealed the proper structure and high quality of coating. Dendritic structure with primary crystals growing in the direction of heat dissipation was revealed. No defects such as cracks, lack of fusion or porosity were found. Iron content in the most outer area of the layer made by PPTA with a heat input of 277–514 J/mm, thickness from 1.2 to 1.7 mm, between 4% and 5.5% was observed. Iron content in the most outer area of the layer made by HPDDL surfacing with output power of 1000–1600 W and scanning speed 3.3–4.7mm/s, from 0.6 to 1.3 mm in thickness, between 5.1% and 7.5% was observed. In coated pipes made by either technology high quality of surfaced layers, conforming to requirements posed on protective layers manufactured for prolonged exploitation in temperatures up to 625 °C, were observed. High temperature resistance examinations are the focus of further, yet unpublished, research. The obtained results point to slight differences in the parameters and properties of nickel-based superalloy layers surfaced on 16Mo3 pipes based on the technologies used. However, the process parameters optimization in the case of PPTA was simpler compared to HPDDL surfacing.

scholarly journals Investigation of the Heteroepitaxial Process Optimization of Ge Layers on Si (001) by RPCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 928
Author(s):  
Yong Du ◽  
Zhenzhen Kong ◽  
Muhammet Toprak ◽  
Guilei Wang ◽  
Yuanhao Miao ◽  
...  
Keyword(s):  
High Temperature ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Crystalline Quality ◽  
Initial Growth ◽  
Two Dimensional ◽  
High Quality ◽  
Reduced Pressure

This work presents the growth of high-quality Ge epilayers on Si (001) substrates using a reduced pressure chemical vapor deposition (RPCVD) chamber. Based on the initial nucleation, a low temperature high temperature (LT-HT) two-step approach, we systematically investigate the nucleation time and surface topography, influence of a LT-Ge buffer layer thickness, a HT-Ge growth temperature, layer thickness, and high temperature thermal treatment on the morphological and crystalline quality of the Ge epilayers. It is also a unique study in the initial growth of Ge epitaxy; the start point of the experiments includes Stranski–Krastanov mode in which the Ge wet layer is initially formed and later the growth is developed to form nuclides. Afterwards, a two-dimensional Ge layer is formed from the coalescing of the nuclides. The evolution of the strain from the beginning stage of the growth up to the full Ge layer has been investigated. Material characterization results show that Ge epilayer with 400 nm LT-Ge buffer layer features at least the root mean square (RMS) value and it’s threading dislocation density (TDD) decreases by a factor of 2. In view of the 400 nm LT-Ge buffer layer, the 1000 nm Ge epilayer with HT-Ge growth temperature of 650 °C showed the best material quality, which is conducive to the merging of the crystals into a connected structure eventually forming a continuous and two-dimensional film. After increasing the thickness of Ge layer from 900 nm to 2000 nm, Ge surface roughness decreased first and then increased slowly (the RMS value for 1400 nm Ge layer was 0.81 nm). Finally, a high-temperature annealing process was carried out and high-quality Ge layer was obtained (TDD=2.78 × 107 cm−2). In addition, room temperature strong photoluminescence (PL) peak intensity and narrow full width at half maximum (11 meV) spectra further confirm the high crystalline quality of the Ge layer manufactured by this optimized process. This work highlights the inducing, increasing, and relaxing of the strain in the Ge buffer and the signature of the defect formation.

scholarly journals Dendritic Structure Analysis of CMSX-4 Cored Turbine Blades Roots

2016 ◽  
Vol 61 (2) ◽  
pp. 1129-1134 ◽  
Author(s):  
J. Krawczyk
Keyword(s):  
Single Crystal ◽  
Cross Sections ◽  
Induction Furnace ◽  
Turbine Blades ◽  
Dendritic Structure ◽  
Root Structure ◽  
Sem Images ◽  
X Ray ◽  
Nickel Based Superalloy

Abstract The microstructure of as-cast cored turbine blades roots, made of the single-crystal CMSX-4 nickel-based superalloy was investigated. Analysed blades were obtained by directional solidification technique in the industrial ALD Bridgman induction furnace. The investigations of the microstructure of blades roots were performed using SEM and X-ray techniques including diffraction topography with the use of Auleytner method. Characteristic shapes of dendrites with various arrangement were observed on the SEM images taken from the cross-sections, made transversely to the main blades axis. The differences in quality of the structure in particular areas of blades roots were revealed. Based on the results, the influence of cooling bores on blades root structure was analysed and the changes in the distribution and geometry of cooling bores were proposed.

Refractory equipment for firing aluminum nitride substrates

2020 ◽  
pp. 7-9
Author(s):  
Yu. K. Nepochatov ◽  
P. M. Pletnev ◽  
A. A. Denisova
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
The Body ◽  
Special Design ◽  
High Quality ◽  
Reducing Environment ◽  
Recovery Medium

The features of firing aluminitride substrates, characterized by a high temperature of more than 1800 0С and the presence of a reducing environment, are described. It is shown that the high quality of substrates in parallelism, thermal conductivity, and other properties can be achieved, along with the establishment of optimal firing modes, using a special design of a capsule based on boron nitride, which is a container that consists of a body - a box of rectangular cross section, bottom and plane-parallel dividing plates with supports. To create a local (inside the capsule) clean recovery medium, thorn-groove interlocks between the body and the bottom are provided, filled with a heat-resistant inert powder.

An Investigation of Heat Affected Zone of Round Steel Rods Welded by Friction Welding

2012 ◽  
Vol 217-219 ◽  
pp. 2198-2201
Author(s):  
Chawalit Thinvongpituk ◽  
Surasing Arayangkun
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Heat Affected Zone ◽  
Friction Welding ◽  
Welding Process ◽  
High Strength ◽  
High Quality ◽  
Joint Property ◽  
Welding Technique

Friction welding is a welding technique that has been studied and developed continuously. This is due to its advantages, such as it provides high quality of joint, high strength of joint. It can make welded zone through the whole section without bubble. However, there is heat generated in the welding process that can change the phase of materials. Hence, the hardness and strength of joint are affected. This paper is aimed to investigate the microstructure at the joint, which is called heat affected zone. The experiment was conducted with a number of steel rods of 10 mm. diameter. The welded specimens were tested for strength, hardness and microstructure. The temperature gradient of specimen under welding process was also recorded. It was revealed that the strength of welded element is higher but the hardness is lower. The photo of thermo scan revealed that heat is generated around the lip of interface, resulting high temperature in heat affected zone. This causes some change in microstructure composition as well as joint property.

scholarly journals Mechanical and Microstructural Characterization of Arc-Welded Inconel 625 Alloy

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3690
Author(s):  
Daniel Kotzem ◽  
Lucas Beermann ◽  
Mustafa Awd ◽  
Frank Walther
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Dendritic Structure ◽  
Microstructural Characterization ◽  
Industrial Applications ◽  
High Yield ◽  
Inconel 625 ◽  
Compression Tests ◽  
Static Compression ◽  
Aerospace Material

The objective of this work was to verify a relatively new fusion-based additive manufacturing (AM) process to produce a high-temperature aerospace material. The nickel-based superalloy Inconel 625 (IN625) was manufactured by an arc-based AM technique. Regarding microstructure, typical columnar-oriented dendritic structure along the building direction was present, and epitaxial growth was visible. The mechanical behavior was characterized by a combination of quasi-static tensile and compression tests, whereas IN625 showed high yield and ultimate tensile strength with a maximum fracture strain of almost 68%. Even quasi-static compression tests at room and elevated temperatures (650 °C) showed that compression strength only slightly decreased with increasing temperature, demonstrating the good high-temperature properties of IN625 and opening new possibilities for the implementation of arc-based IN625 in future industrial applications.

scholarly journals Analysis of fluid inclusions in vein quartz of the Fenkina-Lampi deposit by gas chromatography

2019 ◽  
Author(s):  
Евгения Светова ◽  
Светлана Шанина
Keyword(s):  
Gas Chromatography ◽  
High Temperature ◽  
Low Temperature ◽  
Fluid Inclusions ◽  
Glass Melting ◽  
Raw Material ◽  
High Temperature Region ◽  
Vein Quartz ◽  
High Quality

The composition and content of fluid inclusions in the main structural and technological types of vein quartz of the Fenkina-Lampi deposit were studied by gas chromatography. It is shown that H2O dominates (90–99%) in the gases composition released from quartz under heating to 1000°C, CO2, CO, N2 and hydrocarbon compounds contents are much less. Quartz is characterized by high gassing in the high-temperature region (600–1000°C) comparable to gassing in the low-temperature interval (100–600°C), which is a negative indicator of the quality of quartz as a raw material for high-quality glass melting. It is necessary to develop a special purification technology for this quartz, which will take into account the features of its saturation with gas-liquid inclusions.

Influence of technology parameters of free-cutting steel continuous casting on the billet internal structure

2020 ◽  
Vol 76 (2) ◽  
pp. 139-142
Author(s):  
A. T. Kunakbaeva ◽  
A. M. Stolyarov ◽  
M. V. Potapova
Keyword(s):  
Regression Analysis ◽  
Continuous Casting ◽  
Internal Structure ◽  
Sulfur Content ◽  
Manganese Content ◽  
High Quality ◽  
Correlation And Regression Analysis ◽  
Cutting Steel ◽  
Continuously Cast

Free-cutting steel gains specific working properties thanks to the high content of sulfur and phosphorus. These elements, especially sulfur, have a rather high tendency to segregation. Therefore, segregation defects in free-cutting steel continuously cast billets can be significantly developed. The aim of the work was to study the influence of the chemical composition of freecutting steel and casting technological parameters on the quality of the macrostructure of continuously cast billets. A metallographic assessment of the internal structure of cast metal made of free-cutting steel and data processing by application of correlation and regression analysis were the research methods. The array of production data of 43 heats of free-cutting steel of grade A12 was studied. Steel casting on a five-strand radial type continuous casting machine was carried out by various methods of metal pouring from tundish into the molds. Metal of 19 heats was poured with an open stream, and 24 heats – by a closed stream through submerged nozzles with a vertical hole. High-quality billets had a cross-sectional size of 150×150 mm. The macrostructure of high-quality square billets made of free-cutting steel of A12 grade is characterized by the presence of central porosity, axial segregation and peripheral point contamination, the degree of development of which was in the range from 1.5 to 2.0 points, segregation cracks and strips – about 1.0 points. In the course of casting with an open stream, almost all of these defects are more developed comparing with the casting by a closed stream. As a result of correlation and regression analysis, linear dependences of the development degree of segregation cracks and strips both axial and angular on the sulfur content in steel and on the ratio of manganese content to sulfur content were established. The degree of these defects development increases with growing of sulfur content in steel of A12 grade. These defects had especially strong development when sulfur content in steel was of more than 0.10%. To improve the quality of cast metal, it is necessary to have the ratio of the manganese content to the sulfur content in the metal more than eight.

Experience of clinical testing of personal telemedicine system ‘Obereg’ for remote monitoring of patients in intensive care units

2020 ◽  
pp. 52-58 ◽  
Author(s):  
A. A. Eryomenko ◽  
N. V. Rostunova ◽  
S. A. Budagyan ◽  
V. V. Stets
Keyword(s):  
Intensive Care ◽  
Intensive Care Units ◽  
Remote Monitoring ◽  
Clinical Testing ◽  
Transportation Of Patients ◽  
High Quality ◽  
Telemedicine System ◽  
Accuracy Of Measurements ◽  
Hospital Equipment

The experience of clinical testing of the personal telemedicine system ‘Obereg’ for remote monitoring of patients at the intensive care units of leading Russian clinics is described. The high quality of communication with the remote receiving devices of doctors, the accuracy of measurements, resistance to interference from various hospital equipment and the absence of its own impact on such equipment were confirmed. There are significant advantages compared to stationary patient monitors, in particular, for intra and out-of-hospital transportation of patients.

INFLUENCE OF FORCED CONVECTION IN LIQUID INSIDE THE TIN ON DURATION OF STERILIZATION IN THE COURSE OF FISH PROCESSING

2017 ◽  
pp. 137-144
Author(s):  
Gennadiy Valentinovich Alexeev ◽  
Elena Igorevna Verboloz
Keyword(s):  
High Temperature ◽  
Liquid Phase ◽  
Forced Convection ◽  
Thermal Process ◽  
Processing Time ◽  
Fish Processing ◽  
Study Results ◽  
Equipment Modernization ◽  
Bottom To Top

The article focuses on the process of intensive mixing of liquid phase in the tin during high-temperature sterilization, i.e. sterilization when temperature of the heat carrier reaches 150-160°C. It has been stated that for intensification of the thermal process during sterilization of tinned fish with liquid filling it is preferable to turn a tin from bottom to top. This operation helps to increase the driving power of the process and to shorten warming time. Besides, high-temperature sterilization carried out according to experimental modes, where the number of tin turnovers is calculated, greatly shortens processing time and improves quality of the product. In this case there is no superheating, all tins are evenly heated. The study results will contribute to equipment modernization and to preserving valuable food qualities.

METHODOLOGICAL ASPECTS OF VISUALIZATION OF CORONARY ARTERIES WITH TRANSTHORACIC ECHOCARDIOGRAPHY

2018 ◽  
pp. 26-35
Author(s):  
Z. A. Agaeva ◽  
K. B. Baghdasaryan
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Coronary Arteries ◽  
Transthoracic Echocardiography ◽  
Second Harmonic ◽  
Anatomic Reconstruction ◽  
High Quality ◽  
Acoustic Window ◽  
Methodological Aspects

The transthoracic echocardiography made by multifrequency probes with support of the mode of the second harmonic imaging, is a competitive method for visualization of the main coronary arteries and allows to estimate coronary blood flow with high quality. Of course, the method has considerable restrictions, most important of which is the low spatial resolution of a method, due to small acoustic window. Because of this the transthoracic visualization of coronary arteries perhaps will not become the leading method of anatomic reconstruction of separately taken coronary artery and especially all coronary arteries system. However uniqueness and indisputable advantage of this method is an opportunity to noninvasively estimate a coronary blood flow both once, and in dynamics.

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