scholarly journals Investigations of surface layer temperature and morphology of hard machinable materials used in aircraft industry during abrasive electrodischarge grinding process

2018 ◽  
Vol 49 (5) ◽  
pp. 568-576 ◽  
Author(s):  
M. Gołąbczak ◽  
R. Święcik ◽  
A. Gołąbczak ◽  
C. Nouveau ◽  
P. Jacquet ◽  
...  
Keyword(s):  
Surface Layer ◽  
Grinding Process ◽  
Aircraft Industry ◽  
Materials Used ◽  
Surface Layer Temperature

Ultrajet Mesodiagnostic Probabilistic Model for Surface Layer’s Variable Defectiveness of Complex Technology Products

2021 ◽  
Vol 882 ◽  
pp. 289-295
Author(s):  
Andrey Leonidovich Galinovskiy ◽  
Aleksandr Aleksandrovich Barzov ◽  
Mary Alekseevna Prokhorova
Keyword(s):  
Surface Layer ◽  
Sufficient Conditions ◽  
Calculated Data ◽  
Hydrodynamic Effect ◽  
Topographic Features ◽  
Technology Products ◽  
Complex Technology ◽  
Materials Used ◽  
Necessary And Sufficient

Technologically, ultrajet mesodiagnostics (UJM) consists of local hydroerosive indentation by ultrajets (UJ) of water on the surface of the analyzed object (OA) and the subsequent study of the results of this minimally invasive microdestructive effect on its surface layer. Obviously, mathematical models’ construction of the functional relationship between the informative-physical signs of hydroerosive UJ destruction and the surface layer’s state parameters of various OA, primarily their defectiveness, is very important for the development of this potentially promising technology for ensuring the quality of critical products, mainly aviation and other industries. In this regard, the work proposes a probabilistic UJM model, which consists of analyzing the kinetics of the formation of an aggregate set of eroded particles, as a process caused by a combination of appropriate necessary and sufficient conditions for its implementation. The former include the topographic features of the microdefectiveness’ characteristics of the surface layer material, and the latter consist of a certain variational-force hydrodynamic effect of the diagnostic UJ on it. This approach made it possible to obtain calculated data related to probabilistic distribution of the UJ-eroded particles’ sizes of hypothetical OA, as a coordinate function describing the microdefects’ concentration in its surface layer. These functions are close to the available results of experimental UJM of typical and promising materials used in the manufacture of machinery technology.

Plastic Deformation of Nanometric Grinding Process for FCC Metal

2010 ◽  
Vol 154-155 ◽  
pp. 1336-1341
Author(s):  
Wei Wen Zhang ◽  
Gang Guo ◽  
Yun Huang ◽  
Zhi Huang
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Grinding Process ◽  
Face Centered Cubic ◽  
Grinding Processes ◽  
Cubic Structure ◽  
Simulation Results ◽  
Face Centered ◽  
Dislocation Defects ◽  
Fcc Metal

This paper focuses on the simulations of nanometric grinding process on face centered cubic structure (FCC) single metal crystals (Cu, Ni) using Molecular dynamics. In order to analyze the plastic deformation of sample metals in nanometric grinding processes, we propose an approach using techniques of central symmetry parameters and neighbor changing ratios. The simulation results show that besides the normal dislocation defects, weak slipping defects locating on {111} crystal planes are found under the surface layer. In addition, the distribution of the neighbor changing ratio indicates that the nano grinding processes will likely cause the global plastic deformation in the surface layer.

An Analytical Study of Energy Partition in Grinding

2016 ◽  
Vol 686 ◽  
pp. 80-85 ◽  
Author(s):  
Marin Gostimirović ◽  
Vladimir Pucovsky ◽  
Pavel Kovač ◽  
Milenko Sekulić ◽  
Borislav Savković
Keyword(s):  
Surface Layer ◽  
Analytical Study ◽  
Past Research ◽  
Efficient Production ◽  
Grinding Process ◽  
Heat Distribution ◽  
Distribution Factor ◽  
Energy Partition ◽  
Workpiece Material ◽  
Mechanical Parts

This paper indicates the occurrence of high thermal energy in the surface layer of workpiece material during the process of grinding. To help identify the share of heat which affects the workpiece, firstly the analysis of past research in the field of heat transfer during grinding was conducted. Further there is a proposition of analytical expression for heat distribution factor to the workpiece in the grinding process. Goal of this analytical dependence is to achieve more efficient production of mechanical parts without thermal defects in the surface layer of the part. Presented equation for energy partition has a characteristic of widespread practical use.

Measuring the surface-layer temperature of rolling-mill rolls

1969 ◽  
Vol 12 (11) ◽  
pp. 1575-1576
Author(s):  
A. A. Zgura ◽  
V. F. Frolov ◽  
N. N. Oksamitnyi
Keyword(s):  
Surface Layer ◽  
Rolling Mill ◽  
Surface Layer Temperature

scholarly journals Surface layer temperature inversion in the Bay of Bengal: Main characteristics and related mechanisms

2016 ◽  
Vol 121 (8) ◽  
pp. 5682-5696 ◽  
Author(s):  
Pankajakshan Thadathil ◽  
I. Suresh ◽  
S. Gautham ◽  
S. Prasanna Kumar ◽  
Matthieu Lengaigne ◽  
...  
Keyword(s):  
Surface Layer ◽  
Bay Of Bengal ◽  
Temperature Inversion ◽  
Surface Layer Temperature

scholarly journals INFLUENCE OF THE GEOMETRIC CHARACTERISTICS OF THE DISCONTINUOUS PROFILE WORKING SURFACES OF ABRASIVE WHEELS FOR PRECISION AND TEMPERATURE WHEN GRINDING

2021 ◽  
pp. 115-125
Author(s):  
Oleksiy Yakimov ◽  
Liubov Bovnegra ◽  
Vladimir Tonkonogyi ◽  
Vladyslav Vaysman ◽  
Victor Strelbitskyi ◽  
...  
Keyword(s):  
Surface Layer ◽  
Heat Stress ◽  
Elastic System ◽  
Dynamic Interaction ◽  
Grinding Wheel ◽  
Stable Operation ◽  
Grinding Process ◽  
Abrasive Wheel ◽  
Working Surface

Grinding is the most common finishing method for hardened steel parts. Grinding is accompanied by a large heat release in the cutting area, under the influence of which structural changes appear in the thin surface of the processed parts, tensile stress and even microcracks, which significantly reduce the operational reliability of machines that include these parts. The use of abrasive wheels with an intermittent working surface makes it possible to reduce the temperature in the area of contact of abrasive grains with the material of the workpiece and, as a consequence, stabilize the quality of the surface layer of the workpieces. High-frequency vibrations in the elastic system of the machine, accompanying the work of an intermittent wheel, are a positive factor that reduces the energy consumption of the grinding process. However, under certain conditions of dynamic interaction of the tool with the workpiece, parametric resonance may occur, which worsens the geometric and physical-mechanical parameters of the quality of the surface layer of the processed part. The aim of the work is to realize the possibility of predicting the quality parameters of the surface layer of parts during intermittent grinding by studying the influence of the design features of the macrotopography of the working surface of abrasive wheels and processing modes on the nature of the dynamic interaction of the tool with the workpiece and the heat stress in the cutting area. It was found that the parametric vibrations of the elastic system of the machine tool can be shifted to a more stable area, due to an increase in the number of interruptions of the working surface of the abrasive wheel with a constant ratio of the length of the protrusions and depressions. The increase in the number of breaks on the wheel also contributes to a decrease in temperature in the cutting area. It was found that to maintain the stable operation of the elastic system of the machine, it is necessary to reduce the number of cavities on the grinding wheel with an increase in the cutting speed. However, both of these actions are accompanied by an increase in the heat stress of the grinding process. It has been experimentally established that for ordinary (pendulum) grinding, it is possible to achieve an increase in processing productivity by increasing the speed of the longitudinal movement of the table.

Ultrastructure and Composition of Enamel in Human Dental Fluorosis

1989 ◽  
Vol 3 (2) ◽  
pp. 203-210 ◽  
Author(s):  
T. Yanagisawa ◽  
S. Takuma ◽  
O. Fejerskov
Keyword(s):  
Surface Layer ◽  
Dental Fluorosis ◽  
Fluoride Concentration ◽  
Occlusal Caries ◽  
Electron Microscopic ◽  
High Fluoride Concentration ◽  
High Fluoride ◽  
Materials Used ◽  
High Degree ◽  
Hexagonal Crystals

Materials used in this work were 13 permanent molars exhibiting dental fluorosis (between 5 and 9 on the Thylstrup-Fejerskov scale, 1978) obtained from adults (aged 20-40 years) living in regions with 3.5 ppm fluoride in the water supplies. Small but deep occlusal caries lesions necessitated extraction. Light and polarized microscopic, microradiographic, electron microscopic, and electron-probe- and ion-micro-analytical studies were made. Enamel surfaces were generally cloudy to opaque, with several pits or defects of various sizes and degrees of brown-staining. An extensively hypomineralized area extended from the inner enamel to the surface layer, which was mineralized to a high degree. The hypomineralized area contained sparsely arranged, flattened, hexagonal crystals with either perforated centers or defects extending from the perimeter and indicating either no or low fluoride content. The highly mineralized surface layer, however, was composed of many large, flattened, hexagonal crystals and extremely small, irregularly shaped crystals. Both types were free of central perforations and defects. A high fluoride concentration was determined in the highly mineralized surface layer. These findings suggest that the hypomineralized area undergoes caries-like changes in terms of crystal dissolution and that the highly mineralized surface layer contains hydroxyapatite and fluoridated-hydroxyapatite, or fluorapatite, or both.

Sign in / Sign up

Export Citation Format

Share Document