Investigation of Cooling Process of a High-Temperature Hollow Cylinder in Moving Induction Heat Treatment

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
H. Shokouhmand ◽  
S. Ghaffari
Keyword(s):  
Heat Treatment ◽  
Temperature Distribution ◽  
Moving Boundary ◽  
Work Piece ◽  
Cooling Process ◽  
Temperature Dependent ◽  
Time Step ◽  
Heat Treated ◽  
Rate Of Cooling ◽  
Temperature Dependent Properties

The hardness of heat treated steel and probability of occurrence of quenching cracks depend on the cooling time and temperature distribution. Therefore, the investigation of cooling process is a crucial issue in heat treatment to evaluate the obtained structure of the work-piece. In the present work, a vertical hollow circular cylinder is heated up to a specific temperature by a moving coil at a given velocity along it, and the heated parts then quenched by a moving water–air spray. After passing the spray, the cylinder is cooled by natural convection with the surrounding air. An analysis of coupled magnetic problem and transient conjugated thermal problem between the solid and the surrounding air is performed using finite-element method to obtain temperature field in each time step. This procedure includes moving boundary conditions, effect of radiation with ambient, temperature-dependent properties, and change in magnetic permeability of specified alloy at the Curie temperature. The obtained results show how both spray and natural cooling affect the temperature distribution and rate of cooling of the cylinder. Furthermore, the effect of geometry and velocity of coil on the rate of cooling and chance of quenching cracks are investigated.

scholarly journals A new boundary element algorithm for modeling and simulation of nonlinear thermal stresses in micropolar FGA composites with temperature-dependent properties

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohamed Abdelsabour Fahmy
Keyword(s):  
Modeling And Simulation ◽  
Boundary Element ◽  
Thermal Stresses ◽  
Computation Time ◽  
Functionally Graded ◽  
Temperature Dependent ◽  
Time Step ◽  
Kirchhoff Transformation ◽  
Nonlinear Temperature ◽  
Temperature Dependent Properties

AbstractThe main aim of this article is to develop a new boundary element method (BEM) algorithm to model and simulate the nonlinear thermal stresses problems in micropolar functionally graded anisotropic (FGA) composites with temperature-dependent properties. Some inside points are chosen to treat the nonlinear terms and domain integrals. An integral formulation which is based on the use of Kirchhoff transformation is firstly used to simplify the transient heat conduction governing equation. Then, the residual nonlinear terms are carried out within the current formulation. The domain integrals can be effectively treated by applying the Cartesian transformation method (CTM). In the proposed BEM technique, the nonlinear temperature is computed on the boundary and some inside domain integral. Then, nonlinear displacement can be calculated at each time step. With the calculated temperature and displacement distributions, we can obtain the values of nonlinear thermal stresses. The efficiency of our proposed methodology has been improved by using the communication-avoiding versions of the Arnoldi (CA-Arnoldi) preconditioner for solving the resulting linear systems arising from the BEM to reduce the iterations number and computation time. The numerical outcomes establish the influence of temperature-dependent properties on the nonlinear temperature distribution, and investigate the effect of the functionally graded parameter on the nonlinear displacements and thermal stresses, through the micropolar FGA composites with temperature-dependent properties. These numerical outcomes also confirm the validity, precision and effectiveness of the proposed modeling and simulation methodology.

Morphological changes of poly(tetrafluoroethylene) by heat treatment on NaCl

1993 ◽  
Vol 8 (11) ◽  
pp. 2942-2947 ◽  
Author(s):  
Sadaatsu Yamaguchi ◽  
Masaki Tsuji
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Morphological Changes ◽  
Dark Field ◽  
Exothermic Peak ◽  
Lateral Side ◽  
Cooling Process ◽  
Transmission Electron ◽  
Heat Treated

Fine granules of poly(tetrafluoroethylene) (PTFE) were heat-treated/annealed on NaCl near its melting temperature (Tm) and/or at a temperature (Tc) between upper and lower feet of the exothermic peak in the DSC cooling process from Tm. Morphological changes of the granules were examined in the bright- and dark-field modes by transmission electron microscopy. When the granules were heat-treated near Tm, microfibrils of 20–30 nm in width and fibrils of 70–120 nm in width came out of the granules. The microfibrils were also observed in the fibrils. The microfibrils formed by heat treatment near Tm seemed to be identified as microfibrils of 20–30 nm in width which were recognized outside the granules annealed at Tc. It is expected that such a microfibril will grow to be a band in the band structure observed on the surface of bulk PTFE. Since the 0015 dark-field images showed that the PTFE chains in such microfibrils and fibrils are set perpendicular to their fibril axis, the chains should fold back and forth repeatedly at both lateral side-surfaces of the microfibrils and fibrils.

Heat Treatment Variability Effects on the Mechanical Properties of Beta Solution Treated Ti-6Al-4V

2010 ◽  
Vol 638-642 ◽  
pp. 401-406
Author(s):  
J.R. Calcaterra
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Solution Heat Treatment ◽  
Thermomechanical Processing ◽  
Tensile Tests ◽  
Maximum Temperature ◽  
Work Piece ◽  
Fatigue Crack Growth Resistance ◽  
Heat Treated

Beta solution heat treatment is used to increase the fatigue crack growth resistance of Ti-6AL-4V. Unfortunately, the beta solution heat treatment is very sensitive to maximum temperature, time at temperature and cooling rate. In order to determine the effect of these parameters on mechanical properties, several different titanium billets and forgings were heat treated at various times and temperatures. The forgings had differing amounts of work, reflecting the potential for thermomechanical processing differences seen in a die forged component. Fracture toughness and tensile tests were conducted on the billets and forgings. In addition, sections of each work piece were excised and examined microscopically. The results from the study indicate there is a significant effect of heat treatment on thicker section components. In these cases, grains near the surface may grow large, while being barely transformed near the center. The change in microstructure has an effect on mechanical properties. Material with the larger grains tends to have worse ductility, while the fracture toughness properties of the material tend to decrease with grain size.

scholarly journals Investigation of Waves Generated in Transversely Isotropic Micropolar Generalized Thermoelastic Half Space Under Temperature Dependent Properties

2019 ◽  
Vol 24 (4) ◽  
pp. 53-65
Author(s):  
R.R. Gupta ◽  
R.R. Gupta
Keyword(s):  
Temperature Distribution ◽  
Quality Factor ◽  
Half Space ◽  
Elastic Properties ◽  
Transversely Isotropic ◽  
Temperature Dependent ◽  
Phase Velocities ◽  
Generalized Thermoelastic ◽  
Temperature Dependent Properties ◽  
Propagation Of Waves

Abstract The present study deals with the propagation of waves in a transversely isotropic micropolar generalized thermoelastic material possessing temperature dependent elastic properties. After developing the solution for LS, GL and CT theory, the phase velocities and attenuation quality factor have been obtained. The expressions for amplitudes of stresses, displacements, microratation and temperature distribution have been derived and computed numerically. The numerically evaluated results have been plotted graphically. Some particular cases of interest have also been obtained.

Detailed Photoluminescence Studies of Heat-Treated InP

1992 ◽  
Vol 262 ◽  
Author(s):  
Klaus Pressel ◽  
C. Hiller ◽  
G. Bohnert ◽  
F. Prinz ◽  
A. Dörnen
Keyword(s):  
Magnetic Field ◽  
Heat Treatment ◽  
Wavelength Range ◽  
Concentration Level ◽  
Field Studies ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Heat Treated ◽  
Photoluminescence Studies ◽  
Temperature Dependent Photoluminescence

ABSTRACTWe present highly resolved photoluminescence studies on heat-treated nominally undoped InP, which was either unprotected or protected by SiO2 or Si3N4 caps during the annealing procedures. Annealing of InP above 350°C leads to six different sharp emissions in the wavelength range between 8790 and 8900 Å, which are not observed at 4 K in Zn-doped or Fe-doped samples. Based on temperature-dependent photoluminescence studies, time-resolved measurements and preliminary magnetic field studies we ascribe these emissions to isoelectronic bound exciton transitions. It is also shown that the two emissions at 8883 Å (11254 cm-1) (E) and 8889 Å (11246 cm-1) (F) belong to one center. We observe that the lines not only depend on the heat treatment but also on some unintentionally incorporated or residual impurities of a low concentration level. Possible candidates are discussed.

scholarly journals Temperature Distribution in Microwave Sintering of Alumina Cylinders

1994 ◽  
Vol 347 ◽  
Author(s):  
J. R. Thomas ◽  
Joel D. Katz ◽  
Rodger D. Blake
Keyword(s):  
Temperature Distribution ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Heat Transfer Process ◽  
Microwave Energy ◽  
Heating Process ◽  
Temperature Dependent ◽  
Fiber Sensors ◽  
Temperature Dependent Properties ◽  
Multi Mode

ABSTRACTSmall cylinders of high-purity alumina were encased in a “casket” of low-density zir-conia insulation and heated to sintering temperature in a large multi-mode microwave oven. Optical fiber sensors were used to monitor the temperature at several locations in the system. It was found that the alumina samples heat faster than the zirconia insulation at temperatures above 1000°C, and that the temperature distribution in the sample is essentially uniform during the heating process.A two-dimensional mathematical model of the heat transfer process was developed which reproduces the essential features of the observed phenomena. Literature data for all temperature-dependent properties were incorporated into the model. The model suggests that the alumina samples absorb a significant fraction of the microwave energy.

Temperature dependent properties of heat treated aluminium alloys

2013 ◽  
Vol 8 (2) ◽  
pp. 65-69 ◽  
Author(s):  
A. G. Esmeralda ◽  
A. Rodríguez ◽  
J. Talamantes-Silva ◽  
R. Colás
Keyword(s):  
Aluminium Alloys ◽  
Temperature Dependent ◽  
Heat Treated ◽  
Temperature Dependent Properties
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