Papers by Keyword: Local Heating

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Authors: Sang Beom Shin, Ha Geun Kim, Kyeong Gyu Kim
Abstract: The purpose of this study is to identify the principal factors controlling the formability of TMCP steel for curved hull plate. In order to do it, the initial residual stress in TMCP steel was evaluated using flatness measured in the flat bar cut by flame and analytical approach. Changes of the curved profiles in conventional steel and EH 36 TMCP steel of 50mm thick during cold bending and local heating were investigated using 3 dimensional measuring instruments. It was found that the formability in TMCP steel was mainly determined by the excessive distortion by the relaxation of residual stress during cold bending.
Authors: Dmitry Zvezhinskiy, Sergey V. Stepanov, Vsevolod Byakov, Bożena Zgardzińska
Abstract: The terminal part of the e+ track (the positron blob) is formed during ionization slowing down and subsequent ion-electron recombinations produced by a positron. It releases up to 1 keV of energy, which is converted into heat within few picoseconds. If a bulk temperature of a medium is below, but close enough to its melting point, some region of a substance may melt, yielding a peculiar temperature dependence of the lifetime (LT) spectra. We have estimated properties of the molten region with a help of macroscopic heat con- duction equation and suggested a model describing temperature dependence of the ortho- positronium lifetime in frozen methanol, ethanol, butanol and water close to their melting points.
Authors: F.H. Osman (1), D. Ebbatson, M. Hua, Y.F. Guo
Authors: Dmitrii O. Glushkov, Genii V. Kuznetsov, Pavel A. Strizhak
Abstract: Numerical research of heat and mass transfer processes at dispersed condensed substance ignition by metallic particle heated to high temperatures was developed. It was established the influence of “hot” particle parameters on the main integrated characteristic of process – ignition delay time.
Authors: Hong Bo Xu, Ming Yu Li, Jong Myung Kim, Hong Bae Kim, Dae Won Kim
Abstract: The focus of this study was on discussing the novel reflow method ISHR (Induction spontaneous heat reflow) used for high-density area array packaging and assembly. Multi-layer under bump metallization (UBM) and Sn3.5Ag lead-free solder ball were laid in the high frequency electromagnetic field. Because of the induction heating, solder balls melted and spread onto the UBM to form solder bumps. The solder bumps could be formed within 2 seconds through this method; meanwhile, the infrared temperature measurement results showed that the rosin substrate temperature was lower. The shear test indicated that the solder bumps made by ISHR can satisfy the mechanical requirement. Finally, the feasibility experiment was performed to demonstrate the application feasibility of this ISHR technology. Through all these experiments, conclusion can be made that the ISHR as a novel reflow method can be applied in microelectronics packaging.
Authors: Shu De Ji, Xue Song Liu, Jian Guo Yang, Zhen Lei Liu
Abstract: In order to solve the problem of crack appeared in Francis turbine runner, the welding residual stress of Francis turbine runner is regulated and controlled by means of numerical simulation from the view of subsection welding, local heating and local peening. The results show that the length of welding section of blade outlet and the welding direction in the subsection welding process influence the residual stress of the turbine blade. For the local heating technology, the decreasing effect on residual stress increases with the increase of heating time, heating temperature and heating area. The welding residual stress of dangerous region decreases and then increases with the increase of heating distance. Moreover, the peening effect is very clear when the temperature of material in the peening region reaches its own plastic temperature.
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