توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Investigation of Molten Metal Flow Pattern during the Vertical Ingate Filling in Non–Pressurized Bottom Gating System in A356 Alloys
اطلاعات انتشار: اولین همایش بین المللی و ششمین همایش مشترک انجمن مهندسی متالورژی ایران، سال
تعداد صفحات: ۱۸
During the mold filling process, surface turbulence cause the entrainment of oxide films into the bulk liquid which are detrimental to the cast integrity. For avoiding these defects, non–pressurized and bottomgating systems are strongly recommended for reducing the surface velocity of the liquid metal entering into the mold cavity at the early stages of mold filling. In spite of using mentioned gating system in casting process, exceeding surface velocity from the critical value has been observed at the mold entrance.In this study numerical simulation was used to analyze mold filling and distribution of velocity in differentportions of gating system thoroughly, in order to evaluate why surface turbulence was observed even innon–pressurized and bottom–gating systems. It has been concluded that by formation of dead zones and vortex flows in runner's tail, the new entered liquid will push to the ingate and then cavity with a higher velocity. Therefore, it was proved that runner's tail play an important role in making a chaotic regime andunexpected flow pattern in the ingate. This means that, design based on conventional gating system ratio is not valid enough to avoid surface turbulence<\div>

۲Numerical simulation of surface turbulence and bifilms formation in aluminum low pressure die casting (LPDC
نویسنده(ها): ، ،
اطلاعات انتشار: اولین همایش بین المللی و ششمین همایش مشترک انجمن مهندسی متالورژی ایران، سال
تعداد صفحات: ۱۷
Effects of surface turbulence on surface oxide folding have been studied numerically. Bifilms are an unfavorable nucleation sites for volume defects such as cracks, gas bubbles and shrinkage cavities. Major parameter promoting bifilm formation is surface turbulence. This parameter could be characterized bysurface velocity exceeding a critical value. In this study Formation and distribution of bifilms were investigated precisely during mold filling using numerical simulation in an industrial aluminum (Al–7Si– Mg) casting filled by a low pressure die casting process. In a location where liquid metal falls and frontvelocity exceeded critical velocity double oxide films will be generated. Here liquid velocity along withdirection of vectors investigated to show the possibility of bifilms generation. A new model for simulation of bifilms formation and tracing has been used to inquiry where these defects accumulate<\div>

۳Simulation of Thermal Behavior of Wide Gap Thermite Steel Rail Welds
اطلاعات انتشار: اولین همایش بین المللی و ششمین همایش مشترک انجمن مهندسی متالورژی ایران، سال
تعداد صفحات: ۱۵
Thermite welding is a worldwide welding process in truck industries that benefits from the simplicity, portability, and economy. In this study, molten steel was prepared by thermite reaction and poured between two wide–gap rails in a sand mold. SUTCAST, which is finite difference basesoftware, was used to analysis heat transfer in the welding process. The experienced condition was obtained from varying the simulation parameters. The simulation results were in good agreement with the experiment. Effects of weld gap size as well as pouring and rail preheating temperature, were investigated and it is concluded that the mentioned parameters have the pronounced effect in increasing the penetration depth. The optimum conditions for the specified rail gap were also predicted<\div>
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