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Thermodynamic Model for Calculating Activity of Nitrogen and Boron in Fe-C-B-N molten metal

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Journal of Iron and Steel Research International 2009年第3期16卷 15-19页

作者： WANG Shi-jun PENG Jun DONG Yuan-chi LIU Li-xia ZHOU Yun CHEN Er-bao School of metallurgy and Resource Anhui University of Technology Maranshan 243002 Anhui China School ofmetallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

The solubility of nitrogen in Fe-C-B-N system was measured at 1 758 K,and the computational model on activity （action concentration） of nitrogen and boron was established based on phase diagram and the coexistence theory about metal melt structure model. Comparing the computed results with the experimental results,satisfactory conclusion can be obtained. The result shows that BN and B4C can exist in Fe-C-B-N molten metal at high temperature,which consequently restrains the nitrogen removal from the melt. However,B4C content is extremely low. Before graphite is precipitated,the influence of carbon on activity of nitrogen in melt is higher in ternary system than in binary system; however,this effect is contrary to that after graphite is precipitated.

关键词： molten metal coexistence theory action concentration activity

The mystery of molten metal

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China Foundry 2010年第4期7卷 425-437页

作者： Natalia Sobczak Jerzy Sobczak Rajiv Asthana Robert Purgert Foundry Research Institute Department of Engineering & Technology University of Wisconsin-Stout Energy Industries of Ohio

Recent advances in scientific understanding of high-temperature materials processing using novel experimental methodologies have shed light on the complex role of surface and interface phenomena. New in-situ studies on molten metal/solid ceramic interactions using a unique experimental complex at the Foundry Research Institute, Krakow, have revealed a number of unusual observations in materials processing at high temperatures. We present some such unusual observations and their explanation with reference to liquid metal processing of Al, Ni, and Ti, and their alloys in contact with oxide ceramics. In particular, we focus on the following aspects: primary oxidation of Al from residual water vapor or oxygen, capillary purification to remove surface oxide, substrate protection by CVD carbon, roughening due to spinel whisker formation, inclusions in castings due to mechanical detachment, floatation due to buoyancy forces, and segregation due to directional solidifciation, modification of the solid surface morphology by metal vapor ahead of the liquid, and the complication due to multi-component alloys melted in crucibles made from complex oxide-based ceramics. In the case of Ti, rapid reactions with oxides result in undesirable volumetric changes that create difficulty in casting high-quality Ti parts, particularly by investment casting. Nanoscale (e.g., colloidal) coatings based on Y2O3 protect crucibles and hold ladles against such attack. Practical insights and recommendations for materials processing emerging from the fundamental studies on high-temperature interfacial phenomena have been described.

关键词： molten metal high-temperature phenomena in-situ observation casting defects

Analysis of molten metal Distribution in the Mold of a Horizontal Centrifugal Casting

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Open Journal of Applied Sciences 2020年第7期10卷 444-454页

作者： Miguel A. Barron Dulce Y. Medina Joan Reyes Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Mexico City Mexico

It is numerically studied the influence of the angular velocity, the molten metal viscosity, and the mold wall roughness on the molten metal distribution in the mold of a horizontal centrifugal casting process. The undesirable raining phenomenon sometimes arises in horizontal centrifugal casting. It occurs when the molten metal rains or falls from the top of the mold to the bottom while the mold is rotating. Using Computational Fluid Dynamics simulations, the conditions for the emergence of the raining phenomenon were explored in this work. For the system considered, angular velocities less than 77 rad/s cause the emergence of the raining phenomenon and accumulation of the molten metal in the lower part of the mold, whereas angular velocities greater than 77 rad/s produce a constant thickness of the molten metal and prevent raining.

关键词： Angular Velocity Centrifugal Casting Computational Fluid Dynamics molten metal Viscosity Wall Roughness

Temperature Drop of molten metals in Open Channels

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World Journal of Engineering and Technology 2024年第3期12卷 493-500页

作者： Miguel A. Barron-Meza Joan Reyes-Miranda Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Ciudad de Mexico Mexico

The temperature drop of molten metal flowing in open channels is numerically determined. Rectangular, trapezoidal and triangular geometries are considered. The overall heat transfer coefficients for the bottom, side walls and free surface of the channel have been taken from the literature. For each geometry, the volumetric flow rate, mean residence time and temperature drop as a function of the channel inclination angle were determined. The rectangular and trapezoidal geometries present the smallest temperature drops, while the triangular geometry presents the greatest temperature drop. The factors that most affect this drop are the value of the free surface area of the channel, and the average residence time of the molten metal in the channel.

关键词： Free Surface Heat Transfer molten metal Open Channel Geometry Residence Time Temperature Drop

Effect of electromagnetic force on melt induced by traveling magnetic field

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Transactions of Nonferrous metals Society of China 2010年第4期20卷 662-667页

作者：苏彦庆徐严谨赵雷郭景杰傅恒志 School of Materials Science and Engineering Harbin Institute of Technology

A new apparatus was designed to measure the electromagnetic force and a computational study of the traveling magnetic field(TMF)and its application to the Ga-In-Sn melt(with low melting point),then the forces on Al,Mg,and Li melt,were simulated. The result show that the electromagnetic force on the melt increases linearly with the increasing length of the melt in the *** TMF-induced Lorentz force increases with increasing frequency,and then *** maximum value is obtained when the current frequency is 160 Hz,over that frequency the force decreases *** the iron-core is activated,the force increases when the melt closes to the *** Lorentz forces have inversely-proportional relationships with the electrical resistivity,the dfx/dρdecreases and the dfy/dρincreases with the increasing electrical resistivity(df/dρis the slope of the Lorentz force profile).

关键词： electromagnetic force traveling magnetic field Ga-In-Sn melt molten metal

Effects of SiC and MgO on alumina-based ceramic foams filters

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China Foundry 2007年第4期4卷 292-295页

作者： CAO Da-li ZHOU Jing-yi JIN Yong-ming MA Lei SHI Zhong-ning WANG Zhao-wen Shenyang Institute of Chemical Technology Shenyang 110142 China Shenyang Research Institute of Foundry Shenyang 110022China School of Materials and metallurgy Northeastern University Shenyang 110006 China

Alumina-based foam ceramic filters were fabricated by using alumina,SiC,magnesia powder as major *** has been found that this ceramic filter has a uniform macrostructure for filtering molten *** influences of SiC and magnesia content,the sintering temperatures on ceramic properties were ***-based foam ceramic filters containing 2.2 mass% magnesia and 7.6 mass% SiC has a compressive strength of 1.36 MPa and a thermal shock resistance of 5 *** main phases after 1 hour sintering at 1 500℃ consist of alumina,silicon carbide,spinel and mullite.

关键词： alumina-based foam ceramic filters compressive strength molten metal MgO SiC