Design of metal casting mold for ADC 12 aluminium alloy with assistance of 20 kHz ultrasonic vibration

Metal mold casting is widely used in industry because of higher accuracy than sand casting and lower cost than diecasting. Metal mold casting can yield products with complex shapes and adjustable cooling rate. In this work, designing and fabrication of 20 kHz ultrasonic assisted mold casting using 20Cr steel are studied. Some major components such as motor, heater power, melting chamber are selected and calculated. Model for heating and pouring the ADC 12 alloy is designed. Samples with and without ultrasonic vibration are investigated using 3D laser scan.

Karakterisasi Serbuk Timah dari Sistem Atomisasi Gas Argon Panas - Sub Sistem Gas Alir Tabung Gas

<p class="Abstract">The tin powder was used in some applications and technology such as for part manufacture through alloying, pressing, and sintering process, mixing material for the pyrotechnic application, the main material for solder pasta, mixing material on tin chemical, and others. Therefore, the demand for tin powder with a small size, spherical shape, and high purity is increasing severely. Indonesia (PT. Timah Tbk.) is one of the world’s largest producers of tin raw materials. This raw material can be processed be as powder by the atomization method. In this research, hot argon gas atomization system was used to generated tin powder. Raw tin was melted in a melting chamber with temperature variations of 600, 700, 800, and 900 °C. This experiment generates powder with a dominant size of 37 – 150 mm. Meanwhile, for size powder of 0 – 30 mm, dominated by size range of 0 – 10 mm. Furthermore, the size powder of 0 – 30 mm is composed of tin phase, without tin oxide. The tin powder of melting chamber temperature of 900 °C produces the largest tin powder with a size of 0 – 10 mm and spherical powder.</p>

Disintegration and Powder Formation of Nb75M25 (M = Al, Si, Ga, Ge, and Sn) Due to Hydrogenation in an Arc-melting Chamber

Nb75M25 (M = Al, Si, Ga, Ge, and Sn) alloy ingots were prepared by the conventional arc-melting method and then were directly reacted with high purity hydrogen of 0.1 MPa in an arc-;melting chamber without exposing the ingots to air. As the clean surface of the arc-;melted ingots is preserved, the ingots rapidly absorb a large amount of hydrogen without any activation treatments and disintegrate violently into fine particles. The disintegration of ingots depends on the M element. The collected particles are investigated by x-ray diffraction, electron microscopy, chemical analysis, and thermal analysis. The particles are hydrides of Nb75M25 after hydrogenation and have a sharp-edged polygonal appearance. After dehydriding, fine Nb3M powders with A15 crystalline structure are obtained except for Nb75Si25. In comparison with the atomized Nb3M powders, the Nb3M powders prepared by the present study have a smaller average particle size and lower impurity contents.

Low Cost Get-Away-Special (GAS) Furnace

A simple and inexpensive space shuttle experimental apparatus to conduct microgravity melting and solidification is presented. A Get-Away-Special (GAS) space furnace was initially developed as a student design project at the United States Air Force Academy and further refined at the NASA Lewis Research Center. The experiment package consists of a melting chamber, battery power system, temperature data recording systems, and electronic controller. The melting chamber is a thin-walled tube wrapped by heating resistance wire. Thermocouples are used to record the specimen thermal history. Power is supplied by two volt batteries wired to produce 360 watts. The millivolt output of the thermocouples is amplified, cold-junction compensated, and converted to a frequency which is then recorded on an off-the-shelf cassette stereo tape recorder. A back up data recording system which digitizes the amplified signal and records the data on EEPROMs (electrically erasable programmable read-only memory) has also been included. This experimental device demonstrates that basic science research can be kept simple and inexpensive.