Evaluating the Risk of Corona Discharge in Superalloy Vacuum Induction Melting Furnace Applications

2019 ◽  
Vol 14 (4) ◽  
pp. 926-936
Author(s):  
Chadbourne Lovegren
Keyword(s):  
Corona Discharge ◽  
Melting Furnace ◽  
Vacuum Induction Melting ◽  
Induction Melting

Synthesis and Forming of Titanium Matrix Composites by Casting Route

2007 ◽  
Vol 334-335 ◽  
pp. 297-300
Author(s):  
Si Young Sung ◽  
Bong Jae Choi ◽  
Young Jig Kim
Keyword(s):  
Electron Microscopy ◽  
Melting Furnace ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Titanium Matrix Composites ◽  
Electron Probe Micro Analyzer ◽  
Transmission Electron

The aim of this study is to evaluated the possibility of the in-situ synthesized (TiC+TiB) reinforced titanium matrix composites (TMCs) for the application of structural materials. In-situ synthesis and casting of TMCs were carried out in a vacuum induction melting furnace with Ti and B4C. The synthesized TMCs were characterized using scanning electron microscopy, an electron probe micro-analyzer and transmission electron microscopy, and evaluated through thermodynamic calculations. The spherical TiC plus needle-like and large, many-angled facet TiB reinforced TMCs can be synthesized with Ti and B4C by a melting route.

Cycling Stability Performance of La0.75Mg0.25Ni3.5Si0.10 Hydrogen Storage Alloy in Discharge–Charge System

2014 ◽  
Vol 13 (05n06) ◽  
pp. 1460003
Author(s):  
Zhaojiang Liu ◽  
Lei Huang ◽  
Qi Wan ◽  
Xu Li ◽  
Ma Guang ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Electrochemical Properties ◽  
Melting Furnace ◽  
Test System ◽  
Cycling Stability ◽  
Hydrogen Storage Alloy ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Stability Performance ◽  
Charge Discharge

La 0.75 Mg 0.25 Ni 3.5 Si 0.10 hydrogen storage alloy was prepared by vacuum induction melting furnace and subsequently heated treatment at 940°C for 8 h and cooled to room temperature in the oven. The electrochemical properties of La 0.75 Mg 0.25 Ni 3.5 Si 0.10 compound were measured by LAND CT2001A battery test system. The morphologies of the samples were characterized by scanning electron microscopy (SEM). The surface state of samples was analyzed by X-ray photoelectron spectroscopy (XPS). It was found that the charge–discharge rate plays the key impact on the cycling stability of the alloy. During the cycle test, the prepared La 0.75 Mg 0.25 Ni 3.5 Si 0.10 compound presented an excellent capacity retention at the charge–discharge of 1 C while the capacity of sample declined rapidly at 0.2 C. The excellent cycling stability performance of La 0.75 Mg 0.25 Ni 3.5 Si 0.10 electrode at 1 C could be attributed to the less powder and less oxidation of surface effective active elements. The pulverization inevitably leads to the separation of the part of the cracking alloy and the electrode, resulting in reduction of the effective active substance and increasing attenuation of the capacity per cycle. In addition, on the analysis of the different cut-off potential effects on the electrode, it was found that the La 0.75 Mg 0.25 Ni 3.5 Si 0.10 electrode shows good comprehensive electrochemical properties at 1 C cut-off 0.6–0.7 V. During charging, heavy overcharge will not be conducive to cycling stability performance during the charging test.

Effects of Impurities Distribution on the Crystal Structure and Electrical Properties of Multi-Crystalline Silicon Ingots

2011 ◽  
Vol 675-677 ◽  
pp. 101-104
Author(s):  
Qi Zhi Xing ◽  
Wei Dong ◽  
Shu Ang Shi ◽  
Guo Bin Li ◽  
Yi Tan
Keyword(s):  
Electrical Properties ◽  
Minority Carrier ◽  
Crystalline Silicon ◽  
Melting Furnace ◽  
Minority Carrier Lifetime ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Columnar Crystal ◽  
P Type ◽  
Crystal Region

Multi-crystalline silicon ingots were prepared by directional solidification using vacuum induction melting furnace. The content of aluminum and iron deeply decreased in the columnar crystal region of the multi-crystalline silicon ingots. The columnar crystal growth broke off corresponded to the iron contents sharply increased. The height of columnar crystal in the silicon ingots related to the pulling rates had been clarified by the constitutional supercooling theory. The maximum of the resistivity and the minority carrier lifetime closed to the transition zone where the conductive type changed from p-type to n-type in silicon ingots. Further analysis suggested that the electrical properties were related to the contents of shallow level impurities aluminum, boron and phosphorus.

Synthesis and Purification of Silicon Carbide Powders for Crystal Growth

2012 ◽  
Vol 717-720 ◽  
pp. 37-40 ◽  
Author(s):  
Ta Ching Hsiao ◽  
Sheng Tsao
Keyword(s):  
Silicon Carbide ◽  
Crystal Growth ◽  
Acid Leaching ◽  
Melting Furnace ◽  
Impurity Content ◽  
Low Pressure ◽  
Free Carbon ◽  
Vacuum Induction Melting ◽  
Carbide Formation ◽  
Induction Melting

Silicon carbide powders were prepared in a vacuum induction melting furnace (VIM). Silica and silicon were used as sources of silicon, and graphite powder was used a source of carbon. Pressures of 0.1 and 0.01 atm were selected as the operation conditions, and different silicon carbide powders were prepared. Free carbon and remnant silica were removed by high-temperature baking in air and acid leaching. Low-pressure powders show better crystallinity; moreover, free carbon and silica were rarely found in the product after baking and leaching. The low-pressure grains were prismatic whereas the high-pressure grains were porous. This shows that pressure is a critical parameter in silicon carbide formation, and low-pressure makes the low-temperature synthesis of silicon carbide feasible. Glow discharge mass spectra were used to analyze the impurity content in silicon carbide powders. After baking and leaching, the purity is increased from 3N5 (99.95 wt.%) to 4N5 (99.995 wt.%). Further purification procedures will be combined to meet the quality requirements for crystal growth.

(TiB+TiC) Hybrid Titanium Matrix Composites Shot Sleeve for Aluminum Alloys Diecasting

2006 ◽  
Vol 15-17 ◽  
pp. 231-235
Author(s):  
Bong Jae Choi ◽  
Si Young Sung ◽  
Young Jig Kim
Keyword(s):  
Investment Casting ◽  
Melting Furnace ◽  
In Situ Synthesis ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Matrix Composites ◽  
Shot Sleeve ◽  
Titanium Matrix ◽  
Titanium Matrix Composites

The aim of this study is to fabricate an α-case free (TiB+TiC) hybrid titanium matrix composites (TMCs) shot sleeve for aluminum alloy diecasting by in-situ synthesis and investment casting. Granular 1.88 wt% B4C was added to a titanium matrix in a vacuum induction melting furnace. The synthesized (TiB+TiC) TMCs were examined using electron probe micro-analysis and transmission electron microscopy. The results of the in-situ synthesis and investment casting of the TMCs show that our casting route constitutes an effective approach to the economic net-shape forming of TMC sleeves.

Hardness and Microstructure Change During Annealing Process of a Modified Inconel-718

1985 ◽  
Vol 43 ◽  
pp. 340-341
Author(s):  
Chen-Ti Hu ◽  
Yau-Tsurng Syu
Keyword(s):  
Inconel 718 ◽  
Hot Forging ◽  
Solution Treatment ◽  
Melting Furnace ◽  
Annealing Process ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Rockwell Hardness ◽  
Inconel 718 Alloy ◽  
Complete Investigation

A modified Inconel 718 alloy with a higher content of Mo and lower was prepared from metals of electrolytic grade purity with a L-H IS 8/III vacuum induction melting furnace. The results of chemical analysis were shown in Table 1. After about 80 pet reduction in thickness with hot forging, material was then subjected to 1200°C solution treatment for one hour, air cool and 720°C ageing treatment for 16 hour, air cool. An uniformly dispersed γ’ and γ” precipitates was obtained.Material was plastically deformed to 70 pet reduction in thickness by cold rolling treatment. Then all specimens were divided into four groups and annealed in salt baths with temperatures of 750°C, 850°C, 920°C and 1060°C, respectively. 850°C was chosen to conduct a complete investigation of interior microstructures of different time periods: (1) 2 sec (2) 5 sec (3) 10 sec (4) 30 sec (5) 1 min (6) 5 min (7) 10 min (8) 20 min (9) 35 min (10) 1 hr (11) 2hr. Hardness of all thermomechanically treated specimens were examined with a Rockwell Hardness machine, using RC and RB scales.

Electromagnetic Stirring Processing and its Influence on Mechanical Properties of ZL102(or Al-Si) Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 337-340
Author(s):  
Xue Feng Zhang ◽  
Yong Sheng Du ◽  
Li Ying Qi ◽  
Guan Yuan Liu
Keyword(s):  
Mechanical Properties ◽  
Lorentz Force ◽  
Melting Furnace ◽  
Hardness Measurement ◽  
Electromagnetic Stirring ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Medium Frequency ◽  
Vickers Hardness Measurement ◽  
Aluminum Phase

Al-Si alloy was melted by using vacuum induction melting furnace heated with medium-frequency induction and stirred simultaneously under Lorentz force. The experimental results were discussed with respect to the theoretical analysis of the Lorentz force on the molten alloy. It was found that Si phase tends to homogenize and aggregate along the direction of axis in the alloy under the effect of Lorentz force. With increasing stirring duration, Rod-shaped Si phase has a tendency to break and passivate on the edge. Vickers hardness measurement indicated that the microhardness of Al-Si alloy was improved after electromagnetic stirring. This result can be mainly attributed to the improvement in spheroidization of Si phase and aluminum phase.

scholarly journals Fluid flow and mass transfer in a vacuum induction melting furnace

1993 ◽  
Vol 03 (C7) ◽  
pp. C7-1151-C7-1156
Author(s):  
A. JARDY ◽  
D. GOSSET ◽  
D. ABLITZER ◽  
S. WITZKE
Keyword(s):  
Mass Transfer ◽  
Fluid Flow ◽  
Melting Furnace ◽  
Vacuum Induction Melting ◽  
Induction Melting
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