scholarly journals Aluminium Evaporation during Ceramic Crucible Induction Melting of Titanium Aluminides

2012 ◽  
Vol 730-732 ◽  
pp. 697-702 ◽  
Author(s):  
Fernando Gomes ◽  
Joaquim Barbosa ◽  
Carlos Silva Ribeiro
Keyword(s):  
Titanium Aluminides ◽  
Alloy Composition ◽  
Time Pressure ◽  
Melting Process ◽  
Induction Melting ◽  
Chemical Contamination ◽  
Factors Affecting ◽  
Melting Pressure ◽  
Ceramic Crucible ◽  
Induction Skull Melting

Melting TiAl based alloys in ceramic crucibles often leads to chemical contamination, alloy heterogeneity and non-metallic inclusions. The severity of such phenomena usually depends on the nature of crucible materials, the melting stock composition and the melting parameters, namely superheating time and temperature and melting pressure. Among the referred drawbacks, Al loss during melting is a critical aspect, as its concentration in TiAl based alloys has a very strong effect in their mechanical properties. Although a few studies of critical factors affecting the evaporation behaviour of Al during electron beam and induction skull melting of Ti-Al alloys had been carried out, until now no information was released on this subject for the ceramic crucible induction melting process. In this work a Ti-48Al alloy was induction melted in a zircon crucible with Y2O3 inner layer, using 50 and 100 °C superheating temperatures and 0, 60 and 90 second holding times, and poured into a graphite mould. The effect of different temperature/time combinations in the alloy composition, Al loss by evaporation and extent of the metal/crucible interaction was studied for different melting pressures. Al loss was found to increase significantly for melting pressures below around 10-1 mbar, at a rate that increases as melting pressure decreases, until a maximum rate is reached, remaining constant for lower pressure levels. Metal/crucible interaction increased directly with the melting pressure and superheating time, leading to alloy contamination with yttrium and oxygen. For the experimental set-up and conditions used on this work, optimal superheating time/pressure combinations that lead to acceptable alloy composition and sanity have been identified.

Casting and Laser Surface Melting of 316L Stainless Steel from Scrap Resources

2020 ◽  
Vol 835 ◽  
pp. 306-316
Author(s):  
Haitham Elgazzar ◽  
Shimaa El-Hadad ◽  
Hassan Abdel-Sabour
Keyword(s):  
Stainless Steel ◽  
316L Stainless Steel ◽  
Melting Process ◽  
Industrial Applications ◽  
Surface Melting ◽  
Laser Surface ◽  
Laser Surface Melting ◽  
Steel Scrap ◽  
Induction Melting ◽  
Nano Size

316L stainless steel is used in various industrial applications including chemical, biomedical and mechanical industries due to its good mechanical properties and corrosion resistance. Recycling of 316L stainless steel scrap without significantly reducing its value has received recently great attention because of the environmental regulations. In the current work, 316L stainless steel scrap was recycled via casting using Skull induction melting technique. The casted products subsequently subjected to laser surface melting process to improve its surface properties to be used for harsh environment. The results showed defect free surfaces with homogeneous microstructures. Nano size grains were also obtained due to rapid solidification process. Such nano size grains are preferred for extending the usage of the 316L stainless steel in new applications.Corresponding author: E-Mail: [email protected]

scholarly journals Induction Skull Melting of Ti-6Al-4V: Process Control and Efficiency Optimization

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 539
Author(s):  
Xabier Chamorro ◽  
Nuria Herrero-Dorca ◽  
Daniel Bernal ◽  
Iñaki Hurtado
Keyword(s):  
Complex Shape ◽  
Control Method ◽  
Melting Process ◽  
Optimization Strategy ◽  
Power Losses ◽  
Near Net Shape ◽  
Induction Skull Melting ◽  
Development And Validation ◽  
The Impact ◽  
Titanium Melt

Titanium investment casting is one of the leading and most efficient near-net-shape manufacturing processes, since complex shape components are possible to obtain with a very low amount of material waste. But melting these reactive alloys implies the usage of specific melting technologies such as the Induction Skull Melting (ISM) method. In this work the ISM was extensively studied with the aim of deepening the characteristics of this specific melting method and improving the too low energy efficiency and overall process performance. A 16 segment copper crucible and 3 turns coil was employed for the melting of 1 kg of Ti-6Al-4V alloy. Through the calorimetric balance, real-time evolution of the process parameters and power losses arising from the crucible and coil sub-assemblies was displayed. Results revealed the impact of coil working conditions in the overall ISM thermal efficiency and titanium melt properties, revealing the use of these conditions as an effective optimization strategy. This unstudied melting control method allowed more heat into charge and 13% efficiency enhancement; leading to a shorter melting process, less energy consumption and increased melt superheat, which reached 49 °C. The experimental data published in this paper represent a valuable empiric reference for the development and validation of current and future induction heating models.

Investigation of heating and melting in ELTA programs

2019 ◽  
Vol 39 (1) ◽  
pp. 117-124
Author(s):  
Vladimir Bukanin ◽  
Aleksandr Ivanov ◽  
Alexei Zenkov
Keyword(s):  
Optimization Procedure ◽  
Melting Process ◽  
Continuous Heating ◽  
Induction Melting ◽  
Preliminary Evaluation ◽  
Content Type ◽  
Initial Stage ◽  
Crucible Furnace ◽  
The Relationship

Purpose The purpose of this paper is obtaining the optimal parameters of induction heating and melting systems by use of the new programs ELectro-Thermal Analysis (ELTA) 8.0 and Induction Crucible Furnace (ICF) to improve a quality of final products. Design/methodology/approach Simulation of continuous through heating prior a drawing through the draw plate is realized by an optimization procedure. Additional application of ELTA 8.0 “Heating of Wire” reveals the relationship between power, time and thermal profile of load during heating. Rational variants of ICFs for melting processes are obtained using several step-by-step iterations. Findings ELTA 8.0 program permits to optimize the continuous heating of copper, steel, titanium and other wires. ICF ELTA program was used at the initial stage of the development of new technological processes and the ICFs. This program provides a preliminary evaluation of an induction melting process and system before the use of more sophisticated 2D or 3D programs. Results of optimization allowed to find a rational decision of an induction system, the required parameters of a refractory and a power supply. Non-conductive and graphite crucibles of the furnace were compared from electrical and economical points of view. Originality/value Fast calculation of ELTA programs allows the designer to provide the required temperature distribution in a cross section and along the part to control the real-time processes of heating and melting.

Effects of Melting Process on the Microstructure and Thermal Conductivity of Cu-10Ni-5Mo Alloy

2011 ◽  
Vol 415-417 ◽  
pp. 289-292
Author(s):  
Bai Ping Lu ◽  
Hui Xu ◽  
Can Cheng Liu
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Injection Moulding ◽  
Melting Process ◽  
Induction Melting ◽  
Melting Points ◽  
Arc Melting ◽  
Coefficient Of Thermal Conductivity

Cu-10Ni-5Mo alloys have been prepared by arc-melting and induction melting injection moulding. The effects of melting processes on the microstructure and thermal conductivity of Cu-10Ni-5Mo alloys were studied. The results show that the grain of Cu-10Ni-5Mo alloy prepared by arc-melting is coarse and the structure includes α solid solution and Mo-Ni phase. The grain of Cu-10Ni-5Mo alloy prepared by induction melting injection moulding is superfine and the structure is α solid solution. Under this experiment condition, the coefficient of thermal conductivity of Cu-10Ni-5Mo alloy prepared by arc-melting is 56.9 W/(m•K)，while that of Cu-10Ni-5Mo alloy prepared by induction melting injection moulding is 35.7 W/(m•K). The melting points of Cu-10Ni-5Mo alloy prepared by two methods all increase and are little different.

scholarly journals Factors Affecting Students’ Difficulties in Speaking Performance of The Tenth Grade Students of SMA Negeri 1 Tiworo Kepulauan

2019 ◽  
Vol 3 (1) ◽  
pp. 95-105
Author(s):  
Hendriati Afebri ◽  
Aderlaepe . ◽  
Khusnun Muhsin
Keyword(s):  
Random Sampling ◽  
Time Pressure ◽  
Factors Affecting ◽  
Affective Factors ◽  
Tenth Grade ◽  
Quantitative Design ◽  
Listening Ability ◽  
Speaking Performance ◽  
Performance Conditions ◽  
Topical Knowledge

Students’ speaking performance could be affected by factors that come from performance conditions (time pressure, planning, standard of performance and amount of support), affective factors (such as motivation, confidence and anxiety), listening ability, topical knowledge and feedback during speaking activities. The purpose of this study was to analyze, describe and determine factors affecting students’ difficulties in speaking performance of the tenth-grade students of SMA Negeri 1 Tiworo Kepulauan. This study employed quantitative design in the form of survey. The samples were 30 students of X MIA 2 which were taken by using random sampling. The data were collected by using close ended questionnaire and were analyzed by using SPSS version 16. The results of this research showed that of the three factors affecting students’ difficulties in speaking, the highest percentage was linguistic factors including grammar, vocabulary and pronunciation. It was concluded that the students got difficulties in performing speaking task. Keywords: Speaking Performance, Students’ Difficulties

scholarly journals Primary microstructure characterization of Co-20Ni-9Al-7W-3Re-2ti superalloy

2021 ◽  
pp. 44-44
Author(s):  
A. Tomaszewska
Keyword(s):  
Casting Process ◽  
Melting Process ◽  
Alloying Elements ◽  
Technological Problem ◽  
Induction Melting ◽  
Interdendritic Segregation ◽  
Segregation Of Alloying Elements ◽  
Titanium Nickel ◽  
Tungsten Concentration

The characterization of the primary microstructure of the new Co-based superalloy of Co-20Ni-9Al-7W-3Re-2Ti type was shown in this article. The investigated alloy was manufactured by induction melting process from pure feedstock materials. The fundamental technological problem related to Co-Al-W-X multicomponent alloys' casting process is a strong susceptibility to interdendritic segregation of alloying elements, especially tungsten and rhenium. The performed analysis revealed that the observed effect of alloying elements segregation is detectable and much stronger than for Co-9Al-9W and Co-20Ni-7Al-7W alloys, related to titanium, nickel and aluminium migration to inter-dendritic spaces. Consequently, the tungsten concentration gradient between dendritic and interdendritic zones is higher than for Co-9Al-9W and Co-20Ni-7Al-7W alloys. The same situation is in the case of rhenium and cobalt, but Co's concentration in the interdendritic zone is only slightly lower.

Solidification of TiAl-based alloys

2008 ◽  
Vol 1128 ◽  
Author(s):  
Ulrike Hecht ◽  
D. Daloz ◽  
J. Lapin ◽  
A. Drevermann ◽  
V.T. Witusiewicz ◽  
...  
Keyword(s):  
Titanium Aluminides ◽  
Alloy Composition ◽  
Eutectic Reaction ◽  
Solidification Path ◽  
Thermodynamic Calculations ◽  
Processing Conditions ◽  
Equilibrium Thermodynamic ◽  
Microstructure Formation ◽  
Aero Engine ◽  
Near Net Shape

AbstractTitanium aluminides containing high niobium additions emerged as an attractive alloy family for automotive and aero-engine applications. Their processing by near net shape casting is rather demanding, not only due to easy contamination but also due to the fact that microstructure formation during solidification and subsequent solid state transformations sensitively depends on alloy composition and the applied processing conditions. The sequence of phase formation during solidification of the ternary alloy Ti-45Al-8Nb was analyzed based on non-equilibrium thermodynamic calculations and solidification experiments. This alloy solidifies completely via the β(Ti) phase, because the nucleation undercooling for the α(Ti) phase is high enough to prevent its formation. Thermodynamic calculations and experiments are shown to converge at last, with only minor improvements being necessary to correctly describe the metastable eutectic reaction “Liquid → β(Ti) + γ-TiAl” that occurs at the end of the solidification path.

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