scholarly journals Mould Filling Ability Characterisation of Cast Aluminium Alloys Using Design of Experiments

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Samavedam Santhi ◽  
S. B. Sakri ◽  
Dharwada Hanumantha Rao ◽  
Srinivasan Sundarrajan
Keyword(s):  
Process Parameters ◽  
Aluminium Alloys ◽  
Metal Flow ◽  
Filling Ability ◽  
Mould Filling ◽  
Liquid Metal Flow ◽  
Factor Combination ◽  
Flow Heat ◽  
Heat Transfer And Solidification

Mould filling ability characteristic has been influencing the liquid metal flow, heat transfer, and solidification there by affecting the quality of aerospace castings. Mould filling is a critical parameter in the production of sound and quality castings, especially in the case of complex-shaped castings where section thickness is varying considerably. The mould filling ability of aluminium alloys LM6 and LM25 has been studied in the present investigation. Experimentation has been carried out using orthogonal array experimental layout. The process parameters studied in the present investigation are alloy composition, sand fineness, mould coating, and pouring temperature. The mould filling ability of selected aluminium alloy has been studied using pin test piece with cylindrical cores. The results from experimentation are analyzed to find the influence of the process parameters on mould filling ability. Based on the above, LM6 alloy has been found to have better mould filling ability characteristics and the analysis of variance has also revealed the same optimum factor combination.

scholarly journals T-FSW of Dissimilar Aerospace Grade Aluminium Alloys: Influence of Second Pass on Weld Defects

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 525
Author(s):  
Mustufa Haider Abidi ◽  
Nabeel Ali ◽  
Hashmatullah Ibrahimi ◽  
Saquib Anjum ◽  
Dhruv Bajaj ◽  
...  
Keyword(s):  
Process Parameters ◽  
Aluminium Alloys ◽  
Detrimental Effect ◽  
Substantial Reduction ◽  
T Joints ◽  
Friction Stir ◽  
Weld Defects ◽  
Shoulder Diameter ◽  
Aerospace Sector

The restoration of numerous aircraft structures is achievable with effective repair of welded joints. T-joints are often utilized in these structures to provide structural stability, keeping minimal body weight. Multi-pass friction stir welding (FSW) has proved to be useful for improving the quality of aluminium alloy welds employed in the aerospace sector. However, FSW of these alloys in T-configuration has not been sufficiently addressed yet. Even rarer is the discussion of efficacy of second FSW pass, with altered process parameters for improving the weld quality in T-joints. Hence, two commonly used aerospace grade aluminium alloys, namely, AA2024 and AA7075, were friction stir welded in T-configuration, varying three process parameters, i.e., tool rotational speed, welding speed and shoulder diameter. The effect of second FSW pass, performed at an optimum set of parameters, on kissing bond and tunnelling defect was studied in detail. A substantial reduction in the detrimental effect of these weld defects was discussed via tensile testing, micro-hardness and micro-structural observations.

Numerical Modeling of Planar Flow Casting Process

2006 ◽  
Vol 116-117 ◽  
pp. 106-109 ◽  
Author(s):  
Kee Hyeon Cho ◽  
Kee Ahn Lee ◽  
Moon Chul Kim ◽  
Joong Mook Yoon
Keyword(s):  
Heat Transfer ◽  
Process Parameters ◽  
Casting Process ◽  
Computational Domain ◽  
Molten Metals ◽  
Planar Flow ◽  
Planar Flow Casting ◽  
Flow Heat ◽  
Fully Coupled ◽  
Heat Transfer And Solidification

This study sought to examine the effect of various process parameters on the thickness of the amorphous strip produced by Planar Flow Casting (PFC), which is used to solidify molten metals rapidly. The processes were simulated via fully coupled fluid flow, heat transfer, and solidification models. The temperature distribution and velocity profile of melt in the computational domain with given process parameters were investigated according to various melt inlet temperatures, size of gap between nozzle slots, rotating wheel, and ejection pressure. In general, stable shaping of ribbons was obtained given a heat transfer coefficient of 100 cal/cm2/sec/°C. Strip thickness was found to decrease with the pouring temperature of melt. The results evaluated based on the numerical model were verified based on experimentally measured data.

scholarly journals The Influence of the Method of Mould Filling on the Quality of Castings Made of EN AC-44000 or EN AC-46200 Alloy

2014 ◽  
Vol 14 (4) ◽  
pp. 73-76
Author(s):  
M. Nadolski ◽  
Z. Konopka ◽  
M. Łągiewka ◽  
A. Zyska
Keyword(s):  
Wall Thickness ◽  
Negative Pressure ◽  
Aluminium Alloys ◽  
Gravity Casting ◽  
Silicon Crystals ◽  
Mould Filling ◽  
Mould Cavity

Abstract The performed examinations concerning the process of filling the plaster ceramic moulds with aluminium alloys allowed to assess the influence of various methods of introducing the metal into the mould cavity on the macro- and microstructure of the obtained experimental castings. The comparison was performed for castings with graded wall thickness made either of EN AC-44000 alloy or of EN AC-46000 alloy, produced either by gravity casting, or by gravity casting with negative pressure generated around the mould (according to the Vacumetal technology), or by counter-gravity casting. It was found that the silicon crystals grow in size with an increase in wall thickness due to the slower cooling and solidification of castings

Analysis of the Weld Quality of Plasma Arc Welds: A Case Study of Conductor Welds in an Electrical Stator

2009 ◽  
Author(s):  
Hugo I. Medelli´n-Castillo ◽  
Dirk F. de Lange ◽  
Fernando Rami´rez ◽  
Eliel Ferna´ndez
Keyword(s):  
Process Parameters ◽  
Metal Flow ◽  
Flow Characteristics ◽  
Welding Process ◽  
Mechanical Tests ◽  
Weld Quality ◽  
Plasma Arc ◽  
Simulation Tools ◽  
Trial And Error Method

Plasma arc welding (PAW) is a technique used in the electrical component industry for joining electrical conductors in devices such as motors and alternators. With the limited number of theoretical methods and simulation tools to predict the metal flow characteristics and its interaction with the process parameters during the welding process, weld design must still rely on the designers experience and the trial and error method. As a consequence, the process parameters and the weld quality may not be as originally expected at the design process. Based on the fact that a good quality of the final product has to be guaranteed, the analysis of the PAW process and the resulting weld quality is presented in this paper. The aim of the work was to obtain a clear perspective on the influence of various process parameters on the weld quality. In order to measure the influence on quality, first “quality” was defined. Secondly, there were various options to measure the quality, some of them being destructive, others being non-destructive. The development of the measurement methods was then proposed based on electrical tests, mechanical tests and visual inspection of the welds. Finally, using these methods and the experimental data obtained from the actual welding process, a new approach to evaluate the weld quality was proposed and is presented in this paper. The results reveal that the electrical impedance, the mechanical strength and the geometry (visual measure) of the weld are related and can be used to estimate the weld quality.

Mathematical Modeling of the Mold Current and Its Influence on Slag and Ingot Behavior during ESR

2015 ◽  
Vol 15 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Mathilde Hugo ◽  
Alain Jardy ◽  
Bernard Dussoubs ◽  
Jessica Escaffre ◽  
Henri Poisson
Keyword(s):  
Ingot Mold ◽  
Added Value ◽  
Transient Model ◽  
Nuclear Plants ◽  
Slag Properties ◽  
Sensitivity Studies ◽  
Flow Heat ◽  
Melting Current ◽  
Heat Transfer And Solidification

AbstractElectroSlag Remelting (ESR) is widely used to produce high added value alloys for critical applications (aerospace industry, nuclear plants, etc.). In collaboration with Aubert & Duval, Institut Jean Lamour has been developing for several years a numerical transient model of an ESR heat. In the previous version of the model, the crucible was assumed to be perfectly electrically insulated from the electrode-slag-ingot system. However, this assumption must be challenged: the solidified slag skin at the slag/mold and ingot/mold interfaces may actually allow a fraction of the melting current to reach the crucible. In this paper, an evolution of the model is presented that enabled us to take into account the possibility of mold current. The simulation results were compared with actual experimental data. Sensitivity studies showed the influence of slag properties and operating parameters on the final quality of the ingot. Results highlighted that even a weakly conductive solidified slag skin at the inner surface of the model can be responsible for a non-negligible amount of current circulating between the slag and crucible, which modifies the fluid flow, heat transfer and solidification of both the slag phase and the metallic ingot.

scholarly journals Simulation of a new method for supplying and stirring liquid metal in a CCM mold

2021 ◽  
Vol 64 (3) ◽  
pp. 237-243
Author(s):  
V. I. Odinokov ◽  
E. A. Dmitriev ◽  
A. I. Evstigneev ◽  
S. Yu. Aleksandrov
Keyword(s):  
Liquid Metal ◽  
Scientific Literature ◽  
Rectangular Cross Section ◽  
New Technology ◽  
Metal Flow ◽  
Experimental Studies ◽  
Liquid Metal Flow ◽  
New Process ◽  
Flow Diagrams

A significant influence on stability of the process of filling the CCM mold with liquid metal is exerted by the structural and technological schemes and designs of used devices, modes and parameters of filling the mold with the melt. All this is due to the features of the devices used and the improvement of their design. The high requirements for such devices have determined the need to create new devices designs to reduce the time spent on preparation for work and maintenance and to improve the quality of resulting metal billets. In scientific literature, including patents, more and more articles and materials are devoted to the development of new and improvement of the existing methods of supplying and stirring liquid metal in CCM and devices for their implementation. Experimental studies of liquid metal flow in CCM are a long, complex and laborious process. Therefore, mathematical modeling by numerical methods is increasingly used for this purpose. The authors have proposed a new technology for pouring liquid metal into a mold and a device for its implementation due to the use of effect of a deep-bottom submersible nozzle rotating in the mold with eccentric outlet holes. The purpose of this work is to simulate by proven numerical method a new process of filling a rectangular CCM mold with liquid steel and stirring it. Based on the developed numerical schemes and algorithms, a calculation program was compiled. The article describes an example of calculating the steel casting into a mold of rectangular cross-section and flow diagrams of liquid metal in it.

Application Of Cusum Chart In Control Of Paper Quality

GIS Business ◽  
2020 ◽  
Vol 14 (6) ◽  
pp. 1062-1069
Author(s):  
S.Ramesh ◽  
B.A.Vasu
Keyword(s):  
Process Parameters ◽  
Manufacturing Process ◽  
Paper Industry ◽  
Primary Data ◽  
Cusum Chart ◽  
Paper Machine ◽  
Statistical Control ◽  
Operating Characteristics ◽  
Small Shift

This paper is an attempt to assess if the manufacturing process of paper machine is in statistical control thereby improving the quality of paper being produced in a paper industry at the time of process itself. Quality is the foremost criteria for achieving the business target. Therefore, emphasis was made on controlling the quality of paper at the time of manufacturing process itself, rather than checking the finished lots at a later time.  This control on quality will help the industry deduct the small shift in the process parameters and modify the operating characteristics at the time of production itself rather than receiving complaints from customers at a later stage.  This paper describes controlling quality at the time of manufacture itself and helps the industry to concentrate on quality at low cost. The researcher has collected primary data at a leading paper industry during October, 2019.  Though X-bar and Range charges were primarily used, CUSUM charts were used to sense the minor shifts in manufacturing process, to explore the possibility of adjusting process parameters during manufacture of paper.

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