The Experts below are selected from a list of 2409 Experts worldwide ranked by ideXlab platform
Paul Anthony Withey - One of the best experts on this subject based on the ideXlab platform.
-
investigation into the use of cazro3 as a facecoat material in the Investment Casting of tial alloys
Materials Chemistry and Physics, 2015Co-Authors: C Yuan, Paul Anthony Withey, Xu ChengAbstract:Abstract Research was carried out to determine the interactions between the filler and stucco materials in CaZrO3 based facecoats during shell firing as well as between the facecoat and a TiAl alloy during the Casting Process. A ‘flash re-melting’ technique, which gives a similar heating profile to the actual Investment Casting Process, was used to study the phase transformations in the shell moulds. The chemical inertness of the facecoat was then investigated using a sessile drop test using a Ti–45Al–2Nb–2Mn–0.2TiB alloy. In this study, the facecoat compositions and the interaction products between metal and shells were characterized using x-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A severe interaction was found between CaZrO3 filler and Al2O3 stucco, which rapidly damaged the shell surface. As well as oxygen, zirconium and silicon ions from the shell moulds were also observed to penetrate into the TiAl metal to form (Ti, Zr)5(Al, Si)3 phases in the metal/shell interfacial areas.
-
a comparison of the chemical inertness of two y2o3 al2o3 zro2 and y2o3 al2o3 face coat materials through sessile drop and Investment Casting methods
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2014Co-Authors: S Blackburn, C Yuan, Paul Anthony Withey, Xu ChengAbstract:Investment Casting is uniquely suited to the manufacture of Ti alloys for the production of near net-shape components, reducing material waste, and machining costs. Because of the high reactivity of titanium and its based alloy, the molds which are used in the Investment Casting Process require high chemical inertness, which results in them being very costly and non-recyclable. In order to reduce the cost of these molds, traditionally using yttria as the face coat, two alternative molds are developed in this study with face coat materials of Y2O3-Al2O3 and Y2O3-Al2O3-ZrO2. The slurry properties and chemical inertness of the face coats were evaluated for viscosity, thermal expansion, friability, and phase development. The chemical inertness of these two molds were determined using both the sessile drop test and Investment Casting to identify the levels of interaction with a Ti-45Al-2Mn-2Nb-0.2B alloy. The results illustrated that the molds using Y2O3-Al2O3 and Y2O3-Al2O3-ZrO2 as the face coats both showed excellent sintering properties and chemical inertness when compared to the yttria face coat. They can consequently be used as two alternative face coats for the Investment Casting of TiAl alloys.
-
an investigation of a tialo based refractory slurry face coat system for the Investment Casting of ti al alloys
Intermetallics, 2012Co-Authors: Xu Cheng, N R Green, C Yuan, Paul Anthony WitheyAbstract:Abstract The Investment Casting Process offers great freedom of design with the economic advantage of near net shape production and has been widely used to Process TiAl alloys. An investigation was undertaken to develop stable and cheap refractory slurry systems, suitable for use as a face coat in the Investment Casting of titanium aluminides. A TiO2–Al2O3 (TiAlO) based face coat slurry was investigated and compared with a traditional yttria based face coat slurry. After sintering, the chemical inertness of the manufactured shells in contact with molten TiAl alloys was tested by simulating the Casting Process using a flash re-melting test, in which sample shells were in contact with titanium aluminides at given temperatures for varying time durations and subsequently re-solidified. Compared with yttria, the TiAlO face coat had relatively lower chemical inertness against molten alloys, forming a thick hardened layer at the metal/shell interface with massive interaction products along grain boundaries. The reaction also changed the wetting behaviour of the TiAl on the TiAlO face coat with the contact angle decreasing as a function of interaction time.
Hassan Jafari - One of the best experts on this subject based on the ideXlab platform.
-
in situ melting and solidification assessment of az91d granules by computer aided thermal analysis during Investment Casting Process
Materials & Design, 2013Co-Authors: Hassan Jafari, Mohd Hasbullah Idris, Ali Ourdjini, Saeed FarahanyAbstract:Abstract Computer-aided thermal analysis was carried out to precisely measure the thermal characteristics of AZ91D magnesium alloy granules during in situ melting and solidification in Investment Casting Process. Ceramic shell moulds of two different thicknesses equipped with highly sensitive thermocouples at three different locations were prepared to provide a range of heating and cooling rates during in situ melting and solidification. The results revealed that dissimilar thermal regimes were experienced by the granules at different locations of the mould during heating, which led to asynchronous melting of the granules. It was found that both melting commencement and completion were increased with increasing heating rate; in contrast inverse behaviour was observed during cooling. The onset and the end of solidification temperatures and duration decreased with increasing cooling and solidification rates. The information from this approach is very crucial for suppressing mould-metal reaction especially during cooling in Casting of magnesium alloys by Investment Casting Process.
-
an investigation on interfacial reaction between in situ melted az91d magnesium alloy and ceramic shell mold during Investment Casting Process
Materials Chemistry and Physics, 2013Co-Authors: Hassan Jafari, Mohd Hasbullah Idris, Ali Ourdjini, Mohammed Rafiq Abdul KadirAbstract:Abstract The reaction between ceramic shell Investment mold and AZ91D magnesium alloy as well as the related mechanism involved during Investment Casting Process using in-situ melting technique were explored. AZ91D granules were melted in a ceramic shell Investment Casting mold at 750 °C in an argon protected environment and a melting flux. The interface of adhered Investment-AZ91D cast alloy and the residues that appeared on the surface of the Castings, as the mold–metal reaction products, were analyzed to determine the morphology, elements and compounds that may have developed due to the reactions. It was discovered that the high Process temperature and high affinity of magnesium with oxygen developed cracks in the ceramic shell Investment mold. Penetration of molten metal through the cracks also occurred and caused adherence of Investment on the Casting surface. The results showed that the black residue with a granular morphology has the same microstructure as that of AZ91D alloy and also comprises of MgO and Mg2Si on its surface. The findings revealed that two types of products formed on the shell surface due to the mold–metal reaction. The first product formed on the surface as a result of the reaction between AZ91D alloy and the binder producing MgO and MgAl2O4. The second product formed because of the penetration of Mg into the ceramic shell Investment mold followed by reaction with oxygen bearing materials forming MgO and Mg2Si.
Sarojrani Pattnaik - One of the best experts on this subject based on the ideXlab platform.
-
enhancement of ceramic slurry rheology in Investment Casting Process
Arabian Journal for Science and Engineering, 2021Co-Authors: Sarojrani Pattnaik, Mihir Kumar SutarAbstract:Investment Casting (IC) Process utilizes a single use ceramic shell as mold for Casting. The accuracy and surface finish of the interior of the ceramic shells is transferred to the Castings. The quality of the ceramic shell depends upon the constituents and characteristics of the ceramic slurry. The present exploration deals with finding a solution how to maintain the prepared primary slurry characteristics after 24 h duration for future application. The stability of the primary slurry was achieved by forming a thin layer of argon gas over the prepared primary slurry surface so that it is not exposed to atmosphere. The primary slurry properties, i.e., viscosity, density, plate weight and pH value, were determined after 24 h of exposure of the slurry to argon gas. A comparison of the aforementioned slurry characteristics was made between the slurry without (A) and with (B) coverage of argon gas at the top of slurry surface. It was found that the slurries A and B possessed viscosities of 1862 and 1563 cp, densities of 4.31 and 3.74 gm/cm3, plate weights of 0.232 and 0.209 gm/cm2 and pH of 8.3 and 8.9, respectively, at the end of 24 h duration. It shows that argon gas coverlet over the slurry B led to significant improvement in preserving the slurry characteristics. Furthermore, the surface texture of the interior of the primary layer formed using slurry B was better than that by slurry A.
-
A prediction model for the lost wax Process through fuzzy-based artificial neural network
2020Co-Authors: Sarojrani Pattnaik, Benny Karunakar, P K JhaAbstract:Abstract The application of Investment Casting Process is rapidly increasing, specifically for near net shape manufacturing of complex and small engineering components. The Process begins with making of wax patterns, thereafter employing a precision mould, dewaxing, pouring molten alloy and knocking the shell, followed by minor finishing operations. This study is about predicting the quality of responses of the wax patterns namely linear shrinkage and surface roughness using fuzzy-based artificial neural network. The Process parameters considered are injection temperature, injection pressure and holding time, and experiments have been performed as per Taguchi's L 18 orthogonal array. As optimum parameter levels were different for both the responses, fuzzy logic reasoning has been used to combine all the objectives and transform the experimental results into single performance index known as multi-response performance index. Later, modelling of the Process has been done using artificial neural network with experimental Process parameters as inputs and multi-response performance index as output obtained from fuzzy modelling. Further, experiments have been conducted at random combination of parameter levels to validate the developed model, and it has been found that the actual results agreed well with that of the predicted value on the basis of mean absolute percentage error and correlation plots
-
influence of sawdust on the properties of the ceramic shell used in Investment Casting Process
The International Journal of Advanced Manufacturing Technology, 2017Co-Authors: Sarojrani PattnaikAbstract:The quality of the Investment Casting (IC) ceramic shell was enhanced using sawdust as an inexpensive and naturally available additive in the ceramic slurries. The important shell properties such as thickness, porosity, permeability and flexural strength were determined. The ceramic shell accommodated a substantial amount of sawdust because of its low particle density and porous structure which resulted in higher green strength and thickness of the shell. The same shell upon firing led to increased shell porosity and permeability with good knockability characteristic. The addition of sawdust in the secondary layers did not affect the composition of the primary layer of the ceramic shell. The mechanical properties of the aluminium-silicon (Al-Si) alloy Castings obtained from the sawdust-modified shells were found to be comparatively higher than those obtained from the conventional shells.
-
optimization of the Investment Casting Process using genetic algorithm
2015Co-Authors: Sarojrani Pattnaik, Sutar Mihir KumarAbstract:This paper presents a study in which an attempt has been made to improve the quality characteristic (surface finish) of the wax patterns used in the Investment Casting Process. The wax blend consists of paraffin wax (20 %), carnauba wax (10 %), microcrystalline wax (20 %), polyethylene wax (10 %) and teraphenolic resin (40 %), which provided an improved pattern wax composition. The Process parameters considered are injection temperature, holding time and die temperature. The injection Process parameters are optimized by genetic algorithm. Further, verification test have been conducted at the obtained optimal setting of Process parameters to prove the effectiveness of the method. Finally, a good agreement between the actual and the predicted results of surface roughness of the wax patterns has been found.
-
parametric optimization of the Investment Casting Process using utility concept and taguchi method
Proceedings of the Institution of Mechanical Engineers Part L: Journal of Materials: Design and Applications, 2014Co-Authors: Sarojrani Pattnaik, D. Benny Karunakar, Pradeep K JhaAbstract:Investment Casting Process, also known as lost wax Process, is utilized when complex detail, undercuts or non-machinable features and accurate parts are desired. It begins with a wax pattern which is an exact replica of the as cast part. So the properties of the wax patterns are ultimately passed on to the Castings. This article highlights the application of utility concept with Taguchi method for the multi-response optimization of wax patterns made by the Investment Casting Process. The wax injection Process parameters considered are injection temperature, injection pressure and injection time, whereas the responses are linear shrinkage, surface roughness and penetration, respectively. The experiments are planned as per Taguchi’s L9 orthogonal array. The utility concept converts multi-response optimization problem into single response optimization problem and thereafter Taguchi method is applied. The results indicate that injection pressure is the most significant Process parameter influencing the qualit...
Xu Cheng - One of the best experts on this subject based on the ideXlab platform.
-
investigation into the use of cazro3 as a facecoat material in the Investment Casting of tial alloys
Materials Chemistry and Physics, 2015Co-Authors: C Yuan, Paul Anthony Withey, Xu ChengAbstract:Abstract Research was carried out to determine the interactions between the filler and stucco materials in CaZrO3 based facecoats during shell firing as well as between the facecoat and a TiAl alloy during the Casting Process. A ‘flash re-melting’ technique, which gives a similar heating profile to the actual Investment Casting Process, was used to study the phase transformations in the shell moulds. The chemical inertness of the facecoat was then investigated using a sessile drop test using a Ti–45Al–2Nb–2Mn–0.2TiB alloy. In this study, the facecoat compositions and the interaction products between metal and shells were characterized using x-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A severe interaction was found between CaZrO3 filler and Al2O3 stucco, which rapidly damaged the shell surface. As well as oxygen, zirconium and silicon ions from the shell moulds were also observed to penetrate into the TiAl metal to form (Ti, Zr)5(Al, Si)3 phases in the metal/shell interfacial areas.
-
a comparison of the chemical inertness of two y2o3 al2o3 zro2 and y2o3 al2o3 face coat materials through sessile drop and Investment Casting methods
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2014Co-Authors: S Blackburn, C Yuan, Paul Anthony Withey, Xu ChengAbstract:Investment Casting is uniquely suited to the manufacture of Ti alloys for the production of near net-shape components, reducing material waste, and machining costs. Because of the high reactivity of titanium and its based alloy, the molds which are used in the Investment Casting Process require high chemical inertness, which results in them being very costly and non-recyclable. In order to reduce the cost of these molds, traditionally using yttria as the face coat, two alternative molds are developed in this study with face coat materials of Y2O3-Al2O3 and Y2O3-Al2O3-ZrO2. The slurry properties and chemical inertness of the face coats were evaluated for viscosity, thermal expansion, friability, and phase development. The chemical inertness of these two molds were determined using both the sessile drop test and Investment Casting to identify the levels of interaction with a Ti-45Al-2Mn-2Nb-0.2B alloy. The results illustrated that the molds using Y2O3-Al2O3 and Y2O3-Al2O3-ZrO2 as the face coats both showed excellent sintering properties and chemical inertness when compared to the yttria face coat. They can consequently be used as two alternative face coats for the Investment Casting of TiAl alloys.
-
an investigation of a tialo based refractory slurry face coat system for the Investment Casting of ti al alloys
Intermetallics, 2012Co-Authors: Xu Cheng, N R Green, C Yuan, Paul Anthony WitheyAbstract:Abstract The Investment Casting Process offers great freedom of design with the economic advantage of near net shape production and has been widely used to Process TiAl alloys. An investigation was undertaken to develop stable and cheap refractory slurry systems, suitable for use as a face coat in the Investment Casting of titanium aluminides. A TiO2–Al2O3 (TiAlO) based face coat slurry was investigated and compared with a traditional yttria based face coat slurry. After sintering, the chemical inertness of the manufactured shells in contact with molten TiAl alloys was tested by simulating the Casting Process using a flash re-melting test, in which sample shells were in contact with titanium aluminides at given temperatures for varying time durations and subsequently re-solidified. Compared with yttria, the TiAlO face coat had relatively lower chemical inertness against molten alloys, forming a thick hardened layer at the metal/shell interface with massive interaction products along grain boundaries. The reaction also changed the wetting behaviour of the TiAl on the TiAlO face coat with the contact angle decreasing as a function of interaction time.
D. Benny Karunakar - One of the best experts on this subject based on the ideXlab platform.
-
Characterization and Properties of Ceramic Shells in Investment Casting Process
International Journal of Metalcasting, 2020Co-Authors: Sanjay Kumar, D. Benny KarunakarAbstract:Investment Casting is an effective way to produce very thin and most complex components with very high-dimensional accuracy and surface finish. A wax pattern is repeatedly dipped into ceramic slurry, and coarse stucco is sprinkled over it to develop a ceramic shell. Very fine ingredients are used to achieve smooth internal surface in the ceramic shell. These fine ingredients of the inner coat reduce the shell permeability, which lead to porosity defects on the cast part. In the present work, an attempt is made to enhance the permeability of ceramic shell by mixing fine needle coke and coarse needle coke powders to inner and outer coat slurries, respectively. After firing, fine needle coke and coarse needle coke got burnt and left some microspores and macrospores in the inner and outer layers of the shell, respectively. These pores improved the shell permeability to a considerable extent. Modified ceramic slurry with needle coke offered higher slurry retention rate as compared to the conventional slurry. Modified shell also possesses sufficient flexural strength and fair inner surface roughness. Field-emission scanning electron microscope (FE-SEM) is used to examine the microstructure of conventional and modified shells, and it is found that some pores are developed at the inner and outer layers of the modified shell, which lead to increment in permeability.
-
Enhancing the Permeability and Properties of Ceramic Shell in Investment Casting Process Using ABS Powder and Needle Coke
International Journal of Metalcasting, 2019Co-Authors: Sanjay Kumar, D. Benny KarunakarAbstract:In the Investment Casting Process, initially, a wax pattern is made, around which repeated slurry/stucco coatings are applied. The slurry is made up of very fine ceramic ingredients like zircon flour, etc. Once the ceramic slurry is dried out, a ceramic shell is formed around the wax pattern. After drying out of the ceramic shell, the wax is drained out and the shell is fired in an oven for inducing additional strength. Molten metal is then poured into the ceramic shell. Because of the fine ingredients of the ceramic shell, the Investment Casting gets a very fine surface roughness, compared to a conventional sand Casting. However, the ceramic shell exhibits poor permeability, which often results in porosity defects. Hence, in the present work, an attempt was made to enhance the permeability of ceramic shell by mixing certain fillers like acrylonitrile–butadiene–styrene (ABS) powder and needle coke to the ceramic slurry. Fine ABS powder was added to the inner coat slurry in a very small proportion. The ABS powder, upon heating, got burnt and left micropores inside the inner coating of the shell. In a similar way, needle coke was added to the outer coat slurry in a very small proportion. During the firing of the shell, the needle coke got burnt and, consequently, macropores were created in the outer coating of the shell, which would enable escape of undesirable gases that may generate inside the shell. This ultimately would reduce the porosity defects in the final cast parts. Tests conducted on the ceramic shell modified with ABS powder and needle coke reveal that the modified shell possesses higher permeability compared to the conventional one. The modified shell also possesses adequate mechanical properties like flexural strength, hot tensile strength, etc., and fair surface roughness.
-
parametric optimization of the Investment Casting Process using utility concept and taguchi method
Proceedings of the Institution of Mechanical Engineers Part L: Journal of Materials: Design and Applications, 2014Co-Authors: Sarojrani Pattnaik, D. Benny Karunakar, Pradeep K JhaAbstract:Investment Casting Process, also known as lost wax Process, is utilized when complex detail, undercuts or non-machinable features and accurate parts are desired. It begins with a wax pattern which is an exact replica of the as cast part. So the properties of the wax patterns are ultimately passed on to the Castings. This article highlights the application of utility concept with Taguchi method for the multi-response optimization of wax patterns made by the Investment Casting Process. The wax injection Process parameters considered are injection temperature, injection pressure and injection time, whereas the responses are linear shrinkage, surface roughness and penetration, respectively. The experiments are planned as per Taguchi’s L9 orthogonal array. The utility concept converts multi-response optimization problem into single response optimization problem and thereafter Taguchi method is applied. The results indicate that injection pressure is the most significant Process parameter influencing the qualit...
-
Utility-Fuzzy-Taguchi based hybrid approach in Investment Casting Process
International Journal on Interactive Design and Manufacturing (IJIDeM), 2014Co-Authors: Sarojrani Pattnaik, D. Benny Karunakar, P K JhaAbstract:In this paper, the use of the Utility-Fuzzy-Taguchi based hybrid approach in Investment Casting Process for optimizing multiple quality characteristics of wax patterns has been conceptualized. Selection of an appropriate orthogonal array, preference scale construction followed by preference values, generation of multi-performance index (MPI) by fuzzy logic, analysis of means and analysis of variance are employed to study the performance characteristics of the Process. The control factors considered are injection temperature, injection pressure and injection time, whereas linear shrinkage, surface roughness and penetration are the corresponding responses. The optimal setting obtained by the proposed method is validated by confirmatory experiments. This concludes the application feasibility of the proposed method for parametric optimizations in Investment Casting Process. Further, the result of the aforementioned optimization technique has been compared with that of Utility-Taguchi technique. It is found that the optimal condition for both is same, while the most influential Process parameter is different in both cases due to employment of random selection of weights in Utility-Taguchi method.
-
Enhancement of porosity of the ceramic shell in Investment Casting Process using needle coke and camphor
Applied Mechanics and Materials, 2014Co-Authors: Khyati Tamta, D. Benny KarunakarAbstract:Investment Casting Process has been a widely used Process for centuries. It is known for its ability to produce components of complex shapes with dimensional accuracy and excellent surface finish. Investment Casting has been used to make manufacture weapons, jewellery and art Castings during the ancient civilization and today it is used to manufacture engineering components. In Investment Casting wax patterns are made by wax injection and then coating of the wax patterns are done by ceramic slurry, made with silica flour and binder. After dewaxing and firing molten metal is poured in the shell and solidified Casting can be achieved. Investment Casting can be cast any ferrous and non ferrous metal which is difficult in die Casting. Finishing operations are negligible and very thin sections as.75mm can also be cast which is not possible in sand Casting but there are many challenges in Investment Casting. It is relatively slow Process because preparation of ceramic shell consumes a lot of time, permeability of shell is very low which causes gas permeability. Incorporation of chills is very difficult. Among all these challenges gas porosity is main problem because of poor permeability, entrapment of gases due to complex geometry of the shell, reuse of scrap metal. In the present work porosity of the shell can be increase by addition of mixture of Camphor and needle coke. After firing of the shell camphor and needle coke will be burnt leaving pores for the escape of entrapped gases. Mechanical properties of the both shell will be compared with each other.
