Green Compression Strength Research Articles

Studies on Porosity of Al-4.5%Cu-2.5pTiB<sub>2</sub> <i>In Situ</i> Composites

In the present paper, experimental investigation as well as computer assisted casting simulation technique is used to analyse the effect of different parameters like properties of sand and molding methods to predict defects in green sand casting. An attempt has been made to obtain the optimal settings of the moulding sand and mould related process parameters for the casting of Al-4.5%Cu-2.5TiB2 composites. The green sand related process parameters considered in the study are moisture content, green compressive strength, permeability of moulding sand and mould hardness. In the fabrication of composites, porosity is greatly influenced due to improper gating/riser system design. The analysis of porosity is performed using Auto-CAST simulation technique by the introduction of a new gating system designed and the solid model was developed for sand mould cavity. A number of iterations using Auto-CAST simulation software were performed for mould filling and solidification analysis to reduce the level and intensities of porosities in cast Al-4.5%Cu-2.5TiB2 composite. With new gating and feeding system design, reduction in porosity and improvement in yield is observed. The simulation results were found to be in good agreement when compared with the experimental trial.

Development and mechanism analysis of a highly efficient binder in pelletizing of ilmenite used in electric furnace

The development and mechanism of a highly efficient binder in pelletizing of ilmenite from Panzhihua, China, were investigated. It shows that both the drop strength of green pellets and compressive strength of dried pellets were improved when using the mixtures of starch, NaOH and sodium silicate as the adhesive. Adhesive film was formed on the surface of particles as the function of sodium silicate, promoting the filling of gelatinized starch between the adhesive films to bond the particle tightly. The drop strength of green pellet was 1.3 times/(pellet 700 mm), and the compressive strength of dried pellet of 250 °C was 1825 N/pellets when 0.5 wt% NaOH, 1.0 wt% sodium silicate and 2.0 wt% starch were added as adhesive.

Factors Affecting Ballability of Mixture Iron Ore Concentrates and Iron Oxide Bearing Wastes in Metallurgical Processing

Iron oxide bearing wastes (IOBS) are produced at every part of processing stage of sinter, molten iron and steel production. They are hard to handle and in many cases are stockpiled only to be a source of environmental pollution. However, they can be balled into pellets. Pellets characterized by good ballability values are transportable and recyclable as they can withstand stress without disintegrating back to dust. Yet, ballability is affected by certain factors like the grain sizes of the materials, the moisture and binder contents of the ball mix, wettability of the balled materials and the processing perimeters of the granulator. The objective of this research work is to investigate the factors affecting ballability of mixture of iron ore concentrates and iron oxide bearing wastes in metallurgical processing. The parameters under consideration were: grain size of materials, the moisture contents, speed of balling disc, IOBS and bentonite (binder) contents of the balled mix. The investigation was carried out by balling different volume fractions of mix containing iron oxide concentrate and IOBS using a balling disc and testing the resulting balls for green compressive strength using an universal testing machine. It was found that the ballability of the mixture of iron ore concentrate and IOBS increases as grain sizes of the materials reduce but increases as the moisture contents and IOBS content increase up to an optimum value of moisture content in the mix before it starts to reduce. The ballability also increases along with the speed of the granulator (balling disc) within the limit of this work. An increase in ballability with a slight raise in bentonite content in the mix was observed as well.

Optimization of green sand mould system using Taguchi based grey relational analysis

The strength of the mould cavity in sand casting is very much significant to attain high-quality castings. Optimization of green sand process parameters plays a vital role in minimizing casting defects. In the present research work, the effect of process parameters such as AFS grain fineness number, water, molasses, bentonite, fly ash, and ramming, and their levels on the resultant mould properties were investigated and optimized using Taguchi based grey relational analysis. The Taguchi L18 orthogonal array and analysis of variance (ANOVA) were used. The quality characteristics viz., green compression strength, permeability, bulk density, mould hardness and shatter index of green sand mould were optimized using grey relational grade, based on the experiments designed using Taguchi's Design of Experiments. ANOVA analysis indicated that water content is the most influential parameter followed by bentonite, and degree of ramming that contributes to the quality characteristics. The results are confirmed by calculating confidence intervals, which lies within the interval limits. Finally, microstructure observations and X-ray diffraction analysis have been performed for the optimal sand parametric combination. Results show that presence of maximum amount of Si02, which might be the reason for enhancement of the physical properties of the sand.

Evaluation of Mechanical Properties, Economic and Environmental Benefits of Partially Replacing Silica Sand with Biomass Ash for Aluminium Casting

Green sand molding for metal casting makes up around 70% of the total castings produced worldwide. Silica sand mining and its transportation to foundries harm the ecosystem, rendering this metal casting process environmentally unsustainable. This research paper introduces a novel method of partially replacing the silica sand with biomass ash - a waste product of combustion in various processes such as domestic and commercial cooking. Suitable experiments were conducted to measure the effects of mixing progressively higher proportions of biomass ash (from 9% to 30%) in conventional green sand mold. The molds then underwent tests for the evaluation of technological properties such as green compression strength, green shear strength, permeability and compaction. After suitable pattern making, the molds were tested for casting using LM 24 Aluminium Alloy. The obtained Aluminium Alloy castsings underwent micro hardness tests and micro structure study. The results obtained for biomass ash molding sand were compared with the corresponding tests results for conventional sand mold casting and the results were satisfactory.

Study of mould hardness for alpha set type resin bonded moulding sand system using Taguchi approach for metal casting applications

The quality of the castings are depended on many properties of sand mould like mould hardness, green compression strength, shear strength etc. and these properties in turn dependent on factors such as grain fineness number of sand, setting/curing time, amount of resin, amount of hardener, moisture content etc. Mould hardness is very important while transferring mould from moulding station to pouring station when the weight of the mould is above 100kg and may lead to defects. In the present work, an effort is made to study the mould hardness of a moulding sand specimen using Taguchi technique.L9 orthogonal array is used and experiments are conducted randomly. The main factors such as the amount of resin, amount of hardener and setting time were considered. Factors were selected based on Literature review and brainstorming session with foundries. The chemical (resin and hardener) used is alphas set type two part system. From experiments, it was observed that the Amount of resin and setting time are significant for mould hardness. Confirmation tests were conducted to validate the obtained results.

Multi Response Optimization of the Functional Properties of Rubber Seed – Shear Butter Based Core Oil Using D-Optimal Mixture Design

AbstractIn this study, rubber seed/shea butter oil was used to formulate core oil. The formulated core oil was characterised. D-optimal mixture design was used for multi response optimisation of the functional properties of rubber seed-shea butter coil oil. Desirable values for some responses might be obtained from a factor combination while for others responses not so desirable values. Through multiple response optimisations, a factor setting that gives the desirable values for all responses was obtained. The selected optimum mixture setting for the formulated core oil is 65.937% Rubber seed and 34.063% Shea butter oil at desirability of 0.924. Under the optimum condition the functional properties of the core oil was found to be 39.57KN/M2, 626.85KN/M2, 36.63KN/M2, 593.906KN/M2, 412.605 and 167.309s for Green Compressive Strength, Dry Compressive Strength, Green Tensile Strength, Dry Tensile Strength, Permeability and Collapsibility respectively. The optimum conditions were validated with less than 0.2% error. The functional properties of the formulated core oil was compared to the functional properties of linseed core oil. It was found that rubber seed-shea butter core oil can be used for producing cores suitable for Aluminium casting.

Modeling and optimization of furan molding sand system using design of experiments and particle swarm optimization

The present research work is focussed on establishing the complex nonlinear input–output relations of a furan resin-based molding sand system. Further, a set of input parameters, which will result in optimized mold properties, is determined. Grain fineness number, setting time, percentage of resin, and hardener are considered as process variables. Mold properties, such as green compression strength, shear strength, mold hardness, gas evolution, permeability, and collapsibility are treated as the process outputs. Nonlinear input–output relations have been developed and statistical analysis has been carried out by utilizing design of experiments, central composite design. Surface plots are developed to study and analyze the input–output relations. The input parameters that will result in best molding conditions and improve casting quality characteristics are determined by utilizing desirability function approach and multiple particle swarm optimization-based crowding distance (MOPSO-CD) techniques. The optimum value for the process variables namely grain fineness number, furan resin, hardener, and setting time are found to be equal to 55, 1.85, 1.2, and 60, respectively. The quality characteristics of the castings namely yield strength, ultimate tensile strength, hardness, density, and secondary dendrite arm spacing are found to improve by 14.03%, 15.08%, 14.14%, 12%, 2.22%, and 12.24%, respectively for the castings made in optimized molding sand conditions.

Effect of Mechanical Properties with Addition of Molasses and FlyAsh in Green SandMoulding

The quality of cast products in green sand moulds is mainly influenced by the mould properties, such as green compression strength, dry compression strength and permeability etc. Modified Green Sand (MGS)was made by mixing with different percentages of additives such as molasses and fly ash to green sand. Consequently, cylindrical specimens of MGS were prepared based on standard procedures. In order to study the effect of molasses and fly ash additives to green sand, the prepared MGS specimens were subjected to basic sand testing including permeability, green compression strength and dry compression strength using standard methods and equipment. In the present investigation experiments have been carried out that the Modified Green Sand (MGS) specimens containing molasses 2.25% of green sand by weight and fly ash 15% of green sand by weight were exhibit good green compression strength of 185KPa, dry compression strength of 470kPa and permeability 260 (mmWs). It also obtained experimental results were proved that MGS specimens revealed relatively enhanced properties as compared to green sand specimens contained without any additives.

Investigation of ductile iron casting process parameters using Taguchi approach and response surface methodology

To find the optimized levels of various casting parameters in the ductile iron casting, various casting defects and the rejection rate were observed from a medium scale foundry. The controlled values of different casting parameters such as pouring temperature, inoculation, carbon equivalent, moisture content, green compression strength, permeability and mould hardness were selected. Three different melts of metal with 0.4wt.%, 0.6wt.%, and 0.8wt.% inoculation (Fe-Si-Mg alloy and post inoculant) were produced using a 1-ton capacity coreless medium frequency induction furnace. L-27 orthogonal array with 3-level settings were chosen for the analysis. Responses for each run were observed. The signal-to-noise (S/N) ratio for each run was calculated using the Taguchi approach, and the optimized levels of different casting parameters were identified based on the S/N ratio. The analysis of variance for the casting acceptance percentage concludes that inoculation is the most significant factor affecting the castings’ quality with a contribution percentage of 44%; an increase in inoculation results in a significant improvement in acceptance percentage of ductile iron castings. The experiment results showed that with the optimized parameters, the rejection rate was reduced from 16.98% to 6.07%.

Investigation of Some Moulding Properties of a Nigerian Clay-Bonded Sand

Abstract Moulding properties of Isasa River Sand bonded with Ipetumodu clay (Ife-North Local Government Area, Osun State, Nigeria) were investigated. American Foundry men Society (AFS) standard cylindrical specimens 50mm diameter and 50mm in height were prepared from various sand and clay ratios (between 18% and 32%) with 15% water content. The stress-strain curves were generated from a universal strength testing machine. A flow factor was calculated from the inclination of the falling slope beyond the maximum compressive strength. The result shows that the flowability of the samples increases from 18% to 26% clay content, its maximum value was attained at 26% and then it decreases from 30% to 32% clay content. The green compressive strength, dry compressive strength and air permeability values obtained from the mould samples were in accordance with standard values used in foundry practice. The x-ray diffraction test shows that the sand contains silicon oxide (SiO2), Aluminium oxide (Al2O3), and Aluminium silicate (Al6Si2O13). The mould samples were heated to a temperature of 1200 °C to determine the sintering temperature; fussion did not take place at this temperature. The results showed that the sand and clay mixture can be used to cast ferrous and non-ferrous alloys.

Microstructure, consolidation and mechanical behaviour of Mg/n-TiC composite

In this work, the microstructure, consolidation and mechanical properties of pure magnesium, magnesium based composite containing with different fractions (5, 10, 15wt%) of Titanium carbide nanoparticles (n-TiC) were fabricated via powder metallurgy technique. The fabricated composites exhibited homogeneous distribution of TiC with little porosity. Microstructure of the composite and powders was studied using X-ray diffraction, Scanning electron microscope, and Transmission electron microscope. Microstructural characterization of the materials exposed that the accumulation of nanosized titanium carbide reinforcement enhanced the homogenization during mechanical blending. The relative density, compressibility, green compressive strength, sinterability and hardness of the nanocomposites were also examined. The effect of reinforcement on the densification was studied and reported in terms of the relative density and consolidation behaviour of the Magnesium matrix with n-TiC was studied and best compacted fit obtained through the Heckel, Panelli Ambrosio Filho and Ge equations. The compressive strength of the composite significantly increases from 230MPa to 389MPa with content of n-TiC and sintering temperature. Experiments have been performed under different conditions of temperature, n-TiC Content, and compacting pressure.

Assessment of Locust Bean Pod Extract for Foundry Core Making

This paper reports the experimental results on the use of locust bean pod extract as core binder in the foundry industry. Binders appropriate for foundry cores must not only hold the sand grains together, but must also be adequately resistant to high temperature, so as to avoid collapse before the metal solidifies, but after solidification and cooling, they must be able to collapse completely allowing easy removed from the casting. The Locust Bean Pod (Parkia biglobosa) is a waste material that is normally discarded after the seeds had been harvested. Results of the properties of cores produced with the locust bean pod extract as binder showed baking strength of 510 kN/m 2 , green compression strength of 74 N/mm 2 , bulk density of 1840 kg/m 3 , green permeability of 100 perm unit, moisture content of 4.6%, mouldability index of 24 and 45% flowability. The results obtained showed that the locust bean pod extract could serve as an effective binder of high core strength for core making process.

Role of hybrid reinforcement on microstructural observation, characterization and consolidation behavior of AA 6061 nanocomposite

The present investigation had dealt with the synthesis, characterization and consolidation behavior of AA 6061 nanocomposites reinforced with hybrid (TiC+Al2O3) nanoparticles with varying weight percentages (0.0, 0.5, 1.0, 1.5 and 2.0wt.%) prepared by 30h of mechanical alloying (MA) and compared with 2wt.% of various reinforcements such as titanium carbide (TiC), multi-walled carbon nanotubes (MWCNTs), gamma phase alumina (γ-Al2O3) nanoparticles. The microstructure, grain size, lattice strain and lattice parameter of the above powders were examined using different analysis techniques including X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive spectrometry (EDS). The compressibility and sinterability of the prepared nanocomposites at varying sintering temperatures and varying compaction pressures were also studied. Consolidation behavior in terms of particle rearrangement and plastic deformation mechanisms were evaluated by Balshin, Heckel, Panelli and Ambrosio Filho and Ge linear compaction equations. The effect of hybrid and nanolevel reinforcements on mechanical properties such as green compression strength, Vickers hardness and density of nanocomposites were evaluated. Among the above nanolevel reinforcements, hybrid (TiC+Al2O3) and TiC nanoparticles gave maximum green compression strength (211 and 233MPa) and maximum hardness (985 and 1186MPa) for 2wt.% addition to AA 6061 matrix after 30h of MA.

Investigating Approaches for Three-Dimensional Printing of Hydroxyapatite Scaffolds for Bone Regeneration

This study investigated the feasibility of manufacturing hydroxyapatite (HA)-based scaffolds using 3D printing technology by incorporating different binding additives, such as maltodextrin and polyvinyl alcohol (PVOH), into the powder formulation. Different grades of PVOH were evaluated in terms of their impact on the printing quality. Results showed that scaffolds with high architectural accuracy in terms of the design and excellent green compressive strength were obtained when the PVOH (high viscosity) was used as the binding additive for HA.

Application of Molasses as a Binder in Sand Mold Operation

The application of molasses as a binder in sand mold operation was investigated. Standard Sand Mold mixture (5 cm diameter x 5 cm height) were made with 1-5% molasses and Chalawa sand the balance. The molding Properties such as ; Green Compressive Strength(GCS), Green Shear Strength(GSS), Dry Compressive Strength(DCS), Dry Shear Strength(DSS), Green Shatter Index, Green Permeability, Flowability, and Compactibility of sand molasses mixture were obtained. 2% Molasses-sand mixture was selected for molding the prototype cast based on the highest values of the Green Compressive Strength, Green Permeability, and excellent Flowability (96.4%) observed in the experiments. The result shows that molasses alone could not be used as a binder. This is further supported by the low values of Green Shatter Index (31.3%) and Compactibility (25%) reported.

Microstructural observation, consolidation and mechanical behaviour of AA 6061 nanocomposites reinforced by γ-Al2O3 nanoparticles

AA 6061 nanocomposites of nanocrystallite powders reinforced with nano-alumina particles were synthesized and investigated in this study. A uniform distribution of nano γ-Al2O3 in the AA 6061 nanocrystallite matrix was successfully obtained after 30h of mechanical alloying (MA). The compressibility and sinterability of the prepared nanocomposite powders at varying sintering temperatures and varying compaction pressures was also studied. The consolidation behaviour of the AA 6061/γ-Al2O3 nanocomposites was evaluated using the Balshin, Heckel, Panelli and Ambrosio Filho, and Ge linear compaction equations. The compression strength of the green samples and the Vickers hardness of the nanocomposites were also evaluated. A maximum green compression strength of 176MPa and a maximum hardness of 740MPa were obtained for the addition of 2wt.% Al2O3 nanoparticles to the AA 6061 matrix after 30h of MA.

Sugar industry fly ash: an additive for molding sand to make aluminium castings

X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and energy-dispersive spectroscopy studies were performed with molding sand and sugar industry fly ash to evaluate and compare their physical properties. We noted that several physical properties of sugar industry fly ash and molding sand were similar. We then tested the permeability, green compression strength and dry compression strength of various compositions of sugar industry fly ash and bentonite to explore their potential as an alternative to molding sand, thereby reducing the dependency on the latter, as well as to suggest an effective way for disposal of fly ash from sugar industry. We also found that quality aluminium castings could be produced using fly ash, which effectively replaced 24% of molding sand in the foundry, thereby reducing the cost of production and increasing the surface finish of castings.

Fabrication and consolidation behavior of Al 6061 nanocomposite powders reinforced by multi-walled carbon nanotubes

The composite behavior of an Al 6061 nanocrystalline matrix reinforced with different weight percentages (0, 0.5, 1.0, 1.5 and 2.0wt.%) of multi-walled carbon nanotubes (MWCNTs) produced by mechanical alloying (MA) with a milling time of 30h was investigated. MWCNTs were added during the last 2h of milling to avoid structural damage during MA. The milled powders were consolidated by cold uni-axial compaction followed by sintering at different temperatures (450°C, 525°C and 600°C) under a reducing atmosphere (N2) to evaluate the materials' sinterability. The structure of the MWCNTs was evaluated by Raman spectroscopy of as-received pure MWCNTs, Al 6061-2wt.% MWCNT nanocomposite powder after 30h MA and sintered samples of Al 6061-1wt.% MWCNTs & Al 6061-2wt.% MWCNTs. The crystallite size and lattice parameter of the composites were examined. The relative density, compressibility, green compressive strength, sinterability and Vickers hardness of the composites were also examined. The effects of MWCNTs as reinforcement on the consolidation behavior of the nanocrystalline matrix were studied using the Heckel, Panelli and Ambrosio Filho and Ge equations. The fabricated composites exhibited high Vickers hardness of 76HV (818MPa), which is approximately three times higher than that of microcrystalline Al 6061. However, because of MWCNTs that were added during the last 2h of milling, higher hardness values were obtained in this investigation.

Printability of calcium phosphate: Calcium sulfate powders for the application of tissue engineered bone scaffolds using the 3D printing technique

In this study, calcium phosphate (CaP) powders were blended with a three-dimensional printing (3DP) calcium sulfate (CaSO4)-based powder and the resulting composite powders were printed with a water-based binder using the 3DP technology. Application of a water-based binder ensured the manufacture of CaP:CaSO4 constructs on a reliable and repeatable basis, without long term damage of the printhead.Printability of CaP:CaSO4 powders was quantitatively assessed by investigating the key 3DP process parameters, i.e. in-process powder bed packing, drop penetration behavior and the quality of printed solid constructs. Effects of particle size, CaP:CaSO4 ratio and CaP powder type on the 3DP process were considered. The drop penetration technique was used to reliably identify powder formulations that could be potentially used for the application of tissue engineered bone scaffolds using the 3DP technique.Significant improvements (p<0.05) in the 3DP process parameters were found for CaP (30-110μm):CaSO4 powders compared to CaP (<20μm):CaSO4 powders. Higher compressive strength was obtained for the powders with the higher CaP:CaSO4 ratio. Hydroxyapatite (HA):CaSO4 powders showed better results than beta-tricalcium phosphate (β-TCP):CaSO4 powders. Solid and porous constructs were manufactured using the 3DP technique from the optimized CaP:CaSO4 powder formulations. High-quality printed constructs were manufactured, which exhibited appropriate green compressive strength and a high level of printing accuracy.