Effect of Mold Material on Boundary Heat Flux Transients during Gravity Die-Casting

2015 ◽  
Vol 766-767 ◽  
pp. 405-409 ◽  
Author(s):  
S. Sanman ◽  
K.V. Sreenivas Rao ◽  
K.C. Anil
Keyword(s):  
Heat Flux ◽  
Stainless Steel ◽  
Cast Iron ◽  
Die Casting ◽  
Pure Aluminum ◽  
Cooling Curve ◽  
Mold Material ◽  
Data Logger ◽  
Steel Mold ◽  
Iron Mold

Experiments were conducted to study the effect of mold material on boundary heat flux variation during gravity die-casting. Inverse method was used for determining heat flux on the inside and outside surface of the mold during casting of pure Aluminum and Al-B4C composites. Different chill materials were used as mold material on one side of the rectangular mold cavity. K- type thermocouples were used for measurement of mold temperature during casting solidification. The mold temperatures at various locations were recorded using a data logger. These measured temperatures were used as input by the inverse algorithm for the assessment of the surface heat flux as a function of time. It was observed that the temperature difference between the inner and outer surface of the copper is very less in comparison to the cast iron mold and stainless steel mold. The cooling curve of the insulation mold indicates that there is no heat transfer through the insulation mold. The boundary heat flux is much higher in the case of copper mold than in the cases of cast iron mold and stainless steel mold.

Modeling of Interface Heat Flux and Thermal Field of Mold Materials during Gravity Die Casting

2017 ◽  
Vol 895 ◽  
pp. 85-88
Author(s):  
K.V. Sreenivas Rao ◽  
P. Usha ◽  
S. Sanman ◽  
R. Anilchoudary
Keyword(s):  
Boundary Condition ◽  
Heat Flux ◽  
Stainless Steel ◽  
Cast Iron ◽  
Heat Conduction ◽  
Thermal Field ◽  
Temperature Data ◽  
Temperature History ◽  
Steel Mold ◽  
Interface Heat

One of the key controllable and influential factors to obtain a casting simulation, representative of reality, is the choice of boundary condition. The thermal boundary condition to be specified at the metal-mold interface must account for complex heat transfer phenomena associated with solidifying casting. The present study aims at estimating the heat flux at the interface of the mold and the solidifying metal by Inverse Heat Conduction Problem (IHCP) approach. Solidification studies were conducted on casting of aluminum reinforced with boron carbide composite. Copper, cast iron and stainless steel were used as mold materials. The temperature data of the mold was recorded from the beginning to end of solidification using k-type thermocouples connected to temperature data logger. This time-temperature history was used as input to the IHCP algorithm to simulate the interface heat flux and thermal field of the mold. The results indicate that the interface heat flux is highly transient and varies with the variation in the thermo-physical properties of the mold materials. The study also demonstrates that heat conduction is one dimensional in copper mold and two dimensional in cast iron and stainless steel mold during phase change.

The dependency of the microhardnes on microstructure and solidification parameters of directionally solidified Al–4.5wt.%Cu in clay mold

2020 ◽  
Vol 14 (3) ◽  
pp. 7125-7131
Author(s):  
Dedy Masnur ◽  
Viktor Malau ◽  
Suyitno Suyitno
Keyword(s):  
Solidification Process ◽  
Optical Microscope ◽  
Cooling Curve ◽  
Mold Material ◽  
Micro Hardness ◽  
Directionally Solidified ◽  
Steel Mold ◽  
Hardness Tester ◽  
Microstructure Parameters ◽  
Solidification Parameters

Improvement of material properties is achieved by controlling parameters involved in the solidification process; therefore, understanding them and their implication are essential. This work investigated the dependency of solidification parameters (cooling rate (TR), growth rate (VL), local solidification time (tSL), temperature gradient (G)), microstructure parameters (primary (λ1) and secondary (λ2) dendrite arm spacing), and micro-hardness values (HV) of Al-4.5wt.%Cu in the clay mold. The samples were directionally solidified in Bridgman vertical apparatus and the temperature is recorded during the cooling. The solidification parameters were obtained from the cooling curve. The microstructures and micro-hardness were characterized using an optical microscope and micro-hardness tester. The microstructure parameters were measured and plotted as functions of solidification parameters using linear regression. The relation between HV and microstructure parameters are analyzed. The results show the λ1 and λ2 change inversely with solidification parameters except for tSL. Comparison to other works shows the exponent values of solidification parameters of the clay mold are lower than that of the carbon and stainless-steel mold. The exponent value of λ2 in the clay mold is -0.183, close to the value in the graphite mold. The clay has the potential as mold material since it characteristic close to the graphite.

Effect of Stainless Steel Flakes Content on Mechanical Properties and Microstructure of Cast 96.66% Pure Aluminum

2018 ◽  
Vol 21 ◽  
pp. 11-19
Author(s):  
Georgios V. Seretis ◽  
Aikaterini K. Polyzou ◽  
Dimitrios E. Manolakos ◽  
Christopher G. Provatidis
Keyword(s):  
Stainless Steel ◽  
Pure Aluminum ◽  
Matrix Material ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composite ◽  
Performance Comparison ◽  
Aluminum Matrix Composites ◽  
Cast Aluminum ◽  
Microstructural Investigation ◽  
Steel Mold

Stainless steel flakes-reinforced cast aluminum matrix composites were produced using aluminum alloy of 96.66% purity as matrix material and different steel flakes contents as reinforcements. Aluminum matrix specimens with no steel flakes fillers addition were also produced for performance comparison. All specimens were cast into a slightly heated rectangular quenched steel mold, the temperature of which was 35 °C. Both matrix aluminum specimens and aluminum matrix composite specimens underwent tensile and bending tests as well as hardness measurements and microstructural investigation. As observed through microstructural examination, the interdendritic regions do not seem to be affected by steel flakes addition on their at% chemical composition, which remains Al:Fe:Mn:Mg ; 92.28:3.75:2.96:1.01, but only on their size. An increase of the flexure strength of about 20% was achieved by steel flakes-reinforcement of the matrix aluminum. In the case of the highest wt% addition, groups of steel flakes of high directivity towards solidification kernels were observed. These steel flakes group formations resulted in an impressive hardness increase, performing as hard support elements.

scholarly journals Solidification Pattern of Si-Alloyed, Inoculated Ductile Cast Irons, Evaluated by Thermal Analysis

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 846
Author(s):  
Iuliana Stan ◽  
Denisa Anca ◽  
Stelian Stan ◽  
Iulian Riposan
Keyword(s):  
Cast Iron ◽  
Eutectic Reaction ◽  
Influencing Factor ◽  
Cooling Curve ◽  
Major Influence ◽  
Cast Irons ◽  
Minor Elements ◽  
Si Content ◽  
Si Effect ◽  
Positive Effect

The solidification cooling curve itself as well as its first derivative, and related temperatures, reported to the calculated equilibrium temperatures in stable and metastable solidification systems, are used to predict the solidification characteristics of the cast iron. Silicon, as the most representative cast iron element, and inoculation, as graphitizing metallurgical treatment, have a major influence on the transition from the liquid to the solid state. Six experimental programs are performed, with Si content typically for non-alloyed (<3.0% Si), low (3.0–3.5% Si) and medium alloyed (4.5–5.5% Si) ductile cast irons, as Si-content increasing, and inoculation simultaneous effects. Silicon is an important influencing factor, but the base and minor elements also affect the equilibrium eutectic temperatures, much more in the Fe-C-Si-Xi stable system (15–20 °C) than in the metastable system (5–10 °C), comparing with their calculation based only on a Si effect (Fe-C-Si system). The highest positive effect of inoculation is visible in non-Si alloyed cast irons (2.5% Si): 9–15 °C for the eutectic reaction and 3 to 4 times increased at the end of solidification (37–47 °C). Increased Si content decreases inoculation power to 7–9 °C for low alloying grade (up to 3.5% Si), with the lowest contribution at more than 4.5% Si (0.3–2.0 °C). 2.5–3.5% Si ductile cast irons are more sensitive to high solidification undercooling, especially at the end of solidification (but with a higher efficiency of inoculation), compared to 4.5–5.5% Si ductile cast irons, at a lower undercooling level, and at lower inoculation contribution, as well.

Effect of layer thickness on residual monomer release in polymerization of bulk-fill composites

2021 ◽  
pp. 096739112199958
Author(s):  
Vahti Kılıç ◽  
Feridun Hurmuzlu ◽  
Yılmaz Ugur ◽  
Suzan Cangul
Keyword(s):  
Stainless Steel ◽  
Layer Thickness ◽  
Composite Resin ◽  
Ethanol Solution ◽  
Composite Resins ◽  
Residual Monomer ◽  
Steel Mold ◽  
Nanohybrid Composite ◽  
Composite Samples

The aim of the present study was to investigate and compare the quantity of residual monomers leached from the bulk-fill composites with different compositions polymerized at varying layer thickness. Three bulk-fill (X-tra-fil, Beautifil Bulk Restorative, Fill-Up) and a nanohybrid composite (Filtek Z550) were used for the study. The composite resin samples were prepared with a stainless steel mold. For each composite, two groups were constructed. The samples in the first group were prepared using the 2 + 2 mm layering technique. In the second group, the composite samples were applied as a 4 mm-thick one layer and polymerized. Then, each composite samples were kept in a 75% ethanol solution and residual monomers released from composite resins were analyzed with an HPLC device after 24hour and 1 month. The data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. Except the Fill-Up, all of residual monomer elution from the bulk-fill composites was significantly affected by the layer thickness (p < 0.05). The greatest monomer release was detected at 1 month after polymerization as a single 4 mm layer for Beautifil Bulk Restorative. Fill-Up composite showed similar residual monomer release in polymerization at different layer thicknesses compared to other composite resins. In the 2 + 2 mm layering technique, the least monomer elution was detected in the Filtek Z550 composite group. While Bis-GMA was the most released monomer in X-tra fil composite, UDMA was the most released monomer in all other composite resins. During polymerization of the bulk-fill composite, the layer thickness of the composite applied may affect the amount of residual monomers released from the composite resins. Conventional composites may release less monomer than bulk-fill composites when used with layering.

scholarly journals Material Application of a Transformer Box: A Study on the Electromagnetic Shielding Characteristics of Al–Ta Coating Film with Plasma-Spray Process

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 495 ◽  
Author(s):  
Fei-Shuo Hung
Keyword(s):  
Stainless Steel ◽  
Structural Characteristics ◽  
Steel Substrate ◽  
Pure Aluminum ◽  
Multilayer Coating ◽  
Thickness Effect ◽  
Stress Effect ◽  
Coating Film ◽  
Coating Structure ◽  
Frequency Condition

In this study we present the results of two experiments. In the first one, a Ta–Al–SS (stainless steel (SS)) multilayer coating structure was prepared using plasma spraying equipment to investigate the coating structure and interface properties. In the second one, Ta–Al on multilayer glass was prepared using the sputtering process to measure the thickness effect of thin film on electromagnetic wave shielding (EMI) characteristics and on the design of high-power switchboard covers. According to the experimental results, the multilayer structure of Ta–Al on SS improves the mechanical properties of a stainless steel plate by enhancing the explosion-proof property. An appropriate thickness of the plasma-sprayed pure aluminum layer can increase the adhesion to the stainless steel substrate and buffer the stress effect. After heat treatment (annealing), the Ta–Al–SS multilayer structural characteristics are excellent and suitable for shielding effects at different temperatures and humidity, which can be used as a reference for the engineering application of communication rooms and base power stations. According to EMI test of multi-coated glass (Ta–Al–glass), by increasing the thickness of Ta layer, we cannot effectively improve full-frequency EMI shielding with improved shielding at low-mid frequency condition. In addition, the Ta–Al interface formation of an Al–Ta–O compound layer can improve the adiabatic effect to reduce the thermal conductivity.

Solidification Characteristics of Al-1Fe-0.5Si-XMg Die-Casting Alloys for High Conductivity Demanding Applications

2013 ◽  
Vol 634-638 ◽  
pp. 1794-1797
Author(s):  
Ho Seob Yun ◽  
Joon Sik Park ◽  
Jeong Min Kim ◽  
Ki Tae Kim
Keyword(s):  
Die Casting ◽  
Microstructural Characterization ◽  
Industrial Applications ◽  
High Conductivity ◽  
Cooling Curve ◽  
Casting Alloys ◽  
Filling Ability ◽  
Cooling Curve Analysis ◽  
Silicon Based ◽  
Mg Content

Aluminum-Silicon based die-casting alloys have been extensively utilized in various industrial applications, but their relatively low electrical and thermal conductivities make them unsuitable as high conductivity parts. In this research, silicon content was restricted to a comparatively low level for higher conductivity and magnesium was added to enhance the castabilities. Al-1Fe-0.5Si-xMg alloys showed significantly higher electrical conductivity than conventional Al-Si based alloys. As the Mg content was increased, the mold filling ability measured using a fluidity serpentine test mold was a little decreased, however the hot cracking susceptibility was observed to be first increased and then decreased. The relationship between solidification characteristics and castabilities of Al-1Fe-0.5Si-xMg alloys was discussed based on the cooling curve analysis and microstructural characterization results.

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