scholarly journals Assessment of the suitability of a gate design modification compared to the change in pressing velocity considering the distribution of gases in the casting volume

2021 ◽  
Vol 1199 (1) ◽  
pp. 012003
Author(s):  
J Majernik ◽  
M Tupaj ◽  
A Trytek ◽  
M Podařil
Keyword(s):  
Gas Content ◽  
Design Solution ◽  
Gating System ◽  
Melt Flow ◽  
Technological Parameters ◽  
Piston Velocity ◽  
Design Modification ◽  
Casting Cycle ◽  
Gas Entrapment ◽  
Gate Design

Abstract The qualitative properties of high pressure die castings are closely correlated with their internal structure, which is directly conditioned by the gas entrapment in the melt volume during the casting cycle. It is known that the gas entrapment in the volume of the melt and their subsequent distribution into the cast can be reduced by changing the technological parameters of the casting cycle or by the modification of the gating system design. The contribution addresses the issue of which variant of the gas content reduction is more efficient regarding the gas entrapment and the nature of the melt flow in the runners. The experiments are based on a real casting process. The established design solution of the gating system and the technological parameters setting are considered as a referential. Different gating system modifications were designed where the design modification is connected with the cross-section of a gate, in which the final acceleration of the melt flow occurs. The observed melt velocity in the gate is considered as a correlation factor, based on which the modification in the piston velocity is determined. The assessed parameter is the gas entrapment in the cast volume at the end of the filling phase. Assessment of the casting cycle and evaluation of experiments is performed using simulation program Magmasoft. Based on the performed analyses, it can be stated that the gate design modification will affect the filling regime of the die cavity by changing the melt velocity in gate, but the nature of the melt flow in runners remains unchanged. Modification of the piston velocity affects the filling regime of the die cavity, and also the nature of the melt flow as it passes through the runners, thereby promoting the gas entrapment in the melt volume. Therefore, it is necessary to pay an increased attention to the design of the gating system and only after debugging the design to proceed to the optimization of technological parameters.

scholarly journals Research and Evaluation of the Influence of the Construction of the Gate and the Influence of the Piston Velocity on the Distribution of Gases into the Volume of the Casting

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2264
Author(s):  
Ján Majerník ◽  
Štefan Gašpár ◽  
Jozef Husár ◽  
Ján Paško ◽  
Jan Kolínský
Keyword(s):  
Die Casting ◽  
Main Idea ◽  
Casting Process ◽  
Gating System ◽  
Technological Parameters ◽  
Piston Velocity ◽  
Casting Cycle ◽  
Suitable Structure ◽  
Filling Phase ◽  
Die Casting Process

Distribution of gasses to the cast volume and volume of pores can be maintained within the acceptable limits by means of correct setting of technological parameters of casting and by selection of suitable structure and gating system arrangement. The main idea of this paper solves the issue of suitability of die casting adjustment—i.e., change of technological parameters or change of structural solution of the gating system—with regards to inner soundness of casts produced in die casting process. Parameters which were compared included height of a gate and velocity of a piston. The melt velocity in the gate was used as a correlating factor between the gate height and piston velocity. The evaluated parameter was gas entrapment in the cast at the end of the filling phase of die casting cycle and at the same time percentage of porosity in the samples taken from the main runner. On the basis of the performed experiments it was proved that the change of technological parameters, particularly of pressing velocity of the piston, directly influences distribution of gasses to the cast volume.

scholarly journals Influence of Technological Parameters of Furane Mixtures on Shrinkage Creation in Ductile Cast Iron Castings

2014 ◽  
Vol 59 (3) ◽  
pp. 1037-1040 ◽  
Author(s):  
I. Vasková ◽  
M. Hrubovčáková ◽  
J. Malik ◽  
Š. Eperješi
Keyword(s):  
Cast Iron ◽  
Ductile Iron ◽  
Ductile Cast Iron ◽  
Gating System ◽  
Technological Parameters ◽  
Iron Castings ◽  
Steel Castings ◽  
The Impact ◽  
Very High ◽  
Great Development

Abstract Ductile cast iron (GS) has noticed great development in last decades and its boom has no analogue in history humankind. Ductile iron has broaden the use of castings from cast iron into areas, which where exclusively domains for steel castings. Mainly by castings, which weight is very high, is the propensity to shrinkage creation even higher. Shrinkage creation influences mainly material, construction of casting, gating system and mould. Therefore, the main realized experiment was to ascertain the influence of technological parameters of furane mixture on shrinkage creation in castings from ductile iron. Together was poured 12 testing items in 3 moulds forto determine and compare the impact of various technological parameters forms the propensity for shrinkage in the casting of LGG.

Understanding the occurrence of the surface turbulence in a nonpressurized bottom gating system: Numerical simulation of the melt flow pattern

2015 ◽  
Vol 232 (3) ◽  
pp. 230-241 ◽  
Author(s):  
Ali Kheirabi ◽  
Amir Baghani ◽  
Ahmad Bahmani ◽  
Morteza Tamizifar ◽  
Parviz Davami ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Liquid Metal ◽  
Flow Pattern ◽  
Oxide Films ◽  
Critical Value ◽  
Surface Velocity ◽  
Complete Agreement ◽  
Gating System ◽  
Melt Flow ◽  
Surface Turbulence

Surface turbulence during the filling of the mold triggers the entrainment of oxide films, which appears to be detrimental to the soundness of the final casting. Nonpressurized and bottom-gating systems have been employed in order to avoid such casting defects by reducing the surface velocity of the liquid metal. However, recent studies have shown that the melt front velocity in the mold entrance may exceed the critical value in the nonpressurized and bottom-gating systems. Therefore, a study was conducted on numerical simulation melt flow pattern in nonpressurized and bottom-gating systems. It was noted that the liquid metal enters the gate and then mold cavity with a higher velocity by formation of dead zones and vortex flows in runner's end. Therefore, the current designs based on conventional gating system ratio seem to be not optimized and unable to avoid the surface turbulence. Numerical results were in complete agreement with experimental observations. Understanding the reasons for occurrence of the surface turbulence in nonpressurized and bottom-gating systems provides information on the required steps to improve the design of the gating systems and minimize the entrainment of oxide films during the filling of the mold.

RESEARCH OF THE PROCESSES OF NON-ISOTHERMAL FLOW OF MELTING OF A PROPYLENE BLOCKOPOLYMER WITH ETHYLENE IN THE CABLE HEAD CHANNEL

2020 ◽  
Author(s):  
S Ershov ◽  
E Subbotin ◽  
A Scherbinin
Keyword(s):  
Block Copolymer ◽  
Numerical Study ◽  
Isothermal Flow ◽  
Melt Flow ◽  
Technological Parameters ◽  
Head Channel

The article is devoted to the numerical study of the processes of nonisothermal melt flow of a block copolymer of propylene with ethylene in the channels of the forming tool of cable heads when two-layer insulation is applied. The influence of technological parameters on the fields of speeds and temperatures is determined

On determining coal classification indicators for establishing dangerous properties of mines

2020 ◽  
pp. 149-159
Author(s):  
М. Antoshchenko ◽  
◽  
V. Tarasov ◽  
R. Zaika ◽  
O. Zolotarova ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Organic Matter ◽  
Fire Hazard ◽  
Coal Dust ◽  
Gas Content ◽  
Technological Parameters ◽  
Coal Seams ◽  
Volatile Substances ◽  
Main Indicator ◽  
Seam Mining

Currently, more than 20 qualification indicators are known by which degree of metamorphic coal transformations are established. Most of these indicators are designed for determining technological properties with industrial use of coal in mind. Due to sufficient knowledge of the indicators used, industrial classifications are constantly being improved. The modern classification by genetic and technological parameters groups the coals by the grades based on ten indicators. Of these, only one - the mass yield of volatile substances during the thermal decomposition of coal - is used as the main indicator of the manifestation of dangerous properties of coal seams without due scientific justification. Dangerous properties of coal seams during mining include: gas content of coal, a tendency to gas-dynamic phenomena and spontaneous combustion, dust forming ability and explosiveness of coal dust. In industrial classifications, the main indicator is determined for the dry ash-free state of organic matter. Manifestation of dangerous properties of coal seams occurs in the presence of both moisture and mineral impurities. This fact is not taken into account by other auxiliary indicators used to predict the hazardous properties of coal seams. Moisture in coal seams is in at least four states, and it is completely removed while analyzing the samples and is not taken into account in volatile products of thermal decomposition of coal. Thus, when using the indicator of mass output of volatile substances, influence of moisture in any form of its presence in coal on the occurrence of emergency situations is automatically ignored. The probability of emergencies during mining is largely determined by the ratio between components of organic mass (C, O, H, S, N) and mineral impurities. It is also not taken into account in normative documents which regulate safety of coal seam mining. The classification indicators defined in different ways characterize different aspects of coal conversion in metamorphic processes. Volatiles yield and average vitrine reflectance, well studied in industrial applications, correspond to different aspects of degree of conversion of starting organic matter. In order to establish dangerous properties of coal seams, their mutual substitution is unacceptable, which is confirmed by nonlinear connection between them. The existence of a genetic relationship between the outburst and fire hazard of coal seams has been established. This indicates the need to develop a unified classification of the hazardous properties of coal seams by genetic, mining engineering and geological parameters. The scientifically substantiated use in regulatory documents of a set of classification indicators that directly characterize the manifestations of the hazardous properties of coal seams will help to reduce number of accidents and injuries in coal mines.

Effect of the Technological Parameters on the Thermal Conditions of Die-Casting Tool

2013 ◽  
Vol 752 ◽  
pp. 183-192 ◽  
Author(s):  
Jenő Dúl ◽  
Zsolt Leskó ◽  
Borbála Juhász
Keyword(s):  
Cooling System ◽  
Die Casting ◽  
Thermal Conditions ◽  
Technological Parameters ◽  
Cooling Systems ◽  
Casting Tool ◽  
Casting Cycle ◽  
And Function ◽  
The Heat Balance ◽  
Short Times

The heat balance of a casting cycle can be ensured in short times by the annealing of the die-casting tool, by which the well-constructed and well-functioned cooling system can enhance productivity. Incorrect cooling, however, can lead to heat unbalance in the die casting tool, thus causing the destruction of casting quality, reduction of the lifetime of die casting tool and irreversible production-reduction. Beside the theoretical examination of construction and function of cooling system, the evaluation of the effectively removed heat quantities has great importance. The paper presents an analysis of the function of the cooling system of a scraggy thin casting of AlSi9Cu3 alloy, in case of different cooling parameters. Based on the measured results of the inlet and outlet temperatures and the volume flow of the cooling agents, the heat quantities belonging to the cooling circles are determined and an optimization of the cooling system is proposed. The findings of the analysis can be utilized for the construction and optimum operation of die-casting cooling systems.

Assessment of Suitability of the Design of Gating System with the Use of Simulation Software

2017 ◽  
Vol 756 ◽  
pp. 136-141
Author(s):  
Ján Majerník ◽  
Monika Karková ◽  
Ján Kmec
Keyword(s):  
Time Course ◽  
Production Efficiency ◽  
Simulation Software ◽  
Thin Wall ◽  
Design Phase ◽  
Gating System ◽  
Qualitative Properties ◽  
Temperature Changes ◽  
Casting Cycle ◽  
Mould Cavity

The quality of thin wall castings produced by metal die-casting depends on the coherence and consistency of various aspects influencing the process of casting cycle. The qualitative properties of castings should already be considered in the design phase of construction of the gating system. The simulation software is an effective facility for the initial revealing of defects of the design phase. The assessment of casting cycle by the means of simulation predicts an incidence of defects of the casting core in the design phase and therefore reduces both the incidence of defects in the production and the costs while the production efficiency is increased. The article deals with the assessment of the design of the gating system for a particular casting type. The filling of mould cavity, casting solidification and time course of temperature changes occurring in the selected locations of gating system were defined as parameters indicating the assumptions of design accuracy. Simulation tests were carried out in the NovaFlow&Solid program. The tests resulted in a conclusion evaluating and describing the adequacy of structural design of the gating system.

Investigation of Parameters Relevant to Microcellular Foam Injection Molding

2013 ◽  
Vol 785-786 ◽  
pp. 1041-1045 ◽  
Author(s):  
Luo Hong Deng ◽  
Zai Liang Chen ◽  
Fei Wang
Keyword(s):  
Injection Molding ◽  
Gas Content ◽  
Technological Parameters ◽  
Range Analysis ◽  
Microcellular Foam ◽  
Melt Temperature ◽  
Experiment Method ◽  
Molding Materials ◽  
Foam Injection Molding ◽  
Single Factor Experiment

The paper is proposed that we can use single factor experiment method and range analysis method to investigate four technological parameters (Melt temperature, Weight loss, Injection time and Gas content) of the technological parameters in the process of microcellular foam injection molding. By investigating the rules and degree which are obtained from the factors influence on bubbles morphology, it is actually meaningful that we can control and improve the bubbles morphology for improving the capability of Microcellular Foam Injection Molding materials.

Die Casting Improvements through Melt Shear

2009 ◽  
Vol 618-619 ◽  
pp. 33-37 ◽  
Author(s):  
Robert G. O'Donnell ◽  
Dayalan R. Gunasegaram ◽  
Michel Givord
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Shrinkage Porosity ◽  
Thermal Gradients ◽  
Casting Defects ◽  
Melt Flow ◽  
Complex Process ◽  
Casting Cycle ◽  
Die Casting Process ◽  
Contraction Stage

Melt flow and solidification within a die casting cavity is a complex process dependent in part on melt pressure (with or without intensification), melt velocity, melt flow path, thermal gradients within the die, die lubrication and melt viscosity. Casting defects such as short shots, cold shuts and shrinkage porosity can readily occur if casting conditions are not optimised. Shrinkage porosity in particular is difficult to eradicate from castings that comprise thick sections, since these sections will usually solidify late in the casting cycle and may be starved of melt supply during the critical solidification (and contraction) stage. The current work seeks to elucidate the influence of the melt shearing on the die casting process and demonstrates that the modifications made to the melt through introduction of a local constriction in the melt path can generate improvements in casting microstructure and reduce shrinkage porosity.

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