The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform

Maeda Yasuhiro - One of the best experts on this subject based on the ideXlab platform.

  • Mould filling observations of aluminium melts in vacuum-sealed sand moulds
    Jönköping : Ingenjörshögskolan, 1999
    Co-Authors: Bäckman Jonas, Svensson, Ingvar L, Maeda Yasuhiro
    Abstract:

    In order to clarify how the ingate system design influences the mould filling behaviour of aluminium melts in vertically parted vacuum-sealed moulds, some direct observation experiments have been made. A detailed study of how the design of each component in the ingate system affects the mould filling behaviour has been made. The effect of different designs on Downsprue-runner connections, runners and end-wall of the runners as well as the effect of wall friction was investigated. The mould filling process was studied through a glass wall and recorded by a video camera. Still images from the videotape are presented and evaluated. The direct observation method has been found to be a very powerful way to follow the melt behaviour during mould filling. To ensure a good filling of the Downsprue the melt level in the pouring basin has to be above a certain level from the time when the stopper is removed and during the whole filling sequence. A perpendicular connection between the Downsprue and the runner gives a larger flow loss than a rounded type. Due to the larger flow loss the perpendicular connection results in an earlier filling of the Downsprue. A tapered runner results in almost simultaneous filling of the specimens compared to a runner with no tapering. On the other hand the tapered runner gives a more divergent melt front which increase the free melt surfaces in contact with air. An additional pocket at the end of the runner has a beneficial effect on the mould filling. A sharp angled pocket is better than a more rounded type. Decreasing the wall thickness increases the flow loss due to wall friction, and causes more significant heat losses

  • Influence of filter on the mould filling of aluminium melts in vacuum-sealded moulds
    Jönköping : Ingenjörshögskolan, 1999
    Co-Authors: Bäckman Jonas, Svensson, Ingvar L, Maeda Yasuhiro
    Abstract:

    The influence of filters on the mould filling behaviour has been investigated by direct observation experiments. The ingate system was moulded in a vertically parted vacuumsealed sand mould. How the filter in general, and how different filter locations, filter coarseness, active filter area and filter length influence the mould filling has been clarified. The direct observation method is a very powerful way to learn how different ingate system designs and filter conditions affect the mould filling. During mould filling the melt behaviour was recorded by a video camera through a glass wall, from which still images are presented. The general effect of filters is a better filling of the ingate system prior to the filter, and a reduction of the melt velocity, which in turn give smoother filling after the filter. Initially, the Downsprue is completely filled at an early stage of the filling due to the back-pressure from the filter. The back-pressure is built up as a result of friction in the filter. An early filling of the Downsprue prevents the melt from entraining oxide films or air inclusions. Secondly, the filling of the runner is improved by the use of a filter. The better filling of the runner is mainly an effect of the decreased velocity of the melt. The reduction of the melt velocity results in reduced surface turbulence and less splashing. Reduced surface turbulence and splashing of the melt prevents incorporation of oxide films and air in the melt, which has an overall beneficial effect on the quality of the castings. The location of the filter has been found to play an important role in the filling soundness

Bäckman Jonas - One of the best experts on this subject based on the ideXlab platform.

  • Mould filling observations of aluminium melts in vacuum-sealed sand moulds
    Jönköping : Ingenjörshögskolan, 1999
    Co-Authors: Bäckman Jonas, Svensson, Ingvar L, Maeda Yasuhiro
    Abstract:

    In order to clarify how the ingate system design influences the mould filling behaviour of aluminium melts in vertically parted vacuum-sealed moulds, some direct observation experiments have been made. A detailed study of how the design of each component in the ingate system affects the mould filling behaviour has been made. The effect of different designs on Downsprue-runner connections, runners and end-wall of the runners as well as the effect of wall friction was investigated. The mould filling process was studied through a glass wall and recorded by a video camera. Still images from the videotape are presented and evaluated. The direct observation method has been found to be a very powerful way to follow the melt behaviour during mould filling. To ensure a good filling of the Downsprue the melt level in the pouring basin has to be above a certain level from the time when the stopper is removed and during the whole filling sequence. A perpendicular connection between the Downsprue and the runner gives a larger flow loss than a rounded type. Due to the larger flow loss the perpendicular connection results in an earlier filling of the Downsprue. A tapered runner results in almost simultaneous filling of the specimens compared to a runner with no tapering. On the other hand the tapered runner gives a more divergent melt front which increase the free melt surfaces in contact with air. An additional pocket at the end of the runner has a beneficial effect on the mould filling. A sharp angled pocket is better than a more rounded type. Decreasing the wall thickness increases the flow loss due to wall friction, and causes more significant heat losses

  • Influence of ingate system design on mechanical properties for a cast A1-10Si-0.38Mg alloy
    Jönköping : Ingenjörshögskolan, 1999
    Co-Authors: Bäckman Jonas, Svensson, Ingvar L
    Abstract:

    In this work the influence of the ingate system design on the as-cast mechanical properties of an Al-10Si-0.38Mg alloy have been clarified. The Weibull distribution has been seen to describe the spread in mechanical properties very well. The Weibull modulus has therefore been used as a measure of the soundness of an ingate system. Different ingate systems were investigated, including: expanding systems, pressurised systems, systems with and without filter, systems with different designs of the connection between the Downsprue and the runner, and systems with and without an additional pocket at the end of the runner. The modification index of the microstructure was also measured in order to investigate if the spread in data is more dependent on the modification index than on the ingate system design. The results showed that a high Weibull modulus is more dependent on the ingate system design than on the modification index of the microstructure. The ultimate tensile strength was not significantly affected by the ingate system design, while the fracture elongation seemed to be more dependent on the melt quality than on the ingate system design. The Weibull modulus indicates that expanding systems are better than pressurised systems, and that the use of a filter in the runner is very beneficial. An additional pocket at the end of the runner has no beneficial effect when using a filter. The connection between the Downsprue and the runner should have a rounded bend and the change in cross-section between the Downsprue and the runner should be chamfered and not sharp

  • Influence of filter on the mould filling of aluminium melts in vacuum-sealded moulds
    Jönköping : Ingenjörshögskolan, 1999
    Co-Authors: Bäckman Jonas, Svensson, Ingvar L, Maeda Yasuhiro
    Abstract:

    The influence of filters on the mould filling behaviour has been investigated by direct observation experiments. The ingate system was moulded in a vertically parted vacuumsealed sand mould. How the filter in general, and how different filter locations, filter coarseness, active filter area and filter length influence the mould filling has been clarified. The direct observation method is a very powerful way to learn how different ingate system designs and filter conditions affect the mould filling. During mould filling the melt behaviour was recorded by a video camera through a glass wall, from which still images are presented. The general effect of filters is a better filling of the ingate system prior to the filter, and a reduction of the melt velocity, which in turn give smoother filling after the filter. Initially, the Downsprue is completely filled at an early stage of the filling due to the back-pressure from the filter. The back-pressure is built up as a result of friction in the filter. An early filling of the Downsprue prevents the melt from entraining oxide films or air inclusions. Secondly, the filling of the runner is improved by the use of a filter. The better filling of the runner is mainly an effect of the decreased velocity of the melt. The reduction of the melt velocity results in reduced surface turbulence and less splashing. Reduced surface turbulence and splashing of the melt prevents incorporation of oxide films and air in the melt, which has an overall beneficial effect on the quality of the castings. The location of the filter has been found to play an important role in the filling soundness

Svensson, Ingvar L - One of the best experts on this subject based on the ideXlab platform.

  • Mould filling observations of aluminium melts in vacuum-sealed sand moulds
    Jönköping : Ingenjörshögskolan, 1999
    Co-Authors: Bäckman Jonas, Svensson, Ingvar L, Maeda Yasuhiro
    Abstract:

    In order to clarify how the ingate system design influences the mould filling behaviour of aluminium melts in vertically parted vacuum-sealed moulds, some direct observation experiments have been made. A detailed study of how the design of each component in the ingate system affects the mould filling behaviour has been made. The effect of different designs on Downsprue-runner connections, runners and end-wall of the runners as well as the effect of wall friction was investigated. The mould filling process was studied through a glass wall and recorded by a video camera. Still images from the videotape are presented and evaluated. The direct observation method has been found to be a very powerful way to follow the melt behaviour during mould filling. To ensure a good filling of the Downsprue the melt level in the pouring basin has to be above a certain level from the time when the stopper is removed and during the whole filling sequence. A perpendicular connection between the Downsprue and the runner gives a larger flow loss than a rounded type. Due to the larger flow loss the perpendicular connection results in an earlier filling of the Downsprue. A tapered runner results in almost simultaneous filling of the specimens compared to a runner with no tapering. On the other hand the tapered runner gives a more divergent melt front which increase the free melt surfaces in contact with air. An additional pocket at the end of the runner has a beneficial effect on the mould filling. A sharp angled pocket is better than a more rounded type. Decreasing the wall thickness increases the flow loss due to wall friction, and causes more significant heat losses

  • Influence of ingate system design on mechanical properties for a cast A1-10Si-0.38Mg alloy
    Jönköping : Ingenjörshögskolan, 1999
    Co-Authors: Bäckman Jonas, Svensson, Ingvar L
    Abstract:

    In this work the influence of the ingate system design on the as-cast mechanical properties of an Al-10Si-0.38Mg alloy have been clarified. The Weibull distribution has been seen to describe the spread in mechanical properties very well. The Weibull modulus has therefore been used as a measure of the soundness of an ingate system. Different ingate systems were investigated, including: expanding systems, pressurised systems, systems with and without filter, systems with different designs of the connection between the Downsprue and the runner, and systems with and without an additional pocket at the end of the runner. The modification index of the microstructure was also measured in order to investigate if the spread in data is more dependent on the modification index than on the ingate system design. The results showed that a high Weibull modulus is more dependent on the ingate system design than on the modification index of the microstructure. The ultimate tensile strength was not significantly affected by the ingate system design, while the fracture elongation seemed to be more dependent on the melt quality than on the ingate system design. The Weibull modulus indicates that expanding systems are better than pressurised systems, and that the use of a filter in the runner is very beneficial. An additional pocket at the end of the runner has no beneficial effect when using a filter. The connection between the Downsprue and the runner should have a rounded bend and the change in cross-section between the Downsprue and the runner should be chamfered and not sharp

  • Influence of filter on the mould filling of aluminium melts in vacuum-sealded moulds
    Jönköping : Ingenjörshögskolan, 1999
    Co-Authors: Bäckman Jonas, Svensson, Ingvar L, Maeda Yasuhiro
    Abstract:

    The influence of filters on the mould filling behaviour has been investigated by direct observation experiments. The ingate system was moulded in a vertically parted vacuumsealed sand mould. How the filter in general, and how different filter locations, filter coarseness, active filter area and filter length influence the mould filling has been clarified. The direct observation method is a very powerful way to learn how different ingate system designs and filter conditions affect the mould filling. During mould filling the melt behaviour was recorded by a video camera through a glass wall, from which still images are presented. The general effect of filters is a better filling of the ingate system prior to the filter, and a reduction of the melt velocity, which in turn give smoother filling after the filter. Initially, the Downsprue is completely filled at an early stage of the filling due to the back-pressure from the filter. The back-pressure is built up as a result of friction in the filter. An early filling of the Downsprue prevents the melt from entraining oxide films or air inclusions. Secondly, the filling of the runner is improved by the use of a filter. The better filling of the runner is mainly an effect of the decreased velocity of the melt. The reduction of the melt velocity results in reduced surface turbulence and less splashing. Reduced surface turbulence and splashing of the melt prevents incorporation of oxide films and air in the melt, which has an overall beneficial effect on the quality of the castings. The location of the filter has been found to play an important role in the filling soundness

Reilly C - One of the best experts on this subject based on the ideXlab platform.

  • Using the calculated Froude number for quality assessment of casting filling methods
    Minerals Metals & Materials Society, 2009
    Co-Authors: Jolly Mark, Reilly C, Nr Green, Jc Gebelin
    Abstract:

    The reliability of cast components is dependent on the quality of the casting process. This can be characterised by the robustness (repeatability) and specific fluid flow characteristics within the running system. During this transient filling phase the prevention of free surface turbulence and thus oxide entrainment is critical to ensure the mechanical integrity of the component. Past research has highlighted that return waves are major causes of free surface entrainment. To reduce the entrainment occurring during the transitional filling of the runner a steady quiescent flow must be developed. Using FLOW-3D the Froude number has been extracted from simulated casting filling to allow the quantitative prediction of air entrainment for a number of different flow conditions. Different running system geometries have been simulated and the overall quality of the running system performance assessed using the Froude number entrainment criterion. The results have been compared to real-time X-ray imaging of transient aluminum alloy flow in running systems. The results show that, for the designs used, the correctly designed geometry is advantageous. An incorrect design may reduce the Froude number but can greatly increase the persistence of the return wave and entrainment and is therefore extremely detrimental to the cast component. The addition of a filter created a deeper quiescent incoming flow and greatly reduced the persistence giving a low total entrainment value. Additionally, the in-gate design is of utmost importance in controlling the back pressure and thus the persistence of the back wave between the in-gate and the Downsprue exit. This has a direct effect on the level of oxide entrainment. The quantitative Froude number data obtained from the FLOW-3D model were seen to correlate well with the qualitative real time X-ray data, where as the lowest frequency of bubble occurrence and smallest size was observed in systems containing a filter

  • Quality assesment of casting filling method
    Minerals Metals & Materials Society, 2008
    Co-Authors: Jolly Mark, Reilly C
    Abstract:

    The reliability of cast components is dependent on the quality of the casting process. This can be characterised by the robustness (repeatability) and specific fluid flow characteristics within the running system. During this transient filling phase the prevention of free surface turbulence and thus oxide entrainment is critical to the mechanical integrity of the component [1,2,3]. Past research has highlighted that return waves are major causes of free surface entrainment [4]. To reduce the entrainment occurring during the transitional filling of the runner a steady quiescent flow must be developed. Using FLOW-3D(1), the Froude number was extracted to allow the quantitative assessment of air entrainment for four different designs of sump at the end of the runner. The results show that, for the designs used, the addition of a correctly designed sump can be advantageous. However, an incorrect design may reduce the Froude number but can greatly increase the persistence of the return wave and entrainment and is therefore extremely detrimental to the cast component. Additionally, the in-gate design is of utmost importance in controlling the back pressure and thus the persistence of the back wave between the in-gate and the Downsprue exit. This has a direct effect of the level of oxide entrainment

Jolly Mark - One of the best experts on this subject based on the ideXlab platform.

  • Using the calculated Froude number for quality assessment of casting filling methods
    Minerals Metals & Materials Society, 2009
    Co-Authors: Jolly Mark, Reilly C, Nr Green, Jc Gebelin
    Abstract:

    The reliability of cast components is dependent on the quality of the casting process. This can be characterised by the robustness (repeatability) and specific fluid flow characteristics within the running system. During this transient filling phase the prevention of free surface turbulence and thus oxide entrainment is critical to ensure the mechanical integrity of the component. Past research has highlighted that return waves are major causes of free surface entrainment. To reduce the entrainment occurring during the transitional filling of the runner a steady quiescent flow must be developed. Using FLOW-3D the Froude number has been extracted from simulated casting filling to allow the quantitative prediction of air entrainment for a number of different flow conditions. Different running system geometries have been simulated and the overall quality of the running system performance assessed using the Froude number entrainment criterion. The results have been compared to real-time X-ray imaging of transient aluminum alloy flow in running systems. The results show that, for the designs used, the correctly designed geometry is advantageous. An incorrect design may reduce the Froude number but can greatly increase the persistence of the return wave and entrainment and is therefore extremely detrimental to the cast component. The addition of a filter created a deeper quiescent incoming flow and greatly reduced the persistence giving a low total entrainment value. Additionally, the in-gate design is of utmost importance in controlling the back pressure and thus the persistence of the back wave between the in-gate and the Downsprue exit. This has a direct effect on the level of oxide entrainment. The quantitative Froude number data obtained from the FLOW-3D model were seen to correlate well with the qualitative real time X-ray data, where as the lowest frequency of bubble occurrence and smallest size was observed in systems containing a filter

  • Quality assesment of casting filling method
    Minerals Metals & Materials Society, 2008
    Co-Authors: Jolly Mark, Reilly C
    Abstract:

    The reliability of cast components is dependent on the quality of the casting process. This can be characterised by the robustness (repeatability) and specific fluid flow characteristics within the running system. During this transient filling phase the prevention of free surface turbulence and thus oxide entrainment is critical to the mechanical integrity of the component [1,2,3]. Past research has highlighted that return waves are major causes of free surface entrainment [4]. To reduce the entrainment occurring during the transitional filling of the runner a steady quiescent flow must be developed. Using FLOW-3D(1), the Froude number was extracted to allow the quantitative assessment of air entrainment for four different designs of sump at the end of the runner. The results show that, for the designs used, the addition of a correctly designed sump can be advantageous. However, an incorrect design may reduce the Froude number but can greatly increase the persistence of the return wave and entrainment and is therefore extremely detrimental to the cast component. Additionally, the in-gate design is of utmost importance in controlling the back pressure and thus the persistence of the back wave between the in-gate and the Downsprue exit. This has a direct effect of the level of oxide entrainment