• Materials Forming and Structural Control Casting and ...

    The AdStefan can run on UNIX including Linux and MS Windows systems. Our original defects prediction method called "NIYAMA criterion" is favored by casting engineers all over the world because of its ease of use, versatility and robustness. The NIYAMA criterion is a de facto standard, now.

  • About MTI

    of Iowa, studied the use of the Niyama criterion to predict casting quality. The Niyama criterion is a common simula-tion output variable that foundries routinely use to detect solidification shrinkage in steel castings. It is defined as the ratio of the local thermal gradient to the square root of

  • UBIRA ETheses - A study of some of the foundry processing ...

    The Niyama criterion function was validated to predict shrinkage-related porosity in Ti-46Al-8Nb castings, through either thermal or tilt-filling ProCastTM simulation models. Positions in a casting with Niyama values above 4 (°C. min)0.5cm-1; (3 (K. s)0.5mm-1); could be considered completely sound.

  • Microporosity Prediction and Validation for Ni-based ...

    Aug 10, 2015· Unlike the well-known Niyama criterion, application of the dimensionless Niyama model avoids the need to find a threshold Niyama criterion below which shrinkage porosity forms – a criterion which can be determined only via extensive alloy dependent experimentation.

  • Advances in Mechanical Engineering Numerical simulation ...

    Furthermore, the Niyama criterion was used for ana-lyzing the formation of shrinkage defects in the solidi-fication process. The use of casting numerical simulation technology helped not only to overcome the problem of not being able to observe changes in the molten metal in the mold cavity during the tradi-

  • Open Access proceedings Journal of Physics: Conference series

    The Niyama criterion was further developed by Carlson et al. [9]. The aim of this improvement was to predict not only the position of the shrinkage porosity in the casting, but also the amount of the pore volume fraction. The advanced Niyama criterion is also called the dimensionless Niyama criterion and can be calculated according to equation (2)

  • rithna | Casting (Metalworking) | Manmade Materials

    Use of the Niyama Criterion To Predict Shrinkage-Related Leaks in High-Nickel Steel and Nickel-Based Alloy Castings. Casting Defects. Radiograph Interpretation CASTINGS. Ae2253 Prod Tech Unit Test Qp. Dental Casting Defects. Cae. Solidification Analysis of Valve in Investment Casting and its Optimization using Simulation.

  • Metal Casting | Casting (Metalworking) | Building ...

    Use of the Niyama Criterion To Predict Shrinkage-Related Leaks in High-Nickel Steel and Nickel-Based Alloy Castings. Advannced Manufacturing Process. Module 1. The Pocket Foundry. Haystealloy Technical Spec. Permanent Mold. Co2 Molding. Heathrow Airport. …

  • Proactive Defect Detection with Simulation Software

    Nov 13, 2020· [1]Carlson, K.D., and Beckermann, C., "Use of the Niyama Criterion to Predict Shrinkage-Related Leaks in High-Nickel Steel and Nickel-Based Alloy Castings," in Proceedings of the 62nd SFSA Technical and Operating Conference, Paper No. 5.6, Steel Founders' Society of America, Chicago, IL, 2008.

  • Use of the Niyama criterion to predict porosity of the ...

    Abstract The article presents new results on the use of the Niyama criterion to estimate porosity appearance in castings under hindered shrinkage. The effect of deformation of the mushy zone on filtration is shown. A new form of the Niyama criterion accounting for the hindered shrinkage and the range of deformation localization has been obtained.

  • NON DESTRUCTIVE CONTROL ALUMINUM CASTINGS

    Niyama criterion, a criterion that is presently the most widely used criterion to predict feeding-related shrinkage porosity caused by shallow temperature gradients. The solidification simulation software SimCADE v.2.0 calculates the temperature gradient and cooling rate by simulation, compares it against the Niyama criterion and plots the ...

  • Use of the Niyama Criterion To Predict Shrinkage-Related ...

    Carlson, K.D., and Beckermann, C., Use of the Niyama Criterion to Predict Shrinkage-Related Leaks in High-Nickel Steel and Nickel-Based Alloy Castings,Ž in Proceedings of the 62nd SFSA Technical and Operating Conference, Paper No. 5.6, Steel Founders' So ciety of America, Chicago, IL, 2008. 2

  • UNIT 20: Output Criteria: Solidification Time

    ferrous castings. In non-ferrous alloys, especially aluminum, it can be used to predict gross macroporosity, but structural microporosity due to poor or stagnant solidification can best be predicted by other criteria such as Niyama or the FCC Custom Criterion. Indications show areas of likely shrinkage porosity in the casting.

  • Predicting gas and shrinkage porosity in solidification ...

    Jul 15, 2020· It is known that the Niyama criterion is one of the most widely used criteria to predict shrinkage porosity in metal casting. However, the Niyama criterion can only give a qualitative result based on local temperature gradient and cooling rate evaluated at a …

  • Use of the Niyama criterion to predict porosity of ... - CORE

    Use of the Niyama criterion to predict porosity of the mushy zone with deformation . By S. Polyakov, А. Korotchenko and J. Bast. Abstract. The article presents new results on the use of the Niyama criterion to estimate porosity appearance in castings under hindered shrinkage. The effect of deformation of the mushy zone on filtration is shown.

  • El proceso de contracción en piezas fundidas. Formas de ...

    Use of the Niyama Criterion to Predict Shrinkage-related Leaks in High-Nickel Steel and Nickel-Based Alloy Castin. in Proceedings of the 62nd SFSA Technical and Operating Conference. 2008. Chicago, IL. 31. Sigworth, G.K., Prediction of Shrinkage Pore Volume Fraction using a Dimensionless Niyama Criterion.

  • Use of the Niyama criterion to predict porosity of the ...

    The article presents new results on the use of the Niyama criterion to estimate porosity appearance in castings under hindered shrinkage. The effect of deformation of the mushy zone on filtration is shown. A new form of the Niyama criterion accounting for the hindered shrinkage and the range of deformation localization has been obtained.

  • Prediction of Shrinkage Pore Volume Fraction Using a ...

    Nov 26, 2008· Abstract A method is presented to use a dimensionless form of the well-known Niyama criterion to directly predict the amount of shrinkage porosity that …

  • Prediction of Shrinkage Microporosity in Gravity‐Cast and ...

    The Niyama criterion and the dimensionless Niyama criterion are used to predict shrinkage microporosity in Mg–6Gd–3Y–0.5Zr magnesium plates processed by gravity casting and low‐pressure sand casting. Instead of the Niyama evaluation condition recommended by commercial ProCAST software and precious studies, the most appropriate Niyama ...

  • UNIT 22: Output Criteria: Material Density Function

    ferrous castings. In non-ferrous alloys, especially aluminum, it can be used to predict gross macroporosity, but structural microporosity due to poor or stagnant solidification can best be predicted by other criteria such as Niyama or the FCC Custom Criterion. Indications show areas of likely shrinkage porosity in the casting.

  • Materials | Free Full-Text | Prediction of Microporosity ...

    The dimensionless Niyama criterion was used to predict the formation of microporosity in nickel-based superalloy casting, which extended the model application from a simple plate casting to complex thin-wall superalloy casting. The physical characteristics of the superalloy were calculated by JMatPro software. The relation between the volume percentage of microporosity and the dimensionless ...

  • CiteSeerX — Citation Query A Method of Shrinkage ...

    However, to predict phenomena such as porosity requires modelling the interaction of the fluid flow, heat transfer, solidification and the development of stress-deformation in the solidified part of the casting. ... Prediction of Microporosity in Complex Thin-Wall Castings with the Dimensionless Niyama Criterion by Maodong Kang, Haiyan Gao, Jun ...

  • Prediction of Shrinkage Porosity in Ti-46Al-8Nb Tilt ...

    The Niyama criterion function was validated to predict shrinkage-related porosity in Ti-46Al-8Nb castings, in both thermal and tilt-filling ProCast simulation models.

  • Proactive Defect Detection with Simulation Software

    Sep 29, 2020· Carlson, K.D., and Beckermann, C., "Use of the Niyama Criterion to Predict Shrinkage-Related Leaks in High-Nickel Steel and Nickel-Based Alloy Castings," in Proceedings of the 62nd SFSA Technical and Operating Conference, Paper No. 5.6, Steel Founders' Society of America, Chicago, IL, 2008.

  • Use of the Niyama Criterion To Predict Shrinkage-Related ...

    The Niyama criterion, a local thermal parameter that is a common output of casting simulation software packages, is commonly used to predict shrinkage porosity defects in steel castings.

  • Thermal simulations for the prediction of porosity in ...

    Niyama et al.11 also used a thermal criterion to predict shrinkage porosity in steel castings, however, their criterion was based on thermal gradients predicted from a 10 computer analysis. The castings examined were more geometrically complex than those of Pellini et al.9'10 which made Niyama's analysis more applicable to the complex ...

  • Removal of Alumina Inclusions from Molten Steel by Ceramic ...

    Oct 30, 2020· K. Carlson, C. Beckermann, Use of the niyama criterion to predict shrinkage-related leaks in high-nickel steel and nickel-based alloy castings, in Proceedings of the 62nd SFSA Technical and Operating Conference, Chicago, IL, USA (2008)

  • Prediction of Shrinkage Pore Volume Fraction Using a ...

    Jul 28, 2008· THE Niyama criterionis presently the most widely used criterion function in metal casting. It is used to predict feeding-related shrinkage porosity caused by shallow temperature gradients.

  • Correlating shrinkage microporosity with the mechanical ...

    Mar 05, 2016· K.D. Carlson, C. BeckermannUse of the Niyama criterion to predict shrinkage-related leaks in high-nickel steel and nickel-based alloy castings …

  • Specifying Casting Simulation Prediction Requirements ...

    May 04, 2020· Has anyone used casting simulation to predict the quality of a casting for process equipment specifications, and how successful has the simulation tool been to predict casting quality? It is my understanding that there was MTI supported research done in 2008 on the use of the Niyama Criterion for predictions of casting quality thru simulation ...