Study on Casting Defect Control of Austenitic 304 Complex Structural Parts

Ding, Huafeng; Jin, Xianzhi; Chen, Tao; Li, Hongbing

doi:10.1007/s40962-022-00865-y

Cited by 3 publications

(1 citation statement)

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“…Finally, although some advances have been made in determining the threshold Ny for different alloys, this value is not known for all alloys or all steel [18]. Some FEM simulation software gives an Ny value for each point considering only one temperature, which is sometimes unknown or difficult to select with respect to the solidification percentage that it represents [19]. Other applications give Ny for any temperature, for example, VULCAN (Quantech ATZ S.A., Barcelona, Spain).…”

Section: Introductionmentioning

confidence: 99%

A Methodology to Define the Niyama Criterion Reinforced with the Solid Fraction Analysis: Application to Sand Casting of Steel Bars

Manjabacas,

Miguel

2023

Metals

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Niyama and solid fraction criteria are used to predict the solidification porosity and microporosity in computing simulation of casting processes. The solid fraction permits us to determine the areas that solidify last and that are a candidate for presenting porosity if a feeding system is not correctly designed. The Niyama criterion is locally obtained based on the thermal and cooling gradients at a point of the liquid casting. The Niyama value at a casting point varies rapidly from low rates to high ones during the last part of the metal solidification, which demands that the percentage of solidification of the metal is defined to determine the Niyama number. In addition, the Niyama threshold that establishes the soundness of the workpiece can vary according to the nature of the metal or the casting system. In this paper, a methodology to determine the solidification percentage is presented. The method is based on the Niyama number evolution during the solidification process at different key points. These points are validated by the solid fraction criterion as healthy or, on the contrary, as candidates for containing porosity. In addition, some considerations of the solid fraction criterion are visited since the threshold value for which the isolation of the last solidification areas can be defined is not clear. The research is validated by the empirical casting criteria existing in the literature for obtaining sound parts and applied to low-carbon steel bars produced by sand casting.

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Section: Introductionmentioning

confidence: 99%