Effect of shell mold thickness and insulating wool pattern on internal porosity in investment casting of vortex flow meter

Han Wei Tseng, Ting Y.I. Chen, Yi Chen Kao, Cheng Fu Huang, Yu Chen Liu, Sheng Chan Lee, Chih Chi Wang, Chien Wei Chan, Yiin Kuen Fuh

Research output: Contribution to journalArticlepeer-review

Abstract

Investment casting (IC) with different insulating wool pattern and shell mold thickness is investigated for a geometrically complex vortex flow meter in this study. The primary coating consists of zircon (ZrSiO4) with colloidal silica (SiO2) binder. Zircon is regarded as a potential engineering material for high-temperature applications for its chemical stability, strong fracture resistance at higher temperature range, and low thermal expansion coefficient. The fundamental properties of the shell mold, such as mechanical property and thermal properties were experimentally validated. The modulus of rupture was found to be 5.6 ± 0.5 MPa. The Heat transfer coefficient (HTC) was calculated to be in the range of 600–900 W/(m2 K). Later as the input data for numerical simulation. In addition, using a computer-aided numerical (CAE) approach and tests, this research investigated whether the thermal properties of varied layer thicknesses and insulating wool patterns may impact the formation of casting defects. The CAE simulation reveals that the initial layer thickness would result in pipe wall problems. To lessen the hot spot region, the first step is to employ different insulating wool patterns, which could reduce the probability of shrinkage forming by 17%. The second step is to increase the thickness of the mold shell to reduce the percentage of hot spots. It is calculated that the optimal design would reduce the probability of shrinkage defects by 47%. The varying thermal properties may significantly decrease the casting faults of a mass-produced vortex flow meter by altering the thickness of the shell mold. In this study, the best solution for vortex flow meter process improvement has been adopted by an IC foundry and mass-produced. The X ray inspection shows flawless results in the vortex flow meter pipe wall where defects often form, and proves the effect and feasibility of the thermal insulation improvement proposal.

Original languageEnglish
Pages (from-to)2371-2385
Number of pages15
JournalInternational Journal of Advanced Manufacturing Technology
Volume127
Issue number5-6
DOIs
StatePublished - Jul 2023

Keywords

  • CAE
  • Heat transfer coefficients (HTC)
  • Investment casting (IC)
  • Shell mold thickness
  • Shrinkage defects
  • Vortex flow meter

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