Theoretical Prediction of Crack Formation in Axisymmetric Multilayer Shell Molds

Abstract

On the basis of the numerical method, the study has developed a general scheme for solving the problems on stress-strain state of axially symmetric shell molds. The study has developed a mathematical model for the process of casting melting metal into shell molds and hardening of castings. The results of the solution of the problem have showed that stresses of σ22 have the highest values, the stresses of σ11 have order of magnitude smaller values, and the stresses of σ33 vary over time and space like stresses of σ22, but they are 5-10% less in absolute values. The calculations show that the metal hardening in a shell mold starts in 31 seconds, and meanwhile, tensile stresses occur on the metal-mold surface and, therefore, metal tends to depart from the shell mold surface.

Numerical Modeling of Thermal Stress State of "Shell Mold-Casting" System with Phase Change when Inverstment Casting

“…Crack formation in SM is related to temperature impact arising during filling the molds with melt and thermoplastic stress state arising as result of no uniform heating as well as to low ceramic strength. Theoretical researches of these processes carried out by using numerical method are presented in works [1,2,3].…”