The article covers experimental studies of the physical and mechanical properties of composite material of flash heated core. The composite consists of quartz sand particles and a binder based on novolac phenol-formaldehyde resin cured with tertiary amine (cold-box-amine process). This material is used in the metallurgical industry for mould cores in the production of steel castings. The changes of its strength properties during the contact with the melted metal significantly impact the geometric accuracy of die cast parts. The use of new dependence of the core modulus of elasticity on temperature in the ProCAST engineering analysis system makes it possible to simulate deformation processes with 2% deviation of nominal contraction values compared to actual data applied in the machine-building industry.