Graphite Nucleation in Cast Iron Melts Based on Solidification Experiments and Microstructure Simulation

Microstructure strongly influences the mechanical properties of cast iron. By inoculating the melt with proper inoculants, foreign substrates are brought into the melt and eventually the graphite can crystallize on them. The elements and substrates that really play a role for nucleation are yet unknown. Until now there is very little knowledge about the fundamentals of nucleation, such as composition and morphology of nuclei. In this work we utilized EN-GJL-200 as a base material and examined several produced specimens. The specimens were cast with and without inoculants and quenched at different solidification states. Specimens were also examined with a high and low oxygen concentration, but the results showed that different oxygen contents have no influence on the nucleation in cast iron melts. Our research was focused on the microscopic examination and phase-field simulations. For studying the samples we applied different analytical methods, where SEM-EDS, -WDS were proved to be most effective. The simulations were conducted by using the software MICRESS, which is based on a multiphase-field model and has been coupled directly to the TCFE3 thermodynamic database from TCAB. On the basis of the experimental investigations a nucleation mechanism is proposed, which claims MnS precipitates as the preferred site for graphite nucleation. This theory is supported by the results of the phase-field simulations.

Fused Cast Alumina Refractory Products for Glass Melting Furnace

JC/T 494-92(96) 1 ScopeThis standard specifies the technical requirements, test methods, inspection rules, marking, packing, transportation, and storage of fused cast alumina refractory products for glass melting furnace. This standard is applicable to the fused cast alumina refractory products for glass melting furnace (called products for short).2 Normative ReferencesGB 2997 Test method for apparent porosity, water absorption, bulk density and true porosity of dense shaped refractory productsGB 5072 Test method for cold crushing strength of dense shaped refractory productsGB 5989 Test method for refractoriness under load of dense shaped refractory products (Differential, with rising temperature)GB 7320 Test method for thermal expansion of refractory productsGB 10204 Test method for corrosion resistance of refractories for glass melting furnace to molten glassGB 10325 Stacking, sampling, acceptance, storage and transportation of shaped refractory productsGB 10326 Inspections of dimension, appearance and section of refractory productsGB/T 14351 Chemical analysis method of fused cast alumina refractoriesYB 4015 Sample preparation for testing of refractory products for glass melting furnaceYB 4016 Sampling and inspection of refractory products for glass melting furnaceJC 493 Fused cast zirconia corundum refractory products for glass melting furnace