HIGH TEMPERATURE STRESS-STRAIN BEHAVIOR OF ALUMINOUS REFRACTORY CONCRETES FOR STEELMAKING USE

GALLIANO, P.G.; MARTORELLO, L.; TOMBA, A.G.

Fortaleza, Brasil

Congreso; 11th Biennial Worldwide Congress on Refractories UNITECR?09; 2009

Asociacion Brasilera de Cerámica y otros

High-alumina refractory concretes with hydraulic bonding and containing MgO-Al2O3 spinel are used in several applications in steelmaking vessels for liquid steel treatments and transporting. The particular combination of components favors their in service performance in different types of linings. These concretes withstand severe in service thermomechanical loadings: thermal gradients, thermal cycles and thermal shock. In this work, alumina/spinel concretes with calcium aluminates hydraulic bond used as lining of steelmaking vessels containing liquid steel are characterized to evaluate the mechanical behavior in conditions similar to those used in service, and to analyze the results in relation with materials characteristics and microstructural changes occurred during testing. Results showed densification of analyzed materials at temperatures higher than 1300°C, with a strong ó and E decrease at higher temperatures with slight porosity reduction suggest that liquid phase sintering may be taking place.  Stress-strain curves show quasi-brittle behavior at all testing temperatures. Brittle behavior is remarked at lower temperatures, where a lower degree of diffusive damage is expected. Static elastic modulus clearly decreases while increasing testing temperature. This reduction is not accompanied by a decrease in strength, suggesting a complex microstructural thermal evolution in the system