CHAPTER 15 - HIGH TEMPERATURE PROPERTIES

Abstract

This chapter discusses high temperature properties of core material of steel foundry industry. Knowledge of bond strength of a mould material at high temperatures is necessary. Hot compressive strengths is one of the high temperature properties. Hot compressive strengths have been measured by various workers. In isothermal heating, a specimen is heated until the temperature gradient from its outside to the center evens out and then broken under compression. The hot compressive strength increases with increasing temperature to a maximum and falls thereafter. The peak temperature depends on the type of clay. The sodium montmorillonite gives the highest peak hot strength at the lowest temperature, while kaolinite shows a low strength magnitude occurring at a temperature of the order of 1250°C. The chapter presents the study of high temperature properties by using a furnace capable of moving in a vertical direction, the object being to place the rammed-sand specimen on the bottom ram and quickly bring the furnace, held at a predetermined temperature, down on the sample so that the shock heating condition such as it prevails in a mould can be simulated.