Influence of the damage level during quenching on thermal shock behavior of low cement castable

Abstract

In the recent decades, the use of unshaped monolithic refractories has been increasing greatly because of their significant advantages over other shaped refractory bricks of the same class. A low cement high alumina castable was synthesized and sintered at 1300°C in order to investigate thermal and mechanical properties, as well as thermal shock behavior. The water quench test was applied as an experimental method for thermal stability testing. Modification of the water quench test was performed by additional monitoring of the samples behavior during the water quench test such as implementation of image analysis and ultrasonic measurements. The image analysis program was applied on samples in order to measure the level of surface damage before and during the water quench test. Ultrasonic measurements were performed with the aim to measure the Young modulus of elasticity during the testing. Strength deterioration of the samples was calculated by the model based on ultrasonic velocity changes during the water quench test. The influence of monitoring the damage level before and during the quench experiment and its influence on thermal shock behavior will be discussed.

Poslednjih decenija neoblikovani monolitni vatrostalni materijali imaju sve širu primenu zbog brojnih prednosti u odnosu na oblikovane vatrostalne opeke iste klase. U ovom radu ispitivane su termičke i mehaničke osobine i ponašanje pri termošoku niskocementnog visokoaluminatnog vatrostalnog betona koji je sintetizovan, a zatim sinterovan na 1300ºC. Kao eksperimentalni metod za ispitivanje termostabilnosti betona primenjen je modifikovan test klasične metode ispitivanja naglim hlađenjem u vodi koji se sastojao u dodatnom praćenju ponašanja uzoraka prilikom termošoka implementacijom analize slike i ultrazvučnih merenja. U cilju praćenja stepena oštećenja površine pre i tokom testa na termostabilnost, korišćen je softverski program za analizu slike, a ultrazvučnim merenjima promena Jungovog modula elastičnosti. Pad čvrstoće uzoraka izračunat je pomoću modela na bazi promene brzine ultrazvuka tokom testiranja uzoraka na termošok. U ovom radu biće diskutovan uticaj praćenja stepena oštećenja na ponašanje materijala pre i tokom testiranja uzoraka na termošok.