High temperature structural strength
Refractory material in use is mainly affected by the pressure, the compressive strength of refractory materials at room temperature value is very high, but the refractory material is used at high temperatures, and the strength of itshigh temperature decreased significantly.
High temperature structural strength index of refractory materials, is its high load softening point determination method is, diameter 36mm, high 50mm cylinder test, under the pressure of 0.2MPa, velocity and heated in a high temperature furnace with provision for the determination of sample, deformation, compression and compression to4% 40% (collapse) three temperature values.
Load softening temperature is an important index of performance of refractory materials, some materials despiterefractoriness refractoriness under load is high, but low, attention should be paid to the use of. For example,magnesia brick refractory degree exceed 2000 degrees, but its load softening temperature only 1500 degrees, far below its refractoriness.
The slag resistance
The ability to erosion refractory material to resist various molten metal, slag, furnace dust at high temperature is called the slag resistance. For the heating furnace, often encountered is molten iron oxide erosion of refractory material, some heating furnace and heat treatment furnace also note the effect of atmosphere in the furnace for refractory material. The erosion of slag and furnace lining of refractory materials, including chemical erosion,physical dissolution and mechanical erosion three effects, sometimes several effects have both at the same time.Slag ability against the impact is the biggest is the chemical composition of refractory products and slag, chemicalproducts by the attribute divided into acidic, basic and neutral. Acid refractory products with strong anti slag of acid slag, alkali slag to erosion; alkaline refractory products and vice versa.
Thermal shock resistance
Refractory material in the heating furnace temperature changes often work in intense conditions, such as the mouthparts of soaking pit furnace cover, often open, effect of refractory brick here are influenced by temperature changes,is one of the most easily damaged parts. So in this local requirements of the refractory material has good thermal shock resistance, thermal shock resistance.
Determination of resistance to thermal shock resistance of the method is the urgency of refractory products: the sample in the furnace is rapidly heated to 850 degrees, heat preservation time, and immediately immersed in cold water flow, so repeatedly, until the sample falling above weight to achieve the original weight of 20% so far, withrefractory products subjected to thermal shock the number as a measure of thermal shock resistance index.
High temperature stability
Refractory materials used in high temperature, will produce the recrystallization or further sintering phenomenon, at the same time or expansion with volume shrinkage, called heavy firing shrinkage or expansion. This expansionphenomenon of different spoken in front of the thermal expansion, temporary changes reversible thermal expansion and contraction, and heavy firing shrinkage or expansion is irreversible.
Method for the determination of the using temperature of bricks is about 100 degrees heat for 2 hours, then remove the percentage of the volume change. In general, hope refractory products heavy firing volume shrinkage or expansion of not more than 1%.
