(1) Porosity: refers to the percentage of pore volume in the material as a percentage of the total volume of the material. The pores of SKF bearing high temperature resistant materials can be divided into three types according to their existing forms: closed pore, one pore - the pore connected to the outside atmosphere, connected pore - the proportion of the entire pore. The SKF bearing high temperature brick is 7L. The high temperature resistant material of small SKF bearings has the ability to resist erosion and structural strength; the higher the porosity, especially the more interconnected pores, the lower the thermal conductivity of the material. Lightweight adobe bricks, lightweight high-alumina bricks and other insulation materials use a method to increase porosity and reduce their thermal conductivity.
(2) Water absorption: the mass percentage of water absorbed by the pores in the material as a percentage of the dry mass of the material.
(3) Air permeability: The air permeability of SKF bearing high temperature resistant materials can be expressed by the air permeability coefficient, that is, the air volume of SKF in the lm2 area of 1m thick bearing high temperature resistant materials under 1m. The pressure difference is 10 Pa.
For high-temperature resistant materials for SKF bearings, the air permeability of the product should be as small as possible, but in special cases, a certain degree of air permeability is required.
If molten steel is purified through breathable bricks, the breathability of the product is considered one of the main performance indicators.
