When selecting refractory materials, attention should be paid to the following issues: First, we should adapt to the local conditions, be self-reliant, pay attention to the characteristics of regional resources, and reasonably select refractory bricks and other materials; secondly, consider the working characteristics of the furnace masonry and make it technically correct. Different types of heating furnaces and different parts of the furnace body have different working conditions, so the use of refractory materials should fully consider the characteristics of the masonry work.
The working temperatures of different parts of the heating furnace are different. When selecting refractory materials for heating furnaces, different types and grades of products should be used. Furnace masonry or parts that are subject to greater temperature stress should use refractory materials with good thermal stability. Parts that bear greater loads should choose materials with high compressive strength, and the load softening point of the material should be considered when selecting.
Some masonry, such as the bottom of the vibration-type heat treatment bottom, must withstand mechanical vibration and the impact of the workpiece. Alumina cement refractory concrete integral ramming structure can be used. For the bottom of the annular furnace, the impact and friction of the workpiece during loading and unloading should be considered. High-alumina brick masonry or chromium ore knotting can be used. For some parts that have been severely damaged by mechanical means, it is necessary to consider the convenience of local replacement or repair.
For the parts of the masonry that contact the corrosive medium, refractory materials should be selected according to the nature of the chemical reaction. For example, the bottom of the soaking furnace, the soaking bed of the pusher type continuous heating furnace, the furnace mat of the reverberatory furnace, etc., are preferably built with magnesia bricks due to the erosion of iron oxide slag, etc. The ability of various refractory bricks to resist chemical erosion can be found in the furnace building materials section.
In addition, the special requirements of some furnaces should also be considered. For example, in the stainless steel heat treatment furnace heated directly by flames, in order to ensure that the surface of the steel plate will not be affected by the slag falling from the furnace top, which will cause difficult-to-remove marks that affect the quality of the plate surface, it is necessary to use materials with high refractoriness and good thermal stability to build the top; the heat treatment furnace operated periodically requires the masonry to have low thermal inertia, so it is necessary to use lightweight refractory materials with low specific heat and good insulation; for the furnace with protective gas, the selection of masonry materials can be found in the furnace building materials section. When different types of refractory products come into contact with each other at high temperatures, it is also necessary to consider whether they react with each other.
