On 2018-08-08 14:48:54
How to choose the material in the production of heat treatment furnace
Most of the furnace structure materials of heat treatment furnace are refractories and thermal insulation materials, because the heat treatment furnace is usually in a high temperature state when it works. All non-metallic materials that can resist high temperature and bear the physical and chemical effects produced under high temperature are called refractories. In the design and construction of heat treatment furnace, reasonable selection of refractory and thermal insulation materials is of great significance to meet the requirements of heat treatment process, improve the service life of heat treatment furnace, save energy and reduce costs. Here we first understand the commonly used refractories.
Refractory materials commonly used in heat treatment furnace include clay brick, high alumina brick, light refractory clay brick, silicon carbide refractory products, aluminum silicate refractory fiber, refractory concrete, etc.
(1) the main raw materials of clay brick are refractory clay and kaolin. Clay brick is widely used in heat treatment furnace and can be used for building furnace top and furnace bottom. However, due to its weak acidity and corrosion to iron and aluminum heating elements, it can not be used as the lining of electric heating elements and high carbon atmosphere furnace.
(2) high alumina brick and corundum products, with high fire resistance, maximum use temperature up to 1500 ℃, high temperature structural strength, good chemical stability, are mostly used for lining of high temperature heat treatment furnace and salt bath furnace, brick laying of electric heating components, etc. Corundum products, belonging to high alumina bricks, have high temperature structural strength and fire resistance, which are commonly used in resistance wire rod, brick thermowell, high temperature furnace bottom brick, etc.
(3) the starting point of load softening of light refractory clay brick and ultra light refractory clay brick is low, that is, the high temperature strength is low, the chemical stability is poor, and the volume change is large. It should be used as the protective layer of the heat treatment furnace lining. When the high temperature structural strength and fire resistance meet the requirements, the light fire-resistant clay brick should be selected as far as possible.
(4) silicon carbide refractory products, the fire resistance can reach more than 2000 ℃, high temperature structural strength, wear resistance, good thermal conductivity. According to the different manufacturing process, it can be used for the electric heating components of high temperature furnace, the furnace bottom plate of high temperature furnace, etc.
(5) aluminosilicate refractory fiber is a new type of soft fibrous refractory material, which has the function of fire resistance and heat preservation. According to different raw materials, it can be divided into silicic acid Road, quartz, alumina and graphite refractory fiber, etc. it has the characteristics of light weight, good thermal stability, low thermal conductivity, easy processing, convenient installation, and can also be made into prefabricated blocks or prefabricated plates sandwiched in two layers of refractory materials Use between. Aluminum silicate fiber is used in general heat treatment furnace, graphite fiber is used as refractory in vacuum furnace, hot pressing furnace and atmosphere furnace. However, some atmosphere in the heat treatment furnace has corrosive effect on the refractory fiber, which affects its application range.
(6) refractory concrete is a kind of refractory material which is cemented, formed and hardened by cement with bauxite clinker of certain size as aggregate. The utility model has the advantages that the speed of furnace repair and building can be improved, the service life is similar to that of building with refractory bricks, so the cost is low. The disadvantage is low fire resistance.