Anchors for furnace refractory materials are non-metallic or metal parts installed on the furnace shell or the steel structure supporting the furnace lining, and are buried in the lining to anchor and connect. The following is a detailed introduction to anchors for furnace refractory materials:
I. Function
Anchors are an important part of the amorphous refractory lining and a key technical measure to improve the service life of the lining. It mainly fixes the connected liner in a certain position to resist static load, thermal stress, mechanical rotation or vibration. At the same time, anchors help prevent the collapse of the material before the ceramic bond is formed during construction and heating, and also help to make the material shrink evenly, thereby avoiding large concentrated cracks in the lining.
II. Classification
Anchors for furnace refractory materials are mainly divided into two categories: non-metallic anchors and metal anchors:
Non-metallic anchors: The main varieties are furnace wall anchor bricks, furnace roof hanging bricks and refractory fiber lining anchor nails. The technical requirements for anchor bricks are high strength, good thermal shock stability, and no cracks. Therefore, generally, grade 3 high-alumina bricks are more commonly used, and grade 2 high-alumina bricks and grade 1 high-alumina bricks are also used. It is mainly determined by the use temperature of the furnace lining and the quality of the refractory casting.
Metal anchors: Generally welded on the steel plate and water pipe of the furnace shell, the welding must be full, and no false welding or leaking welding is allowed. Its shape varies, and the most commonly used are Y, V and Γ types. Metal anchors are usually used to support and fix thin or heat-insulating integral linings, such as chimney linings, wear-resistant linings of petrochemical catalytic cracking reactors, integral spray gun linings for jet metallurgy, integral linings of DH and RH vacuum degassing devices, and rotary kiln discharge and feed port linings.
3. Performance characteristics
High temperature resistance: anchors need to be able to withstand extreme high temperature environments to ensure that they do not deform or break at high temperatures.
Corrosion resistance: anchors in the refractory industry need to resist the erosion of chemical substances in the furnace, such as corrosive media such as acids, alkalis and salts.
High strength: The anchors need to have sufficient mechanical strength to withstand the scouring and extrusion from the materials and gases in the furnace.
Easy to install: The design of the anchors should be easy to install and disassemble to reduce the difficulty and cost of construction.
IV. Material selection
Non-metallic anchors: Select suitable materials according to the use temperature of the furnace lining and the quality of the refractory castable, such as grade 3 high-aluminum bricks, grade 2 high-aluminum bricks or grade 1 high-aluminum bricks, etc.
Metal anchors: Select suitable materials according to the use temperature, such as heat-resistant steel or ordinary steel. In some high-temperature and critical parts, 310S (commonly known as 2520) heat-resistant steel is usually used.
V. Installation precautions
Quantity: The number of anchors should be reasonably selected according to the type, thickness and use conditions of the refractory material to ensure that the refractory material can be firmly fixed on the furnace shell.
Spacing: On the plane, the anchors in the refractory castable are distributed in a square of approximately 500mm. The nails on any of the square feet are also located in the center of another square.
Welding: Metal anchors should be welded firmly, and no cold welding or leaking welding is allowed. At the same time, the effect of thermal expansion on refractory materials should be considered during welding to avoid damage.
Protection: Before construction, the anchors should be subjected to necessary protective treatment, such as applying asphalt paint or wrapping plastic film, etc., to prevent thermal expansion from damaging the refractory materials during baking.
Anchors for furnace refractory materials play a vital role in the construction and maintenance of kilns. Choosing the right anchor material, quantity and installation method is of great significance to ensure the stability and service life of refractory materials.
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