Continuous Annealing Furnace

Function of annealing furnace During the production of ductile iron casting pipe, it always appears a lot of free cementite, which sometimes are attributed to improper chemical composition, excessive nodulant or insufficient inoculator and chilling effect of water-cooling metal mould, causing fast cooling primary crystallization. The mechanical properties of pipe is deteriorated because of high hardness, low plasticity and large brittleness for free cementite, it shall carry out thermal treatment for annealing of pipes to eliminate the harmfulness on free cementite. Therefore, annealing furnace is a key equipment for producing ductile iron casting pipe. According to the requirement of annealing technology of ductile iron casting pipe, the annealing furnace from charging end to the discharging end along the direction of the furnace length can be divided into four sections, such as heating section, temperature holding section, fast cooling section and slowly cooling section. The length of above sections is made as per the heat treatment cycle curve.