Related issues of roller bottom nodules in roller bottom heat treatment furnace
1. Non oxidizing (nitrogen protected) roller bottom heat treatment furnace (normalizing furnace) uses radiation tube heating. After using for a period of time, the bottom roller of the furnace becomes lumpy. The direct harm of nodules is the formation of pits on thick steel plates, which affects the surface quality.
2. There are congenital defects such as pores and sand holes in the tissue density during casting. Hot rolled bars are used for drawing. After multiple processes such as perforation and tube pulling, the uniformity and density of the composition are better than casting, and the price is much higher. Regardless of the brand, there is a significant price difference between stoves and stoves. They are all made of the same material. The service life is much better.
Generally speaking, roller bottom furnaces that protect the atmosphere will have roller bottom nodules, which is a difficult problem to solve. The formation of nodules on thick plates in roller hearth furnaces is mainly caused by surface impurities such as oxide scales coming into contact with the roller conveyor at high temperatures. Once nodules form, they can scratch the workpiece and exacerbate the nodules. The solution is to add a shot blasting unit in front of the furnace to remove oxide scale and clean impurities such as steel balls. Even with the addition of shot blasting units, it cannot be guaranteed that there will be no nodules at all. Regular inspections are necessary!
4. The outer surface of the centrifugal casting roller cannot be processed better and can maintain a dense structure. The adsorption ability of iron oxide scale or other impurities at high temperatures is weak, but the inner surface has been processed with an accuracy of 12.5, which can effectively ensure the uniformity of the roller wall thickness.