1. The non-oxidation (nitrogen protection) roller hearth heat treatment furnace (normalized furnace) heated by radiant tube is used for a period of time. The furnace roller and furnace bottom roller are nodular. The direct hazard of nodulation is to cause pits in the thicker steel plate. And affect the surface quality, as shown in the following figure, please talk about the effective measures to prevent the furnace bottom roll nodule and the treatment after nodulation.

2. Casting has pores, trachoma and other congenital deficiencies in the density of the drawing. The drawing is made of hot-rolled bar material, and through multiple processes such as perforation and tube drawing, the uniformity and density of the ingredients are better than the casting. The price is much higher than the price. Without considering the brand, the stove and the stove are very different from the price. All said the same material. The service life is much better.

3. In the general protective atmosphere, roller hearth furnace will have nodule phenomenon on the roller hearth roller surface, which is difficult to solve. I ask SAC President Mr. Han Hengji and Mr. LOI Su, they think that the thick plate is on the roller bottom Nodules in the furnace are mainly caused by surface impurities such as oxide scales in contact with the roller table at high temperatures, and once nodules will scratch the workpiece and exacerbate nodules. The only solution is to add a shot blasting unit in front of the furnace, to remove oxide scales, and to wash away impurities such as steel shots. Even if the shot blasting unit is added, there is no guarantee that no lumps will be formed at all. Regular inspections are required!

4. However, foreign experts say that the outer surface of the roller using centrifugal casting is not processed better, it can maintain a dense structure, but the adsorption force of iron oxide scale or other impurities is weak at high temperature, but the inner surface has been machined with an accuracy of 12.5 , Can effectively ensure the uniformity of the wall thickness of the roller.