After the glass sheet is treated by glass tempering furnace, the pitting phenomenon will appear. The pitting phenomenon is also a kind of appearance quality defect of tempered glass. The following are the main reasons:

1. The moistureproof powder on the glass is damped and sticks on the glass or there are impurities on the surface of the glass. It is not cleaned before tempering.

2. Thermal insulation shedding is found in the upper furnace of the heating furnace.

3. The glass is not cleaned after grinding. After long storage, the residual glass powder on the glass is dried and not cleaned before tempering.

4. Ceramic roller in heating furnace has not been properly cleaned, resulting in the accumulation of dirt on it.

5. Glass explosion furnace, there are small glass slag on the roller.

The pitting of tempered glass can be divided into two types:

One is dense. Usually the pitting points are concentrated in orange peel shape, which is due to the long heating time of small glass tempering furnace or the high heating temperature of tempering furnace. This situation can be solved by adjusting the heating time or temperature parameters of the steelmaking equipment. The other is decentralized. Individual pitting points are star-like distribution, which is due to the glass tempering equipment on the table or roller surface is not clean, or under the grille roller is not clean. In order to reduce the occurrence of pitting, glass tempering furnace manufacturers can establish a roll cleaning system and regularly clean glass tempering furnace rollers.