Common defects in the enameling process of glass-lined reactor

Due to the complexity of glass-lined production process, many defects will inevitably occur in the production process. There are many forms of defects, and each form has a variety of reasons and conditions for formation, such as whether the process system is implemented or not, and the use of unqualified raw materials will cause different defects in the ceramic layer.

Common defects can be classified into three categories: porcelain explosion, porcelain layer crack and bubbles in the porcelain layer.

Porcelain explosion is a phenomenon of porcelain layer falling off, which is actually a phenomenon of mechanical action. It has a great and direct relationship with mechanical impact, internal stress, product structure and shape, and gas in the process of product manufacturing. There are various reasons for the formation of cracks in the porcelain layer. Sometimes the cracks can not be seen with the naked eye, and can only be detected with a high-voltage spark instrument. The appearance of crack defects is mainly in the parts with high structural stress; The expansion coefficient of steel plate and enamel does not match; When the firing temperature is low; The part where the temperature drops too fast when the product is discharged from the furnace; The part where some mechanical force acts during the cooling process of the product; The part where the thermal stress is difficult to diffuse when the product is partially heated; Super-thick porcelain layer also causes cracks. Once the porcelain layer crack defect occurs, the main reason is to find out the cause first, and then take corresponding remedial measures.

There are many reasons for the formation of bubble defects in the ceramic layer. From the quality control of raw materials, the implementation of production process discipline to the sense of responsibility of operators, the formation, change and disappearance of bubbles are always accompanied by the firing process of products. This series of changes are mainly controlled by people using existing thermal equipment and corresponding process conditions.

Various defects of the glass-lined layer of the glass-lined reactor may occur at any stage of the enamel process. According to the defects of the porcelain layer, foreign scholar Martin Aldinger pointed out that the possible sources were: metal body (material, structural form, etc.); The raw materials for preparing the glaze and the manufacturing quality of the glaze; Coating and firing process; Thermal equipment and tools. The direct reasons for the defects are: the gas released from the reaction between metal and enamel during the firing process; The physical and chemical properties of metal and enamel, such as residual stress, are not stable enough; Do not follow the process discipline; Dirt, etc.