Since 2000, cast iron enamel has gradually been widely used in enamel ovens, baking grids, pots and other cooking utensils. These enamel products mainly use matte enamel frit. For example, the inner wall of enameled cast iron pots is generally made of matte cast iron enamel frit, while some use glossy white enamel cover coat. As an enamel frit manufacturer, today I will briefly talk about several key points that should be paid attention to when using enameled cast iron pots for food contact.

1. Enameling process of cast iron enamel

There are two ways to apply enamel to cast iron matte enamel: one enamel and one firing, and two enamels and two firings. Enameled cast iron pots are generally made with two enamels and two firings. The first layer is called "white ground coat" enamel, and the second layer is called matte or glossy cast iron enamel.

The ground coat layer with a thickness of 40-120 μm is an enamel that is not completely melted but has been sintered. The firing temperature of the ground coat is 20-50°C higher than that of the cover coat, which is helpful for the cast grill mesh to expel most of the gas during the first firing. The cover coat is then fired a second time at a lower temperature to provide better surface gloss.

2. Enameling of cast iron bottom layer

The cast iron surface is first sandblasted to obtain sufficient surface roughness. Prepare the enamel slurry by placing the cast iron enamel ground coat in a grinder. The enamel slurry is sprayed on the cast iron surface by wet spraying and dried in a drying oven at 110-140°C. Apply enamel to a thickness of 70-100μm and fire at 840°C for 12 minutes.

The preparation method of matte black cast iron enamel is similar to that of ground coat. It is ground into enamel slurry and applied with 100-140μm enamel by wet spraying. The firing time after drying is 12 minutes.

3. Various performance tests of enameled cast iron pots

Cast iron pots are intended for food contact and must be tested for acid resistance and migration. The adhesion performance of cast iron enamel is also very important. Choose a suitable cast iron enamel ground coat and conduct relevant tests. In addition, a thermal shock test must be done. The gloss value of the enamel determines the degree of vitrification of the enamel. The higher the degree of vitrification, the lower the thermal shock resistance of the enamel.

4. Matt cast iron enamel quality parameters

The gloss level of matte enamel is between 3.5 and 5°, which best meets the needs of the enamel market.