For cast iron enamel, especially the enamel grill of the gas stove or the enamel grid or baking pan in the barbecue oven, because it is in contact with food, it will inevitably be corroded by salty liquid, coupled with the characteristics of cast iron enamel, so for this kind of products Salt spray performance is very important.

At present, the standards for salt spray test in the enamel industry are different. Generally, it is required to pass the salt spray test for 48 hours without rust, followed by 72 hours. Internationally, enterprises have higher requirements for salt spray test standards. In fact, 72-hour salt spray resistance is already a relatively high standard, and many companies can't meet it or can only barely meet it. So how to improve the salt spray resistance of cast iron enamel?

1. Selection of enamel frit

Enamel frits play a vital role in the salt spray resistance of enamel products. Some excellent enamel suppliers in China have developed salt-spray-resistant enamel products suitable for enamel hobs or ovens, such as direct-on black salt-spray-resistant enamel. This kind of enamel has strict requirements on the melting process to ensure Enamel products can maintain good exhaust performance during the firing process, allowing the gas generated by the cast iron to be exhausted as much as possible, thereby reducing pinholes and air bubbles in the porcelain layer, and making it difficult for the salt spray in the salt spray test to erode the surface of the cast iron.

2. Metal pretreatment

Castings must be carefully polished and strictly inspected to confirm that the castings entering the production line have no white spots, no burrs, and sand holes on the surface. Sand blasted 2 times. If the surface roughness is too low, the adhesion of the finished product is poor, and the surface of the casting will be uneven if the roughness is high. The porcelain layer in the high place is thin and easy to be eroded by salt spray, and the porcelain layer in the low place is thick, which is not conducive to the gas flow during firing. Emission also has an adverse effect on the results of the salt spray test.

The pretreated enamel castings should be fired as soon as possible to avoid moisture and dirt.

3. Enamelling

If cast iron enamelled products take a long time to enamel, this process may cause rust spots before drying. Therefore, it is best for enamel manufacturers to properly add anti-rust agents when grinding the enamel slurry, arrange the enamelling process reasonably to make the time closer, and dry thoroughly.

Four, firing

The firing time and temperature are subject to the glossiness of the product meeting the requirements. When firing, it is necessary to ensure that the product will not be warped and deformed, so as to avoid cracking of the porcelain layer and affect the salt spray performance.