Element in Cast Iron That Affect Quality of Enamel

Usually, enamel manufacturers mainly use gray cast iron to make enamel products. Its main components are carbon, silicon, manganese, phosphorus, and sulfur. Cast iron parts with different wall thicknesses have different mechanical strengths and different corresponding element contents. Today, let’s talk about the influence of the main elements in cast iron on the quality of enamel products.
cast iron enamel
① Carbon element is the carbon content in cast iron. Because the total carbon content in cast iron is high, graphite-type carbon and cementite are also quite high. When they are fired at high temperature, they will easily decompose a large amount of CO or CO2 gas to cause defects in the porcelain layer, so the carbon content in cast iron should not exceed the standard.

②Manganese element. Generally speaking, the content of manganese element is within the normal range, and generally does not have a significant impact on the quality of cast iron enamel.

③Si element, silicon element has a great influence on the quality of enamel cast iron, and the silicon content in enamel cast iron can be 2.2%~3%. If the silicon content is less than 2.2%, the properties of cast iron tend to be hard and brittle. Silicon has the effect of hindering the formation of cementite, which is beneficial to enamel.

④ Phosphorus element. Phosphorus has the effect of improving the fluidity of the cast iron in liquid form. As a result, thin-walled castings with complex shapes and large sizes can be produced. If the phosphorus content is too high, the cast iron becomes brittle.

⑤ Sulfur, which dissolves in cementite and hinders the graphitization process of carbon. Sulfur is easy to precipitate sulfide on the surface of cast iron, causing cracks or small holes and small bubbles in the cast iron. The content of sulfur in cast iron exceeds 0.12%, and its harmfulness is even more obvious. When the sulfur content is very low (less than 0.05%), it will cause the cast iron to warp and deform. If the silicon content is appropriate, the minimum content of sulfur that increases the strength of the cast iron to prevent warping and deformation of the casting is about 0.065%.

The above is the influence of the main components of cast iron on the quality of cast iron enamel products. Of course, there are many factors that affect cast iron enamel products, such as casting stress, casting process, enamel frit and enameling process, etc., will affect the quality of the final product.