Cast Iron Enamel Technology and Production Process (2)

Release time:

2026-03-11 10:17

Source:

(Continued from previous article)

I. The Influence of Various Chemical Components on Cast Iron

Carbon in Cast Iron: Carbon exists as cementite, bound to free graphite. The total carbon content and the form in which carbon exists in the casting have a significant impact on enamel coating. For example, when cementite exists in the casting, it mainly causes pinholes in the enamel layer during firing. This is because the cementite decomposes during the firing process after enamel coating, releasing carbon that reacts with oxygen in the enamel frit to produce carbon monoxide or carbon dioxide. Therefore, the ratio of cementite in enamel castings must be controlled. This can be addressed by using a high-temperature molten iron low-temperature casting method. Because cast iron has a high total carbon content, the graphite carbon and cementite content are also quite high. During high-temperature firing, they will inevitably decompose and release a large amount of carbon monoxide gas, causing defects in the enamel layer. Therefore, the total carbon content must be controlled to prevent it from becoming too high.

Silicon in Cast Iron: Silicon promotes the precipitation of graphite carbon. Changing the silicon content in cast iron can adjust and fix the ratio between carbon and graphite. The silicon content in enamel castings varies considerably, fluctuating between 1.5% and 3.5%. Thin-walled castings typically contain 2.2% to 3% silicon, while thicker enamel castings may contain 1.6% to 2.1%. While the silicon content in gray cast iron cannot be too low, it also cannot be too high; generally, exceeding 3.7% will cause the casting to become harder and more brittle, which is detrimental to the enamel. Therefore, ensuring that carbon exists in the casting in the form of graphite is harmless to the enamel.

None

Basic Knowledge of Inorganic Pigments (2)

None

Basic Knowledge of Inorganic Pigments (2)

RELATED INFORMATION

The 26th International Enamel Congress (IEC 2026)

The 26th International Enamel Congress (IEC 2026) will be held in Paris, from June 1–4, 2026, at the UIC-P.

01-08

2026

LIFAFRIT Union Activities: Building Bonds Beyond the Factory Floor

As 2025 drew to a close, the LIFAFRIT Union organized a vibrant and rejuvenating year-end event for the employees of the enamel frit factory,

12-30