Chemical castings mainly include large-sized castings for chemical industry, large-sized and medium-sized thin-walled casings, such as casing, volute casing, rear bearing seat, guide ring body, etc. The materials mainly include carbon steel and austenite stainless steel. For this kind of thin wall product the alkali phenolic resin sand moulding is adopted to ensure the good inner quality.  The surface roughness of the inner and the external surface fully meet the designed requirement. The ability to resist intercrystalline corrosion, spot corrosion and pressure is up to standard.