Cast iron stove grates are usually made by grey iron ASTM A48 Class 20, 25, 30. Grey cast iron has good enameled properties, so can do the porcelain finish.
The surface finish includes semi-gloss finish, black paint, enameled stove grates and fire-resisting black painting etc. Borui Casting has made many cast iron stove grates, include top single grates, top double grates, top twin grates, side grates, dual grates, center grates etc.
As for the grates, the surface grinding and polishing is very important, and so the grinding workload is also large. All the corners need to be grinded carefully. This is also a reason that many foundries could not make stove grates. Their workers are not familiar with the careful grinding works.
Borui Casting produced the cast iron grates by green sand casting process, sometimes, it was called floor molding process. The main reason to choose floor molding process is the molten iron needs to be kept in the sand molds for a certain time. At least one night. So, the grates have enough time to become cool in the molds, otherwise, the grates will be deformed after sand blast.
As for the patterns, the metal patterns will be necessary, although the cost of metal patterns are higher than resin patterns, the wall thickness of grates is very thin, and have high requirements to surface smoothness and least surface flaw such as sand holes and air holes. Therefore, the metal patterns are necessary.
During the production of these years, we think the cast iron stove grates are not difficult to produce, but just need the careful works during cast and cleaning processes. Of course, the good surface quality has to be kept by fine sands. The coarse sands can never make good grates.
In addition, just like other stove parts, please notice that the welding remedy was usually not allowable. The welding point will affect the enamel (porcelain) treatment. However, it also depends on the positions, the welding should be all right for some positions which do not need porcelain finish and will not affect the gas tightness.
