What are the types of rubber expansion joint flanges?

Rubber expansion joint is a combination of sphere and flange, the sphere has two kinds of grooved and large flanges, grooved flanges are made of cast steel, forged, stainless steel, large flanges are installed with flat welding flanges, which can also be replaced by grooved flanges.
Flange according to the form of flange sealing surface can be divided into flat, protruding surface, concave and convex surface, tongue and groove surface and ring connection surface and several other.
Flange according to the structure form can be divided into the overall flange, with neck threaded flange, butt welding flange, with neck flat welding flange, with neck socket welding flange, butt welding ring with neck loose sleeve poignant flange, plate type flat welding flange, butt welding ring plate type loose sleeve method, flat welding ring plate type loose open sleeve flange, flanged ring plate type loose sleeve flange, flange cover, etc.
Flange according to the different materials can be divided into: cast iron flange, steel flange, plastic flange, copper flange, etc..
There are three common types of rubber expansion joint flange, cast steel flange, forged flange, stainless steel flange.
Forging flange anti-corrosion, acid and alkali resistance, long service life, etc., strong texture performance, from the appearance of forging flange without sand eyes and air holes. Cast steel flange usually has sand holes and air holes and rougher appearance. But the price is cheaper than forging flange.
Stainless steel flange, this flange material is generally used in the pipeline operating environment with strict acid and alkali corrosion requirements, generally will use stainless steel 304.316 these two for common, stainless steel materials are able to adapt to the very harsh pipeline environment, such as, high temperature, corrosion, wind and sun can effectively protect the safe operation of the pipeline.