The differences between forged flange and casting flange

The differences between forged flange and casting flange

what is the difference between the forged flanges and casting flanges? 

1. the internal structure which makes density different

2. processing way different

3. After treatment is different

4. cost is differnt

   Advantages of cast flange: 1). high machining preciseness 2).complex appearance/shape available 3).simple machining process 4). low machining cost 
   By contrast, the forged flanged has advantage of better density, better inner structure, better seamline, in mean time with higher cost than cast flange.