http://www.anvilfire.com/FAQs/anvil-0.htm

"Today most good quality anvils are made of cast steel the type dependent on the manufacturer. There are also a large number of cast iron "shop anvils" sold. Cast iron anvils are worthless for forging as they are dead (no rebound) and very brittle."


http://www.beautifuliron.com/gs_anvils.htm

"Why not cast iron? Cast iron anvils inherently contain layers or platelets of graphite throughout their mass. The graphite layers in cast iron anvils absorb concussion (hammer blows in our case) and cushion the work. In cast iron anvil this results in a softer work surface that absorbs force of hammer blows- making us work much harder to produce less product over the same time period compared with using a steel or wrought iron and steel anvil. Avoid cast iron anvils. Buy steel anvils."