Manufacturing process
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Melting of selected raw materials takes place in induction furnaces, having a total capacity of 48 tons. Typically, melting is carried out at night, utilizing advantageous power rates. Rigorous chemical composition checks are carried out prior to release for casting. Horizontally split moulds are produced in "green sand" made from mixing precise amounts of silica sand, bentonite, coal dust and water. Sand quality is controlled on a regular basis throughout the production period. Moulding is carried out in a double station, jolt-squeeze machine using specially designed metal patterns.
The molten metal is poured into the sand moulds from a 4 ton holding furnace, with two moulds being filled at the same time. Moulding and pourings speeds range from 90 to 140 moulds per hour, depending on the media size being produced.
After pouring, the moulds are allowed to slow cool prior to the shake out process which separates the castings from the sand (which is recycled). A grinding mill is then used to tumble the castings, following which an automated sorting machine divides the media from the runners, risers and other metal elements, which are then returned for remelting. Prior to the heat treatment process, all media is inspected visually to remove any extraneous material and any defective pieces. The media is then heat treated in a two stage hardening and tempering process with hardness tests and austenite levels being determined after each stage. The final product is then packed in metal drums (or loaded in bulk) prior to shipment to the customer.
Each step in the total process is controlled according to a rigorous quality assurance procedure.
Christian Pfeiffer Mezzomerico SpA has been ISO 9001:2000 certified
