Casting and Molding Process of Grey Iron

Methods of casting and molding

What exactly is molding and casting of iron?

The casting method is prevalently used for making metal parts of varying shapes and complexity depending on its usage. Sand is used predominantly as it has many advantages over other material.

Iron is cast and made into a lot of components and products. It has many uses in automobile industries and other industries as well. The iron ore is first treated to make it fit for casting. The process of casting involves the use of very simple and cost affordable raw materials but require high skills to carry off the actual procedure. Sand casting is mostly used to make mould holding for all kinds of components both big and small, right from automobile parts to big engines.

Sand casting has basic steps such as preparation of molten metal with the right chemistry. Then the sand mold is prepared by using a pattern that is just the copy of the shape we finally require the mold is finally cooled and broken to take out the prepared mold. Then the rough areas are polished and heat treatment provided.

Sand used is usually green sand which is wet sand mixed with certain chemicals and prepared for pattern placing by various methods.

The most crucial part in the process of molding is the pattern design and mold preparation. The pattern must be exact for mold preparation. There are some differences in the final product got and these are deliberately marked to allow for the metal to shrink or adjust to the right size. Then hot molten metal is poured into the pattern and time allowed for cooling the resultant rough cast is polished or further treated. Also allowances are made for molten metal overflow and special space is created for it. Vents are also placed for the gases formed to escape.

The mold consists of two equal parts called the drag and the cope which are the lower and upper sides respectively. There is a parting line which is found in the mould. The main idea is to remove the product carefully in order to keep the pattern and mold intact for further use. The mold however may be damaged in this process. The pattern can be used to create further mold required for production. The cast metal is removed and some polishing is done as there are likely to be imperfections. In fact sand casting product can be easily identified by the surface of the finished product. Air molded products have a smooth finish also easily discernable.

This process of metal casting can be attempted only by skilled engineers as most of the components for critical machine parts are obtained from this. There are reputed concerns with advanced machines which ensure precision in every step of the way. Right from studying the drawings to making the pattern and mold to accurate standards to finishing products to the required shape.


Post time: 05-31-2017