Article excerpt from the TheMetalCasting.com.Foundry sand is used for making castings, and is primarily generated by the automotive industry and its part suppliers. It consists of clean silica sand, which is of high quality; or lake sand, which is bonded to make molds for ferrous (iron and steel) and non-ferrous (copper, aluminum, brass) metal castings. The following types of sands are used for making molds in the foundry industry: Green Sand, Resin Coated Sand, Molasses, Cold Box Sand, Hot Box Sand, and CO2 Sand.
These types of sand can be obtained directly from the foundries located in the Midwest states such as Illinois, Wisconsin, Michigan, Ohio, and Pennsylvania.
Sand Casting Processes in the Foundry
The two commonly used casting processes in the foundry system are as follows:
- Sand Cast Systems - The sand used for making sand cast molds for ferrous castings is largely green sand, which comprises of silica sand of high quality, around 10 percent bentonite clay, which acts as the binder, up to 5 percent water and about 5 percent sea coal, which is an additive for improving the casting finish. This green sand forms more than 90 percent of the molding materials utilized in the process. Various types of metals can be cast and it is the type of the metal that determines the gradation of the sand and the additives that are used in these systems.
- Chemically Bonded Sand Cast Systems - These systems are used for cores to produce cavities not easily constructed through usual molding procedures. This system is also nonferrous casting molds. Here one or more organic binders are used along with catalysts and various setting techniques. Foundry sand constitutes around 97 percent of this mixture.
While before being used, foundry sand is uniformly graded. The spent sand often contains:
- Remnants of metal from the casting process as well as mold and core material with the binder in a partially degraded form
- Contaminants such as heavy metals and phenols, which are absorbed by the sand in the course of the molding procedures. Thermal decomposition produces these phenols at high temperatures from the organic binders during the metal pouring process
- High concentrations of elements such as cadmium, lead, nickel, zinc and copper in brass and bronze foundries
More News from TheMetalCasting.com
Casting Process: Basic Steps
Hill and Griffith Customer Service
The Hill and Griffith Company's green sand metal casting foundry supplies help achieve the EPA's M.A.C.T. standards and reduce Benzene emissions. Our variety of environmentally sound release agents, coatings, partings, lubricants, core oils and specialty products will help you meet your metal casting's needs. We're known for our hands-on approach. Let us visit your plant and recommend products that suit your needs.
We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »
Technical Services & Support
On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »