Process Capabilities and Limitations of CGI Sand Casting


Sand Casting Compacted Graphite Iron (CGI) – Process Capabilities and Limitations

December 1st, 2021

What is sand casting with compacted graphite iron (CGI)?

Compacted graphite iron (CGI), also known overseas as vermicular graphite iron, is a metal commonly used when cast iron is too heavy and not strong enough. CGI is approximately 75 percent stronger and 75 stiffer than gray cast iron. It is also much lighter than cast iron. For example, an assembled auto engine using CGI is approximately nine times lighter than one using traditional gray cast iron.

As with sand casting using other materials, this process involves creating a void in the sand, pouring the molten CGI into that void and allowing the object to cool gradually.

Impro produces CGI sand castings mainly for engine cylinder heads on marine vessels, with weights ranging from 40kgs to 300kgs. We consistently achieve over 90% vermicular graphite.

When is CGI a good fit?

Just a few of the common applications for CGI include diesel engine blocks, brake discs on high-speed rail trains, cylinder heads, exhaust manifolds and turbo housings. CGI is the go-to metal for high-performance engines, such as those used on race cars. Nearly all NASCAR racing teams use CGI engine blocks in their cars.

What are some limitations of CGI?

While CGI is a great fit for many projects, there are a few limitations. For one, the strength of this material makes cutting and finishing it can be more of a challenge and take more time than with cast iron. In addition, CGI is generally more expensive than gray cast iron.

Working with Impro

Impro offers a number of manufacturing technologies, including sand casting with CGI. We’re pleased to have been rated among the global top five sand casting companies for complex high-performance iron sand castings by the “Roland Berger’s 2019 Report”. What sets our company apart from our competitors is our one stop shop business model. We don’t think you should have to work with half a dozen different companies for your manufacturing needs. That’s why we offer design support, prototyping, product development, full production, logistics and supply chain support, in addition to our manufacturing technologies.

Whatever your industry or application, you can count on Impro to deliver ready-to-use products and services quickly and accurately. Get started on your next project by contacting our team today.


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