General Applications for Cast Iron

Cast Iron has been a staple of our society for as long as the USA has been a nation. While the Automotive sector is a large one, it isn’t the only large sector.  Piping and plumbing applications are extremely large segments of the industry, though foreign competition has eroded the US foundry base.  Interestingly, the cast iron cookware segment enjoys a great reputation for specialty castings.  While foreign competition is also competing for the cookware market, Lodge Manufacturing has added capacity and enjoying a popularity for both seasoned and enameled cast iron skillets and pots.

Automotive applications for cast iron parts has slightly declined for the past 10 years but is not projected to change much for the next 5 years.  This is likely because most automotive vehicles will still be using gray iron for all brake rotors and some of the brake caliper related structures.  

No overall increase is forecast, however demand for cast iron cookware (pans, pots, utensils) and plumbing fittings will grow slightly. Unfortunately the automotive shift to light metal alloys for engines and automotive parts offsets the cookware and plumbing increases. Iron properties, such as stiffness, high thermal conductivity, and wear resistance, make it useful for cookware.

Image Credit:
“Metal Casting Market Size, Share & Trends Analysis Report By Material (Aluminum, Iron, Steel), By Application (Automotive & Transportation, Building & Construction, Industrial), By Region, And Segment Forecasts, 2019 – 2025”
Published by Grand View Research, Inc, Aug-2019.


Image Source:
The Road Ahead: Aluminum Content Growth Surge (2017 Ducker Study Webinar).

Automotive Applications

With the overall vehicle weight being reduced by approximately 270 lbs between 2015 and 2025, the cast iron content is still forecasted to comprise 8 percent of the total weight.  Therefore, while maintaining the same proportional content, the designers will still be reducing the cast iron hardware weight content over 20 lbs.  In some cases, this will be accomplished by substituting aluminum for cast iron, such as brake calipers or steering knuckles.  Other actions can be attributed to eliminating cast iron exhaust manifolds with new cylinder head designs and fabricated stainless steel manifold construction.  For the foreseeable future, brake rotors will continue to be cast from gray iron, particularly with a reasonably high carbon content, thus increasing the internal material damping of the rotor. 

In the area of engine design, most cylinder heads have already been converted to aluminum castings to post weight savings to date.  As of this writing, there is a new movement to integrate exhaust manifold into the aluminum cylinder heads, thereby allowing exhaust gas flow directly into a turbocharger or a catalyst brick contained in stainless steel housing.  

Integrated Exhaust Manifold
By integrating the traditional cast iron exhaust manifold inside of the aluminum cylinder head, the designer achieves a weight savings and a performance improvement.

Image Credits:
Shunk, Chris; “Here’s why the 2012 Camaro V6 makes 11 more horsepower”, Autoblog, May 17, 2011.

Integrated Exhaust Manifold

For the 2012 model year 3.6L V6 gasoline engine, GM design engineers managed to remove 13 pounds of weight by integrating the exhaust manifolds into the aluminum cylinder head.  This change eliminated the ductile iron manifolds, 12 bolts, a pair of gaskets and heat shields with their own six more bolts.

Beyond weight savings, these changes also eliminate the potential for gasket failure and improved fuel efficiency. 

Integrated Exhaust Manifold
2012 Camaro cylinder head integrates the exhaust manifold into the cylinder head for better scavenging efficiency and lower vehicle weight

Image Credits:
Shunk, Chris; “Here’s why the 2012 Camaro V6 makes 11 more horsepower”, Autoblog, May 17, 2011.

Regional Iron Casting Capacity

An interesting commentary on cast iron applications is as that there is a short-fall of cast iron foundries in North America.  This current capacity short fall is a result of off-shoring cast iron parts new foundries in China 2000-2015 time frame.  During this same period, many cast iron foundry operations in North America had to close due to decreasing prices and legislated cost increases associated with OSHA mandated capital projects aimed at the elimination of all air-born silica particles in foundries.  Many iron foundries closed their doors because there was no profit for the investor, therefore no opportunity to continue.

However, as the cost of shipping from China continued to rise and the quoted prices from Chinese foundries also continued to rise, the business case started to swing to the favor of North America, particularly to Mexico (where the more restrictive OSHA mandates from the USA were not enforceable).  Since 2015, there have been several new iron foundries launched in both the USA and Mexico that are highly efficient and environmentally responsible.  These new foundries are particularly focused on The efficient production exhaust manifolds and brake rotors.

Cast Iron Example Parts

FCA 3.0L V6 Diesel Cyl Block
FCA 3.0L Diesel CGI Block, produced by Tupy-Brazil using SinterCast process

Image credit:
Foundry Management & Technology Magazine, “Diesel Options Drive CGI’s US Market Gains”, Robert Brooks, author, Feb 18, 2013.

Ford 2.7L CGI Block
Ford 2.7L CGI Cylnder Block - A transformational architecture for Gasoline Cylinder Blocks

Image credit:
Car and Driver Magazine, “Leave the Iron On: Ford Buries New-Age Iron in Its Aluminum-Intensive 2015 F-150”, Don Sherman, author, Roy Ritchie, photographer, April 24, 2014.

George Fisher Knuckle

Image Credit:
Georg Fisher Casting Solutions website

Image Credit:
CWC-Kautex, division of Textron.

CWC manufactures engine components (camshafts, balance shafts, bearing caps) for a variety of applications including automotive, agricultural and power sports engine programs.  CWC is a technical leader in lobe hardening required in most modern engine applications and is sought after for its technical expertise and focus on quality. Using flame heat, oil quenching and cryogenic freezing and tempering techniques, CWC alters the metal microstructure to each customer’s unique specifications

Main Bearing Caps
Ductile Iron main bearing caps are typically cast in a single cluster and separated during machining.

Image Credit:
JEGS auto parts, Dart Big Block Chevy Rear Main Cap in Ductile Iron

Differential Housing
Cast Iron differential housings are used for pickup and industrial vehicles.
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