The History of Iron Casting Part 3

Iron played a vital role in early world history, and its impact remains pivotal in recent history, today, and into the future.

Iron in World War II

Iron was a key element in military power during World War II. It was used to build British planes called Spitfires and Hurricanes, ship propellers and submarine parts, and hydraulic shell banders. Lawton helped improve the accuracy and range of guns on American ships during World War II by building a machine to band artillery shells.

Cast Iron was also used to produce “pineapple” grenades, named because of their shape and design. Finally, iron was used to produce firearms. Because of this wide range of uses, not including non-war uses, iron was very valuable, and everyone was eager to get their hands on it.

During World War II, Germany depended heavily on iron ore from northern Sweden, a region rich in this valuable mineral. Much of it was shipped through the northern Norwegian port of Narvik. In 1939, the Germans discovered that Britain planned to stake its claim on several military bases in Norway. Possessing these bases meant Britain could easily block German iron imports as a war tactic.

To prevent this from happening, Hitler considered seizing the bases before the British army could reach them. The German Navy told Hitler that controlling Norway would let it dominate the nearby seas; the bases could also serve as staging areas for future submarine operations against Britain.

However, Hitler decided to stand by a directive he had recently issued, which stated that Germany’s main war effort would be a land offensive through the Low Countries. So, Britain occupied the bases as planned. Germany soon regretted this decision. During the Battle of the Atlantic, Britain and France set up a naval blockade to prevent Germany from receiving its iron and other supplies. It weakened Germany’s armed forces. Without the possession and control of iron, the Allied Powers may not have won the war.

When Churchill became Prime Minister of England, he assigned William Maxwell Aitken, known as Lord Beaverbrook, as the minister for aircraft production. In this role, Beaverbrook had to figure out how to procure the desperately needed raw materials so Britain could build warplanes called Spitfires and Hurricanes.

Lord Beaverbrook’s clever solution to this materials shortage was to repurpose the iron railings and gates used to enclose cemeteries, parks, and squares in Britain's towns and cities. This was done in 1940; as a result, authorities removed many hundreds of tons of iron for the war effort.

Despite this setback, the Spitfire was one of the most important technologies in history. A brilliant, maneuverable, and super-fast fighter, the Spitfire was pivotal to Britain’s strength against the Nazi air force, which was known as the Luftwaffe.

Thanks to the Spitfire, Britain’s Royal Air Force (RAF) was able to fight off the Luftwaffe in the Battle of Britain, despite being at a large disadvantage. Hitler had been building up his forces since the 1930s. During that time, British defense spending was at historic lows, limiting its ability to prepare for such a battle. The Luftwaffe entered the Battle of Britain with 2,600 operational planes while the RAF had only 300 Spitfires and 500 Hurricanes. However, because of the Spitfire’s speed and agility, the Germans were unable to neutralize the RAF.

As a result, a German invasion of the British Isles was prevented. Had it succeeded, D-Day would never have happened. The United States would have never liberated France from German occupation. German occupation of Britain would probably have cost the lives of 430,000 British Jews. It might even have given Germany the lead in the race for the atomic bomb.

However, history unfolded as it did in part because of iron planes. It makes you wonder what our world would be like today without cast iron.

Advances in austempering & technology

In our last article, we discussed the austempering process, in which metallurgists use austenite to improve steel’s mechanical properties and eliminate distortion in cast iron or steel. During World War II, this process was used to make gun parts. This process yielded minimal distortion, and the resulting parts were tougher than those made from untreated metal. Many important gun parts are still austempered today for these very reasons.

The downside was that the equipment needed for austempering was inefficient, which made it expensive. Despite its high cost, by the 1950s the austempering process was used regularly in the production of steel and malleable iron parts. But its relatively high cost limited its use to only high-performance parts.

Also in the early 1950s, the second Industrial Revolution began as technology evolved, with a focus on the growth of solidification science and computational modeling. This age began with the work of scientists like Chvorinov on the mathematical correlation between casting volume, surface ratio, and solidification time of metal, and Chalmers’ formulation of the constitutional undercooling criterion based on the redistribution of atoms during the solidification process, which led to the understanding of how the cooling rate relates to the microstructure and hardness of cast alloys.

The age of virtual cast iron began with computational models of cast iron microstructure and properties. The first to do this was a scientist named W. Oldfield. He created a computer model that could calculate the cooling curves of gray iron. He was also the first to try predicting the solidification microstructure of cast iron using a computational model. By 1985, solidification modeling of cast iron had become an important research topic as models continued to improve. Today, computer software can simulate and model the entire process, including mold filling, solidification, and the structures and properties of iron castings.

In 1966, the C.A. Lawton Co. began production of nylon tooth gears. This was the first major innovation in decades for power transmission and was designed to reduce noise levels in manufacturing facilities. It was a huge success, especially in the paper industry. To learn more about this and Lawton’s other innovations, check out our articles on Lawton’s 135-year history.

In 1972, Atmosphere Furnace Company developed a pusher austempering furnace. This furnace processes materials that rely on continuous heat in a protective gas atmosphere. As the metal moves through the furnace, processes such as carburizing, preheating, washing, tempering, and cooling occur in sequence. This process increased austempering productivity and drove down costs, making it competitive with conventional heat treatments.

Also in 1972, the austempering process was first commercially applied to produce Austempered Ductile Iron (ADI) at one of Atmosphere Furnace Company’s facilities. With ductile iron’s superior castability, austempering produces a material that can be cast into complex shapes with greater quality consistency, often at lower cost. As austempered ductile iron developed, cast iron strength increased over the years, eventually rivaling many types of steel. This made iron an even more important and competitive material for the manufacturing market.

Automatic ladle pouring systems

Foundries have used automatic ladle pouring systems since the early 1990s. However, because of their cost, many foundries did not use them until more recently. Although automatic ladle systems offer benefits such as ladle capacities up to 5,500 lbs., the ability to pour synchronously with continuously moving mold lines, and the ability to accommodate changes in the grades of iron to be poured, drawbacks still exist. The biggest drawback of ladle systems is the lack of heated vessels. As a result, these systems must pour the iron they hold within 5 to 6 minutes to ensure proper pouring temperature.

Robots & breakthroughs in sustainability

Recent innovations have centered on technology, but that is probably not surprising; what is surprising is how amazing these innovations are! In 2014, Siemens VAI, a known innovator in steel-industry technology, launched a robot that can withstand harsh conditions such as furnace heat. The robot, called SIMETAL LiquiRob, can perform tasks such as automatic temperature and sample measurement. Because of its capabilities, this robot allows these tasks to be performed more safely and efficiently.

More recently, the industry has faced issues such as energy efficiency and sustainability. To address these issues, the American steel industry has worked since 2014 to develop new iron- and steel-making technologies that will reduce or eliminate CO2 emissions. The initiative is called the CO2 Breakthrough Program, and the American Iron and Steel Institute (AISI) believes we can change how iron and steel are manufactured. This opens the door to many new innovations.

Although this change is not expected for another 15 years, some breakthroughs are already happening. The Massachusetts Institute of Technology is currently working on producing iron by molten oxide electrolysis. This technique generates near-zero CO2 emissions. Another project underway is called Ironmaking by Hydrogen Flash Smelting at the University of Utah. This process replaces carbon as a blast furnace fuel with hydrogen. Finally, AISI members are working on making a Paired Straight Hearth Furnace that can process waste from steel plants and virgin iron materials. AISI hopes to make this equipment available for commercial demonstration within five years, and they project that these innovations could reduce energy use by about 30 percent.

Because the iron industry has reached maturity, its growth may not be as swift today, but it’s still evolving. We at Lawton believe there is always room to improve. That means you never know when the next innovation will come around to heat up the industry until it’s hotter than molten iron.

Works Cited

Iron and Steel. Accessed April 29, 2019. http://www.encyclopedia.chicagohistory.org/pages/653.html.

U.S. and Global Iron and Steel Industries. Accessed April 29, 2019. https://cber.cba.ua.edu/rbriefs/iron&steel.html.

"About Metalcasting." American Foundry Society. Accessed April 29, 2019. https://www.afsinc.org/about-metalcasting. "Air Respirator Reduces Foundry's Eye Injuries." The Free Library. Accessed April 29, 2019. https://www.thefreelibrary.com/Air Respirator Reduces Foundry's Eye Injuries.-a068967102.

"Automatic Iron Pouring: Necessity or Luxury?" The Free Library. Accessed April 29, 2019. https://www.thefreelibrary.com/Automatic iron pouring: necessity or luxury?-a093612704.

"Blockade of Germany (1939–1945)." Wikipedia. April 15, 2019. Accessed April 29, 2019. https://en.wikipedia.org/wiki/Blockade_of_Germany_(1939–1945).

"Casting Software." The Free Library. Accessed April 29, 2019. https://www.thefreelibrary.com/Casting Software.-a060015023.

"Grenade." Wikipedia. April 20, 2019. Accessed April 29, 2019. https://en.wikipedia.org/wiki/Grenade.

Harford, Tim, and Tim Harford. "Tim Harford's Adapt: What the RAF's World War II Spitfire Can Teach Us about Nurturing Innovation and Radical Ideas." Slate Magazine. May 16, 2011. Accessed April 29, 2019. https://slate.com/business/2011/05/tim-harford-s-adapt-what-the-raf-s-world-war-ii-spitfire-can-teach-us-about-nurturing-innovation-and-radical-ideas.html.

"History." Applied Process. Accessed April 29, 2019. https://www.appliedprocess.com/about/company-history/.

"Inoculating Iron through Filters." The Free Library. Accessed April 29, 2019. https://www.thefreelibrary.com/Inoclulating iron through filters.-a0129812686.

Iona Stanley. "Latest Trends in the Steel Industry." Gulf News – No.1 in UAE and Dubai for Breaking News, Opinion and Lifestyle. October 29, 2018. Accessed April 29, 2019. https://gulfnews.com/business/latest-trends-in-the-steel-industry-1.1294557.

"Iron and Steel Casting Market - Global Industry Analysis, Size, Share, Growth, Trends, and Forecast 2018 - 2026." Market Research Reports Search Engine. Accessed April 29, 2019. https://www.mrrse.com/iron-steel-casting-market.

"Operation Weserübung." Wikipedia. April 16, 2019. Accessed April 29, 2019. https://en.wikipedia.org/wiki/Operation_Weserübung.

"Swedish Iron Mining during World War II." Military Wiki. Accessed April 29, 2019. http://military.wikia.com/wiki/Swedish_iron_mining_during_World_War_II.

Theditor. "Pusher Furnace - Debinding / Delubing / Dewaxing, Pre-Sintering, Carbonization, Sintering, Reduction." Therelek. May 30, 2018. Accessed April 29, 2019. https://www.therelek.com/products/pusher-furnace/.

"Was Recycled Iron Used in WW2 British Fighter Planes." Aircraft of World War II - WW2Aircraft.net Forums. Accessed April 29, 2019. https://ww2aircraft.net/forum/threads/was-recycled-iron-used-in-ww2-british-fighter-planes.23555/.