Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


High-energy X-rays give industry affordable way to optimize cast iron


Cast iron can be modified through the manufacturing process to optimize its mechanical and physical properties, such as strength and durability.

This makes it a material of choice for use in the transportation and machinery industries, which rely on cast iron's resistance to wear, deformation, and rusting to design high-performance bridges, tools, and engine parts.

(a) The 2? casting block and a 2 mm diameter rod that is electrical discharge machining (EDM) cut out of the sample. (b) A typical slice of tomographic image obtained in the present study. (c) An un-etched metallography image of the same region in (b) under optical microscope (OM). (d) The reconstructed 3-D model of the graphite particles in (b). It shows that the 2-D features observed in (b and c) belong to a coral tree-like structure with flat, rounded branches that span ?200 μm in the iron matrix. (e) The left is the slicing surface and the graphite structure beneath the surface. The right side is the same CG structure but sliced in a different orientation. It shows the same feature (red arrow) could be identified as either nodular graphite (NG) or compact graphite (CG) in 2-D analysis depending on where one slices it.

Credit: Scripta Materialia

But the manufacturing process is as much art as science, producing good results yet not capturing cast iron's full potential. Controversy still exists over the correlation between manufacturing casting parameters and desirable properties. Limited by typical industrial 2-D imaging techniques or time-consuming 3-D laboratory studies, researchers have been unable to pinpoint the exact processing parameters needed to elicit the ideal properties for each cast iron application.

Finding an easier way to peer deep inside the alloy to get a definitive answer could be a boon for consumers as well as give the U.S. industry a competitive advantage. According to a study released in the journal Scripta Materialia, high-energy synchrotron X-rays can provide that insight.

"By understanding the structure, it will be possible to develop alloys with improved mechanical and thermal properties. This implies that for applications, such as vehicle engine and engine components, one could use less material and reduce overall vehicle weight that would translate into fuel savings," said Dileep Singh, Group Leader of Thermal-Mechanical Research at Argonne National Laboratory's Center for Transportation Research and the technical lead of this study at Argonne.

For the transportation industry, the ability to modify manufacturing processes to create high-performance materials could aid in the development of more fuel-efficient engines or engine parts that can withstand heat better to have longer lifespans.

"Researchers at Caterpillar are actively seeking to improve our understanding of cast iron alloys in order to provide innovative product solutions to our customers," said Richard Huff, a Technical Team Leader with Caterpillar Inc., which supplied engine alloy castings for use in the proof of principle study.

The study results showed that high-energy X-ray tomography can reveal previously unknown behaviors of graphite in cast iron, such as the growth of nodules, as it undergoes various treatments. The X-rays also can unambiguously classify the particle type involved in the behavior, which is critical to identifying the structure-process relationship. These insights hold the key to manipulating the atomic structure of the graphite through manufacturing treatments such as changing the chemistry of the melt and altering the inoculants added to the liquid cast iron.

The research team included Huff from Caterpillar, and Argonne researchers Singh, Chihpin Chuang and John Hryn from the Energy Systems Division and Jon Almer and Peter Kenesei from the X-Ray Science Division,. Advanced Photon Source (APS), a DOE Office of Science User Facility based at the U.S. Department of Energy's Argonne National Laboratory was used as part of this research.

Synchrotron X-ray analysis has several advantages over the current techniques used to evaluate graphite microstructure.

Three-dimensional imaging of the structure of graphite, its spatial arrangement in the alloy, and its phase connectivity, are key factors that determine the properties of cast iron. These parameters cannot be attained reliably by the current industry standard 2-D test. Less frequently used, but more effective is the use of focused ion beams (FIB) and transmission electron microscopy, which can provide high-resolution 3-D images, but is labor-intensive, time consuming and destroys the sample. High-energy X-rays penetrate inhomogeneous samples up to a centimeter thick under real operating conditions. This avoids the challenges of FIB and TEM techniques while also providing a better statistical representation of parameters in bulk material.

The research team found that the synchrotron characterization methods enable new insight into why compacted graphite iron, which is used by Caterpillar in heavy-duty engine components, can conduct heat better than ductile iron while maintaining good ductile strength. The answer lay in the shape, size, and distribution of the graphite particles in the cast iron.

"The 3-D characterization of the material enables greater insight into the structure formation and structure-property relationships," Huff said.

The results were published in the journal Scripta Materialia in the article "3D quantitative analysis of graphite morphology in high strength cast iron by high-energy X-ray tomography". Work was conducted at beamline 1-ID at the APS.


The Vehicle Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy, supported the work, and the Office of Science supported the use of APS.

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC, for the U.S. Department of Energy's Office of Science.

DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit

Media Contact

Tona Kunz


Tona Kunz | EurekAlert!

More articles from Materials Sciences:

nachricht Meter-sized single-crystal graphene growth becomes possible
22.08.2017 | Science China Press

nachricht Nagoya physicists resolve long-standing mystery of structure-less transition
21.08.2017 | Nagoya University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>



Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

More VideoLinks >>>