Blacksmith's secret revealed

November 15, 2002

In an international study into the fine structure of steel, Technology Foundation STW researchers have revealed how strong steel is formed. By analysing red-hot steel with an x-ray microscope, the researchers discovered how at a temperature of 900 oC, numerous microscopic crystals suddenly developed in the steel. The findings were published in the journal Science on 1 November 2002.

The microscopic crystals in steel are a measure of the metals strength and determine the deformation characteristics. Steel with many small crystals is stronger than steel with a few large crystals. With these new findings, the steel industry can further refine and better manage the steel production process.

In this joint Dutch-Danish-French project into the formation of the microstructure of steel, the research team directed an intense beam of x-rays onto a piece of steel heated to over 900 oC. That happened with a special x-ray microscope (ESRF) in the French city of Grenoble. The diffracted x-rays provide information about the internal structure of steel.

The research team allowed the temperature of the steel to decrease by 5oC per minute. At 822 oC the steel acquired a different crystalline structure. Whereas at high temperatures crystals with a diameter of 50 microns occur, the size of the crystals below 822 oC is 10 to 40 microns. This was the first time that the formation of such steel crystals had been so clearly visualised.

The mechanical properties of steel are largely determined by the rate at which atoms rearrange themselves. Rapid cooling results in many small crystals and thus strong steel. The traditional blacksmith already knew that steel could be strengthened by suddenly placing red-hot steel in cold water.

The formation of new crystals seems to be much easier than material researchers had previously thought. The energy required to make the conversion from the structure with large crystals to the 'cool' structure with many small crystals, is several orders of magnitude smaller than current models predict.

The research team contained material experts from Delft University of Technology, The Risø National Laboratory in Denmark and the European Synchotron Radiation Facility (ESRF) in France. The Dutch part of the study was financed by the Technology Foundation STW.
Further information can be obtained from Erik Offerman (Interfaculty Reactor Institute, Delft University of Technology), tel. +31 (0)15 2783673, fax +31 (0)15 2788303, e-mail, website

Netherlands Organization for Scientific Research

Related Technology Articles from Brightsurf:

December issue SLAS Technology features 'advances in technology to address COVID-19'
The December issue of SLAS Technology is a special collection featuring the cover article, ''Advances in Technology to Address COVID-19'' by editors Edward Kai-Hua Chow, Ph.D., (National University of Singapore), Pak Kin Wong, Ph.D., (The Pennsylvania State University, PA, USA) and Xianting Ding, Ph.D., (Shanghai Jiao Tong University, Shanghai, China).

October issue SLAS Technology now available
The October issue of SLAS Technology features the cover article, 'Role of Digital Microfl-uidics in Enabling Access to Laboratory Automation and Making Biology Programmable' by Varun B.

Robot technology for everyone or only for the average person?
Robot technology is being used more and more in health rehabilitation and in working life.

Novel biomarker technology for cancer diagnostics
A new way of identifying cancer biomarkers has been developed by researchers at Lund University in Sweden.

Technology innovation for neurology
TU Graz researcher Francesco Greco has developed ultra-light tattoo electrodes that are hardly noticeable on the skin and make long-term measurements of brain activity cheaper and easier.

April's SLAS Technology is now available
April's Edition of SLAS Technology Features Cover Article, 'CURATE.AI: Optimizing Personalized Medicine with Artificial Intelligence'.

Technology in higher education: learning with it instead of from it
Technology has shifted the way that professors teach students in higher education.

Post-lithium technology
Next-generation batteries will probably see the replacement of lithium ions by more abundant and environmentally benign alkali metal or multivalent ions.

Rethinking the role of technology in the classroom
Introducing tablets and laptops to the classroom has certain educational virtues, according to Annahita Ball, an assistant professor in the University at Buffalo School of Social Work, but her research suggests that tech has its limitations as well.

The science and technology of FAST
The Five hundred-meter Aperture Spherical radio Telescope (FAST), located in a radio quiet zone, with the targets (e.g., radio pulsars and neutron stars, galactic and extragalactic 21-cm HI emission).

Read More: Technology News and Technology Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to