New research led by the University of Leicester (le.ac.uk) has made a breakthrough in understanding how solidification cracking occurs during the welding of steel, which is an important engineering alloy.

In a new study published in the journal Scientific Reports, a team from the university’s Department of Engineering proposes that solidification cracks grow by linking micro-porosities in the meshing zone in the solidifying weld pool.

This is the first time that researchers have observed solidification in steel, and it sheds new light on why the alloy may crack during the process.

Professor Hong Dong said: “Welding is the most economical and effective way to join metals permanently, and it is a vital component of our manufacturing economy. It is estimated that more than 50% of global domestic and engineering products contain welded joints.

“In Europe, the welding industry has traditionally supported a diverse set of companies across the shipbuilding, pipeline, automotive, aerospace, defence and construction sectors. Solidification/hot cracking is the most common failure mode during metal processing.”

The team used the synchrotron X-ray beamline equipment at the European Synchrotron Radiation Facility to observe the crack formation in real time. With modern advances in synchrotron X-ray and imaging techniques, it is possible to see through metals.