Tougher steel recipe could strengthen structures

Scientists at the University of Queensland in Australia have found a way to make steel stronger. The research could help prevent accidents such as bridges and buildings fracturing because of trapped hydrogen gas, which can cause cracks around rods and bolts.

Such ‘hydrogen embrittlement’ can happen during the manufacturing and processing of steel, when hydrogen atoms weaken the metal at the grain boundaries. 

This causes corrosion and loss of flexibility, leading to catastrophic failures of engineering projects, such as nuclear power stations, hydrogen storage and construction sites. This is exactly how the San Francisco–Oakland Bay Bridge fractured during construction in 2013. 

To deal with the problem, the team stopped hydrogen gas from spreading through steel alloys “at the scale of a single atom,” said Roger Wepf, a microscopy expert at the university. Together with his colleagues, he added large amounts of hydrogen gas, prepared at very low temperatures and then frozen using cryogenic liquid, to samples of steel. This led to concentrated clusters of trapped hydrogen atoms.

While Wepf's team say their research is a success, not everyone is convinced by the technique. “Identifying where and potentially how hydrogen is getting into the steel” could be a better solution, says Jenifer Baxter, head of Energy and Environment at the Institution of Mechanical Engineers, who was not involved in the research. 

It's not the first time researchers attempt to hydrogen spreading in steels. In 2014, scientists at the University of Illinois at Urbana-Champaign took a different approach - working with advanced coatings to avoid hydrogen embrittlement.