Metallurgist: More Hydrogen Embrittlement Data Needed, But It Will Be Costly to Obtain
05/08/2017 - Metallurgists have been studying hydrogen embrittlement for more than 140 years, but to solve the nagging problem, more real-world data is needed, University of Cambridge Prof. Harry Bhadeshia said on Monday.
Bhadeshia, who delivered AIST’s 2017 Howe Memorial Lecture, said that to better understand embrittlement, researchers need access to steel parts and components that have been used in the applications for which they were designed.
“No one in the industry has been able to identify how much hydrogen they expect the steel to absorb during service,” he said during the lecture. The lecture marked the official start of AISTech 2017, which is being held this week in Nashville, Tenn., USA.
Bhadeshia said that although steels can be engineered to “trap” hydrogen atoms and prevent embrittlement, it is not known whether a steel’s capacity to trap hydrogen will be exceeded by the amount that is absorbed over its life.
“I said to you we can trap about 8 parts per million. Is that enough? I have no idea.”
To obtain that information, researchers need to analyze used steel components. Unfortunately, the costs involved in pulling a compoent from active use make it much easier said than done.
For example, it’s been estimated that to remove a steel component from a subsea application and replace it would cost about US$40 million, he said.
“You might argue that $40 million is not a lot, given the problems that arise when you get hydrogen embrittlement,” he said.
Also during his lecture, Bhadeshia said steelmakers ought to be aware of the potential to introduce hydrogen embrittlement to certain high-strength steels through acid pickling.
He said that for some high-strength steels, those of around 1,000 MPa and rolled into thin sheets, it may not pose an issue, if the hydrogen can diffuse out of the material.
“But if we are forming really strong steels -- 2 GPa of strength -- hydrogen will be an issue, which you need to think about.”
Given that, he said steelmakers may need to re-evaluate traditional processing steps, such as pickling, to ensure that they are not unintentionally introducing more hydrogen to their products.
“No one in the industry has been able to identify how much hydrogen they expect the steel to absorb during service,” he said during the lecture. The lecture marked the official start of AISTech 2017, which is being held this week in Nashville, Tenn., USA.
Bhadeshia said that although steels can be engineered to “trap” hydrogen atoms and prevent embrittlement, it is not known whether a steel’s capacity to trap hydrogen will be exceeded by the amount that is absorbed over its life.
“I said to you we can trap about 8 parts per million. Is that enough? I have no idea.”
To obtain that information, researchers need to analyze used steel components. Unfortunately, the costs involved in pulling a compoent from active use make it much easier said than done.
For example, it’s been estimated that to remove a steel component from a subsea application and replace it would cost about US$40 million, he said.
“You might argue that $40 million is not a lot, given the problems that arise when you get hydrogen embrittlement,” he said.
Also during his lecture, Bhadeshia said steelmakers ought to be aware of the potential to introduce hydrogen embrittlement to certain high-strength steels through acid pickling.
He said that for some high-strength steels, those of around 1,000 MPa and rolled into thin sheets, it may not pose an issue, if the hydrogen can diffuse out of the material.
“But if we are forming really strong steels -- 2 GPa of strength -- hydrogen will be an issue, which you need to think about.”
Given that, he said steelmakers may need to re-evaluate traditional processing steps, such as pickling, to ensure that they are not unintentionally introducing more hydrogen to their products.
