This edition of the Fastener Training Minute with Carmen Vertullo was originally published May 12, 2017 as “10 things you need to know about Hydrogen Embrittlement” during episode 116 of Fully Threaded Radio.
Well, Hi everybody, this is Carmen Vertullo with the Fastener Training Minute and the Fastener Training Institute coming to you from the Carver FACT Center in San Diego. This past week the Fastener Training Institute conducted in an amazingly great program on hydrogen embrittlement in Wixom, Michigan near Detroit. Salim Brahimi and myself put the program on, with some help from Lawrence Klaus at a facility he set up for Ejot Fasteners.
It was a very good, well-attended, hands-on, two and a half day program. Out of that program I made a list of 10 things that are the absolute minimum you should know about hydrogen embrittlement. If you’re involved in fasteners, when we return I’ll tell you about them in a sort of rapid-fire fashion. So get out your pencil and write this stuff down.
It’s going to be more than a minutes and it’s going to be fast. Today we’re talking about hydrogen embrittlement, and specifically internal hydrogen embrittlement. The kind that occurs when we plate a high hardness fastener. So I’m going to tell you 10 things. They’re not all technical, and I’m not going to go into a lot of detail. So here we go.
Fasteners above the hardness of Rockwell 39c are susceptible to hydrogen embrittlement.
Zinc electroplating is the main coating to be aware of but there are other processes that provide the source of hydrogen that is needed.
There are three must have components for hydrogen embrittlement to occur: high hardness of the parts, a source of hydrogen and a high load. That is the fastener must be tightened down.
The sign of a hydrogen embrittlement failure is a delayed failure. That is the fastener does not fail immediately upon installation. It takes a little bit of time and a brittle fracture surface. I also see two other common threads in hydrogen embrittlement failures. One of them is no or poor quality management system in place and the end-user says we’ve been doing this for years and never had a problem
A prevention strategy is to bake after plating and to test after baking. Some specifications require it.
There are some excellent technical Resources that you should have, one of which is Salim Brahimi’s paper “Fundamentals of Hydrogen Embrittlement in Steel Fasteners” that’s free at the Industrial Fasteners Institute website, and two articles that I recently did for Link Magazine: one on baking, and one on failure analysis.
You must get some training in hydrogen embrittlement. The Fastener Training Institute offers training and the Carver FACT Center here in San Diego offers hydrogen embrittlement training.
You must have a comprehensive hydrogen embrittlement risk management strategy.
Get some help. Even if you have a good strategy, get another set of eyeballs on it, and I can help you with that.
Be prepared when this occurs. Don’t have a hydrogen embrittlement failure suddenly appear and not be prepared to deal with it. One way that we can get prepared is to get some training.
Well that is the absolute least you must know about hydrogen embrittlement. Each one of those 10 things is probably worth a couple of hours of discussion. So, contact me at the Carver FACT Center or contact the Fastener Training Institute and get prepared to deal with the hydrogen embrittlement issue.
This has been Carmen Vertullo with the Fastener Training Minute. Thank you for listening.