Verification Test for Hydrogen De-embrittlement?

[valter.souza]

David, many people use a hammer and hit the heads, but its don't work well, after some minutes/hours after electroplating, the fastener don't crack, could be crack after 24 hours (normally) with this practice. It is possible you send a bad bacth for your customer.

 

[David DeLong]

Volter Souza:

In my previous post on this subject, I was a Customer rather than a supplier so the product certainly was produced over 24 hours previously.

 

[Hershal]

Not sure if this is what you may be seeking, but LRA laboratories in Newport Beach, CA does testing regarding hydrogen embrittlement. Their customers include aerospace and also anchor manufacturers. University of Stuttgart also does testing regarding hydrogen embrittlement.

 

[Baggie]

The phenomenon of hydrogen embrittlement is a deep and dark subject, essentially to the manufacturing community there is NO non-destructive test, as the above posts you wWill have to sacrifice some samples.

If you were in a Uni with an extensive budget you could spend a lot of time and effort using SEM to look for structural anomolies at grain boundaries and correlate these to failures.

Far easier to stress the fastener IMO.

 

[Ron Rompen]

I have done extensive testing for hydrogen embrittlement/de-embrittlement in the past, and unfortunately I have never come across a non-destructive method, or for that matter, a fast method (at least, not beyond hitting the screws with a hammer level of testing). To make matters even worse, there is nobody (that I have found) who will state that any given level of hydrogen contamination of a part is 'bad'. They all agree that the more there is, the worse it is, but there is no 'cutoff' point.

As was pointed out earlier, the method of removing hydrogen embrittlement is well understood, and my suggestion would be to load the requirement onto your supplier; have them provide evidence that each lot has been properly processed to relieve hydrogen embrittlement.

The torque testing noted earlier would also be a good method, and would allow you to independently verify your suppliers findings.

 

[w_grunfeld]

Hai,

We are one of the Automotive component suppliers. We had a complaint of screw head(low carbon, cold forged,bought-out from sub vendor) breakage in one of our model. Currently we are perfoming Hydrogen De embrittlement process for the screw to overcome the above said problem, but our customer asks for some type of verification test to ensure that de embrittlement has been done on screws and checking to be carried-out daily i.e., for every lots. Now we are conducting destructive test to find out the torque at which screw head breaks. Can anyone specify en easier test method for ensuring embrittlement is done on screws without breaking the part.

regards,
Guru Prasad

Hi,
Reading to the thread , any NDT methods are still in the research phase.
I am in a similar situation, our customer (defense) is satisfied by indirct evidence such as signoff on the batch traveller that de-embeitlement has been performed+a printout of the oven temp-time graph for each batch.
You may complement this with what you do now, except you may reduce the sample you test.
Hope you manage to convince your customer that this is the best he can realistically expect
Regards,

 

[TamTom]

Hi,

I can not help but I asked my self by reading the thread if not the introduction of the CQI-9 (Control of Heat Treatment processes) was just for that discussed matter, there are no non-distructive test, so the target ist to control the processes to avoid failures?

And just as an note Ford has a special specification for embrittlement WSS... (Sorry I can not give the total name) maybe that helps as well.

Regards,

TamTom

 

[valter.souza]

Hello,

TomTom, Isn't CQI-9 (heat treatment process), is CQI 11 that works in process to became the process better and previne failure like the Hydrogen Embrittlrment.

Valter Souza

 

[Miner]

Hello,

TomTom, Isn't CQI-9 (heat treatment process), is CQI 11 that works in process to became the process better and previne failure like the Hydrogen Embrittlrment.

Valter Souza

These are the CQI's:

CQI-9 - AIAG Assessment Manual for Heating Treating
CQI-11 - AIAG Assessment Manual for Plating Processes
CQI-12 - AIAG Assessment manual for Coating Processes

You could argue that both CQI-11 and CQI-9 apply. Hydrogen embrittlement is typically the result of a plating process, but is usually addressed by a heat treatment after plating.

 

[TamTom]

Hello,

TomTom, Isn't CQI-9 (heat treatment process), is CQI 11 that works in process to became the process better and previne failure like the Hydrogen Embrittlrment.

Valter Souza

Hi,

that's ok for me, but the question is not which CQI, the question is if not the use of the CQI could help here?

TamTom