finishing.com -- The Home Page of the Finishing Industry

HomeFAQsSuggested
Books
Help
Wanteds
Advertise
on this site
FORUM
current topics
Live! From Pine Beach NJ: The world's most popular metal finishing website, and the internet's friendliest corner

topic 17536

Testing for Embrittlement with a Microscope


2002

Greetings,

I recently posted a letter (16470) regarding alternatives to zinc plating, due to hydrogen embrittlement issues.

We are maintaining the zinc plating and incorporating a new bake cycle to prevent the embrittlement. Thanks to everyone who contributed...

My next question relates to testing for hydrogen embrittlement. My QC guy tells me that you can see the effects with a regular microscope, but I am not so sure about that. Any thoughts?

Scott Dupre
- Fall River, MA USA


2002

I don't think so. I think you plate and bake notched bars or parts and mechanically test them. What your QC guy is alluding to is probably that some people who are skilled in hydrogen embrittlement feel they can rule it in or rule it out as the cause of failure by inspection of failed parts.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey
We need "Aloha" now more than ever


2002

Thanks for the response, Ted...so it is possible to see the effects of failure? Perhaps not the evidence of embrittlement itself, but is there a definite characteristic that can be identified with the microscope to either verify that embrittlement is the issue, or rule it out? Perhaps the metal fails in a way that is indicative of embrittlement?

I tried looking at some pieces myself under the scope, but couldn't really say one way or the other what I was looking for. I have read that you can see the effects with a scanning electron scope....

Scott Dupre
Lightolier - Fall River, Massachusetts


2002

Yes, it is my understanding that a metallurgist skilled in such analysis can attribute the failed part to hydrogen embrittlement--but I lack the expertise to comment any further on the topic. Hopefully someone else can help you.

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey
We need "Aloha" now more than ever


2002

Scott, are you using notched bars to test for hydrogen embrittlement, or just bending a strip of spring steel and holding it for a while? That might be an easier test for you. Take a look at ASTM A143 [link by ed. to spec at TechStreet] , "Safeguarding Against Embrittlement of Hot-Dip Galvanized Structural Steel Products and Procedure for Detecting Embrittlement". Yes, it's not electroplating, but the three point bend test described in the specification would be valid for your purposes, and likely easier.

And yes, the intergranular fracture surface that is characteristic of classic hydrogen embrittlement of hardened steel has a clearly different appearance than does classic overload. I've seen enough of them to easily recognize it under a stereomicroscope, but the scanning electron microscope is still the definitive instrument to use.

Good luck!

lee gearhart
Lee Gearhart
metallurgist




If you have a question in mind which seems off topic, please Search the Site

ADD a Q, A, or Comment on THIS topic START an UNRELATED topicView CURRENT HOT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices


©1995-2019 finishing.com, Inc., Pine Beach, NJ   -   About finishing.com   -  Privacy Policy
How Google uses data when you visit this site.