finishing.com -- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing.
    no popups, no spam
HomeFAQsSuggested
Books
Help
Wanteds
Advertise
on this site
FORUM
current topics

topic 4496

Hydrogen Embrittlement Testing

(2000)

Hello-

What's a good test to establish whether or not the failure is due to Hydrogen Embrittlement (for fittings)?

Is a sustained load test for 72 hrs with 85% max. allowable load a good criterion?

Fittings are made from 8740 steel, Heat treat to 170-190 ksi and CAD plated per QQ-P-416 [link by ed. to spec at Defense Logistics Agency, dla.mil] and subsequently baked for 23 hrs.

KA

Kamal A.
- New York, New York


(2000)

Notch bar testing is the most common method and use to be cross referenced in the spec.

James Watts
- Navarre, Florida


(2000)

James is correct. A sustained load test on a notched tensile bar is the preferred method for testing for hydrogen embrittlement. I am not up on the current requirements, but the test used to be 200 hrs minimum at a sustained load of 75% of the ultimate tensile strength of the material. I do not believe that 72 hours or a load of 85% of max allowable is adequate. Assuming that the max allowable is probably only 25% of yield, this load is less than 1/4 of the typical sustained load test criterion.

Without a machined notch, the effective stress is even less.

larry hanke
Larry Hanke
Minneapolis, Minnesota



This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Comment to THIS thread START a NEW threadView CURRENT 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


©1995-2018 finishing.com, Inc., Pine Beach, NJ   -   About finishing.com   -  Privacy Policy
How Google uses data when you visit this site.