Stud "corrosion"

BramanteCummins

BramanteCummins

ADD maniac
Joined
Nov 1, 2012
Messages
636
I just wanted to get an opinion from you guys of acceptable corrosion on a stud. I came home to a stud mark in my shop ceiling... Engine has never been run and studs were torqued to their specs. I asked them about it and they said "...serious corrosion that is clearly visible on your stud." It doesn't look very much like corrosion to me... Slight discoloration from the fracture and random spots here and there. Just strange it happened under less than mild circumstances.

They are A1 H11 in a 12v.

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I am no expert, but the fracture does seem to propogate from the one side (where your index finger is in the third pic). What this is caused by, material flaw, corrosion ect I do not know enough to make a judgement. And the fact the engine had no heat cycles to me means that a fatigue failure should be unlikely.

Here is a little more info on the subject:
ARP-bolts.com | ARP - World-leading Fastener Technology
 
This looks exactly like my break.

"4. CYCLIC FATIGUE FAILURE ORIGINATED BY HYDROGEN EMBRITTLEMENT.

Some of the high strength “quench and temper” steel alloys used in fastener manufacture are subject to “hydrogen embrittlement.” L-19®, H-11, 300M, Aeromet and other similar alloys popular in drag racing, are particularly susceptible and extreme care must be exercised in manufacture. The spot on the first photo is typical of the origin of this type of failure. The second is a SEM photo at 30X magnification."
 
It had some pitting around the break. Are your h11s silver looking or what? Mine are black.


Sent from my iPhone 4s
 
Here is a pic of my broken stud. They might have been silver when new, I don't remember. Anyways...ImageUploadedByTapatalk1371130965.131631.jpg



Sent from my iPhone 4s
 
BramanteCummins said:
Mine look like that. Yours are new?
Click to expand...

Yes, installed them a couple months ago. I smeared anti-sieze all over the studs before installing, after reading on here about corrosion issues. I hope that keeps me from having any issues. I dont personally think thats your issue, but im no expert.
 
Does this happen with arp's as well? Never heard about/seen a stud snapping.
 
Take it with a grain of salt, but they nailed it with the material inclusion during manufacture. IMO. Beyond that, even corrosion would have allowed cyclic loading as it fractured and then the new void corroded. I know there is better data available here on the site but my first thought from my training aligns with an inclusion/enbrittlement like others posted.

From my Not-So-Smart phone
 
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