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Up Topic Welding Industry / Processes / Ever see a failure like this before?
- - By Bill M (***) Date 03-23-2012 17:56
This is a first time for me.  the bolt broke off with minimal torque, the short end that was stuck in the nut turned out by hand.
Attachment: brokebolt.jpg (406k)
Parent - By eekpod (****) Date 03-23-2012 19:06
WOW that is cool, Iv'e never seen that before and we have a nice collection of broken bolts from over the years.
Parent - - By welderbrent (*****) Date 03-23-2012 20:17
Looks like a definite  OOPPSS to me.  First time I've seen one like that.

BTW, thanks for the fingerprints.  Sent those in to get me through a background check....  LOL!!

Have a Great Day,  Brent
Parent - - By Bill M (***) Date 03-23-2012 20:30
Yeah that zoom is pretty good!  just don't run the prints on "Americas Most Wanted" please...
Attachment: bolt2.jpg (407k)
Parent - - By welderbrent (*****) Date 03-23-2012 23:32
That is such a perfect cone.  Makes one wonder just what they did.

Have a Great Day,  Brent
Parent - By Dualie (***) Date 03-24-2012 05:01
I have seen close to that but not such a perfect cone.    its almost pretty.
Parent - By Joseph P. Kane (****) Date 03-24-2012 13:43
Wow!  I wonder if the failure analysts would call this a "Cup and Cone" failure?!?!?
Parent - - By jwright650 (*****) Date 03-25-2012 23:35
reminds me of one of those trick bolts used in magic tricks.

Very interesting in the way it failed.....
Parent - - By 803056 (*****) Date 03-26-2012 03:25 Edited 03-26-2012 03:33
Looks suspect to me. The location of the failure indicates there is not enough tread length to even engage half a nut, never mind a full nut. The engaged threads (only three) should have stripped if someone was tightening the bolt, yet there is no visible indications of galling or other signs of a nut being even partially threaded on to the nut. 

One would expect the failure to be in the first one or two threads engaged in the nut, i.e., between the underside of the bolt head and the nut. One would not expect the last engaged thread to fail, i.e., the thread toward the end of the nut that is on the outside toward the free end of the bolt. 

Something smells of a prank.

Al
Parent - - By DaveBoyer (*****) Date 03-26-2012 06:23 Edited 03-26-2012 06:27
What do You think of the color/look of the cone shaped parts? Doesn't look like a fresh break except for at the thread.

Possibly from a slag seam that somehow survived the rolling of the stock and the manufacturing process?
Parent - - By 803056 (*****) Date 03-26-2012 15:45
I was thinking along the lines of when they draw the raw stock, but it looked to perfect.

I'm no bolt expert, so I'll wait to see if someone here has an answer that seems reasonable.

Someone mentioned it could be where two separate coils were welded together. That sounds reasonable.

Al
Parent - - By DaveBoyer (*****) Date 03-27-2012 00:51
A poorly made joint of 2 coils sounds like a reasonable explanation, if that is done in the industry.

But joining material for a part loaded in tension sounds like a risky procedure to me, but perhaps it is done all the time.
Parent - - By 803056 (*****) Date 03-27-2012 03:29
I can see where it would be reasonable to make coils continuous if there was a drawing process involved or to make the rolling process continuous, but you would expect the joint would be removed once the runs were completed.

This is where someone that knows how bolts are made could jump in and clarify the situation.

Best regards - Al
Parent - By DaveBoyer (*****) Date 03-27-2012 03:49
I am no longer in contact with guys I worked with that had previously worked at the Bethlehm Steel fastner plant in Lebanon, Pa..
They probably would have known how it was done there, at least.
I worked with a guy from Standard Pressed Steel, a specialty fastner manufacturer as well, but no longer in contact with Him either.

These 2 places were/are quality concious, other places may do things differently.
Up Topic Welding Industry / Processes / Ever see a failure like this before?

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