416 SS cracked nuts
416 SS cracked nuts
(OP)
Hi,
I have this weird issue and can't figure out what's going on. Chemistry is OK, Mechanical properties are ok...but this nut sometime fails during assembly. (assembly is with automatic electric guns with preset torque. So overtorquing ain't an issue.
The nuts crack right at the corner of the base and the hex. The crack propagates until the mid of the hex. See attached pictures.
Any similar experiences??
Oh the nuts are annealed btw.
Thanks,
Herc
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I have this weird issue and can't figure out what's going on. Chemistry is OK, Mechanical properties are ok...but this nut sometime fails during assembly. (assembly is with automatic electric guns with preset torque. So overtorquing ain't an issue.
The nuts crack right at the corner of the base and the hex. The crack propagates until the mid of the hex. See attached pictures.
Any similar experiences??
Oh the nuts are annealed btw.
Thanks,
Herc
http:
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RE: 416 SS cracked nuts
Is friction what you think it is?
RE: 416 SS cracked nuts
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: 416 SS cracked nuts
I would think that overtorquing would strip the threads or at least elongate them.
I got a buch of squirrels in my backyard that have cracking nuts all winter, may be that's one them.
RE: 416 SS cracked nuts
RE: 416 SS cracked nuts
RE: 416 SS cracked nuts
RE: 416 SS cracked nuts
RE: 416 SS cracked nuts
RE: 416 SS cracked nuts
RE: 416 SS cracked nuts
RE: 416 SS cracked nuts
RE: 416 SS cracked nuts
I see this with stainless steel fasteners from time to time. In some cases it can be magnified by thermal variations from the surroundings.
That first picture looked like intergranular separation in the substructure of the parent material. Follow the crack to the surface, OD or ID, you will find a notch which is the stress riser for the phenonema.
Hope this helps.
Regards,
Cockroach
RE: 416 SS cracked nuts
Not all fasteners are equal.
RE: 416 SS cracked nuts
RE: 416 SS cracked nuts
Are the nuts subjected to any chemical treatments that could account for intergranular corrosion prior to assembly else how could SCC be a factor in the above instances?
300 series SS's are susceptible to sensitization if held in or slow cooled through the temperature range 800-1500F. I don't know if sensitization applies to 416 but because these nuts are annealed there might be a connection.
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