[TowerTalk] GRADE 5 BOLTS

[WØQFC]

I've also heard the argument that grade 8's are more brittle than grade 5's 
and that's why you shouldn't use them. Well, first you need to understand 
what the term "brittle" really means. Brittleness in bolts is defined as 
failure at stresses apparently below the strength of the bolt material with 
little or no evidence of plastic deformation. Typically, fasteners are not 
brittle below 180 ksi ultimate tensile strength. Grade 5's have an ultimate 
tensile strength of 120 ksi and a grade 8 fastener has an ultimate tensile 
strength of 150 ksi. This is why brittle is a relative term. Nearly all 
fasteners are considered ductile except some made from PH 15-6 Mo, 17-4 PH 
and 17-7 PH.


Gene, WØQFC
Spring Hill, Florida
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http://www.w0qfc.com