ASME B31.3 Table A-2, Design Stress for Bolting Materials, Bolt vs. Nut

[McDermott1711]

Hi everybody,
As you browse through table A-2, it will be found out that allowable stresses for different bolting materials are tabulated, but when it comes to nuts, you encounter with note (42) which says: "This is a product specification. No design stresses are necessary.". Why the code has different behavior to bolt and nut? Isn't bolt's specification, a product specification?

Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes

 

[XL83NL]

Bolts are considered the weaker component, therefore no design stress is required for nuts. The only thing that the designer must do is select the correct nut spec which meets the systems design and service requirements.

 

[SnTMan]

The nut spec generally (I didn't check 'em all) specifies a proof strength or proof stress rather than allowable stress as with bolting. Presumably exceeding the bolt strength.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[McDermott1711]

Bolts are considered the weaker component/quote]

Would you please tell me where in the ASME B31.3 this assumption is declared. Please note that we are speaking about code requirements and if it is not regulated by code then it is possible to have stronger nut mated with weaker bolt.

Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes