Sect VIII Div 2 "Fatigue Assessment of Bolts"

[elem]

Hi, I am confused by the language in 5.7.3.1 a) of Sect VIII Div 2 (2015 edition).


The fasteners are Inco 718 and the min spec tensile strength is greater than 100ksi, so if this applies to UTS lower than 100ksi it seems not applicable to my fastener. However, b) is also not applicable due to my bolt material:


5.7.3.2 just says that the fatigue damage fraction must be less than or equal to one.

My question(s): should I be evaluating bolts per 5.5.3 using design curves from Annex 3-F? What is the logic behind the statement referring to "materials which have a min spec tensile strength less than 100ksi" in 5.7.3.1? Almost all alloy steel bolts that I've used have tensile strength much higher than 100ksi, so I feel like I'm missing something with this statement.

Thanks!

 

[TGS4]

This is a question better asked of the ASME Code Committee. Please submit your question in a Request for Interpretation -

https://cstools.asme.org/Interpretation/InterpretationForm.cfm

After you have submitted your request, please return to this forum with the "BC2018-XXXXX" tracking number provided to you by ASME. There are several Code Committee members who frequent this forum and can follow-up.

 

[elem]

Thanks for the suggestion. I submitted a question as best as I could using the required format and my record number is 18-2712. I'll check back in when I get a response.