Stainless Bolts - Strengths and types?

[Tim Good]

What are the different types of stainless in terms of strength of a bolt?

Is A4-80 stainless steel equally as "marine grade" as a normal stainless bolt?

 

[rgarside]

http://www.bssa.org.uk/cms/File/Mic...ades A1,A2_A3_ & A4_A5_ to BS EN ISO 3506.pdf

 

[vyv_cox]

Yes, as the BSSA link says, the A4 defines the composition and the 80 the strength. 316 is not hardenable by heat treatment but is more cold worked on manufacture for the 80 grade than the 50.

 

[Tim Good]

Yes, as the BSSA link says, the A4 defines the composition and the 80 the strength. 316 is not hardenable by heat treatment but is more cold worked on manufacture for the 80 grade than the 50.

Ok so its A4-80 I want. A lot of sites don't distinguish between 70/80 but fortunately there is a place call Avon Stainless Fastners near me which appears to do them.

Does anyone know if there is a difference between bolts that have the tread the whole way and ones which are solid? When going through GRP I'd imagine I'd want them solid:

vs.

 

[Momac]

For the purposes of connection design of bolts in structural timber or GRP (which has similar strength) the GRP will always fail before the bolt. However you are quite correct in that a solid portion of shank will potentially develop a more even bearing on the connecting surfaces under an applied shear force.
But to be honest I wouldn't be too concerned if the bolt was in fact a screw (fully threaded).

 

[Tim Good]

the GRP will always fail before the bolt.

Not sure that's the case is it? Sure it depends on the bolt size and bro thickness and load direction? 2500kg for an M10 bolt to shear I think.

 

[davidej]

Ok so its A4-80 I want. A lot of sites don't distinguish between 70/80 but fortunately there is a place call Avon Stainless Fastners near me which appears to do them.

Does anyone know if there is a difference between bolts that have the tread the whole way and ones which are solid? When going through GRP I'd imagine I'd want them solid:

vs.

The one with the smooth bit is a bolt - the other is a machine screw

 

[Momac]

Not sure that's the case is it? Sure it depends on the bolt size and bro thickness and load direction? 2500kg for an M10 bolt to shear I think.

In shear the bearing of the bolt on the GRP will fail the much weaker GRP before the steel yields.
In pull out a connection in very thick section of GRP or a very well spread backing plate would have the potential for the bolt to fail first.
.