stainless steel bolts 4

[joshsd]

I have not designed with stainless steel bolts before, but our customer is requiring us to use them in our design instead of going with galvanized bolts. Is there a good design manual to use for SS bolted connections?

 

[desertfox]

hi joshsd

Well its really no different to using ordinary steel bolts but you might want to look at this site for strength and gade of stainless steel bolts.

http://www.roymech.co.uk/Useful_Tables/Screws/Strength.htm

this link is for the main index of screws lots of good info here

http://www.roymech.co.uk/Useful_Tables/Screws/index_screws.htm

the other thing to watch out for if using plain stainless is bimettalic corrosion with other materials.

desertfox

 

[joshsd]

Are there any other design considerations I need to account for since the yield strength is so much lower than the ultimate strength for tensile design?

 

[desertfox]

hi joshsd

Well you might want or need to look at fatigue and the fact the bolts have lower yield strength you might need to increase the number of bolts in your joints.

desertfox

 

[TVP]

I think this topic has been discussed on Eng-Tips in the past-- try a keyword search to find it. The following has some general information on stainless steel fasteners:

http://www.ssina.com/view_a_file/fasteners.pdf

 

[desertfox]

hi joshsd

TVP beat me to it just going to post the same link.
Lots of info in it too.

nice one TVP

desertfox

 

[SnTMan]

I would add that you should pay attention to coefficients of thermal expansions, bolt load can be lost this way.

Regards,

Mike

 

[unclesyd]

Here is another source for a lot more information concerning SS fasteners from Marine Fasteners.

http://www.marfas.com/technicalcont.shtml

 

[MintJulep]

And pay attention to material. Many stainless fasteners are made of "no name" grades of stainless steel like the ubiquitous 18-8.

If whatever you are bolting together is important you want fasteners made from a material made to a "name brand" standard like ANSI 301 or 304.

The ANSI standards limit the amounts of things that make stainless behave badly for important applications that can be in the mix in large quantities in "18-8".

 

[Ron]

Take a look at ASCE 8-02. This has various grades of stainless steel bolts and their allowable shear and tension stresses.

 

[desertfox]

hi joshsd

Here are some more references relating to stainless steel bolts used in structures.

desertfox

http://www.steel-stainless.org/designmanual/Docs/En/English.pdf

http://www.stalforbund.com/Fagboker/Rustfritt/Dim_stainless/Commentary_EN.pdf

 

[btrueblood]

"If whatever you are bolting together is important you want fasteners made from a material made to a "name brand" standard like ANSI 301 or 304."

I'd go a bit further and suggest you purchase a copy of either ASTM F593, or ASTM A193, both of which describe a variety of available corrosion- and heat-resistant fasteners. "No-name" 18-8 stainless bolts are a good thing to avoid, but there are alloys in the listed standards that deviate quite a bit from the 304 spec., giving a great increase in strength without losing much, if anything, in corrosion resistance.

It can be tricky to find good quality ss fasteners at reasonable prices. I do know that our supplier, Fastenal, uses ASTM F593C as a base grade, which makes me happy.