304 S.S. bolt shear 2

Where can I find a Chart showing shear values for 304 s.s. hex head bolts both at the thread and on the flats?

 

[TVP]

I am not aware of any charts that document shear strength for stainless steel bolts. ASTM F 593 - 02 Standard Specification for Stainless Steel Bolts, Hex Cap Screws, and Studs does not list a requirement for shear testing, such as that required by ASTM A 394 - 00 Standard Specification for Steel Transmission Tower Bolts, Zinc-coated and Bare. However, you should be able to calculate a suitable value for shear strength based on tensile test data.

First, the proportional limit in shear (all elastic deformation, no plastic deformation) has been shown to have a ratio of 0.557 to the proportional limit in tension (National Bureau of Standards testing for MIL-HDBK-5). Therefore, if you want to use yield as the criteria, take the tensile yield strength requirement and multiply by 0.557 in order to obtain the appropriate value in shear.

On the other hand, if you want to obtain ultimate values in shear instead of yield values, then the ratio should be ~ 0.62 of the tensile ultimate strength. This is the ratio used in ASTM A 394. Failure theories predict a value of around 0.67, so 0.62 is somewhat conservative.

FYI, stainless steel bolts can be ordered in a number of conditions, which results in different strength levels for a given chemical composition (such as Type 304). Typical ASTM designations include the following:

AF - headed & rolled from annealed wire/rod, then re-annealed
CW - headed & rolled from annealed wire/rod, with no subsequent thermal treatment
A - machined from annealed wire/rod
SH - machined from cold-worked or strain-hardened wire/rod

 

[dozer]

See ASCE-8-90 "Specifications for the Design of Cold-Formed Stainless Steel Structural Members". There may be a later edition, but this is the one I have. Properties for bolts are in Table 6 on pg. 29. As TVP said be sure you're looking at the right type and condition. If you're using ASD see Appendix E.

 

[DD3]

HI I came from the old school since i am around 70 years old i never did pickup the metric math very well. When we talk about bolt strength we alwaws used psi or yield at.
Now would some one out there please explane KSI. Thanks DD3

 

[boo1]

KSI= 1000 pounds/ square inch

Old school but still young enough to learn!

 

[boo1]

Shear loading in the thread area have a substantial loss of strenght. This is caused by the smaller net "stress" area and stress concentration factors. Typically a reduction of up to 20% is allowed for designing threads is the bearing area. Thread class, finish, pitch, temper, hardness and fabrication technique are some of the contoling factors.

 

[trainguy]

I've even seen a 30 % reduction when the threads are intercepted by the shear plane.

GA

 

[boo1]

AISC Manual of Steel Construction lists:
Fv=0.17 Fu when threads are in shear plane
Fv=0.22 Fu when threads are excluded from shear plane

8th ed Table 1 D

 

[Lcubed]

When the shear plane passes through the threads, the threads are in bearing on one or both sides of the shear plane. This is such bad design practice that the shear strength of a bolt so loaded is probably of secondary importance.

 

[CoryPad]

boo1,

Your values show a shear connection to have ~ 20% of the strength of a tensile connection, but your earlier statement says a 20% reduction, which I assume means Fv = 0.8 Fu. Can you explain this contradiction?

 

[boo1]

My thread listed shear loading, I intended to imply a reduction of average shear stress.

borrowing from TVP post (0.577)
Fv=0.577*Fu*0.80