Yield Strength of 316 SS

If you're really, "planning on using plain old annealed rod stock" isn't 30-42 close enough? Is this something you have on the shelf? We don't know what it has to do.

If it's going on a spacecraft, you can get material certifications and even lot/batch testing/traceability data that attests the material is per some AMS/MIL/ WHATEVER specification.

Milo?

Vendor data is about as good as it gets as the strength will depend on the particular metallurgy used to manufacture the material. There are standards that call out percentage of each ingredient that are allowable to call the end product "metal x" or "metal y" etc. but a very small difference in the ingredients can result in dramatic differences in material properties as well as the process used to get the end product IE cold drawn, hot rolled etc. Get the data for the exact material you are going to use from the manufacturer that made it. Err on the side of caution.

I would mean no disrespect when I said yes i think that there is a bit of naivete in expecting multiple vendors and multiple sizes to have a single value of yield strength.

The percent cold work differs by size, and so smaller sizes would be expected to have higher properties than those much larger. I use SAE nominals for carbon and alloy, 1" rounds, and always expect different sizes, shapes, and vendors to diverge.

Nominal is nominal. As some else posted, if you need moon shot precision, spec it at time of purchase.

Repost with diameter and I will look up carpenter book values in the AM.

Milo

Thanks for your answers, seems like this more or less sums it up. I'll consider the range of values during my calculations and err on the side of caution, as RVZ717 recommended.

Milo, what is this "carpenter book" you mentioned? The diameter is 1".

Pg 65 Carpenter Specialty Alloys Carpenter Stainless Steels Selection Alloy data fabrication guide. Copyright 1999

project 70 stainless

AnnealledYS 36ksi; annlld + Cold drawn 75ksi;

UTS annlld:82ksi; annlld +cd 96 ksi;

% elong Annlld:68%; annlld +cd 42%;

% reduction of area annlld: 76; Annld +cd 75;

Rockwell B mid radius Annlld 80; annld + cd 96;

Charpy V notch 240 ft/lb- did not fracture completely; annld + cd 140.

Like I said these are Nominal and would vary from heat to heat as well as by size from a single supplier; now throw in the variability in the whole wide world...

But in court I would use these data.

Milo

Milo, thank you! I think I'll have to get my hands on one of those books.

Check your CR4 email.

Milo

Engineering ToolBox is also a good place to look for "nominal" values...

Tritium -- This is a hard thing to get across to a lot of American mechanical engineers, whose designs are not constrained by the building codes the civil engineers work under. You cannot rely on any published tensile or yield strength data for AISI spec steels. This is because strength is not part of the AISI spec. You get what you get.

Whatever strength, whether tensile, yield, fatigue or any of the others, are your responsibility will usually come for your use as an engineer only after you put some extra cost in your design. (with the heavy weight of some type of liability hanging over your head). Heat treat for carbon steels, rigidly specified cold work for austenitic stainless steels like your 316, buy something with a guaranteed spec you like or some other appropriate processing for other alloys.

You can do a bunch of homework on the effect of the allowable range of constituents and defect allowed in the particular steel you are dealing with. Or if you spec some more expensive proprietary form of the alloy you want and you rely on whatever the supplier will guarantee. That probably won't keep your company out of court but at least it will strengthen their defense.

You can rely on some "maximum working stress" or other rule of thumb (10ksi max for low carbon hot rolled steel) to keep you out of trouble.

Or you can make your design based on modulus of elasticity (which is well known for metals) and/or design the failure mode to be failsafe.

And here you though machine design was so straightforward when it came to metal failure....... Ed Weldon

Frankly, I consider a handbook from an organization such as the ASM to be a more reliable source than a manufacturer's data sheet or a web based source. The Metals Handbook contains properties data in various conditions, and will also refer you to applicable specifications. When you are required to justify your work, web based data may lack credibility.

ASME B31.3 for pipe material strengths. ASME Section II Part D for material strength for just about everything else.

These have some standard values for various grades of steel. Also, try a Metals Handbook.

Meaning no disrespect to ASM or Metals Handbook, or any of my fellow commenters, but much of that data is very old and from processes no longer employed. Ingot cast. Bessemer steels. Some volumes have been edited and revised, some content is just cut and paste from earlier versions. ASM is a prestigious publisher, And I have many of their volumes at hand.

But I would take a manufacturers data (AS I KNOW or can figure out the process and practice that made it) over a general book's numbers any day.

As I said, I'll testify on Carpenter's data.

Milo

Bravo, Ed! Very well stated.

milo

Excellent response, GA sir.

Ed, thanks for your insight. It is tempting to think that I could just "pick out a number that I like" from a table, but it is understandable that this just isn't the case. The brief bit of metallurgy education that I received in college has helped me to navigate the various information that I've found on this subject, but unfortunately the theoretical bias of my coursework never pointed out the complexities and nuances of actually specifying a material for a given design. I suppose that's what real life experience is for! I will say that it is much more satisfying to dig your mind into something and try to fully comprehend it rather than just picking a number a taking the table's word for it.

How do you know that the material is 316 stainless?

Any supplier of steel will have test reports for their material.

Check the ASTM specification for the grade to obtain minimum yields.

We in the aviation industry work to the material specs in MMPDS, maintained by the FAA (formerly Mil-HDBK-5).

Beware: it costs ~$700US, and is agonizing to work with. But, then, if the FAA is managing it, it's never gonna be easy.

Hooker