B16.11 A182 Stainless 1/8" Plugs - Cold/Hot Form?

[metmike]

Normally my company machines small NPS (1/8" & 1/4") ASME B16.11 stainless (304,316) hex head plugs directly from small diameter bar, at great tooling and machine expense.
I am exploring the idea of cold forming/heading OR hot-forged hex head plugs with rolled threads. A couple hurdles arise in order to meet ASTM A182 (as required per B16.11):
A) Need to solution anneal parts after cold forming followed by "liquid" quench. With such small final parts, I would assume vacuum quench to minimize distortion and scale with built-in oil/water quench bath is perhaps the only solution? (since gas quench is not technically liquid)
B) Need to perform a tensile test after annealing. Smaller NPS Hex Head Plugs are only ~0.75" long, while the smallest tensile is 1.25" long minimum. I've inquired a couple suppliers on the option to cold head essentially a longer plug at ~1.5" as a representative tensile sample, but no dice. I have yet to look into a hot-forged option, but similar issues may arise...

Any advice or experience would be appreciated!

 

[metengr]

You have several material specification options included in B16.11, one of which is
ASTM A 403. I would consider ASTM A 403 material specification versus ASTM A 182.

 

[EdStainless]

High pressure gas quench is commonly used on SS. You just need to prove that your furnace loading method allows for uniform rapid cooling.
When people bright anneal in hydrogen they are using that atmosphere as the quench media.
I would just use a piece of bar as the test piece.
This is an easy anneal, 1950F for 10 min minimum soak, rapid cool, and you are good

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P.E. Metallurgy, Plymouth Tube

 

[metmike]

Thank you for the replies!
metengr: A403 does allow for "other rapid cool" so gas would count to solve problem (A), but ideally I would like to get a liquid quench if possible to certify to both.
EdStainless: I have no doubt on the metallurgical integrity of a gas quench for rapid uniform cooling. It would likely be better than a liquid dunk. But ASTM A182 specifically requires "liquid" quench. Also, would the original bar that was cold worked to the plug really mechanically represent said plug, even after the anneal? My original thought was NO.

Would this be the best forum to discuss logistics of cold heading? Or would it be wise to copy it over to the Mech Engineers forum?

 

[EdStainless]

You could start another thread here to talk about the forming.

You aren't going to work these a lot, it will only be superficial. Nothing like cold finished rod. Even if you have the entire rod threaded you would be machining off all of that outer portion when you make the tensile bars. You are just looking for validation.

And there are a lot of people that would argue that gasses count when you are quenching stainless. The problem with liquid quench is that it will require an acid pickle for descaling. You will need permits for Nitric and HF, and live with the roughened surfaces.

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P.E. Metallurgy, Plymouth Tube