1/4, 1/2 Hard 316 Sheet, Availability/Experience?

[rideHPD]

Hi all,

Has anyone sourced 1/4 hard or 1/2 hard 316 SS sheet before, say in the 14/16 gauge range? I can find it in shim stock, certain specialty round bar/wire, and in sheet in other 300 series grades, but not 316, which tells me I'm probably missing something.

Additionally, parts as currently designed need to be laser cut, so I'd be interested in hearing what kind of HAZ range I'd be looking at or if I'd have to redesign for waterjet.

My apologies if that's open-ended and light on detail to start, I don't get to work hands-on with metal much.

Appreciate it!
Eric

 

[TugboatEng]

I think any stainless steel that has been cold rolled but not annealed is 1/2 hard. If you need more hardness look for nitrogen stainless steel such as 316LN.

After laser cutting consider acid pickling or electro-polishing to restore corrosion resistance of the cut surface. Carbide precipitation should be minimal in the L series alloys.

 

[rideHPD]

Perfect, thank you!

I actually had that realization earlier, that it would probably be easier to just order it not annealed as opposed to trying to get it to ASTM spec, so I asked my supplier to look into it but he wasn't sure what degree of CW it would be. This makes me much more optimistic!

It's not the hardness I'm after, but the yield strength, as these parts are subject to angry fish thrashing around on the deck and they deform too easily on impact as-is, so any significant improvement would be suitable. Edit: Looks like 316LN yield strength is still roughly equivalent to standard 316, which tracks, I just read the TDS wrong initially.

Post-lase these parts all get vibe tumbled from deburr to near-mirror polish, that should be sufficient over pickling or electro, correct?

 

[EdStainless]

If it isn't made to A666 then the level of cold work will be variable from coil to coil and may not be anywhere near that you are looking for.
This is heavy material for 1/2 hard.
Why not use another alloy?
Not like 316 has much more corrosion resistance than other 300 alloys

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P.E. Metallurgy, consulting work welcomed

 

[rideHPD]

As long as there's no warpage or other deformation induced from residual stress I think any variability won't be an issue as any deformation resistance will be beneficial, and I wouldn't think that would arise as the parts are simply laser cut, deburred, and polished; there are no bending or other forming ops, nor significant localized annealing.

Mechanically the annealed parts perform just fine, it's incidental deformation that while still functional may be interpreted by consumers as a quality issue. Since these parts will live on ocean-going/slipped vessels I'm of the understanding they need to be 316 to resist staining as much as possible, which would definitely be interpreted as a quality issue. It's inevitable, but would be harder to justify and explain via marketing using 304.

That said, my instinct may be wrong, my opinions are not hardened (pun honestly not intended), and I'm very interested in differing opinions.

 

[EdStainless]

If you just want some deformation resistance then 1/8 or 1/4 hard should be plenty.
Have you shopped for ASTM A666, and any of the 316 variants (316, 316L, 316LN) should work.
It is really just a myth that you can use 316 in seawater exposure.

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P.E. Metallurgy, consulting work welcomed

 

[rideHPD]

I had my supplier try to find ASTM rated matl for a while and he turned up no leads, called around to all the big names, no dice, a lot of "in 30 years I've never heard of it (in sheets)," tried boatyards all around to see if I could get a lead, nothing.

Still waiting to get a quote for unannealed sheet, but he told me it's been difficult. Guessing that means they don't want to deviate production for one sheet.

If anyone has a lead to a mill that makes it that would be great.

 

[EdStainless]

Have you called Ulbrich?

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P.E. Metallurgy, consulting work welcomed

 

[TugboatEng]

No staining? Have you considered composite shims?

https://www.lamecogroup.com/fabric-peel-shim.html#Characteristics