Stainless?

[DangerZone]

I'm still new. Is there anything to be worried about forging stainless as a beginner? I understand welding stainless and the fumes created from that are particularly bad for people, but does anyone forge stainless and take extra precautions over what you would do for regular steel?

 

I work at a food production company, and can sometimes snag random drops of metal. A lot of it ends up being worn out food grade stainless.

[JHCC]

Forging doesn't get stainless up to the temperature where the alloying elements are going to be off-gassing. For that to happen, you basically need the metal to melt, which is what happens in arc or OA welding.

I'd recommend snagging every one of those drops you can get. Even if you don't forge them yourself, you can always use them as trading stock.

[ThomasPowers]

I like stainless for items where I don't expect the end user to do regular maintenance to keep them from rusting.

[Kozzy]

Most likely T304 but possibly T316 unless your food company is doing something weird.  Ok to forge but don't expect to make anything edged with it as the grades normally used in food processing are not hardenable.  Rarely, you can find something like T430 which can be hardened "at home" --the only way to make a guess at that is the 400 series stainless will stick to a magnet quite well where the 300 series barely sticks (work hardening and forming makes 300 series a bit "stickier" so judge vs plain old carbon steel comparison of magnetic attraction)

There are a couple of other grades like 17-4PH but that'd be much rarer to see.  200 series might show up if the equipment is "cheap"--that grade replaces  the expensive nickel with manganese to save money.  It tends to be a bit brittle and even harder to work.

One thing about stainless--it doesn't like to move under the hammer.  Something larger like a shaft will be a bear to work alone so you might need a striker or power hammer to be efficient. Smaller stuff just takes longer and wears you out.  Ok, 2 things not one--you also tend to have to work it hot or it can crack/split under the hammer.  Don't push your luck and do any major hammering toward the cold side of bright red-yellow.

It will not generally be nearly as "stainless" after the kind of forging a home smith can do as it's almost impossible to shield the parts from oxygen when hot.  Pickling may help so a soak in vinegar or citric acid will improve the surface by dissolving the iron that concentrates there--less potential rusting (called "roughing" when it happens with stainless and is mild).

[Steve Sells]

FYI stainless contains iron, it is a form of steel, I relocated this for you from the non ferrous section.

[Kozzy]

1 hour ago, Kozzy said:

(called "roughing" when it happens with stainless and is mild).

Sorry--typo that I didn't catch.  Rouging as in rouge...reddish discoloration that isn't as bad as downright rust.  They call it "stainless" because it stains LESS.  Otherwise it would have been called stain-free steel.

[bertie_bassett]

iv forged stainless a fair bit over the last year or so, only in small diameters for pendants and similar objects. it is quite tough to hammer on but if you keep it hot it moves ok.

it also likes to crack on thin sections, again working hot seems to give less issues.

normally ill give it a good scrub whilst hot then soak it in warm citric acid. once you have cleaned it up it can look lovely.

 

[Frosty]

Stainless electro-polishes beautifully too.

Frosty The Lucky.

[Kozzy]

17 hours ago, Frosty said:

Stainless electro-polishes beautifully too.

Frosty The Lucky.

I've got a job currently where the customer insisted that about 8000 lbs...250 pcs x 8" x 8+ feet long all get electropolished.  Talk about a gigantic hassle!  Polishers all just groaned and didn't want to take on something that was going to tie up their operations that long, putting the other stuff they normally do behind.  It aint a super fast process.  But...as you said, once done it's beautiful.

[Frosty]

Aie yi yi! That calls out for an automated process, I'm thinking a conveyor through ring electrodes. How are you handling it?

Frosty The Lucky.

[Kozzy]

Found one guy in town willing to take it on...but he isn't happy and is charging to reflect that.  Customer is paying the bill so I only care that it's getting done.  Total job cost is about a third of a million so the electropolishing barely makes a dent.

[Frosty]

Ayup, that's what specialty subs are for. I hope your bid covered it properly.

Frosty The Lucky.

[Savage11]

I have 304 and 316L stainless steel rod and flat drop that I'm looking forward to forging.

[bluerooster]

Only stainless I have is tubing.  And a bunch of it is rusty (exhaust).

[arftist]

304-316 is best worked at near white heat.