Forging Stainless Steel- experts please!!

[tzonoqua]

Hello all,

I am interested in beginning a project using stainless, forging flowers. I have never worked in Stainless before, so am a complete novice to it and really need some advice.

From what I have gathered on this site and others, is that it takes between 30%-50% more force to forge. I am not sure which grade of stainless is best for forging- I have read 304L but someone else has advised me that that grade isn't suitable. The project is ultimately going to live outside. Will be comprised of bar and sheet work.

I have both MIG and MMA to weld, wondered which would be better to use? (most likely won't be doing forge welding with it). I will be using a gas forge.

I understand that after forging it would need to be passavated, and/or electropolished after as will become contaminated with tools from forging.

The ultimate look I am after is achieving the subtle colours from heat application.. blues, reds etc. inspired by the work by Giuseppe Lund, (Queen Mother's gates in London)

I wondered if anyone else has experimented with this, or works in this regularly, so that I may "pick your brains" and I would be most grateful for any advice you could give me.

Regards,
Colleen

[Rich Hale]

My guess is get some ss and give it a go..nothing like forgfe work to sort out wot works and not. good luck.

[Steve Sells]

I forged 440 and 304, works harder than simple steels, but no worse than tool steels. I never forged 304L so I do not know if that makes a difference on the forge or not.

There is MIG wire for SS and I was advised to use straight argon, not the CO2/Argon mix. So I don't know how the mixed gass work either. Some expert huh:

Edited May 22, 2009 by steve sells

[Frosty]

It has a narrow working range of temps compared to steel. Yes, it takes more force to forge though I don't have any numbers but I sweat more when I forge SS. Passivation is necessary to restore the shine and there are products a LOT safer than nitric acid, etc. There's a citrus product that is supposed to work VERY well and is non-toxic. No, you probably won't be forge welding it, it's possible just a PITA. I like tigging SS, it's wonderful to tig weld, almost recreational.

Your best bet is to build a fire and take a lash at it, you'll adapt to the differences quickly enough. Then when you run into a quizical something puzzling you'll have specific questions and a good base for interpreting our meandering and oft windy replies.

Frosty

[myloh67]

I have used 316 in the past and found hand forging it DEVELOPMENTAL to say the least. Like Frosty said tig welding, i also find the best. With electropolishing ..the initial finish resembles a chroming finish..so be prepared to take it further..!

[Fe-Wood]

I have forged 304 and found it very resiliant to hammer blows almost bouncy as in tough. SS is my favorite for tig welding. As frosty said, almost recreational. I use straight argon, Mixed gas 75/25 will work I believe, just not as clean.
Good luck and show pics....

[Charlotte]

I've not forged stainless bar stock but I have used 316 to forge fireplace shovles over a form. A process that is very like working silver or copper and upsetting the material into itself and making a smooth transistion.
Depending on how many flowers you want to make you might decide to forge some forms and then work sheet stock over the forms. I found that, in thin sections, 316 goes from workable to falling apart abruptly. My experience with 316 was that it did not cold work worth a toot. One advantage of using stainless steels for decorative work is that it is possible use much thinner (ie more naturalistic) sections for the same degree ridigity.
However, again in thin sections in my experience, 316 was easier to work with a soft reducing flame in a acetylene welding tip. Than with forge heat.

P.S. I just checked a scrap piece I have in my box. Looks like I was working on 21 gauge about 0.0329.

Edited May 19, 2009 by Charlotte
add ps.

[unkle spike]

Not an "expert" by any means, but I can tell you to forge my one Aussie Leaf out of 7/16" 304 took alot of doing. On 304 I worked it HOT, orange minimum, and when it cools the slightest quit or it will crack. I did like maybe 10 quick hand blows before reheat, much cooler and you won't get anywhere anyway.

304 would be a good choice in my book, you can find 304 LSI wire easier than most, and it is a pretty forgiving one to weld. I have some experience mig welding it, and with the LSI wire it is pretty good to work with. For finer stuff TIG is the way to go, especially when doing "jewelry" type welds, you really have no need for any filler on the smaller stuff, the base metal will be enough if you are joining smaller parts.

Edited May 19, 2009 by unkle spike

[easilyconfused]

I've only worked with Misc. stainless which sucks because I wish I knew so I could pass it on. Other than it being tough to beat I didn't have any issues with cracking. Mind you, I only was using 3/8. Not that much harder than other higher carbon steels of similar size for the stuff I had. I seem to have worse problem with cracking when I use bought known mild steel than unknown metals which are usually higher carbon steels.

[Walking Dog]

May I suggest . . . cheap, garage sale stainless "silverware" is forgeable, and can be used for low-cost practice. I have forged a number of lilies, with leaves, out of spoons and knives. One warning: some of the cheap stuff has hollow handles. If so, drill a hole, or break the handle open somehow, before putting it in the forge! I got a real surprise when I found out about this. The closed handle exploded and threw flaming coals all about my shop.

Edited May 19, 2009 by Walking Dog
fix pour speling

[johnptc]

re 304L

Steel 304L is an extra low-carbon variation of Type 304, that eliminates carbide precipitation due to welding. AK Steel 304L can be used in the "as-welded" condition, even in severe corrosive conditions. It often eliminates the necessity of annealing weldments except for applications specifying stress relief. It has slightly lower mechanical properties than Type 304.

from http://www.matweb.com/search/datasheettext.aspx?matguid=8379d9f31c8243acbf350273660ea83e

[eddie]

I have forged stainless and the window for forging will close on you pretty quick. Power hammer forging is the way to go because it will generate heat into the bar. I make things like key ring fobs out of 3/8. Doing fine tapers you will have to grind it because it gets real brittle at the end of any taper. I make crosses from 1" stock and split it. This is almost crazy doing it out of stainless because of the time. I am going to try a bear head out of 11/2" square next. Estimated time is 4 hours compared to 11/2 hrs in mild steel. I have also done a fish that was textured and then tig welded together before expanding with air pressure. It takes as much time to finish the work as it does to forge it. I usually wire brush with a stainless brush and then buff it.
Good luck

[Dave Leppo]

some past threads:

http://www.iforgeiron.com/forum/f21/passivation-stainless-10765/

http://www.iforgeiron.com/forum/f7/question-about-stainless-9902/

http://www.iforgeiron.com/forum/f7/forging-stainless-steel-7900/

http://www.iforgeiron.com/forum/f7/working-stainless-4308/

[Che Guevara]

where do you live at charlotte as g.lund is only about an hour from me and could probably be contacted directly by you

[tzonoqua]

Hello Thank you for all your responses.

I don't actually have a power hammer, but have access to one so that might be the way to go for some of the work.

As for the welding, I've never attempted TIG before, but my MMA inverter welder has TIG facility on it so I might just get the TIG leads and Gas and have a play.

Great idea to practice on cutlery.

I have actually emailed Giuseppe Lund directly who has very kindly got in contact with me and is willing to share his expertise.

I will let you all know my progress. Again thanks for the replies.

Colleen

[Frosty]

If you can gas weld you'll LOVE tig welding, especially on SS.

Oh yes please, progress pics will be enjoyed muchly.

Frosty

[Sam Thompson]

Does anyone remeber David Townsend's review of those gates in British Blacksmith?

[arftist]

Although much information is covered in the replies already submitted, I would like to add a few things. Please forgive any repeats. 304 is a good general stainless steel for forging. 316 would be prefered for certain extreme enviroments, such as exposure to sea water or the mists thereof, or intallations in the vicinity of Cedar wood, and possiby other woods. 304L(the L indicates low carbon) could be a benefit for such reasons as structural soundness of welds or less chance of carbon embrittlement. Stainlees Steels should be forged at a "near white heat", and require much greater impact for metal movement. Bending can be acomplished at a bright cherry, almost orange heat.
Acid passivation is not the only way to preserve the original stainlees propertys, nor is it always called for. For example, hot forged and worked s.s. retains the apearence of freshly forged iron, and need not be restored to s.s. if used in a nonrusting enviroment. Sand blasting (with clean new media) will restore properties as will manual polishing if done correctly (successive new abrasives).
For those not in direct contact with Geo Pepsi, oxide colors are most visible on highly pollished metal.
Finaly an aside, 303, which resists corrosion to a much lower degree than 304, is a free machining metal, easier to machine than even cold finnished steel, in fact only surpassed by free machining brass(such as 360) in ease of machining.

[ornametalsmith]

FWIW, Citrisurf is the NON TOXIC stuff that Frostilio mentioned. Stellar Solutions

and to see some amazing forged SS.......check out Giusseppe's work. He gets some killer "temper colors". He doesn't always passivate.
Metalgarden | where to bend next...

and Ries':
Ries Niemi Industrial Artist

happy hammering,

[Frosty]

Citrisurf is the stuff.

Thanks Bill.

Frosty

[jbin]

304L or 304 forges much hotter than you will be used to. Minimum forging temperature is 1700 F 926 C and it is very stiff down that low. Upper forging temps are in the 2200 F 1204 C range. Even at high temps it is not easy to work. 304L is the low carbon version and would be preferred but if you keep it above 1700 F and quench it before it has a chance to cool from that temp you will not need the properties that the low carbon variety provides. It has to do with chromium carbides that form at lower temps and cause loss of strength and corrosion resistance. But if you heat the whole item to 1750 F and quench you will break down the chromium carbides and return it to its original state.

Heavy forging scale can be removed by electro-striping the work in a bath of citric acid with the work hooked up to a 12 volt DC source (battery charger) as the anode (+) and a cathode plate of stainless or even mild steel hooked up to the (-) pole.