Arc welding Stainless Steel

[Dani99]

hey lads, iv been welding for a few years on cars, but iv always used gasless wire as my jobs never warranted a gas bottle, iv also had a fair amount of time on my arc welder for the heavier jobs iv needed to do,

But in now building a custom turbo manifold using 3mm 304 SS butt weld bends and 2mm 304 SS tube, iv also got to weld the SS to mild steel flanges i have a sip Mightmig 105 mig and Topweld 140 arc welder..

i will be welding 3mm 304 buttwelds to 2mm 304 tube i no this is thin for arc welding but with care could this be done??

i believe i need 308l for the SS to SS and iv read ill need 312 for the SS to mild steel is this correct??

i no it would be easier mig welding but for both the SS to SS and mild steel to SS ill need separate gas and wire as its only a small project i don't won't to have to spend a fortune on gas and wire.

would i be best of just stumping up the money for the wire and gas or could this be done with my arc?


sorry if i have got anything wrong but thanks for any help and advice

 

[BrokenBiker]

i don't find 2mm to be a problem with stick. Stainless rods get hotter quicker though so you may need to tweak the amps down a bit as you go. Practice on scrap, i find its easier for me to set the amps for about 95 and then motor on through keeping as tight an arc as you can keep a good rod angle and don't hesitate.

using the rule of 1 thou per 1 amp 95 amps is about right for a full pen weld just over 2mm in perfect conditions, but perfect never happens really so just do what works for you

 

[dan.taylor.1]

Not to poo poo your plans, but if the 3mm is for the flanges, I dare say it's no where near thick enough, 10/12 would be nearer the mark.

Dan

 

[BrokenBiker]

i assumed from the op that the 3mm was wall thickness being welded to 2mm wall thickness. However, if it is a flange it wont last at all

 

[Dani99]

sorry i didn't describe that correctly..

the bends are 3mm the tube is 2mm and the flanges are a good 10mm

 

[Dani99]

flanges are 10mm and 15mm bends 3mm and tube 2mm

 

[BrokenBiker]

personally i would prefer to tig it with a purge, second choice would be mig with argoshield or similar but it could be done with arc. Depends most on what you have available and how good you are at using it. I have all 3 processes but would still mig certain things that may be better with tig as i am better at mig

 

[Dani99]

Tig would be the perfect choice but don't have access to one, never used one and don't no anyone with one..

mig is possible but not sure mine is up to welding the flanges plus the gas and wire i would need will add up fast but if thats whats needed to get the best and strongest result so be it...

would i not need 2 different gases for the SS to SS compared to the SS to mild?? same with the wire

 

[BrokenBiker]

Not really. When welding stainless to mild you can either use wire to match the stainless, or wire to match the mild, but either way the mild is still going to rust and cause the stainless to corrode quicker at the joint. Argoshield will cover everything you want to mig steel wise afaik

 

[Dani99]

so i could get away with 308l for all the joins?

i read i needed 97.5% Argon +2.5% CO2 for the SS to SS and 309l for the SS to mild to prevent cracking...

with me just doing a few welds would i be ok using the larger disposable bottles or a hobbyweld 5 bottle 93% Argon, 5% Carbon Dioxide and 2% Oxygen OR hobbyweld15 83% Argon, 15% Carbon Dioxide and 2% Oxygen

 

[BrokenBiker]

i have welded stainless to mild with mild wire a few times. Not sure what the best out of those gasses would be, when i asked about it not long ago i was told to avoid argon mix and go for something like stainshield or argoshield

 

[Dani99]

I'm just trying to find somewhere local i could get something like stainshield or argoshield without a contract :/ proving difficult

 

[Welderpaul]

Yeah, welding stainless with MAG/MIG you need stainless wire and Stainshield.
Or...stick weld - the cheaper option - no problems stick welding 2/3mm with 2.5mm dia rods - stainless welds nicely; just watch the slag which flies off with some force as it cools.

 

[Dani99]

would something like this be suitable for all the joins?

http://www.ebay.co.uk/itm/MIG-WELDI...832?pt=LH_DefaultDomain_3&hash=item2a32b33940

welderpaul what would you say i would be better with doing? arc or mig, iv had more time on my arc but never down to 2mm where as iv had plant of time on mig at 2mm.

if i went arc would i use 308 for the SS to SS and 309 for the SS to mild?

 

[Welderpaul]

It would be ok for mild steel.

 

[Tiggy_dorset]

If you state roughly your location, maybe there is someone on here nearby who could tig it for you.

 

[Dani99]

welderpaul what would you say i would be better with doing? arc or mig, iv had more time on my arc but never down to 2mm where as iv had plant of time on mig at 2mm.

if i went arc would i use 308 for the SS to SS and 309 for the SS to mild?

Im in derbyshire

 

[Welderpaul]

Yeah, if you are welding mild to stainless you might as well use mild steel wire/rods cos its going to rust anyway.

Stick welding stainless is cheaper. If it was only a few bits i would stick weld it personally - save fiddling about changing gas and wire.

 

[Dani99]

i only have 6 joints to weld all 2" in diameter but strength and crack prevention is a must... so i think ill go with stick welding. rusting is not an issue as its not on view...

so 308 for the SS and 6013 for the flanges? l

and last question whats the best quality brand / supplier to get the rods from

 

[Welderpaul]

If crack prevention is a 'must' you need to weld it with the right consumables. If you weld stainy with mild steel consumables you might as well use mild steel for the whole job.
Yes - 308 for welding 304. Bit of info here.

Consumables...Esab, Lincoln, Bohler, EWM etc