[DanW]

Hi guys,

I've been playing around with a welder at home now, playing mainly with stainless using 2.5mm (1/10 in) 316L electrodes welding 3mm sections.

I'm having some dramas with slag inclusions mainly when doing fillet and lap joints.

ive done plenty of fillet/lap joints on mild steel with 7018 and 6013 general purpose rods and never had this problem. i get a decent looking bead with the stainless but every now and then a dirty great hole full of slag.

At first I thought maybe rod angle, so increased the angle by a fair bit but still happening..

then i thought maybe i'm holding the arc too close and that seemed to help a little bit, then i tried cranking the heat up and that seemed to help quite a bit. got some really nice clean smooth welds at this point, but I ended up using around 85-90A which I thought is getting a bit hot for 3mm stainless.

If anyone would like to add their input into this i'd love to hear it.

many thanks!

[rickbreezy]

85-90 Amps seems quite right for the rod your using. SS welding is prone to leaving slag holes and porosity, and is known to be "runny", meaning it has a tendency to swish around and run much easier than a C/S puddle would.

So don't fret.

My advice with SS is to run a little hot, keep a tight, tight arc, and try not to weave the puddle around much.

Oh, and a good rule of thumb is that any SS rod, should run about 10 amps hotter than a 7018 rod of the same size. At leats, that what I always do. Maybe thats why its so damn runny!

http://www.weldingtipsandtricks.com/wel ... steel.html


good luck,

-Rick

[DanW]

Thanks Rick. I always thought the opposite though, like the first message on jody's tips page there, "stainless steel takes about 1/3 less amperage than carbon steel!.. "

I'll have to try keeping a very tight arc with the heat cranked up a bit more, when i get a theory in my head i tend to run with it so I have been a little hung up on thinking i'm keeping too short an arc and the rod is burying in slag causing the inclusions. I did a few runs this morning running at about 80-85A (top of the range recommended on the box) and found the results ok, but probably holding too long an arc. I got 3 small holes in a total of 6 welds, a pipe fillet to plate and i guess you'd call it an obtuse angled fillet welding some scrap angle to plate

all up though the results were much better than when trying the same welds colder, thats for sure.

pics:





for reference, the welds are approximately 7mm wide

thanks again

[rickbreezy]

Glad I can help!

Yeah, alot of manual will tell you to run SS colder, and obviously this is jody's advice as well.

But the important thing is to go with what works for you right?

-Rick

[DanW]

yep i'm with you on that, definately helps with the inclusions turning it up a bit so thats what i'm doing. gets the job done quicker too