Click here to subscribe to my Video of the Week!
::Tig Welding Stainless Steel using pulse TIG::
Unless the pulse rate for tig welding stainless steel is 1 pulse per second, I hate slow pulse rates. they make my head numb.
I like 30 pulses per second or more. that gets me out of the epileptic seizure range.
39 pulses per second
30% pulse on time
30% background current.
These are pretty good pulse tig settings for agitating the puddle and limiting heat input.
High pulse rates above 300 pps helps to focus the arc and limit heat input.
Higher pulse settings like 100-150 pps really focus the arc.
Especially when welding on or near the edge of metal. High pulse rates can actually increase travel speed too…if that is something thats important to you.
You might think that 100 pulses per second is so fast that its just like no pulse at all….but you if thats what you think, then your wrong.
think about a shower head that has a pulse feature.
you can feel it. It makes a difference.
When Tig welding stainless steel parts, limiting heat input also helps to prevent discoloration and distortion…not a night and day type change, but a help nonetheless.
Customers expect stainless steel to have colors. Not to be gray or black.
And for good reason. When stainless steel discolors to gray , it loses some of its corrosion resistance.
I have a friend who welds small bore stainless steel tubing for food service applications where inspectors visit years after welds are made to inspect for bacteria inside the pipes.
He has learned over the years, which welds maintain corrosion resistance and which welds rust over time.
He has noticed that welds that were overheated and turned gray or black rusted after a year or two.
Even though He polishes each weld he does, they still rust if they got too hot.
He makes the original welds on jobs, and when his customer sees the quality hey puts into the job, he then gets the maintenance contract too. So he gets to inspect his own work for years.
There is a lot to be learned from welders who maintain the welds they make for years and years.
The stainless parts I tig welded today will be plastic coated for the most part, and only a small portion of the stainless steel parts will be exposed to the elements.
Still, I want them to look good, hold up to whatever the real world throws at them, and to not rust….ever.
The brackets are made from 304 stainless and I welded them using 308L filler wire.
I used a # 12 cup ( thats 12/16″ or 3/4″) because I needed to extend the electrode out nearly an inch in order to film the arc for some of the welds.
CNI http://www.ceramicnozzles.com/catalog.html
is the place where you can order large diameter gas lens type tig cups.
But a warning….
you will need an additional diffuser in order to make the #12 cup work.
I used scotch brite, but I have also used stainless wire mesh screen material too.
In order to limit heat input, I used around 39 pps with 30% on time and 30% background.
( And as always, feel free to visit us at our sister site, WeldingTipsAndTricks.com. )
Click here to subscribe to my Video of the Week!
Leave a Reply