Welding a plasma cut piece of steel

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I read somewhere that sometimes, due to the introduction of nitrogen during plasma cutting (which is just in the air anyway) it can cause issues with welding.  Is this so? what kind of issues?  If there are issues, how to get around them through either a: changing how you plasma cut or b: weld preparation after a plasma cut (such as grinding)If you have to do some grinding after a plasma cut, at what depth do you have to worry about?I will be welding with MM 251.The Lord has declared, "This is my work and my glory--to bring to pass the immortality and eternal life of man"  Moses 1:39Link: My name is John, and I am a member of The Church of Jesus Christ of Latter-Day Saints.-- ColdCreekWorks.com --
Reply:Material steel or alum?.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by DSWMaterial steel or alum?
Reply:have no experience on al, but I grind to bright metal before welding if at all possible. The only time I do not get all the way there is with 6011 rods. I would assume you need to clean even more with AL.
Reply:Al you are going to have to clean the cut completely by means that leaves no residue or embeds any particles into the material Stainless you are going to have to grind completely clean to get a good weld(esp with tig). I've had some success with stick welding cut eges that are just knocked down not 100% clean. Solid wire welding only just barely tolerates cut slag better than tig. Carbon steel with solid wire its going to have to be relatively clean even with -6 wire. most dual shield wires will tolerate the thin scale left on the cut surface but not any slag deposits hanging onto the bottom edge of the cut. I've had success with 6011 through the thin scale too. 7018 will tolerate it...kind of. Never got UTed with 7018 so I'm not as sure about that one as the dual shield. The scale doesnt go that deep. Just think of it as mill scale and smack it with a grinder.
Reply:Originally Posted by i4sillypwrThe scale doesnt go that deep. Just think of it as mill scale and smack it with a grinder.
Reply:Originally Posted by BoostinjdmYou took the words right out of my mouth...I just got done welding some plas cut strips of 1/4".  Hit the cut edge with a grinding stone till it was shiny and welded them down.
Reply:Originally Posted by SandyYou've never seen my cuts. Peaks and valleys. Gotta grind the peaks to get to the valleys.