Cleaning a weld in stainless/welding 304ss to mild steel

by Zack
(North Carolina)

Hey
I need to weld a "V" track for a motorized gate i am building. The track needs to be 22' long, so I am welding two pieces of 304 1x1x1/4" angle together. How can I keep that welded area that I will finish grind from rusting? Will it rust if I grind it with clean SS abrasives? if so...
Is there a EASY chemical treatment to bring the effected area back up to stainless quality?
Any advice?

After I weld the track, I need to weld it to mild steel tubing (using a TIG). I read to use er309 on here and some other places. Do I need to worry about the stitch welds oxidizing? Also got any advice on keeping that track straight? My experience is that stainless moves like a bitch...excuse the language!

Thanks for the help.

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zack,

make sure your abrasives only touch stainless. dont use grinding wheels or sanding discs that have been previously used for carbon steel. Its a good idea to color code with paint and store your stainless discs separate from other abrasives.

one shop i worked in made us paint all the carbon steel tools one color and stainless steel tools a different color. Even files, grinders, carbide burrs, wrenches , etc were marked with paint.

the 309 wire is pretty corrosion resistant but i would leave those dissimilar welds alone after welding so you wont smear carbon and iron particles on the stainless part.

yes you will have issues with warping.

you can make a strongback out of channel or i beam or anything sturdy enough to clamp to for rigidity.

you can also do some straightening after welding.

chemical solutions are available but will only remove free iron particles and will not put back any corrosion resistance lost from excess heat used in welding or from wrong filler rod.

here is a url to a site that offers a passivation chemical fyi

http://www.citrisurf.com/cs77info.htm