Is it possible to spotweld a .188" thick structural steel (ASTM A36) to a .050" thick AISI type 409 stainless steel (annealed)? Are there any issues that may arise from this combination? Also, are there any recommended references books regarding spotwelding dissimilar materials? Thank you for any information.

-- Dan Choi (dchoi@rgrayclamps.com), April 27, 2000

Answers

I can give part of an answer; The thickness ratio is over 3 to 1, so you will have a (minor) problem with nugget placement. The nugget grows where it is hottest, and that is the center of the sheet, as the surfaces are cooled by water-cooled tips. Your faying surface will not be in the middle, but you can adjust the nugget placement with tip geometry. Use a large tip and a small tip, and the heat will be greater near the small tip. The very best way to observe this is to saw the welded assembly right through a weld, polish it, etch it with acid (any kind will do...) and you will see the welded area in detail. I was able to reliably weld 5:1 thickness sheets of stainless for milk coolers at Dairy Equipment in Madison Wisconsin this way.

-- David Bacon (dbacon@updatetechnology.com), October 03, 2002.