welding ss 304 and mild steel 1

[hobbywelder]

When welding Stainless Steel (304) and mild steel to each other,
are there any corrosive problems. Pieces are powder coated.

 

[welding1]

The problem with welding ss to carbon steel is the dilution that occurs in the carbon steel, this creates a very hardenable chrome steel. Therefore you use an over alloyed filler wire such as a 309 to overcome this problem. The other problem with welding ss is carbide precipitation. This occurs when the ss is heated during welding, the chrome tends to migrate to the grain boundaries and form chrome carbides. This effectively depletes the chrome content making the weld suspect to corrosion near the weld. If you are using low carbon L grade of ss its not really a problem unless you are heating it for prolonged periods.

There are other corrosion mechanism but they would destroy your carbon steel first

Not sure what effect the powder coating would have, I presume it will just disintegrate in the vicinity of the weld.

I am going to do an article on welding metallurgy on my web site

http://www.gowelding.com,

as soon as I can get a round tuid. Unfortunately round tuids are hard to find these days!

 

[dropkick]

I want to Weld Austenitic ss to A-36 44W steel what do I need to know?
Electrode size
Amperage
Current DCEN, DCEP
Amperage
Preheat
Problems to look for