Stainless to mild steel

[Tman]

Hi all don't know why or where one of my customers managed to get stainless steel s527 aircraft grade sills made for his Nissan 300zx. But any ideas best way to weld to mild steel. Mig,oa, what gas wire or filler. Thanks in advance.

 

[aametalmaster]

Mig loaded with tri mix gas and 309 wire would be the best way...Bob

 

[pedrobedro]

If you're welding them to mild steel you may as well use mild wire. The join is going to rust quicker anyway due to the reaction between the two metals

 

[Lawnmowerboy]

Quite likely they'll work harden and crack possibly on the weld seam/ weld points on the join between sill to arch. Cars need to flex unless you are building a track car and looking for some more rigidity.

 

[Philip Hodkinson]

There are a number of mixed metal wires made from the same materials as arc rods.
Armex 2 is one I've used

 

[Tman]

Quite likely they'll work harden and crack possibly on the weld seam/ weld points on the join between sill to arch. Cars need to flex unless you are building a track car and looking for some more rigidity.

Don't know what he's building rocket a think. Itis for the track some kind of drag racing. Full of nos supercharger and many other mods

 

[pedrobedro]

Quite likely they'll work harden and crack possibly on the weld seam/ weld points on the join between sill to arch. Cars need to flex unless you are building a track car and looking for some more rigidity.

Cars don't need to flex, designers have been trying for years to eliminate body flex so that the suspension can be tuned to work properly

 

[hotrodder]

No such thing as a perfectly rigid body. Cars may be less flexy these days but shells still flex a fair bit and many of us have probably noticed this when jacking up a corner and then opening a door, especially on something older even a rust free example. Unless i've missed it we don't know how old the 300zx is so it could be an early eighties example

Disimiliar wires like the 309 mentioned aren't about rust, they're about metallurgy. Dilute stainless steel with mild (or visa versa) and the result can be brittle. 309L etc are overalloyed to produce ductile welds when joining mild to stainless. Outside of aerospace s527 is generally known as 347 stainless

 

[Rig Pig]

Bad plan to mix mild and s/steel, the stainless will eat the metal around it, the sill will make a lovely battery as soon as it gets wet!