stainless to mild steel

[aidank]

Was welding a bit of stainless to mild steel galvanized 2" pipe over the weekend, a handy DIY bracket.

I had a 304 rod on my Inverter buzzbox DCEN, 90amps. 4mm thick SS and 4mm walled galvanized pipe.

Action 1 - Just a tack, sticks nicely
Action 2 - Fillet Weld 50mm long - However Weld didn't seem to want to stick to the galvanized 2" pipe. Slag only sticking the 2 together.
Action 3 - Grind off previous attempt and go again with the 304. Same result.

Action 4 - Grind off last attempt and go again this time with a 29/9 rod. Perfect everything sticking together as expected.


Any over see a rod not wanting to stick like that

 

[Memmeddu]

Was welding a bit of stainless to mild steel galvanized 2" pipe over the weekend, a handy DIY bracket.

I had a 304 rod on my Inverter buzzbox DCEN, 90amps. 4mm thick SS and 4mm walled galvanized pipe.

Action 1 - Just a tack, sticks nicely
Action 2 - Fillet Weld 50mm long - However Weld didn't seem to want to stick to the galvanized 2" pipe. Slag only sticking the 2 together.
Action 3 - Grind off previous attempt and go again with the 304. Same result.

Action 4 - Grind off last attempt and go again this time with a 29/9 rod. Perfect everything sticking together as expected.


Any over see a rod not wanting to stick like that

Clean the zinc coat off the pipe prior to weld and use at least 308L they should weld great together ,grind a little bevel too.
Stainless needs more heat but not that much current compared to mild steel.
So you have to go DCEP and around 70-80A using 2.5mm (3/32") rods

 

[Barking Mat]

Right, don't quote me on this, but....

If joining stainless to mild steel, you should be using s/steel welding rods, 308 or 316.

Someone will probably back me up or poo, poo, me.

 

[E T]

Right, don't quote me on this, but....

If joining stainless to mild steel, you should be using s/steel welding rods, 308 or 316.

Someone will probably back me up or poo, poo, me.

Poo, Poo Mat. 309 or 312(which is 29/9).

But 307, 308 and 316 will also work. 304 is not the best choice.

 

[aidank]

What are 304 rods recommend for, welding 304SS to 304SS only ? would 29/9 do just as nicely.

 

[Popcorn]

29/9 is the same as 312 used for joining dissimilar metals, funnily enough I was only looking it up the other day.