welding dissimilar steels

[RobbieKnobbie]

I want to have a piece of flame hardened 1040 welded to a HRS plate...
the 1040 is about 2x2x39 while the plate is 1x6x39

how hard can I reasonably expect 1040 to get? Above Rc40?

would I be better off with 4140 instead of 1040?

Cost is not the issue... not pissing off the welder is

[loose nut]

Well they really aren't dissimilar metals in the sense that welding stainless or chrome to c.s. is but welding 4140 requires a little different procedure to prevent cracking, not a problem for the welder as long as he is familiar with it, can't tell you about what the hardness will be like afterwords though, slow cooling may soften it some????

[madman]

I just welded my Homemade machine lifting tgrack Jack wich is a hydraulic chinese?? who knows what materrial base (cast steel??) to a piece of mild steel with my mig welder. I actually welded the jack foot to the plate of steel . Then i lifted a pile of machinery for levelling purposes and none of my **** welds cracked or broke? I guess i was lucky but maybe chinese cast welds nicely to 1020 or 1018 plate steel ? What do i know? Not much./

[torker]

Whew...now there's some welding huh?
Pretty big pieces no?
I'd be doing a bunch of bevel prep on the 2X2...preheat the crap out of it.
I'm thinking around 400F then weld (I'd likely used 8018 )
I can't remember but you need some pretty high post heat with that steel.
You could look up "Welding 1040 steel"
You're going to be at the mercy of the welding gods in the HAZ as far as tempering goes.
Russ

[loose nut]

Torker, what about using 309 SS, it has more give and is less prone to cracking on touchy metals, should eliminate the need for PWHT, at least at a high heat. 8018 would need stress relieving.