Welding cast steel
 

The turbo I am using has a cast steel downpipe section which is a press fit in the turbine housing. There is a ring of sorts that holds it in place. In fabricating the rest of the downpipe I need to weld to this cast section. I tacked it in numerous locations around the circumference before running small beads 180* apart from each other. Well, after several beads I heard a crack and noticed a nice fault line had formed across approx. 1.5" of bead.
What's the correct procedure for welding exhaust tubing to cast steel?
Do I need to heat the cast first? I assume it's the temp. variations that are causing it to crack? Is the tubing cooling too quickly compared to the cast steel?
I don't want this bitch to crack apart when I install it and put it through a heat cycle or two.
Help! :)

Re: Welding cast steel
 

I've heard to heat it first, but personally I just welded the ---- out of it with a flux core. Holding for almost 2 years now daily driven with no problems.

---- I can't find pics of it

Re: Welding cast steel
 

im an illiterate ------.
lmao


yeah, weak penitration & bad prep. Yes, pre-heat it.

Re: Welding cast steel
 

^-Cast steel my friend, probably to mild steel tubing.

Probably just not getting good enough penetration. Are you mig'ing or tig'ing? Probably has more to do with differences in wall thickness of the two pieces your welding (I'm guess the cast piece is quite a bit thicker, so it retains more heat).

*Disclaimer: I don't know ---- about welding.
8)

Re: Welding cast steel
 

I'll try heating it first. Actually it was prepped fairly well. I took a wire wheel to both pieces and then wiped them off with acetone.
I was using the second to highest amp output the welder has to offer. It's a Lincoln 135 and I'm sporting the fluxcore goodness. The cast piece is much thicker than the mild steel tubing. I didn't want to turn the amperage up all the way because I feel certain it will blow right through the tubing.

Re: Welding cast steel
 

Oh, I also remember starting on the cast piece, and then drag some of the weld onto the pipe. I had problems with burning through the pipe if I didn't do that.

Re: Welding cast steel
 

Push the weld from the cast into the tubing. This will keep from blowing out the mild steel and it will also help keep the cast hot.

Re: Welding cast steel
 

Take every little advantage you can.
lmao!

Re: Welding cast steel
 

last time i welded cast to mild, i started by cleaning the cast contact area with a grinder (better penetration than wire wheel prep), then fired up the oxy/acet and heated the ---- out of the cast. fit up the pieces and puddled the weld deep as i could on the cast and just "washed" the puddle up the edge of the mild piece. that was my root pass with 6011 or 13. let it cool a little so i didn't blow through and put a cover pass of 7018 on top. looked good and was strong but i was using stick weld. when i did it with flux core i turned up the amps and welded pretty much the same way except i didn't change spools of wire. never cracked but the welds looked like pigeon ----.

Re: Welding cast steel
 

I suppose I'll grind, heat, and add some pidgeon ---- of my own :y
Thanks fellas!

Re: Welding cast steel
 

What filler material are you using? We had good luck with a combo weld with mild steel tacks and then 309 rod to fill in on top of it.

Re: Welding cast steel
 

i just hit mine up w/grinder and went slow speed high heat flux-co nigga.
although i was welding to a tube, u was welding a flange on.

Re: Welding cast steel
 

Heat it and use nickel rod. Then cool it by burying it in sand.

Re: Welding cast steel
 

DONT do this, because its NOT cast IRON.

definately clean it, and definately preheat it. and then run 1" long beads alternating back and forth on opposite sides of the pipe, 180* apart untill they meet. Keep going untill its all done, use the highest amperage setting, and focus most of the heat on the cast portion, allowing the puddle to flow into the pipe, as was said above. If possible, put the fucker in a preheated oven when done and slowly cool it down to room temp.