Re: welding mild steel to some very hard steel

If you don't know what the steel is you had better be careful.
Odds are good that the block is either high carbon or high alloy.
Any attempts to weld will leave you with a HAZ boundry layer that
will be extremely brittle. A hanging load, a few weeks or months
of vibrations, and down it comes.
I do a demo for students where I have them weld 2 tool steel bars
together with a solid 3/8" bead. Let it cool, drop it on the
floor and it shatters. Extremely harsh reminder about keeping
track of the HAZ.
You could attempt to 'butter' the joint area with some high
nickle or maganese rod but you are still on shaky ground. 200
amps on Sched 80 is about as high as you dare to go using a 5/32
rod. If you are using 1/8" rod, it is WAY too high.
Cheers.
Jimmy wrote:

> Ive been trying to butt weld a piece of schedule 80 pipe to what has turned
> out to be a block of very hard steel. Why it was hardened I do not know. It
> is part of a bracket for hanging a CRT display from the ceiling. IMO it dont
> need to be that stout. Any way to get any kind of penetration into the block
> I burn a hole in the pipe. My welding experience is kind of limited. I am
> starting back after 25 years of not touching a welder. I was thinking about
> turning the welder up to about 200 AMPS and laying down a patch of bead on
> the block where the pipe would meet he block then trying to attach the pipe
> at a more suitable lower current. Do you think this would work? Have any
> suggestions?. This metal is really hard, like some kind of tool steel. BTW
> using an AC/DC stick welder.
Reply to
Roy Jenson
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Thanks guys. I finally got everyone to agree today that this was the wrong way to go. W chunked the hardened steel bar for a piece of mild steel. Got rid of the schedule 80 pipe and replaced it with a mild steel rod the same size as the pipe. Drilled and tapped the bar. Threaded the rod to match and the only weld it got was a tack weld to keep it from coming undone.
Reply to
Jimmy

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