Mystery steel work hardened after welding?

[Ben Dono]

This is a PITA! I though it was some 1020 rod stock.......I did label it a long time ago but the rust around here soon fixed that up.

I got no idea what this stuff is as it must have been a rusty bit I picked up along the way.

I turned up 4 slugs and pre drilled them for a 1/2" tap. Welded them in place and cleaned them up. Was trying to tap them and the bloody things are rock hard! The tap just skated on it. I tried to enlarge it 11.5mm just past the lip...no luck... Any thoughts fellas? It's buried in a piece of 75 by 50 by 3 and welded both sides.... Lovely!

[BobL]

Did you quench after welding?

Anyway - just heat them up to red again and then let them air cool and you should be OK.

[Ben Dono]

No water quench, they were hot and quick mig welds.. I was thinking about trying that. I might have to duck up to my neighbours place as I do not have an oxy and the part is big enough to act as it's own heat sink.
I sharpened up a masonry bit to bust through to skin an have managed to get one of the 4 tapped. Here is to hoping it's just the first 5mm that hard!

[nearnexus]

Did you quench after welding?

Anyway - just heat them up to red again and then let them air cool and you should be OK.

I'm not so sure that is going to work.

Seeing as it air cooled from welding, trying to anneal it is a long shot.

Rob

[Ben Dono]

I got lucky! Broke a sweat and chipped a tooth on the tap but I eventually got them done!
I'm going to spray the 1020 with pink paint from now on! I'm not in a hurry to do that again.

It could have been a bit of D2 I had floating around from years back. Or I just was unlucky with what was in the scrap pile...? It machined like gummy mild steel...