O1 welding blues (pics added)

[weo]

Hello all. This question is for those of you who regularly incorporate O1 into their billets.
Over the last 3 days, I've had a few failed welds and not quite sure why.
Here's what I'm going for:

The five pieces of 15N20 welded and the O1 welded to the 1080/15N20 pieces fine, but the O1 didn't weld to the 15N20 in these 2 billets. (The brown spots are rust from drops of water left overnight)

I thought this piece was solid until I was drawing it out and I noticed the seam. I put the piece in the vice and whacked it with a 4# hammer about a dozen times before it split apart.

Here's a close up of the partial weld

I initially thought I might have worked the pieces too cold, but another piece with similar composition forged out fine. One thing I did notice was that when I was cutting the O1 with a cut-off wheel, the sparks were very muted and orange. Also, when I was cutting the handle off the other billet that I forged out, there was a significant spark change as mentioned above which told me I was in the O1(?) section.
My thermocouple was reading 2150F during this welding session, so I should have been hot enough for welding.

Any thoughts? Thanks

 

[Tom Lewis]

Since no one else has responded I will.
How long was the billet in the forge at 2150? That might make a difference.
What kind of flux did you use?
I know 2150 is hot enough to weld in but I like a hotter temperature when I weld.

 

[weo]

Hi Tom, thanks.
I let it soak at that temp for at least 10 minutes, but it might have been as long as 20.
No flux, I made the billet a few days earlier and it was in kerosene until going into the forge. I used a 25-ton press to set the weld 3x with the large flat dies, then switched to the comb/drawing dies, but didn't really draw it out only really tried to set the weld a bit stronger 2 more times with the flat side of the combo dies. I let it get back up to 2150 and let it sit for about 5 minutes between each heat.

I don't think this should matter, but I use a stick welder with 6013 rod to weld up my billets and handles.

 

[Tom Lewis]

How did you clean the pieces before you stacked them up to weld?
I would grind both pieces clean, re-stack, flux, and put in the forge at 2250. After it looks like it's ready to weld I would wait 5 to ten minutes longer.

 

[weo]

Hi Tom. I prep my pieces by grinding flat on a used 60g belt.
I haven't used flux for the past couple of years.

Am I correct in that the O1 grinds with relatively dull orange sparks?

 

[DevinT]

O1 is not the best steel for forging due to the small amount of chromium in it.

O1 throws a dull orange spark because of the tungsten it is alloyed with.

Switch to 1095 or 1084.

Hoss

 

[weo]

O1 is not the best steel for forging due to the small amount of chromium in it.

Now that you mention it, I think I've heard that before, perhaps even from you.
Because there's always an acceptable range, should I infer that the 4-5 prior successful billets I've done were on the low end and this piece on the high end (assuming all other things were equal, of course)?

Switch to 1095 or 1084

But I want the added contrast with the manganese!!!! (said in a 4-year old tantrum voice....I couldn't find the appropriate emogee)