Ahhh! More cracks along the spine!

[Joseph Bandeko]

OK so I have a big problem, this has happened several times with both CruForgeV and 52100.
The problems is that every now and then after I forged a blade out, while I’m ruff grinding before HT I will notice cracks running down the spine! But here‘s the kicker the cracks run down the blade length only and there’s NO cracks anywhere else. I don’t think it’s because I’m forging to cold, and I do my forging by hand so I don’t think I’m moving metal to fast either.
I don’t know what’s happening and any thoughts would be much appreciated.
Here’s some pics (the cracks were pretty difficult to photograph)

 

[Joshua Fisher]

52100 is notorious for cracking when worked too cold, if you are hitting the steel at all when at a red heat chance are you are too cold, it has a shorter forging range than simpler steels like 1080. In my opinion that’s the issue, try another blade and only forge in the yellow and orange heats.

 

[huntingsgr8]

I agree with the above. I've seen cracks like this in O1, and they were caused by the metal being too cold. Somewhere on the net you can find a data sheet with the recommended forging temp range for you steel.

 

[Joseph Bandeko]

Well that’s the thing is I am not forging it below orange (maybe it’s the lightning? and I actually am forging to cold) I know the temp range of those steels, and why is it not happening anywhere else?

 

[Joseph Bandeko]

I just realized something, I put my blades in the vise to get them straight, and obviously that sucks a lot of heat out of it so could straightening it like that be the the problem? But it’s not like I’m really moving the metal doing that either