What is this weird-ness in my steel

[JTknives]

So today I was working on a D2 puukko for a budy who is going to be doing some wild game testing with it. The blade is D2 that is from a planer blade that I annealed. I have a lot of these blades do I have been looking for a use and it's perfect size for puukko blades. So any way I was grinding away on it and when I switched from the blaze belt to the 300 gator belt this weird spot showed up. I kept grinding and it never went away. I dont know how deep it goes but it's not on the other side and I'm at my desired edge thickness of .02 so I don't want to remove any more befor heat treat. Looks like aloy banding but that's usaly spread out in waves not a patch of what looks to be a softer section. Thanks guys, I'm not real concerned as this is just a test blade and cosmetics are not top priority at this time.

Here is the little funky spot

As you can see it's not on the other side.

But like I said befor this is a mule of sorts to just test heat treat and cryo treatment on an oven annealed D2 planer blade.

 

[Jesenius]

I believe that is steel impurity. Sometimes happened to me too. Only way is grind it away...or ignore it.

 

[DevinT]

Worm hole, prevalent in the north west. You slso need more radius between tang and blade.

Hoss

 

[Nathan the Machinist]

^ yeah, good call on that radius I think


That looks like it goes in, not out, meaning it probably isn't a big plate carbide. My guess would be a large soft inclusion, which doesn't bode well for the quality of the melt.

I've used a lot of D2 and I've never seen that before. It's known for some weirdness, but not like that. This is pretty typical :

You can see the carbide banding there. That's pretty typical and not a bad thing.



Is it possible you have a spot of soft decarb? Didn't you do some in the forge annealing? I don't know, but perhaps there was a spot that didn't play nice due to a hole in some foil, etc?

 

[JTknives]

Yeah I completely spaced out the radius. Got it set up for filing and grabbed a sharp shoulder file and went at it. I do blan on fixing it.

I did aneal this D2 but I did not do it in foil. I stacked 9 blades (each blade is 26" long) in the oven and ran the program, took somthing like 16hrs if I remember correctly. I'm hoping it's just a weird anomaly that I never see again. But I does seams softer becaus it's created a low spot in that area.