Heat treating D-2 Question

[kenvia]

Heat treated a knife out of D-2 today and when I was cleaning off the scale there are lots of spots on the steel. Is this caused by an improperly done heat treat? Or is this standard ops? Pictures don't really show it that well but here they are.

 

[Gossman Knives]

Did you have it wrapped in stainless foil? If not, it's decarb. You'll just have to spend some time grinding.
Scott

 

[mete]

New to D2 ? The carbon steels heated to ~ 1550 scale and decarb some but the stainless steels heated to 1800 or more will scale and decarb far more !!! That's why they use the stainless steel foil -prevents scale and decarb.

 

[kenvia]

I've done a couple D-2 blades before but this is the first one that looked like this but this time I let it soak in the forge longer because the last ones didn't come out hardened enough. As for the steel foil I don't have any so have to look into getting some. Thought the spots might be an indication I didn't do something right.
Some better pics

 

[Gossman Knives]

That's definately decarb especially not using foil. You might want to talk with Larry Nowicki. He forges D2. I'm not sure if he heat treats it in his forge.
Scott

 

[flatgrinder]

Yep, that's decarb.

 

[Steve Hayden]

Do you have temperature control on your forge? If not you should send out the D2. If not hardened at the right T and soaked for the full times called for by the manufacturers, you are wasting your money on D2.

 

[Rob!]

Steve is right. D2 should be held between 1825 - 1875F for 30 - 45 minutes. This would be VERY advanced for an experienced smith I would think. To get the best out of this steel, I would recommend either sending it out for HT or - as I think you mentioned - asking a friend to coach you through the process with their equipment.

Rob!