D2 at 65+ hrc?

[dfarm]

I just found out about a maker that uses d2 at 65+ for hunting knives.

Has anyone ever tried this or used a blade in d2 at similar hardness? It seems like it should be like a piece of glass if it was thin enough to cut well.

 

[SirSpice]

That's harder than the as-quenched hardness according to the datasheets that come up in Google.

 

[Stacy E. Apelt - Bladesmith]

I didn't chime in because the question was for anyone who used it at Rc65. However, I doubt anyone used it at 65 for the reason the last poster stated.

 

[Seedy Lot]

That's harder than the as-quenched hardness according to the datasheets that come up in Google.

In Larrin's book he has heat treatment data showing that 65 is possible with low temper and cryo.

While D2 at 65 is weaker than I would like it still has similar toughness to M390 or S110V at 62.

 

[dfarm]

That's harder than the as-quenched hardness according to the datasheets that come up in Google.

That's what I found as well. I started looking because someone inquired about me making them a knife at that hardness and told me about the smith that they used to buy knives from.

Asking ai shows that 65+ after cryo and before tempering is possible but I have to imagine a blade wouldn't last very long in that state, if it's actually possible (I don't trust ai responses unless I can verify the sources).

 

[dfarm]

In Larrin's book he has heat treatment data showing that 65 is possible with low temper and cryo.

While D2 at 65 is weaker than I would like it still has similar toughness to M390 or S110V at 62.

I'll look at that. I have a chunk of d2. It might be a fun experiment.

 

[shqxk]

I’m pretty sure you can increase the austenitizing temp combine with rapid quench and cryo to get to 67HRC as quenched with D2 then tempered it down to 65 but I don’t think that would be a great choice for most knife.

 

[Seedy Lot]

I'll look at that. I have a chunk of d2. It might be a fun experiment.

I would imagine any side loading of a thin edge would be in the danger zone.

I had ingot D2 at 62 and was able to pop out little chips with scopping cuts into wood but it was a fierce cutter.

Same heat treat and CPM D2 was a champ that actually impressed me.

 

[DevinT]

Not recommended, I suggest a maker switch to M2 for a high hardness steel.

Hoss

 

[Stuart Davenport Knives]

Not recommended, I suggest a maker switch to M2 for a high hardness steel.

Hoss

Yep. Looks like M2 has slightly better toughness at 64HRC than D2 does at 60HRC.

 

[JoeBusic]

I tested it. 66HRC was the top hardness after extreme grain refining and 120°C temper (3hx3). Grain refinement adds almost 2HRC. Wasn't using cold treatment. Strength gains were almost 3x. 2-4mm thick with full height bevels was not able to withstand any torque in real use. 6mm saber and 0.5mm behind the edge was solid everywhere. Still I advise against ledeburitic steels no mater the gains in HT. It was tested alongside D3, D6 and N690. Economically it is better to use higher end steel in it's recommended HT. Time is money and any prolonged HT methods adds to the price. Want hard, choose native hard steel.