Heat Treating: D2 vs CPM D2

['cacci]

I'm considering moving blade material from D2 to CPM D2. I am questioning whether I need to alter my D2 ht process. I was told that the partical metallurgy will not affect the outcome, but I want more assurances!
Thanks for any help.

'CACCI

 

[SBuzek]

No differance in heat treat at all,but with the CPM version you will get cleaner finishing blades.
Stan

 

[mgysgthath]

While on the subject, could you go over the HT procedure for D2? I just found a bar in my dresser, and I bought it when I knew nothing, but I plan on getting a kiln before too long.

 

[SBuzek]

Here is what I do.
Ramp to 1100 F hold for 15 min,ramp to 1400 F hold for 15 min,ramp to 1850F hold for 40 min.Plate quench,LN cryo overnite,temper at 400 F for 2 hours,back into cryo for 20 min,temper at 400 for 2 hours.
Results 60.5-61 Rc.
Stan

 

[mgysgthath]

Thanks Stan I guess I'll have to send that one out, didn't know it was air hardening, I'm not set up for cryo.

 

[james terrio]

The CPM version will definitely take a nicer finish. At least in theory, it should be a little tougher too, but honestly I haven't done extensive enough testing to say how much.

 

[Darrin Sanders]

You can do a sub-zero quench with dry ice and denatured alcohol. That will get you down to about -100.

 

[mgysgthath]

Thanks again Darrin, I might try that

 

['cacci]

stan,
I follow about the same procedure, less the cryo. Do you have the experience to make a comparison with vs without cryo? I know that including the cryo improves the conventional recipe, but what is improved? Is it toughness, abrasion resistance, what? Secondly, how much improvemnt is found? 10%, half again, what?
Thanks to you all for valuable information.

 

[SBuzek]

D2 is a steel that when quenched will have alot of retained austinite,the cryo treatment will convert most of it to marstinite.
D2 also is one of the few steels that any cold treatment will help. home freezer,ok. dry ice better. LN cryo best.
Stan

 

['cacci]

Stan,
Thanks for the help. It seems that you, as a hobbyist, use LN. If so, how do you achieve it? I am trying not to bother you by scouring the net for info, without results. Can I, without investing $$$$, use LN in my shop?

Jerry Marcacci
'cacci

 

[SBuzek]

No,it costs a few bucks to set up for cryo.I bought a semen dewar off e-bay for 350.00 for a 25 litre.Costs me 50.00 to fill it at my local welding supply.A fill will last me about 6 weeks.
Stan

 

[Robert Carter]

I finally got my hands on some D2 but only have access to oil quenching and air quenching I do however have a freezer but what process would you recommend for me to heat treat d2 I have a large even heat so heating it up won't be a problem.