can a guy with an evenheat properly HT and temper M2?

[Charlie Mike]

I've tried following the instructions on the crucible site and only reached 56-57 as quenched in parks50. Austinizing temp was 5 minutes 2075F with a 10 minute equalization at 1450F.

 

[Larrin]

Temper it first and then see.

 

[Charlie Mike]

Temper it first and then see.

What temperature would you suggest? I'm gonna try 1050F.

 

[butcher_block]

M2 shouldnt need parks and woudl likly crack are you sure thats the right steel. if your at 2075 soaking 10-15 min will get more alloy into the mix would also help with the 2nd hardening curve (i cryo and 400f temper my high alloy steels ) when i plate quench from proper temp and cryo before tempering im always with in a point of what the data sheets are calling for

 

[rodriguez7]

This is my recipe for M2, 2050 by 30 minute soak, plate quench, then into cryo, 30 minutes to 10 hours, your choice, temper 3 times at 400 degrees gets me 61-62 rc.

 

[Charlie Mike]

M2 shouldnt need parks and woudl likly crack are you sure thats the right steel. if your at 2075 soaking 10-15 min will get more alloy into the mix would also help with the 2nd hardening curve (i cryo and 400f temper my high alloy steels ) when i plate quench from proper temp and cryo before tempering im always with in a point of what the data sheets are calling for

Thanks, I'll try that on the next piece.

 

[Charlie Mike]

BTW, I don't have deep cryo... I make do with dry ice and 91% alcohol for 12 hours.

 

[rodriguez7]

Y

I've tried following the instructions on the crucible site and only reached 56-57 as quenched in parks50. Austinizing temp was 5 minutes 2075F with a 10 minute equalization at 1450F.

your soak was to short, try my recipe above, and let me know how it goes! I use frozen quench plates too, about 10-40 seconds between the plates is good, then take them out of the foil and air cool, then into cryo, or dry ice slurry.

 

[Charlie Mike]

Also... Do you preheat/equalize at 1100 and 1450 before you ramp to 2050 soak?

 

[me2]

I think that 5 minute soak assumes you are using a salt bath.

 

[Stacy E. Apelt - Bladesmith]

BTW, I don't have deep cryo... I make do with dry ice and 91% alcohol for 12 hours.

I don't know how you maintain a dry ice bath for 12 hours? It only needs a few minutes, anyway. All the dry ice bath does is reach the Mf ( or as close as it will get). Once there nothing else happens. I would get it into the first temper as soon as it warms up to room temp after a 15 minute soak in the dry ice bath.

 

[Charlie Mike]

Kept in my freezer.

 

[rodriguez7]

Also... Do you preheat/equalize at 1100 and 1450 before you ramp to 2050 soak?

I don’t, I let my oven get to 2050, let it settle for a while, then put the blades in, when it comes back to 2050, start my timer for the 30 minute soak. I’ve heard conflicting things on the preheat, I remember Nathan saying it doesn’t do much. And I’ve been getting good results like this. Edge retention is great, and I’m really surprised by how tough M2 is, considering I’ve heard it’s a brittle steel. It really is not!!

 

[butcher_block]

might be why i have lower soak times i full speed to 1500 hold 5 then full ramp speed to target temp. i hold XHP for 20min and im sure it gets plenty of time to let alloy to do its thing

 

[Charlie Mike]

66 as quenched... Thanks!

Warped a bit but I'll straighten on the 2nd temper.

 

[Nathan the Machinist]

The problem with the Evenheat ovens I've used is they're not particularly even with their heat, they create hotspots. This was due to exposed coils and coils in the back and not at the door.

So, in my opinion you should not have your work in them when they ramp up because they'll burn it in spots.

My process with an Evenheat at 2050 would be:
preheat oven empty at 2150 (100 over temp) and let it soak a while
turn it off, open the door, put your work in
close the door and turn it on and switch to the next program set at 2050

When you get your timing right the oven comes back on pretty close to the desired temperature and doesn't spend much time in ramp up. This approach minimizes time spent with the coils blazing on the work, but obviously precludes the use of a pre-heat (unless you have two ovens).

Preheat is important on tool and die where there are complex sections, thin and thick, that go through different phases at different points and can cause distortion. It's not just thermal growth, the transition from BCC to FCC comes with some dimensional changes. The steel is quite soft at these temps so if the transition is done too suddenly these dimensional changes are enough to yield the metal which will results in distortion in the tool and die work. That kind of harm is totally preventable and unnecessary for tool and die, hence the use of preheat is industry "best practice". But except for things like integrals it's not particularly applicable to most knives, so I recommend skipping the preheat if you're using an Evenheat because the harm from having your knife in the oven while it's changing temperatures outweighs any benefit, IMO.

 

[Natlek]

The problem with the Evenheat ovens I've used is they're not particularly even with their heat, they create hotspots. This was due to exposed coils and coils in the back and not at the door.

For the last few days I've been reading a lot about HT oven .Many things still are not clear to me , mostly because of that English is not my native language ...BUT I know this now .In most commercial HT oven for best control and computer operation , single thermocouple has been located at the hottest known point in the area..... Installing the internal fan would correct this problem .Most of the industrial and lab.oven have fan..... ?? They call it forced convection....