Quenching 1084: How low can you go?

[E.Carlson]

I just finished the HT on a batch of small 1084 blades. As I was quenching the last one, I realized I was running my program for 15N20. I do my 15N20 at 1465. (I've got the flu and probably shouldn't be messing around out there anyway)
Now it's not a big deal to redo the quench, at 1500, but I ground a few clean and I'm getting consistent 65hrc.
Does anyone else run their 1084 at lower temps like this? Kevin Cashens site mentions not over 1500, but what are the risks of running on the low side.
Couldn't find a chart on Larrin's page.

 

[DevinT]

You should be fine. I think you can get peak hardness from as low as 1350-1375’f. With all steels there is a sweet spot where you get peak hardness and peak toughness. Too low or too high and you lose toughness. You’re probably very close to the sweet spot.

Hoss

 

[E.Carlson]

Yeah, everything looks pretty good on all the blades. Gets me thinking, a lot of pattern welded steel is 15n20/1084. What temp do you Damascus guys use? 1475 ish?

 

[Willie71]

I typically use 1475 with 1084. I get Rc66/67. I’ve used 1450 going for a hamon. Still got Rc65/66. No better activity on the hamon though.

 

[Stacy E. Apelt - Bladesmith]

1465°F for 1084 will be fine.

 

[Willie71]

Yeah, everything looks pretty good on all the blades. Gets me thinking, a lot of pattern welded steel is 15n20/1084. What temp do you Damascus guys use? 1475 ish?

I’m no expert on Damascus, but with my W2/15n20, I used 1460f, and got Rc67 out of quench. With my 1084/15n20 billet coming up, I will use 1470f. 15n20 like 1460-1470f in my shop. W2 likes 1460f, 1084 likes 1470-1480f. 1450-1500f will all work, but the middle is the sweet spot.