Trouble Heat Treating Baker Forge Bronze SanMai


I bought a very expensive piece of Bronze SanMai from Baker Forge. It is made with bronze and 80CRV2. I followed their heat treat instructions to the "T" and I am unable to get it past 50 HRC. I have Paragon Knife Kiln that is very stable. I also have an oil heater for my quench oil with a temp control. I am using Parks AAA as recommended. I tempered the blade at 320 for two 2 hour cycles.

I have made sure to remove all the scale from the blade and I'm testing a nice clean spot. I've tried to avoid setting the diamond on my Rockwell tester on anything that looks like bronze.

Here are their instructions...any ideas? I emailed them and they said I should be able to get 58-59 HRC with no problems.

For Billets with 80crv2 Cores:
  • Normalize at 1600F, 1500F, and 1400F letting cool to black between each cycle.
  • Heat to 1550 F
  • Hold for approx 10 mins for "knife blade thickness"
  • Quench in warm quench oil (not Canola) 86 F-122F
  • Temper immediately for 2 hours, cool in water and temper for another 2 hours
Just curious if you ever figured this out? With the San Mai and Cu Mai type stuff, I wonder if the layer of the softer metal throws off the indenter by cushioning it, even if you ground a spot to the 80CRV2 core.
Chris, I remember when you first posted the question and planned to follow the responses, but it seems to have fallen by the wayside.

A question, the billet you mentioned, what is the cladding metal? The core metal is what's of concern when HT'ing. Larrin responded that the cladding (with copper, 416 SS, etc) wouldn't affect the core HT. Just HT for the core and don't worry about the cladding was his advice.
I have been able to test a couple of places that I felt were as far from the copper as possible. I have been able to get a reading of 57 HRC. I've just decided to settle for that. I did follow the recommended heat treat from the web site. The knife itself has actually fallen by the wayside due to other projects. I hope to have it finished and tested soon...

My uncle wants a Bowie knife and my dad wants an 8" chef's knife so I'm working on those. My uncle is 84 this year and I want to get his Bowie knife to him ASAP so he can enjoy it!
Be sure you post photos of them when finished - we LOVE to see knife photos:)

where you tested the core, was it parallel sides? Remember when there's an angle the Rc isn't as accurate as it could be. Testing the core has always been an issue with me in San Mai billets. Larrin said if you wish to know the core Rc, test a coupon of the core steel. He says it will be the same whether it's got cladding or bare.