Laminated Hitachi White 2, iron sides hardened?

[JWhobbyist]

Weird situation. First time using laminated Hitachi White #2 billets. 1 mm white #2 between 1.5mm iron layers. Profiled blanks were heat treated by Petersons. Went to break the sharp edges of the bevels before grinding and a file just skates off, which should be soft iron. Thought maybe a hard oxide surface and ground off most of the surface and a file still skates off. I'm confused, because the iron outer layers shouldn't harden, no matter how it is heat treated.

Has anyone experienced this?

Also, I sent some unlaminated white #2 blanks to Petersons for HT at same time, but I wouldn't think that would affect anything.

 

[Stacy E. Apelt - Bladesmith]

Are you sure you aren't checking the white #2 blades?

I have used lots of those Hitachi core billets. I can't say that I ever tested the iron post HT, but it grinds and etches as soft.
A file can fool you sometimes. Grinding will tell if it is soft or hard.
Grind the bevels and see what you get.

 

[JWhobbyist]

Thank you for your response. It definitely is a laminated blank. I just spent some time grinding and it grinds as hard. Similar to hardened O1 and definitely harder than the unheat treated blanks which I also did a lot of file work on. I'll proceed with the bevel grinding as I'm not sure I can do anything about it.

 

[Stacy E. Apelt - Bladesmith]

You may have a layer of hard scale or such to get through. Soak the blade in Sodium Bi-sulfate pickle overnight and it may file/grind easier. Ph-Down is what to use. 1 cup Ph-down to a gallon of H2O is a good mix for stripping scale. Remember, this is a strong chemical and use proper safety around it.

I keep 3 gallons of it in a dry-wall bucket and close it tightly when not in use. I soak forged blades to remove scale before grinding. On carbon steel blades I give them a couple hour soak after tempering to remove any oven scale. After rinsing well, a scrub with a Scotch Brite pad or wire brush cleans them right up.