Interesting/disturbing heat treat instance

[Danbo]

Just got a few blades back from Paul Bos. They were all A2(4 were Greco blade blanks that I reprofiled and flat ground, and 3 were ground from precision ground A2 stock.) The 4 ground from the old Greco blanks heat treated fine, but the other 3 were wrapped together along with a little note from Paul. The note said that these 3 blades were not A2, and that he suspected they were 300 series stainless and only Rockwelled 20!

I distinctly remember taking the wrap off the precision ground A2 stock. It was 1/8" thick and 1" wide. I'm really confused about this. If these blades were NOT A2, and were heat treated as A2, say they were an oil hardening steel. Wouldn't they get harder than 20 Rockwell? This brings up the question of how to find out exactly what these blades are. I have never bought any 300 stainless barstock, so if they are 300 stainless, somebody must have mislabled the precision ground stuff I bought. Pretty big mistake, don't you think?

 

[Mike Hull]

If they are 300 series SS, they won't harden at all, no carbon in it.

Try a magnet. 300 series SS is non magnetic. Also try some cold blue. It shouldn't take if they are SS.

Mistakes are not at all uncommon in the metal supply field. The person taking the order may know all about steel, but that doesn't mean the person filling the order does, or even cares.

Hope you get this resolved.

 

[Danbo]

Well, I'm pretty sure the're magnetic, as I always use a magnet to hold them against my flat platen(to correct any grinding mistakes), and I'm sure these were no exception. But, I don't have the blades here with me, so I will check them tonight when I get home.