Hey thanks and yeah I do have a very good understanding of hardening tempering and annealing processes through my welding journey I don’t have much time to reply to this so I am just giving a quick skim over and those planer blades are quite possibly carbide most I have encountered have been I know I am just restating what you already know but it never hurts to be reminded since things are forgotten I am a prime example of that I will read over more later today and again thanks!
And I do have a decent understanding of identifying scrap steel for properties whenever I get a new larger price of steel I always go through and test harden it in water and oil and test different temper colors