Noticed something on an old Collins

[AR fan]

When I was cleaning/smoothing up a Collins I just bought I noticed a faint line. It isn't cracked, it's just a faint line from side to side about 3" back from the edge.
I am thinking its a quench line from the tempering procedure.
Has anyone seen this before?

I am pointing with my thumb at the mark.

 

[Bushman5]

that might be where the old coating stopped. IE: on my iltis there is black coating and then smooth blade.

 

[cherokee tj]

That's indeed the temper line. I can see this same temper line on a lot of my old axes.

 

[AR fan]

Thanks for the info, I really appreciate it.
This is a great site, alot of helpful people here.