Here's the deal - it MUST!! be an oxygen free weld, and there can be absolutely NO oxidation/coloring on the steel.
Even if you have a slight little bluing from heat - it won't weld in that spot.
What I'm saying is, a person might be able to weld up a "can" with the right welder, but I only have a stick welder, which means that you'd get the billet so hot and discolored, that you wouldn't get it welded. Make sense?
So, I just go around the perimeter with a 3/32 rod and make random little tiny weld 'dots' here and there to hold it together.
Then it goes in a double layer wrap of high temp stainless steel heat treat foil, into which has been placed some paper to eat up any oxygen while it's getting hot.
It soaks at welding heat - around 2200 - for 20 minutes.
Then into the press with big dies so it hits the entire billet in one press.
Hold 10 seconds.
Back in the forge to 2200 and soak 10 minutes.
Back into the press dies for a 10 second squeeze.
Then remove foil - which is a pain.
Grind edges until any un-welded areas are removed.
Draw out and then thermal cycle billet before making knife.