Any kind of welder / weld will do. I have used stick, mig and tig....and they all do fine. Remember to clean/ grind the surfaces and keep them flat.
Temperature is the same as any other weld ...1200/1300 degrees celsius. After the first weld I keep the billet at forgewelding temperature for 10 - 15 min. ....To ensure proper bonding.
as you will notice from the pictures ...the scale is different from plain carbon steel and the activity in the laminated steel depends on the kind of stainless used. 316 stainless gives almost no activity ...while 400 series ( 416, 420, Ae