Can a laser welding machine penetrate a weld of 10mm stainless steel?
This paper from Hunan University in Changsha illustrates 12mm penetration welding of stainless steel using a 10kW fiber laser and shielding gas supplied both sides.
There are also references to other papers, generally with higher powers available. I didn't look at them. In any case, it appears 10kW should be sufficient for 10mm SS.