There is no P-No for this material. The ASTM A 355 is a Standard specification for Steel Bars, Alloys for Nitriding.
What exactly are you doing? You have a low alloy, moderate hardenability steel that can be surface hardened by induction or nitriding, and you want Stellite deposited on the surface??? If you need Stellite hardfacing, I would select a more suitable alloy that has better weldability.