we would like to weld 415 martensitic stainless steel(UNS S41500). can anyone suggest what filler material cand be used to get almost equal to the base metal strength and there is no scope of PWHT.
What C level is your material?
You may not be able to use no-PWHT as it could be very brittle in the HAZ.
If the material is normalized (and not Q&T) you might get away with a lot of preheat.
The Ni will help some with this.
There are fillers with Ni in them but be careful.
If the Ni is too high it will lead to retained ferrite, which will later revert to un-tempered martensite.
In Europe I have seen a 410Ni (or 410NiMo).
This will take some serious qualification testing to assure that you have serviceable welds.