In terms of purely the material, 4140 can be through hardened and surface hardened to give a high impact and decent wear resistant part.
I need to maintain the same impact strength or close to it and purely increase wear life. Cost is still a consideration and even small baby steps would help...
The reason 4140 was used was purely availability. I have looked at some higher chrome but haven't looked at NiHard. Is this a readily available material? I looked it up and it is known for wear resistances and can be heat treated to 700 BHN. Of course I don't need it that hard but the wear...
I am working with a product which is investment casted of 4140, through hardened to 400 BHN and surfaced hardened to 550-600 BHN. All kinds of abrasive material impacts and wears down my product as the system processes it.
Examples include: 6" minus material; Rock, broken glass, dirt(compost)...