I know this is not what you asked for but some of it apply's to your question and some of the rest might be helpful also.
This could be someones opinion, or he could know what he is talking about.
Lots of welders figure that a E7018 etc. has 70ksi TS so its stronger than the base material. Strength has nothing to do with it. Using welding / joining electrodes for buildup is a bad idea because E7018s, E71T-9 cored wires etc have little compressive strength. Take a MIG, E7018 weld and beat it with a chipping hammer. Now try that with a proper alloy buildup deposit
This can cause any hard facing over the so called buildup to spall off as the buildup mushrooms flat . This might not matter for if your blade sees ZERO pounding / impacts but this is seldom the case. Bottom line you are wasting time with E7018 etc.
ROLLERS - you need a "Metal on Metal" product. This is typically a martensitic tool steel. Typically in the industry ( ie Caterpillar specs ) calls for products approximately 40Rc to 55Rc . If you need more than 3 layers of hard facing to bring part to proper dimension then use a "build up" product for the first few layers .
Typical products would be Lincore 40 or Lincore 55 ( Not lincore 50 ). These are LA Martensitic products
Now for the 2nd most common wives tale on hard facing: Hardness is the important spec. Truth is it does not tell you everything. Because of this do NOT walk into a welding supply store and just ask for XX Hardness
For example: all the following popular hard facing products can be 55Rc
1. Low Alloy Martensitic - great for metal to metal sliding wear ( wheels / idlers / gears / shafts
2. Austentic Manganese - great for severe impact. You find these products on railway frogs , build up prior to hard facing , hammer parts
3. Chromium Carbide - probably the most common . This is typically what you think of when you think hard facing. Very good performance with abrasion ( dirt / sand / wood ) . Poor impact resistance, somewhat poor metal to metal performance
Best choice for this application is a chromium carbide in the 50Rc range . Lots of people also go up to the next level 60Rc for blades but it will not take impacts very well. No need for a buildup / buttering layer if you only need 1/4 "
Typical product would be Lincore 50 ( NOT Lincore 55 ) or Lincore 60 or equivalents . These are chromium carbide products
I also assume your welder knows to only hard face the one side of a cutting / bucket edge ( so it will continue to self sharpen ).
Don't even think of using MIG / E7018 etc