wondering how the hardness of 7018 rod compares to various U/C parts?   Chain, bushing, rollers, idler, sprocket etc? any contact/wear points?
-Rockwell numbers etc..?
-experiences?

all 7018 is a low hydrogen electrode. its reasonably tough. there is some info in the mebers library about reclaiming rollers etc by welding and it does specify types of electrode.

heres some data about reconditioning by welding.
 

any of the soft hardface electrodes so abrasicord 600 etc

thank you Trainzkid88....yes there's loads of information in those conservation manuals...anything is possible with time and effort (sometimes you have to give up flogging a dead horse though)
-was mainly looking for personal experiences with regards to wear and toughness of rebuilding with 7018 etc..?
-and the Rockwell Number of 7018...if anyone has references...or ?

www.google.com/search?client=firefox-b-1...kwell+Number+of+7018

it's just high grade mild steel and isn't wear resistant. you need to use a proper wear compound rod. you can however use it to build up worn areas before doing a outer layer of wear rod.(thus you can save material cost as hard face alloy isn't cheap)

this is known as buffering its often done with stainless steel rods for the more difficult hard-facing alloys as they wont bond well to certain steels but a stainless alloy will and they bond well to that.

you super maintenance rods aka "weld alls'' are all based on stainless steel.

yes sometimes the labour is simply to costly to recondition the parts. and after market parts are the answer. but it depends are you doing the work yourself? is it on a "working" machine or is it retired and what price do you put on your time.