I'm looking to manufacture roller chain sprockets from cast iron instead of mild steel.
1. Is doing this technically beneficial?
2. Will the life of sprocket be same as that obtained from mild steel?
The main reasons for swithcing over to cast iron are my ease to access to cast iron and cost considerations.
Sprockets have been made from cast iron for ages. There are a lot of different "flavors" of iron out there and many will hold up longer than mild steel. Higher carbon steel might be a wash for durability but with the cost of more chain wear. The load on the system will be a factor in making your material selection as well.
The cast iron graphite nodules act as a lubricant on the chain and reduces wear. To fully attain the benifits of the graphite nodules you should allow stock in your casting for machining of the sprocket teeth. This will expose more of the graphite than an "as cast" condition. You need to peel a little of the bark off to expose the graphite.