Most chainrings are made out of aluminium and we've always used these are they are the most common. A few years ago we stumbled across a Raceface steel ring in the sale and thought we'd give it a go. RRP is $19.99 or around £25. We have used this ring now for about 2.5 years and covered around 5000 miles on it.
It looks identical to the ali version.
It performs identically to the ali version.
We previously had an identical RF cinch ring on the bike, and got around 2000 miles / 1 year out of it. This has been roughly in line with the lifespan of other chain rings we've used from Shimano and FSA. The fact that the steel version is still going heading on towards 3 years is impressive. It is starting to show wear now, and we doubt it'll go another full year but its still got life in it, and we've not had it slip. It's performing as well as it was when it was brand new.
So what's the catch? Weight? The 32t steel ring comes in at 158g with the ali version around 70g. Whilst that is more than double the weight, it's double what is a very insignificant amount. The ali version RRP is $67.99 or about £55 so more than double the cost for something that lasts around a third of the time. Throwing 3 or 4 ali rings in the bin for every 1 steel and paying ~£200 compared to £25 for a steel for the same time period means that we won't ever be using ali rings again. If you are really bothered about weight you can use the money saved to make bigger gains elsewhere. Environmentally and economically it just makes no sense to use ali rings. Off the back of this we have recently purchased a full steel cassette which will be start testing soon.