It is not recommended that you use it to cut steel chains, because steel chains usually have a quenching hardness of around HRC40. If it is not quenched, it can be cut.
Handheld Rebar Cutter RC-22 w/Box, Steel Bolt Chain Cutting tool* cutter blade broke second cut on 3/8 chain. Are there replacement blades, and do you have anything to cut Gr 70 chain?