You don’t indicate what lengths you are starting with and cutting off.
Yes, the above will do the job easily, but at some cost.
Other options:
I would have thought that a mini lathe might well part-off near to 40mm diameter.
Suppliers will often supply in required lengths (likely with a cutting charge, of course).
A small, second hand power hacksaw might well be another option to consider.
An angle grinder is yet another, at least for the lesser diameters (can do the wider cuts by turning the bar).
I used to use my 115mm ‘bodge’ angle grinder, mounted in a frame for cutting purposes. One/two millimetre thick cutting discs are available for the purpose.
You are not going to alter the metallurgy cutting mild steel. Other materials could be…