Clearly an angle grinder would be one of the best tools to cut a 16 mm hardened steel. But my budget is limited.
If I had to use a hacksaw, could anyone recommend a blade? Would it be better to use 14 TPI or 24 TPI?

More importantly, how long does it take to cut through? Like 10 minutes? or 60 minutes?

P.S. I lost my keys to my bike lock recently.