Good to post your location in your profile as that may help in the way members answer your posts.
I used to make cutters with drill rod to cherry and low red and then quench.
I think drill rod and silver steel are the same things and they get through hard/ not case hard.
But there are different kinds of drill rod, air , oil and water hardning. A-2, 01 and W-1 and perhaps other kinds..
Silver Steel is a UK description, evidently out in the colonies it's likely the same stuff