What kind of steel are these lathe chisels?

[Chuck Wintle]

I have a set of marples lathe chisels. On the box its marked M1002 made in sheffield England. How can I determine what type of steel they are manufactured from?
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[Myk Rian]

I believe it's called Sheffield steel.
Sort of a secret recipe.

[Joe Angrisani]

What did Marples say when you contacted them? No better place for that info than the horse's mouth, unless you want to pay for analysis/Rockwell testing.