The set is store brand of Lowes called Kobalt, made in China. What isn't these days!!
Stuff that works and meets our expectations.
It would not surprise me at all if the dies where just carbon steel. "Kobalt" is meaningless Chinese nonsense that tells you nothing about the steel. If they are not at least "High Speed Steel" they are junk and even if they say they are, they probably are not.
Here is a good example of Chinese junk as it relates to steel.
About six months ago I decided to use my listening half of our reading hour to exercise my forearms using those wooden handled springs that have been around since men started doing exercises.
I have broken 3 sets of these since I started. That is, 6 Chinese springs just snapped when squose too many times. It's pretty scary to think that they can not make something as simple as a spring when you consider all the stuff we buy from them.
About two months ago, my wife found a pair made in Taiwan and they will probably last forever.
No matter what the diplomats say, Taiwan is not China.
js