Is E52100 steel the same as 52100 chrome steel?

There appears to be a single specification for 52100 steel; SAE would not likely use the same number for two different steels. Carbon 0.98 - 1.1 Chromium 1.3 - 1.6 Iron Balance Manganese 0.25 - 0.45 Phosphorus 0.025 max Silicon 0.15 - 0.35 Sulphur 0.025 max from a supplier website. We don't use or specify this one ourselves, so have no personal knowledge. C.J.