Says it is stainless from Carpenters.
From Carpenters website
CTS® XHP
CTS® XHP alloy is a powder metallurgy, air-hardening, high carbon, high chromium, corrosion-resistant alloy. It can be considered either a high hardness 440C stainless steel or a corrosion-resistant D2 tool steel. CTS® XHP alloy possesses corrosion resistance equivalent to 440C stainless steel and can attain a maximum hardness of 64 HRC and a minimum hardness of 60 HRC when air cooled from hardening temperatures of 1850 to 2000°F (1010°C to 1093°C), making it more forgiving during heat treatment than similar alloys.
TYPE ANALYSIS
Carbon (Maximum)
1.6
Silicon (Maximum)
0.4
Nickel (Nominal)
0.35
Manganese (Maximum)
0.5
Chromium (Nominal)
16
Molybdenum (Nominal)
0.8
Iron (Nominal)
Balance
Vanadium (Nominal)
0.45