Temperture of 3000 PSI steam?

Answer 1

Looking at the phase diagram of water,
at 3000 psi (~20684 kPa, ~2.1 E6 Pa), water can exist in the vapor phase at rougly any temperature at or above 500 Kelvin (rough estimate based on graph).

There is no one specific, constant, temperature of steam at a given pressure.

Answer 2

According to my steam table, 3000 psia steam has a temperature of 695.36 degrees F. It of course can be super heated above that temperature, but at saturation it is 695.36 degrees.