The increase of temperature of the steam at a constant pressure beyond the dry saturated state is nothing but superheating.
Let's understand superheating using T-s (Temperature-entropy) plot.
Above figure shows T-s plot, vapor dome, and constant pressure lines.
At x=0 the point on constant pressure line represents the saturated liquid point and at at X=1 the point on constant pressure line represents the saturated vapor point.
The liquid gets completely converted into steam at X=1 point in boiler of rankine cycle.
If the steam is further heated beyond saturated vapor point the steam gets superheated.
As shown in the figure the steam is superheated between points 3 and 3' at constant pressure.