Forging heat-resistant steel and its manufacturing method, and manufacturing method forged parts

The present invention provides an embodiment of the forging heat-resistant steel, wherein the mass percent basis, C: 0.05 ~ 0.2, Si: 0.01 ~ 0.1, Mn: 0.01 ~ 0.15, Ni: 0.05 ~ 1, Cr: 8 or more and low to 10, Mo: 0.05 ~ 1, V: 0.05 ~ 0.3, Co: 1 ~ 5, W: 1 ~ 2.2, N: 0.01 to less than 0.015, Nb: 0.01 ~ 0.15, B: 0.003 ~ 0.03, remainder comprising Fe and unavoidable impurities.