The invention relates to a high-performance non-quenched and tempered
steel bar for a fan shaft and a manufacturing method of the high-performance non-quenched and tempered
steel bar, and belongs to the field of iron-based alloys. The steel comprises the following chemical components in percentage by weight: 0.37 to 0.43 percent of C, 0.30 to 0.60 percent of Si, 1.20 to 1.70 percent of Mn, less than or equal to 0.025 percent of P, 0.030 to 0.070 percent of S, less than or equal to 0.50 percent of Cr, 0.10 to 0.30 percent of Ni, less than or equal to 0.30 percent of Mo, less than or equal to 0.30 percent of Cu, 0.010 to 0.030 percent of Al, 0.005 to 0.025 percent of Ti, 0.05 to 0.15 percent of V, 0.0100 to 0.0200 percent of N, less than or equal to 0.0002 percent of H, less than or equal to 0.0015 percent of O and the balance of Fe and inevitable
impurity elements. The manufacturing process comprises the steps of converter / electric furnace
smelting, LF furnace refining, RH / VD furnace vacuum degassing,
continuous casting,
casting blank reheating, cogging rolling,
flame cleaning, intermediate blank finishing, intermediate blank heating, bar rolling, cooling and
stress relief tempering. The total cross-section structure of the bar is a ferrite and
pearlite structure. The bending degree per meter is smaller than or equal to 0.5 mm, the surface defect depth is smaller than or equal to 0.10 mm, and the
internal quality meets the A-level requirement of the GB / T4162 standard.