Abstract: The test steel (/% ： 0.24C, 0. 01 Mn, 0. 06Si, 0. 001S, 0.002P, 13.42Co, 11.32Ni, 3.05Cr, 1. 18Mo, 0. 015Al, 0. 015Ti) Φ300 mm bar is forged with 3 times upsetting and forging-out from Φ600 mm ingot melted by 6t vacuum induction furnace + vacuum arc remelting process and annealed at 650 ℃ for 20 h (grains rating 6. 0). The effect of temperature (900 ~ 1 200 ℃ ) forging the Φ300 mm bar to Φ250 mm bar (deformation 30% ) and conditioning heat treatment (normalizing at 860 °C and 900 °C) on grain size of steel has been tested and studied. Results show that with forging at 1 000 ~ 1 140 °C and deforming 30% , the steel has fine and complete recrystallization grains (rating 7. 0). With normalizing at 900 °C the steel has homogeneous and fine grains (rating 7. 0).

摘要： 实验钢（/%:0.24C,0.01Mn,0.06Si,0.001S,0.002P,13.42Co,11.32Ni,3.05Cr,1.18Mo,0.015Al,0.015Ti）为6 t真空感应炉+真空自耗熔炼的Φ600 mm锭经3次镦拔锻制的Φ300 mm钢棒,并经650℃ 20 h退火处理（晶粒度6.0级）。实验研究了Φ300 mm钢棒至Φ250 mm钢棒（变形30%）的锻制温度（900~1 200℃）和预备热处理（860℃和900℃正火）对钢的晶粒度的影响。结果表明,锻造温度1 000~1 140℃,变形量30%时可获得细小的完全再结晶晶粒（7.0级）。900℃正火处理该钢可获得均匀细小的晶粒（7.0级）。

关键词: 超高强度钢23Co-Ni, 锻造, 温度, 变形量, 预备热处理, 晶粒度