Abstract: The production process flowsheet of wind power gear ring of steel F42CrMo4 is hot metal-100 t EAF-LF- VD-Φ500 mm CCM-slow cooling-forged to Φ2000 ~ 3900 mm ring forgings. The analysis on sampling at wind power gear ring defect region by ultrasonic positioning shows that the main causes for some batch of wind power gear ring of steel F42CrMo4 unqualified by detection test are aluminum oxide inclusions and porosity defects of casting bloom. With the process measures including controlling EAF end carbon >0. 15% , the end point of LF was fed with 0.5 kg/t calcium wire, and after fed with calcium, argon was blown soft >10 min, after VD the argon blowing rate increasing to 2 X30 L/min from original 2x25 L/min, and controlling liquid super-extent 10 ~ 18 ℃，the nitrogen, hydrogen and oxygen content in steel decrease respectively from ≤80 x 10^-6, ≤ l. 5 x 10 ^-6 and ≤ 20 x 10^-6   to ≤ 75 x 10^-6, ≤ 1.2 x 10^-6 and ≤ 15 x 10^-6 and the detection qualified rate of forgings increases to more than 98.95%.

摘要： F42CrMo4钢风电齿圈的生产工艺流程为热装铁水-100 t EAF-LF-VD-Φ500 mm CCM-缓冷-锻制成Φ2000～3900 mm环形锻件。对探伤不合格的风电齿圈缺陷部位运用超声波进行定位取样,分析表明,氧化铝类夹杂物以及铸坯疏松缺陷,是造成部分批次风电齿圈用F42CrMo4钢探伤不合格的主要原因。通过控制电弧炉终点碳≥0.15%,LF终点喂钙线0.50 kg/t,喂钙后软吹氩≥10 min,VD后氩气流量由2×25 L/min增加至2×30 L/min,控制钢水过热度10～18℃等工艺措施使钢中氮、氢和氧含量分别由原≤80×10^-6、≤1.5×10^-6和≤20×10^-6降低到≤75×10^-6、≤1.2×10^-6和≤15×10^-6,锻件探伤合格率提高到98.95%以上。