Abstract: During performance testing of 6200 mm YG1900 ultra-high strength steel produced by 6 t VIM + 6 t VAR double vacuum process smelting + forging material process, the uneven performance is found. In this paper, the scanning electron microscopy and electron probe analysis are carried out on the microstructure of samples with uneven performance, the result shows that the segregation of carbides in structure caused by the segregation of W and Mo is the reason of uneven performance. After conducting a series of measurement by reducing the melting rate of vacuum consumable smelting from 4 ~ 5 kg/min to 3 ~ 4 kg/min, increasing the homogenization temperature of forged steel ingots from I 200 ~ 1 220 °C to 1 230 ~ 1 250 °C , and increasing the total forging ratio of forging production increased from 24 ~ 30 to 50 〜56, the problem of uneven performance of YG1900 ultra-high-strength steel is improved after process improvement.

摘要： 6t真空感应+6 t真空自耗双真空工艺冶炼+锻造成材工艺生产的Φ200 mm YG1900超高强度钢,在性能检测时发现性能指标有离散现象。本文对性能指标离散的试样显微组织进行扫描电镜及电子探针分析,结果表明:由于W、Mo偏析使组织中碳化物偏聚是导致性能指标离散的原因。将真空自耗冶炼熔速由4～5 kg/min降低到3～4 kg/min,锻造钢锭均质化温度由1 200～1 220℃提高到1 230～1 250℃,锻造生产总锻比由24～30增加到50～56,通过工艺改进后改善了YG1900超高强度钢性能指标离散问题。