真空时效加热到温时间滞后现象对FV520B钢组织及性能的影响

通过对FV520钢真空热处理温度实时跟踪,分析了不同加热温度下到温时间滞后的情况,并研究了在600 ℃时效温度下不同保温时间对显微组织及力学性能的影响。结果表明:真空炉加热到温时间滞后的现象随着加热温度的降低,滞后时间随之延长;FV520B钢在真空时效保温初期时,由于心部温度尚未达到加热设定的温度,随着保温时间的延长,显微组织发生较大转变,残留奥氏体含量增加,沉淀相逐渐析出;屈服强度随保温时间的延长而降低,冲击吸收能量随着保温时间的延长而增加;可以通过真空炉电能消耗判断工件是否均温,可用于指导热处理工艺参数的制定。

Effect of heating arrival time lag on microstructure and properties of FV520B steel during vacuum aging

By real-time tracing of vacuum heat treatment temperature of FV520B steel, the heating time lag at different heating temperatures was analyzed and the effect of different holding time on the microstructure and mechanical properties aging at 600 ℃ for different time was studied. The results show that the time lag of vacuum heat treatment increases with the decrease of heating temperature. In the early stage of vacuum aging of the FV520B steel, due to the time lag, the temperature in the workpiece core does not reach the set heating temperature. With the extension of the holding time, the microstructure changes greatly, the content of retained austenite increases and the precipitated phase gradually precipitates. The yield strength decreases and the impact absorbed energy increases with the prolongation of holding time. The power consumption of vacuum furnace can be used to determine whether the workpiece temperature is uniform, which can be used to guide the design of heat treatment process parameters.