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本文通过硬度值测定和平板冷弯P-f曲线估算K_(IC)值,筛选出15CrMnMoV钢板材“预时效+冷轧+终时效”的最佳强韧化工艺参数为940℃×25分+550℃×90分+冷轧(55％～75％)+580℃×90分。板材断裂韧度标准测试方法(表面裂纹法)的实测结果表明,由平板冷弯P-f曲线估算的断裂韧度K_(IC)~b和表面裂纹法实测K_(IC)对冷轧形变率、时效温度和时间的变化规律基本一致。特别在时效温度高于550℃时,K_(IC)~b值与K_(IC)值非常接近;时效温度低于550℃,由于P-f曲线上裂纹失稳扩展的开始点P_1很难准确确定,使K_(IC)~b值的计算偏离K_(IC)值较大。
In this paper, the K_ (IC) value was estimated by measuring the hardness value and Pf curve of flat cold-rolled sheet. The optimum toughness parameters of 15CrMnMoV steel sheet pre-aging, cold-rolling and final aging were 940 ℃ × 25 ℃ + 550 ℃ × 90 minutes + cold rolling (55% -75%) + 580 ° C × 90 minutes. The measured results of the standard test method (surface crack method) of the plate fracture toughness show that the fracture toughness K_ (IC) ~ b and the actual measured K_ (IC) The law of temperature and time are basically the same. Especially when the aging temperature is higher than 550 ℃, K_ (IC) ~ b value is very close to K_ (IC) value. When the aging temperature is lower than 550 ℃, the starting point P_1 of crack instability propagation on Pf curve can not be accurately determined. So K_ (IC) ~ b value deviation from the K_ (IC) value is larger.