采用Gleeble-3500热循环模拟试验机研究了PQ700热轧高强钢铸坯表面温度为800~1200益时温度波动对第二相粒子析出的影响,并利用Thermo-calc热力学软件计算PQ700连铸过程中第二相粒子的析出规律。结果表明：温度大于1050益时,由温度波动引起的析出物尺寸变化明显；温度小于900益时,由温度波动引起的析出物数量变化明显；Nb的含量变化对析出相( Nb,Ti) C摩尔分数影响较大；Ti的含量变化对析出相Ti( C,N)有很大影响。
Influence of temperature fluctuations on the precipitated second phase was studied by using a Gleeble-3500 thermal simulator, when the surface temperature of PQ700 hot rolled high strength steel slab is from 800 to 1200℃. Precipitation of the second phase particles of PQ700 in the continuous casting process was calculated by using the thermodynamic software Thermo-calc. The re-sults show that when temperature is more than 1050℃, precipitate size caused by the temperature fluctuations changes significantly. When temperature is less than 900℃, the number of precipitation caused by the temperature fluctuations changes significantly. The change of Nb content has a great influence on the mole fraction of ( Nb,Ti) C. The change of Ti content has a great influence on the mole fraction of Ti( C,N) .