本文用定量金相法研究了第一道轧制(初轧)压下率及终轧温度对轧后奥氏体晶粒平均直径及铁素体晶粒平均直径的影响。结果表明,轧后奥氏体晶粒平均直径随第一道轧制压下率增加而减小,随终轧温度降低而增大;轧后铁素体晶粒平均直径随第一道轧制压下率增加和终轧温度降低而减小。在820℃(A_(r3)附近)终轧时,轧后铁素体晶粒最细小;略低于A_(r3)终轧会引起铁素体晶粒粗化。 In this paper, the effects of the first rolling (initial rolling) reduction rate and finishing temperature on the average austenite grain size and average ferrite grain size after rolling were studied by quantitative metallography. The results show that the average austenite grain size decreases with the increase of the first rolling reduction and increases with the decrease of the finish rolling temperature. The average ferrite grain diameter after rolling increases with the first rolling Decreasing the reduction rate and reducing the finish rolling temperature. At the finish rolling of 820 ℃ (A r (r3)), the grain size of the ferrite after rolling is the smallest. The finishing rolling slightly below A r3 causes the ferrite grain to be coarsened.