Abstract: The impact energy samples of non-quenched-tempered steel JGF45V hot-rolled state by finishing rolling at 1 000℃ and normalized state by normalizing at 860℃ are analyzed by metallography and scanning electron microscope. It is obtained that grain size is an important parameter affecting room temperature impact energy of non-quenched-tempered JGF45V steel. Through process test of decreasing the finishing rolling temperature from 1 000℃ to 900 ~930 % with the cooling rate being 0. 3 ℃/s, the grain size rating of steel increases from 5 to 7, and the room U-shaped impact energy increases from 32 J to ≥55 J.

摘要： 对非调质钢JGF45V终轧1 000℃热轧态和860℃正火态冲击功试样进行金相分析和扫描电镜分析,得出晶粒度是影响非调质钢JGF45V室温冲击功的重要参数。通过终轧温度由1 000℃降低至900~930℃,冷却速度为0.3℃/s的工艺试验,晶粒度级别由5提高到7,室温U型冲击功由32 J提高到≥55 J。

关键词: 非调质钢JGF45V, 冲击功, 晶粒度, 终轧温度, 冷速