【摘要】 微合金化非调质钢35MnVN在860℃至1200℃进行正火处理后,随着正火温度的提高,钢的显微组织由细到粗,先析铁素体由块状均匀分布到呈网状分布且相对量减少,使钢的强度、硬度升高,而塑性和冲击韧性降低。在950℃以下正火,因未溶沉淀相粒子V(C.N)强烈阻止奥氏体晶粒长大,钢的显微组织被高度细化,使钢在保持足够高的强度下,其冲击韧性比钢在锻后空冷态提高了1.5倍以上。更多还原

【Abstract】 The influence of normalizing in the temperature range from 880℃ up to 1200℃ after forging on the micro-structure and properties of mieroalloyed steel 35MnVN is investigated in this paper. It is found that the increase in normalizing temperature leads to the coarsening of steel grains, the decrease in the volume fraction of pre-eutectoid ferrite and the change in distributed morphology of the ferrite.Therefore with increasing normalizing temperature, the strength and hardness of the steel are increased, while the ductility and impact toughness are decreased. The normalizing below 950℃, due to austenite grain growth being intensely inhibited by the presence of undissolved V(C, N) precipitates, results in highly refining of the microstructure and consequently greatly improve the impact toughness of the steel (the impact value increases by more than 2.5 times as compared with that of the as-forged steel) is greatly i mproved, the steel is still maintained sufficiently high strength.更多还原