Abstract: Mathematical model for Nb( C ,N) precipitation in ferrite of micro niobium HSLA steel and calculated NbC nucleation radius, nucleation rate and growth rate in ferrite with 900 ~ 1200 ℃. austenization are presented. The test results by some authors indicated the precipitation of niobium carbo-nitride needed higher dislocation density and the amount of NbC formed in ferrite was relatively minor as compared with that formed in austenite； and the tensile strength of steel sheet with coiled at 680 °C was obviously higher than that of sheet without coiled direct cooling to room temperature.

Key words: HSLA Steel, Ferrite, Niobium, Precipitation Strengthening

摘要： 介绍了含微量铌的高强度低合金(HSLA)钢铁素体中Nb(C,N)析出的数学模型,以及计算经900～1200℃奥氏体化处理后的铁素体中NbC形核半径、形核率和形核长大率。一些研究者的试验结果表明,Nb的碳氮化物在铁素体上的析出需要较高的位错密度,与奥氏体中形成的NbC相比较,铁素体中形成的NbC相对较少,在680℃卷取钢板的抗拉强度较未经卷取直接空冷至室温的钢板抗拉强度有明显提高。

关键词: 高强度低合金钢, 铁素体, 铌, 析出强化