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首页> 外文期刊>Revista de metalurgia >Modelo de precipitación en aceros microaleados tanto en condiciones isotérmicas como de enfriamiento continuo
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Modelo de precipitación en aceros microaleados tanto en condiciones isotérmicas como de enfriamiento continuo

机译:等温和连续冷却条件下微合金钢的析出模型

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Niobium and vanadium precipitates (nitrides and carbides) can inhibit the static recrystallization of austenite but this does not happen for Ti, which form nitrides at high temperatures. RPTT diagrams show the interaction between recrystallization and precipitation allowing study the strain induced precipitation kinetics and precipitate coarsening. Based on Dutta and Sellars’s expression for the start of strain-induced precipitation in microalloyed steels, a new model has been constructed which takes into account the influence of variables such as microalloying element percentages, strain, temperature, strain rate and grain size. Recrystallization- Precipitation-Time-Temperature (RPTT) diagrams have been plotted thanks to a new experimental study carried out by means of hot torsion tests on approximately twenty microalloyed steels with different Nb, V and Ti contents. Mathematical analysis of the results recommends the modification of some parameters such as the supersaturation ratio (k s ) and constant B, which is no longer a constant but a function of k s . The expressions are now more consistent and predict the Precipitation-Time-Temperature (PTT) curves with remarkable accuracy. The model for strain-induced precipitation kinetics is completed by means of Avrami’s equation. Finally, the model constructed in isothermal testing conditions, it has been converted to continuous cooling conditions in order to apply it in hot rolling.
机译:铌和钒的沉淀物(氮化物和碳化物)可以抑制奥氏体的静态再结晶,但对于Ti(在高温下会形成氮化物),这不会发生。 RPTT图显示了重结晶和沉淀之间的相互作用,从而可以研究应变诱导的沉淀动力学和沉淀粗化。根据Dutta和Sellars对微合金钢中应变诱发析出开始的表达式,构建了一个新模型,该模型考虑了诸如微合金元素百分比,应变,温度,应变率和晶粒尺寸等变量的影响。由于借助热扭转试验对大约20种不同Nb,V和Ti含量的微合金钢进行了新的实验研究,因此绘制了重结晶-沉淀-时间-温度(RPTT)图。结果的数学分析建议修改某些参数,例如过饱和率(k s)和常数B,该参数不再是常数而是k s的函数。这些表达式现在更加一致,并以惊人的准确性预测了降水时间温度曲线(PTT)。应变诱发的降水动力学模型是通过Avrami方程完成的。最后,在等温测试条件下构建的模型,已将其转换为连续冷却条件,以便将其应用于热轧。

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