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本文研究了控制轧制工艺参数对含铌与不含铌低碳钢的铁素体晶粒细化的影响规律。试验结果表明,热轧后铁素体晶粒尺寸d_f不受形变速度的影响(当ε为7～76秒~(-1)时),而形变量ε、形变温度T_d、轧前的奥氏体晶粒尺寸d_a、轧后冷速及钢的成分对d_f有重要影响。在单道次轧制中,所试验钢种的铁素体晶粒直径与各工艺参数的综合定量关系,可用下式表达。d_f=[55th((d_α-90)/25)+α]·ε~(-1)+b(T_d-750)~(1/2)+cd_α式中常数项a、b、c与钢的成分,冷却速度有关。试验表明,该式所表达的规律对其他低碳钢也适用。文中通过分析在细化晶粒方面,多道次轧制与单道次轧制的关系,将d_α推广为“等效奥氏体晶粒尺寸”,则该关系式可应用于多道次轧制,成功地予测了多道次轧制后铁索体晶粒尺寸。
In this paper, the effect of controlled rolling parameters on the grain refinement of ferrite containing niobium and non-niobium mild steel was studied. The results show that the ferrite grain size d_f after hot rolling is not affected by the deformation speed (when ε is 7 ~ 76 seconds -1), while the deformation ε, the deformation temperature T_d, the austenite before rolling Body size d_a, cooling rate after rolling and the composition of steel d_f have a significant impact. In a single pass rolling, the test steel species ferrite grain size and the process parameters of the quantitative relationship can be expressed by the following formula. d_f = [55th ((d_α-90) / 25) + α] · ε -1 + b (T_d-750) ~ (1/2) + cd_α In the formula, the constants a, b, Composition, cooling rate. Experiments show that the expression of the law of the other low carbon steel is also applicable. In this paper, by analyzing the relationship between multi-pass rolling and single-pass rolling in terms of grain refinement, and extending d_α to “equivalent austenite grain size”, the relation can be applied to multi-pass rolling System, successfully predicted the multi-pass rolling ferrite crystal grain size.