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首先建立能够准确预测304不锈钢大型厚壁管挤压成形过程中动态结晶组织演化行为的精确有限元模型。其次,利用所建有限元模型,通过正交回归法确定对管材晶粒尺寸及其均匀性影响显著的因素。最后,通过单因素法分析了影响显著参数对管材晶粒尺寸及其均匀性的影响规律。结果表明:挤压速度(V),挤压比(λ)和坯料预热温度(T b)是影响晶粒及其均匀性的主要因素,影响显著次序分别为T b>λ>V和T b>V>λ。并且随着挤压速度的增加管材平均晶粒尺寸增大,管材晶粒均匀性降低;随着坯料初始温度的升高和挤压比的增大管材晶粒尺寸减小,管材晶粒分布更加均匀。
First, an accurate finite element model was established to accurately predict the evolution of dynamic crystalline structure during the extrusion of 304 stainless steel thick-walled tubes. Secondly, by using the finite element model, the factors affecting the grain size and uniformity of the pipe are determined by orthogonal regression. Finally, the influences of the significant parameters on the grain size and uniformity of the pipe were analyzed by single factor method. The results show that extrusion speed (V), extrusion ratio (λ) and preheat temperature (T b) are the main factors influencing the grain and its homogeneity. The order of importance is T b> λ> V and T b> V> λ. And as the extrusion speed increases, the average grain size of the pipe increases and the uniformity of the pipe grain decreases. As the initial temperature of the billet increases and the extrusion ratio increases, the pipe grain size decreases, and the pipe grain distribution more Evenly.