Microstructure Responses to Key Extrusion Parameters of Large-Scale Thick-Walled 304 Stainless Steel Pipes Extrusion

摘要:

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(Tb)是影响晶粒及其均匀性的主要因素，影响显著次序分别为Tb>λ>V和Tb>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

Abstract:

A finite element (FE) model for the extrusion process of large-scale thick-walled 304 stainless steel pipes was firstly developed based on DEFORM-2D platform, which can predict the DRX evolution behavior by coupling with a DRX model of 304 stainless steel. Secondly, the influence of the above key extrusion parameters on the average grain size and the grain uniformity of the extruded pipe were investigated by a liner orthogonal regression method. Finally, the influence laws of the key parameters on the average grain size and the grain uniformity were analyzed by a single factor method. The results show that extrusion speed V, initial billet temperature Tb and extrusion ratio λ have more obvious effects on the average grain size and the grain uniformity than other ones, and the influence sequences of these parameters to the average grain size and the grain uniformity are Tb>λ>V and Tb>V>λ, respectively. And the average grain size becomes smaller and the grain uniformity gets enhanced with the decrease of V and the increase of Tb and λ