(大連交通大學(xué) 連續(xù)擠壓教育部工程研究中心，大連 116028)
摘 要: 為了解鎂合金連續(xù)擠壓擴(kuò)展流動規(guī)律與工藝條件的關(guān)系，基于DEFORM-3D軟件，建立鎂合金的剛塑性有限元模型，通過數(shù)值模擬分析連續(xù)擠壓過程坯料沿縱向?qū)ΨQ面上的速度演變規(guī)律，探討擠壓輪轉(zhuǎn)速對坯料各層面速度分布的影響機(jī)制。結(jié)果表明，在連續(xù)擠壓過程中，金屬流動速度在各變形區(qū)呈不同變化趨勢。輪槽區(qū)的速度呈現(xiàn)由輪槽底面向封料面逐漸降低的分布形態(tài)；直角彎曲區(qū)的流道底部速度最高；擴(kuò)展區(qū)由中心向兩側(cè)流動速度逐漸減小；在阻流區(qū)和模具區(qū)，流動速度的差別減小。隨著擠壓輪轉(zhuǎn)速的增大，直角彎曲區(qū)和擴(kuò)展區(qū)各層面金屬的速度差值增大，流動的不均勻程度增加。連續(xù)擠壓過程中金屬的這種流動分布特點(diǎn)緣于輪槽面的摩擦驅(qū)動力與型腔壁摩擦阻力的相互作用。
關(guān)鍵字: AZ31鎂合金；連續(xù)擠壓；數(shù)值模擬；流動速度
（Engineering Research Center of Continuous Extrusion, Ministry of Education,
Dalian Jiaotong University, Dalian 116028, China）
Abstract:For understanding the relationship between the expansion flow and process conditions, based on the DEFORM-3D software, the model of rigid-plastic FEM was established. The velocity evolution rule on the longitudinal symmetry plane was analyzed during the forming process through numerical simulation. The effect of extrusion wheel velocity on the metal velocity distributions of all surfaces was investigated. The results show that the metal velocity presents various changing forms in different deformation regions. In the groove region, the velocity gradually decreases from groove bottom to enclosing surface. In the rectangular bending region, the velocity at the channel bottom is the highest. In the expansion region, the velocity gradually decreases from the center to the two sides. In the choked flow and die regions, the flow velocity differences are smaller than those of other regions. With the increase of wheel velocities, in the rectangular bending and expansion regions, the differences of the highest and lowest velocities and the non-uniformity of flow increase for all surfaces. The flow distribution characteristics of the continuous extrusion are induced by the interaction between the driving force of the wheel groove and the friction resistance of the cavity wall.
Key words: AZ31 magnesium alloy; continuous extrusion; numerical simulation; flow velocity
