模具锥角对AZ31镁合金棒材热减径挤压的影响规律

模具锥角α是影响镁合金型材热减径挤压动态再结晶行为的重要参数之一,通过建立AZ31镁合金棒材热减径挤压工艺动态再结晶预测模型,并针对模拟结果进行了挤压实验,对模具锥角α的影响规律进行了研究。结果表明:晶粒尺寸沿径向由中心向表层逐渐细化,沿轴向呈带状分布;随模具锥角α的增大,型材表层金属晶粒尺寸细化程度不断加剧;当模具锥角α从50°过渡到90°时,挤压型材表层金属平均晶粒尺寸细化程度提升25%,实验与模拟结果吻合良好。

Influence law of die-taper angle on thermal-ironing extrusion process of magnesium alloy AZ31 bar

Die-taper angleαis one of the important parameters influencing dynamic recrystallization behavior during thermal-ironing extru-sion process of magnesium alloy profile. Therefore, through establishing the prediction model of dynamic recrystallization during thermal-ironing extrusion process for magnesium alloy AZ31 bar, the extrusion test for simulation result was conducted, and the influence law of die-taper angle αwas studied. The results show that the grain size decreases gradually from the center to the surface along the radial direc-tion, and the grain distributes in ribbon state along the axial direction. However, with the increase ofα, the grain size located nearby the surface of extruded bar decreases gradually. When the die-taper angleαincreases from 50° to 90°, the average grain size of the extruded surface metal is improved by 25%. The results from simulation and from actual experiments are in good agreement.