挤压铝型材表面拉毛形成原因分析

Analysis on Causes of Surface Galling of Extruded Aluminum Profiles

文章利用直读光谱仪和扫描电镜等先进设备,分析了合金成分、挤压工艺和铸棒表面质量对型材拉毛缺陷的影响,讨论了拉毛产生原因。结果证明:拉毛缺陷前端有明显的划痕,这种痕迹沿着挤压方向,且呈台阶状,末尾有不规则形状的瘤状颗粒物;成分和基体较接近,其周边分布高含量的异质颗粒,如铜(C)、硅(Si)、铁(Fe)等;挤压速度快、出口温度较高,铸棒表面粗糙现象明显,从而表明形成拉毛。

Using advanced equipment such as direct reading spectrometer and scanning electron microscope,this article analyzes the effects of alloy composition,extrusion process and surface quality of cast rods on the galling defects of profiles,and discusses the causes of galling.The results exhibit that there are obvious scratches at the front of the galling defect,which are along the extrusion direction and are stepped,and there are irregularly shaped tumor-like particles at the end;the composition is close to the matrix,and a high content of heterogeneous particles,such as copper(C),silicon(Si),and iron(Fe),are distributed around it;the extrusion speed is fast,the outlet temperature is high,and the surface roughness of the cast rod is obvious,which indicates the formation of galling.