针对特宽挤压型材用国产大型扁挤压筒生产时中内套出现的严重裂纹 ,建立了扁挤压筒内套的有限元分析模型 ,分析了扁挤压筒在实际工况下的应力场 ,找出了过早失效的主要原因 ;运用有限元形状优化设计理论与方法对扁挤压筒型腔进行形状优化设计 ,使应力集中值降低21 % ,该研究结果为扁挤压筒设计提供了理论依据 Aiming at the severe cracks in the inner sleeve of the domestic large flat extrusion tube used for extra-wide extrusion profile, a finite element analysis model of the inner sleeve of the flat extrusion tube was established. The stress of the flat extrusion tube under actual working conditions Field, to find out the main reason for premature failure; use of finite element shape optimization design theory and method of flat extrusion cavity shape optimization design, the stress concentration value is reduced by 21%, the results of this study for the flat extrusion cylinder design Provided a theoretical basis