标题： 基于增强颗粒介质的管材液压强化 显示英文标题

标题： Enhanced granular medium-based tube press hardening

摘要： 主动和被动的内部压力控制策略用于颗粒介质热成形管材和型材，进行了描述。 颗粒介质的力传递和塑性变形进行了实验研究。 管材、颗粒介质和模具之间的摩擦以及外部应力场被证明对过程理解至关重要。 管材的起皱、变薄和成形不足确定了主动压力工艺的工艺窗口。 通过改进冲头几何形状和控制摩擦条件，扩展了工艺极限。 被动压力工艺的例子揭示了管材和型材热成形的新机会。 显示英文摘要

摘要： Active and passive control strategies of internal pressure for hot forming of tubes and profiles with granular media are described. Force transmission and plastic deformation of granular medium is experimentally investigated. Friction between tube, granular medium and die as also the external stress field are shown to be essential for the process understanding. Wrinkling, thinning and insufficient forming of the tube establishes the process window for the active pressure process. By improving the punch geometry and controlling tribological conditions, the process limits are extended. Examples for the passive pressure process reveal new opportunities for hot forming of tubes and profiles.