论文部分内容阅读
建立了等通道转角挤压有限元模型,分析了不同模具与试样结构条件下摩擦应力随试样行程的变化规律,研究了模具过渡圆角半径与试样过渡圆角半径对挤压过程中摩擦应力大小的影响,获得了不同挤压条件下摩擦应力在挤压过程中的变化特性。结果表明,摩擦应力在挤压初期与挤压中后期呈现出不同变化特性,挤压初期试样左侧最大摩擦应力波动较大,试样右侧最大摩擦应力波动较小。挤压中后期试样两侧最大摩擦应力均波动较小,最大摩擦应力大小趋于一稳定值。模具外角过渡圆角半径变化对挤压初期试样左侧最大摩擦应力有重要影响,而模具内角过渡圆角半径对挤压中后期试样右侧最大摩擦应力的稳定值有重要影响。试样最下端增加一过渡圆角可显著减小挤压初期的最大摩擦应力大小。
The equivalent channel angular extrusion finite element model was established. The variation of frictional stress with the sample stroke under different mold and sample structure was analyzed. The effects of the transition radius of the die and the transition radius of the sample on the extrusion process The influence of the frictional stress on the frictional stress was obtained under different extrusion conditions. The results show that the friction stress shows different changing characteristics in the initial stage of extrusion and in the middle stage of extrusion. The maximum friction stress fluctuates greatly on the left side and the maximum friction stress on the right side of the specimen during initial extrusion is small. The maximum frictional stress on both sides of the sample in the mid-and late-crush period fluctuated less and the maximum friction stress tended to be stable. The variation of fillet radii of the outer corner of the die has an important influence on the maximum frictional stress on the left side of the sample during extrusion. However, the fillet radii of the inner corner of the die have an important influence on the stability of the maximum frictional stress on the right side of the sample in the middle and later stages of extrusion. Adding a transitional fillet at the lowest end of the specimen significantly reduces the maximum frictional stress at the initial stage of extrusion.