辊压机辊轴断裂分析及冷却水孔结构仿真应用

辊压机辊轴是设备的核心部件,根据某现场辊轴轴承位断裂情况,文中对辊轴断裂面进行材质取样化验,并复查辊轴质检报告等,排除了材质及制造问题。通过观察辊轴内部冷却水孔断裂面,发现辊轴实际加工中冷却水孔出现刀痕错位情况。对辊轴及冷却水孔建立模型,采用力热耦合分析的方法,在辊面、轴承位及冷却水孔设置不同的工况温度,并建立冷却水孔加工面刀痕错位模型,通过与正常加工模型进行对比,发现冷却水孔刀痕错位处应力值相对正常加工高约20%。辊面及轴承位温度偏高时,该处应力绝对数值较大。考虑到辊轴材质硬度由外层向内层逐步降低的情况,刀痕位置容易局部出现裂纹,并持续扩大,最终导致辊轴断裂。根据分析结论,对辊轴冷却水孔结构设计进行了改进,并减小了冷却水孔直径,在制造过程中一次镗孔成型,防止加工时出现刀痕错位情况,加强了深孔加工的质量控制,避免了辊轴断裂情况的再次发生。

热成形模具冷却水道的CAE分析与研究

本文以高强度钢U形冲压件为研究对象,设计了常规圆管和微孔两种结构的冷却水道,并采用仿真软件对两种冷却水道对模具冷却系统的冷却效果影响进行分析。分析结果表明,微孔冷却水道的冷却效果比常规圆管冷却效果要好,在5s接触时间后,微孔冷却水道较常规圆管冷却后的温度大大下降,冷却效果更好。

Improving Film Cooling Performance by Using One-Inlet and Double-Outlet Hole

The film cooling performance of a trunk-branch hole is investigated by numerical simulation in this paper. The geometry of the hole is a novel cooling concept, which controls the vortices-pair existing at the mink hole outlet using the injection of the branch hole. The trunk-branch holes require easily machinable round hole as compared to the shaped holes. The flow cases were considered at the blowing ratios of 0.5, 0.75, 1.0, 1.5 and 2.0. At the low blowing ratio of 0.5, the vortices-pair at the outlet of the trunk hole is reduced and the laterally coverage of the film is improved. At the high blowing ratio of 2.0, the vortices-pair is killed by the vortex which is produced by the injection of the branch hole. The flow rate of the two outlets becomes more significantly different when the blowing ratio increases from 0.75 to 2.0. The discharge coefficients increase 0.15 and the laterally averaged film effectiveness improve 0.2 as compared to the cylindrical holes. The optimal blowing ratios occur at M=1.0 or M= 1.5 according to the various locations downstream of the holes.