一种提升AutoForm分析效率的方法

介绍提高AutoForm软件分析效率的两种途径,分别是:针对每个零件制作各自的设置模板文件,通过引用模板文件,减少操作步骤,可节约分析时间15 min,同时将分析文件的存储空间减小到原来的45%左右;针对每个零件建立模面控制线数据库,通过引用控制线数据库,将拉延模面的建立的效率提高了20%,进而提高了整体分析效率。     

热冲压工艺参数对22MnB5马氏体钢汽车B柱性能影响的有限元模拟

通过有限元仿真软件Autoform分析了热冲压过程中工艺参数的变化对22MnB5马氏体钢B柱起皱、回弹、减薄、马氏体量以及强度的影响。结果表明:22MnB5马氏体钢B柱热冲压最优化工艺参数为加热温度930 ℃,冷却速率80 ℃/s。该工艺参数下,热冲压过程各处均完成马氏体转变,硬度分布均匀,材料减薄率较低,热冲压成形效果好,尺寸精度高,冲压件强度均大于1400 MPa。     

新型热冲压模具钢的组织与性能

采用SEM、TEM、LF457型激光导热仪,DSC404型差示扫描量热仪和UMT-3型高温摩擦磨损试验机对高强钢板热冲压用新型模具钢的组织和热稳定性能、热物理性能及高温耐磨性能进行研究。试验结果表明:该模具钢具有良好的抗回火软化性能、热稳定性、高热导率和高温耐磨性,能更好地适应高强钢板热冲压工况。新型模具钢的碳化物以Mo₂C和VC为主,使得该钢有更好的抗回火软化和热稳定性。新型钢具有高热导率,在室温下是H13钢的1.4倍。其低Si、Mn、Cr和高Mo的合金化特征是其高热导率的原因。该钢较H13钢有更好的高温耐磨性能,尤其是温度高于600 ℃后耐磨性要远远优于H13钢。新型模具钢良好的耐磨性能有益于减少模具修理频次,提高模具寿命。     

Evolution of rotated Brass texture by cross rolling: implications on formability

In the present work, the possibilities of tailoring crystallographic texture via cross rolling are presented. It is shown that a strong rotated Brass texture develops upon cross rolling in aluminium alloys which also remains intact during the subsequent recrystallisation annealing treatment. The governing mechanisms behind the evolution of deformation and recrystallisation texture are discussed in terms of effect of strain path on stability of deformation texture components and strain-induced boundary migration mechanism, respectively. In addition, the likelihood of rotated Brass texture having a positive effect on formability is discussed in terms of sluggish cross-slip criteria as the rotated Brass texture presents a unique scenario where cross-slip is inhibited along all the three principal directions.     

Influence of trace Ca addition on texture and stretch formability of AM50 magnesium alloy sheet

The AM50, AM50–0.1Ca, AM50–0.3Ca and AM50–0.5Ca (wt.%) alloys were hot-rolled and their mechanical properties were determined for the purpose of investigating the effect of trace Ca addition on the texture and stretch formability of AM50 alloy. The results show that the addition of trace Ca can effectively modify the basal texture, which is characterized by the split of basal poles deviated from the normal direction (ND) after the hot rolling, while a broad spread of the basal planes toward the transverse direction (TD) after the annealing. Such change of the basal texture is related to the prior formation of massive compression twins and the decrease of the c/a ratio. Erichsen value increases from 2.25 to 4.21 mm with the increase of Ca content. The enhancement of stretch formability is ascribed to the weakened basal texture, which results in the increase of n-value and the decrease of r-value.     

基于区域特征和质心关系的两步法阀板检测

针对冲压阀板中毛刺、冲压孔堵塞等缺陷的检测问题,提出了一种基于面积特征的通孔数目检测和基于质心关系的快速模板匹配检测的两步视觉检测方案。首先采用通孔数检测初步判定零件是否存在冲压孔堵塞缺陷,之后采用模板匹配精确检测边缘毛刺缺陷。利用区域面积特征实现通孔数检测;提出了一种限定条件的最小二乘法圆拟合方法和一种基于圆心特征的快速模板匹配方法,实现边缘毛刺等缺陷的精确检测。实验结果表明,这种两步检测方案检测速度快精准度高,能够满足阀板生产线的检测要求。     

一种适用于超高速冲压新型产品的冲裁模具结构

为实现超高速模具量产,对经典的U型冲裁结构进行了优化,将原始的分离式U型冲裁和下废料双工位优化为单工位一步式冲裁和下废料工艺,新结构将产品切除和废料切除工位融合到一起,提高了U型凸模的强度、缩短了模具长度、减小了跳废料率,保证了产品质量;新结构在同一工位上同时获得产品且切除废料,无需采用连料方式传送废料,从而缩短了原材料的宽度,降低了材料成本,减少了误送。同时,模具速度从原有的800次·min-1提高到2000次·min-1,实现了超高速的目的,并且该新结构被成功地推广到其他相类似的结构中,实现了技术的互通性。     

虚拟冲压仿真关键技术及其发展趋势

在全面分析虚拟冲压仿真技术发展现状的基础上,对其关键技术组成进行总结,介绍了各项核心技术的重要性、作用、研究历史、现状及主要内容。考虑现代工业生产对冲压加工及其仿真技术提出的新要求,结合虚拟冲压仿真技术的发展现状及所存在的问题,指出了新一代虚拟冲压仿真技术的发展趋势,为该项技术的研究指明了方向。