接地簧片级进模废料回跳及单边90°弯曲回弹的调整

分析了接地簧片在高速冲制过程中废料回跳及单边90°弯曲回弹大产生的原因.并介绍通过凸、凹模结构形式的改变解决废料回跳及单边90°弯曲回弹大的方法.     

接地簧片级进模废料回跳及单边90°弯曲回弹的调整

分析了接地簧片在高速冲制过程中废料回跳及单边90°弯曲回弹大产生的原因。并介绍通过凸、凹模结构形式的改变解决废料回跳及单边90°弯曲回弹大的方法。     

PA端子板弯曲冲裁级进模的维修与改进

针对PA端子板弯曲冲裁级进模在使用过程中遇到的废料翻料和弯曲回弹等问题,对模具的结构进行了分析和合理改进,实现对翻料做到可防,对回弹做到可调可控,同时在新模具制造时,优化了模具材料的选用,在提高模具使用寿命、延长模具维修周期、提高生产效率、稳定制件质量方面进行有效探讨,对类似精密模具相应问题的解决有参考价值。     

汽车电源连接器弹簧卡模具设计

确定长、短弹簧卡3副单冲模冲制：1副冲槽、压腰形泡、落料；1副打弯；1副推弯成形。落料模实现了连续无废料冲裁，打弯考虑了材料的回弹变形，成形采用斜楔滑块机构。     

轴对称问题的回弹变分原理

本文引入了回弹反耦联系统和回弹反耦联方程的概念。应用加权余量法于该回弹反耦联方程 ,建立了轴对称问题的回弹势能原理和回弹余能原理。应用拉氏乘子法于该回弹势能原理和回弹余能原理 ,建立了轴对称问题的广义回弹势能原理和广义回弹余能原理。同时 ,应用该回弹势能原理于纯弯曲梁的回弹变形计算     

带双浮动机构的汽车外板冲切、弯曲一体模具设计

汽车外板冲压件的生产方式为先滚压出所需型材,后利用冲压模具进行切断的同时对其截面进行直弯曲。针对后者,利用双浮动机构实现同一工位的两种工序——冲切分离与弯曲成形的冲制。为有效解决冲裁毛刺突出问题,凸、凹模刃口形状按照型材截面走势进行设计,实现与型材协同冲切;为有效降低冲裁力,冲切凸、凹模采用波纹斜刃结构;为使废料能够顺利排出,凸模局部采用三角形状尖凸刃口,实现无凹模废料分段冲切;鉴于在冲切后的缺口处进行直边弯曲时,缺口外角部出现弯曲瘤,因此,采用局部冲切—直弯曲—完整冲切的模式;针对弯曲回弹大于90°,通过对凸模刃口进行角度负修正—过渡校正,实现对回弹角的控制。冲切、弯曲一体模具已完成试制并投产,能够满足冲压件生产的相关工业要求。     

基于有限元分析控制车架纵梁腹面回弹

对纵梁存在的腹面回弹问题进行系统研究。通过分析回弹机理及影响回弹的主要因素,建立回弹预测模型,探讨回弹预测,在准确预测回弹量的基础上,针对纵梁的成形特征,研究纵梁回弹补偿,得到纵梁弯曲的回弹量和回弹补偿量,有效地控制了纵梁回弹误差。在此基础上确定一套合理的回弹补偿量控制方案,并有效地解决了卡车纵梁存在的回弹问题。     

杆系结构的回弹变分原理及其应用

本文引入了杆系结构的回弹反耦联系统和回弹反耦联方程的概念。应用加权余量法于回弹反耦联方程, 建立了杆系结构的回弹势能原理和回弹余能原理。应用表明, 回弹变分原理为求解杆系回弹变形提供了一个新的途径。     

板料卷圆回弹分析及数值模拟

回弹是板料冲压成形中普遍存在的现象,它的存在影响了零件成形的质量。本文探讨了板料弯曲回弹产生的力学机理及回弹产生的原因;分析了有限元方法计算回弹的特点;采用显示和隐式相结合的方法模拟了扳料卷圆的成形及回弹过程;实现了对板料卷圆回弹的预测。通过调整有限元方法的计算参数,提高了模拟回弹的精度。     

弯曲成形板条的回弹变分原理

本文建立了弯曲成形板条的回弹最小势能原理 ,回弹最小余能原理 ,广义回弹势能原理和广义回弹余能原理。同时 ,应用回弹最小势能原理于一弹塑性变形悬臂梁的回弹变形计算     

On the principles of the deformation methods of grain refinement in aluminum alloys to ultrafine size: II. Ultrafine-grained alloys

The applicability and efficiency of the principles of optimum structural heterogeneity and stage-by-stage grain refinement in relation to the formation of an ultrafine-grained (UFG) structure (with a grain size smaller than 1 μm) in bulk billets during severe plastic deformation are analyzed. The evolution of the criteria of these principles is considered when going from a fine-grained structure to a UFG structure and from conventional deformation treatment to severe deformation treatment. The dependence of the intrinsic mechanisms of grain refinement to ultrafine size on the initial structure of an alloy, including the heterogeneity of the initial structure, is analyzed.     

Nanostructurization of Nb by high-pressure torsion in liquid nitrogen and the thermal stability of the structure obtained

The evolution of the Nb structure upon high-pressure torsion (HPT) in a Bridgeman chamber in liquid nitrogen and a subsequent annealing in the range from 100 to 600°C has been studied by the TEM method. With an increase in the degree of deformation, the structure exhibits three stages of refinement: dislocation cellular structure; mixed structure consisting of cells and subgrains; and submicron or nanocrystalline grain structure. The HPT using 3 and more revolutions of the anvils at 80 K leads to the formation in Nb of a nanocrystalline structure with an average grain size of ∼75 nm and a record high microhardness of 4800 MPa. The structure is stable at room temperature but possesses a relatively low thermal stability, i.e., the recrystallization starts at lower temperatures than it does after conventional deformation or an HPT at room temperature.     

反凸轮机构在多工位冲模排废料装置中的应用

利用反凸轮机构成功地解决了机针多工位冲模废料如何排料的难题 ,并介绍了排废料装置的结构。实践证明 ,该装置结构紧凑 ,动作可靠     

大学内部权力结构及其调整

大学内部权力结构经历了从一元结构向二元结构和多元有机结构演进的历程。当前我国大学内部权力结构的特征是行政权力膨胀 ,学术权力式微 ,学生权力缺失。与此相应 ,规范行政权力 ,加强学术权力和提升学生权力应成为我国大学内部权力结构调整的方向。     

钢表面热浸渗铝层组织中的调幅分解及初期波长

利用透射电子显微镜(TEM)研究了钢表面热浸渗铝层的调幅分解组织,利用点阵驻波理论分析了调幅分解初期形成的波长,其波长由表面到内部从0.63nm到10.6nm逐渐增大,调幅结构形成后调幅组织经过长大其波长由表面向内部从3nm到30nm逐渐增大.调幅组织的形成经过从连续相变到非连续相变的过程.     

密封条钢芯级进模结构的改进

阐述了密封条钢芯级进模排样的改进对模具结构的影响 ,以及所带来的经济、技术方面的变化特点。介绍了模具新结构 ,分析了冲压过程中遇到的问题及解决方法     

Investigation of the structural changes in Widmanstätten ferrite during the annealing of low-carbon steel

Transformation of austenite by a shear mechanism in an intermediate range leads to the formation of structures consisting of plate and acicular ferrite. The acicular structure of Widmanstätten ferrite has not found practical application and has not been adequately studied, although the inherited effect of this structure in lowering the ductility of steel is of practical importance. The present article is devoted to a detailed analysis of this structure and its effects.Volgograd Polytechnical Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 14–16, November, 1994.     

色拉油瓶盖注射模设计

分析了瓶盖塑件的结构特点 ,即有4处需强制脱模 ,故在设计模具时采用了与传统结构不同的五板四开式结构 ,并介绍了模具的工作过程。     

Metallographic studies of the copper patina formed in the atmosphere

The green coating (patina) which forms on copper has been metallurgically investigated by examining 14 samples exposed to the atmosphere for periods of 1–100 years. Various samples in cross-sectioned form are shown to have a layered structure with numerous voids throughout. Oxides and sulfates predominate in the patinas, and small amounts of chlorine and phosphorus can also be found. Extremes in patina growths manifested as color variations are shown to result from variations in grain structure brought about by different heat treatment prior to exposure of the copper to the elements.     

On the problem of the formation of structural modifications in Ni nanoclusters

The processes of melting and crystallization of Ni nanoclusters with a diameter to 3.6 nm have been studied by the molecular-dynamics method based on tight-binding potentials. The effect of the particle size on the stability of the structural modifications obtained has been investigated. The dependence of the process of the cluster-structure formation on the conditions of cooling from the liquid state has been noted. Upon slow crystallization, an fcc structure was mainly formed, whereas upon rapid cooling an icosahedral phase was formed in the majority of cases. Thus, the simulation performed indicates the possibility of some control of the structure formation of Ni clusters upon crystallization.