弹簧片弯曲模精度控制技术研究

弹簧片是某型号弹射装置上的关键零件,对其装配精度要求较高。针对目前弹簧片成形变形量大、加工精度低等问题,对弹簧片的弯曲成形模技术进行了研究。采用分步式弯曲模,并使用三维建模软件UG对弹簧片弯曲模结构进行三维实体建模。生产实践表明,使用该弹簧片弯曲模结构,降低了弹簧片变形量,提高了弹簧片一次弯曲成形精度。     

转轴式弯曲模设计

通过支承板转轴式弯曲模的加工实例，对其产生的无法开模故障进行了系统分析，找出了原因，改进了模具，消除了故障，保证了零件形状及尺寸精度要求；并推导出保证转轴式弯曲模正常开模情况下，转轴设计的数学表达式。     

齿座冲压工艺改进及模具设计

针对齿座加工过程中难以满足形位公差要求等质量问题,对原加工工艺进行了系统分析,找出了原因。通过对零件的部分结构进行改进和将原弯曲模改进成压槽-弯曲复合模等措施,解决了原加工工艺出现的质量问题,有效地提高了生产效率及零件的加工质量,优化了工艺,降低了操作人员的工作强度,满足了产品要求。     

级进模中弯曲回弹的克服

级进模中弯曲回弹的克服安徽蚌埠电子部四十所高乃杰在继电器行业中，由于级进模生产效率高，零件一致性好，所以得到广泛应用。由于材料在弯曲卸载后出现弹性回复现象，使弯曲臂产生回弹。当材料弹性模数愈小，弹性变形量就愈大，这些因素常使得零件弯曲角的精度达不到设...     

基于起皱分析的钛合金异形盒件缺陷控制研究

针对钛合金异形盒零件成形起皱问题开展研究，对零件热成形过程中失稳起皱的原理进行分析，结合鼓动产生前后接触压力矢量分布情况得到成形过程中材料流动趋势以及褶皱产生的原因。通过监测零件成形过程中受压侧褶皱折弯角度及零件最大应变情况，发现在合模间隙为6 mm时零件发生失稳变形。对该状态下零件型面进行光顺，设计出零件2道次成形的过渡工装型面，并对工装排布与毛料结构进行优化，最后进行试验验证，成形后的零件贴模间隙为0～0.15 mm。结果表明，改进后的工艺方法将零件变形进行分解，使材料变化均匀，过渡型面消除了成形过程中的褶皱问题，实现了零件的精确成形。     

椭圆形弯曲件的回弹控制

分析了椭圆形弯曲件产生回弹的原因,阐述了减少弯曲回弹的措施,并通过计算设计出了相应的弯曲模结构,此模具结构生产出了合格零件,可为类似零件的成形提供参考。     

方锥形件拉深整形凹模受力变形的数值模拟分析

方锥形件一般通过拉深整形工艺成形，整形压力大，凹模变形也较大，成形零件的精度不容易控制；根据整形凹模的结构特点和它在整形工艺中的受力状态，运用有限元方法对凹模在整形压力下的变形进行计算，分析凹模变形对成形零件精度的影响，并就凹模的设计与加工精度提出合理建议。     

翻转模块式精密弯曲模

介绍了翻转模块式精密弯曲模的实用结构及模具工作过程和结构特点。该弯曲模凹模由翻转模块与垂直浮动的托件板铰接而成 ,使毛坯变形时始终与凹模紧密贴合 ,不滑动 ,毛坯已有的凸部与凹模不干涉 ,因此模具工作可靠 ,弯制的零件精度高。     

L形支架弯曲模设计

叙述了L形支架的弯曲工艺,介绍了弯曲模的结构特点,生产实践证明,凸模头部采用滚针结构,减少了弯曲时的摩擦力,延长了模具零件的使用寿命,使弯曲后的零件表面光滑,对类似零件的成形提供一定的参考作用。     

风扇电机固定支架弯曲与翻边复合模设计

通过对排风扇电机支架的成形工艺进行分析,阐述了排风扇电机固定支架零件弯曲、翻边复合模的设计方案,并介绍了零件经级进模加工完成后的弯曲、翻边工序在同1副模具上一次成形的工艺过程。生产实践证明,复合模工序设计合理,结构可靠,成形的零件质量稳定,对同类零件的模具设计具有一定的参考作用。     

卷焊空心筒表面淬火变形分析

针对大直径薄壁空心卷焊筒表面淬火后产生较大变形的现象,对现行工艺进行分析,认为减少变形的关键是减少差异,提高机体强度。提出了新的控制卷焊筒变形的工艺方案。     

Mn18Cr18N护环钢热变形特性的试验研究

应用热力模拟实验和数值分析方法研究了Mn1 8Cr1 8N钢在热变形条件下的力学行为。回归计算出该钢在不同热变形参数下的应力应变关系并分析讨论了热变形参数对本构关系的影响。进行了热变形动力学分析 ,回归得出了该钢的激活能 (Q)、应力指数 (n)及动态再结晶临界应力方程。建立了该钢的高温屈服应力模型。试验研究结果可为计算机模拟和工艺优化提供依据     

带内花键零件的畸变控制方法

由于热处理畸变导致的内花键塞规检查不合格一直是带内花键零件常见的问题。鉴于带内花键零件热处理畸变影响因素众多,借助“淬火畸变公差带”概念,综合分析了零件结构类型、零件热处理前的工艺尺寸、热处理工艺参数(奥氏体化温度、时间、装炉量、冷却速度、装卡方式等)、材料类型、锻造正火工艺等对带内花键零件热处理畸变的影响,综合考虑各种因素的耦合状况,提出了解决带内花键零件热处理畸变问题的一系列解决方案。     

Effect of Ti content on TiN morphology,microstructure and toughness in coarse‐grained heat affected zone of Ti‐containing steels

It is well known that weld distortion, which has a negative influence on material properties, structural fabricability and structural integrity, should be controlled appropriately. There are many methods to control or reduce weld distortion, but most of them involve some costly process in addition to welding. In-process control of weld distortion becomes more preferable than post-welding process or other methods, when manufacturing efficiency is considered. In recent years, in-process control welding by additional cooling has been proposed as one of techniques for reducing weld distortion and partially applied for thin-plate structure in industries. However, the effectiveness of additional cooling method has not yet been fully clarified. In this study, the effectiveness of additional cooling method and appropriate cooling condition for effective reduction in weld distortion are investigated by three-dimensional thermal elastic–plastic analysis. In addition, the effect of locally cooled temperature distribution on generation behaviour of plastic strain is discussed. As a result, it is concluded that the effectiveness of additional cooling and appropriate cooling condition for reduction in weld distortion are dependent on weld distortion under consideration and welding conditions. Especially, it is necessary for reduction in weld distortion to set the cooling torch at the appropriate position. For example, in order to reduce angular distortion effectively, the appropriate cooling position is dependent on the mechanical melting length during welding.     

"畸变工程"--生产过程中的畸变控制

直到最近为止，人们认为淬火是造成零件畸变的一个主要工艺过程，特别是淬火的具体操作过程。而今，众昕周知淬火过程只不过是释放了零件在整个加工过程的一系列操作中积累起来的畸变潜能。然而，迄今为止，还没有一个以系统的方式来研究和精确测定整个过程以及每一个加工步骤对零件的几何尺寸、成分偏析、显微组织和残余应力分布的影响。从2001年开始，由Deutsche Forschungsgemeinschaft(德国研究基金)在不来梅大学成立了“畸变工程”(SFB570)合作研究中心．本文介绍了这一长期工程的基本研究方法和构架。     

行星轧机的运动形式和轧管组织变化

文章结合三辊行星轧机的结构描述和工作原理，分析了轧制过程中轧管运动形式和轧制过程中轧管不旋转的条件。同时对变形区中的坯料的组织变化规律进行分析，阐明了各部分组织的变化。     

Welding distortion investigation in fillet welded joint and structure based on iterative substructure method

Abstract

In this paper, prediction and controlling angular distortion in fillet welded joint and structure were investigated. First, two methods to reduce angular distortion in fillet welded joint were investigated by experimental and numerical analysis. One was to apply a constant external force in-process and the other was rigid clamping. In numerical analysis, a new in-house finite element code has been developed based on the idea of iterative substructure method (ISM) to calculate welding distortion in rational time. During experimental analysis, the constant external force was designed and applied in-process to reduce angular distortion of fillet welded joint. The results showed that the distortion can be efficiently predicted by ISM, which were in good agreement with the experimental ones. Applying constant external force in process was a more effective method to reduce distortion than using rigid clamping. In addition, with a constant load distance from weld bead, the locations of the applied constant external force and rigid clamping along the longitudinal direction (welding direction) have little influence on the magnitude of welding angular distortion. Finally, the angular distortion of a large fillet welded structure was predicted with ISM and also controlled with applying a constant external force based on the simulation results of the fillet welded joint.     

薄壁容器压铸模结构设计

分析了ZL 104铝合金铸件的工艺性,针对铸件的形状特点,模具设计采用活块移出模外利用开模力抽芯的结构,并采用推件板方式推件,有效地解决了侧抽芯力大和铸件壁薄容易变形的问题.详细叙述了模具的结构设计,介绍了模具工作过程.利用该模具生产出了合格压铸件.     

薄壁矩形管弯曲过程截面畸变的三维有限元分析

薄壁矩形管的弯曲成形是一个受材料性能和工艺参数等诸多因素交互作用的复杂成形过程,在弯曲过程中极易产生截面畸变等缺陷,导致成形质量难以达到要求。为此,文章提出了薄壁矩形管弯曲成形过程截面畸变的描述方法,并基于ABAQUS/Explicit软件平台,从截面形状变化、截面畸变量大小和弯曲过程中的能量变化等方面,研究了芯棒与管坯间隙和管坯与防皱块之间的摩擦对截面畸变的影响规律。该研究对薄壁矩形管弯曲过程工艺参数的选取,提供了理论依据。     

X-ray diffraction study on Ni---Al---Se amorphization by mechanical alloying

In this paper, the amorphization process in mechanical alloyed Ni---Al---Se powders has been investigated by X-ray diffraction. The influence of Se on the amorphization of Ni---Al alloys, and the influence of milling time on the powder structure, microcrystallites size and phases lattice distortion are presented. Also, the Fe and Cr content from the milling medium, after 400 h, was determined.