Modeling and simulation of metal forming equipment

The demand for components made from hard-to-form materials is growing, as is the need to better understand and improve the control of metal forming equipment. Techniques are presented for developing accurate models and computer simulations of metal forming equipment for the purpose of improving metal forming process design. Emphasis is placed on modeling the dynamic behavior of hydraulic vertical forge presses, although similar principles apply to other types of metal forming equipment. These principles are applied to modeling and simulation of a 1000 ton forge press in service at Wright-Patterson Air Force Base, Ohio, along with experimental verification.     

炮弹壳体液态模锻模设计

采用液态模锻工艺生产杯形、薄壁深筒形炮弹壳体,依据零件图设计了液态模锻工艺用锻件图、试验用模具,并生产出试验产品。经过试验产品分析,最终设计制造出生产用模具。模具结构简单、紧凑,工作平稳,生产的零件符合设计要求。     

汽轮机叶片无余块锻造

针对汽轮机叶片锻造余块给后续加工带来困难,分析了汽轮机叶片锻件上的余块结构特点,提出了无余块锻造工艺.采用一个过渡面,实现叶根(或叶冠)分型面与叶型分型面过渡,取缔了原有的锻造余块过渡,经实践证明是可行的.这一新工艺节省材料,提高生产效率,降低了生产成本,促进汽轮机叶片锻造技术进步,对于其他具有余块锻件的工艺改进有参考价值.     

板材脉冲激光微冲击成形技术及研究现状

激光微冲击成形是利用脉冲激光作用于材料时引起的等离体爆轰波的冲击作用,使超薄板材产生塑性变形的新技术,可以用于微弯曲、微拉深、微胀形等。文章介绍了脉冲激光微冲击成形技术的原理和特点,概括了激光微冲击成形的影响因素和有限元模拟关键技术,从激光诱导冲击波、板材变形机制、冲击后材料力学性能和微观组织变化等方面,综述了激光微冲击成形技术的研究进展,并对其发展趋势进行展望。     

金属板料台阶孔冲锻成形工艺研究

提出了台阶孔两步冲锻成形优化工艺。研究表明,台阶孔两步冲锻成形工艺较好地提高了钣金零件台阶孔的表面质量和强度,且成形模具寿命长、生产效率高。     

Simulation of bulk metal forming processes using one-step finite element approach based on deformation theory of plasticity

The bulk metal forming processes were simulated by using a one-step finite element(FE)approach based on deformation theory of plasticity,which enables rapid prediction of final workpiece configurations and stress/strain distributions.This approach was implemented to minimize the approximated plastic potential energy derived from the total plastic work and the equivalent external work in static equilibrium,for incompressibly rigid-plastic materials,by FE calculation based on the extremum work principle.The o...     

铝硅铜合金液态模锻工艺

在ZL102合金中加入4%的铜为原料,采用正交试验方法进行工艺实验研究,确定了最佳工艺参数。实验结果表明,采用液态模锻工艺,制件力学性能明显提高,热处理后组织得到细化,硅颗粒分布均匀;Al2Cu强化相析出,使得抗拉强度比热处理前的抗拉强度提高11.8%,比金属型提高44.5%。     

模锻成形过程中金属变形流动的测试方法

利用此方法对叶轮锻件成形过程中两个典型截面上4条流线及其轴向应变进行了测量分析,并定量给出该复杂锻件成形过程中变形及应变分布规律。因而该方法是测试模锻成形过程中金属塑性变形流动较为有效的实验手段。     

半固态模锻变形机制研究

通过帽形件的半固态模锻成形,阐述了半固态浆料变形的物理模型,研究了半固态浆料变形过程及变形机制。实验表明:半固态浆料模锻成形的变形方式是不同的,不同的固相率下其固液两相的塑性流动机制也是不同的;而且制件不同部位的微观组织形貌也有差异。     

新型金属热模锻用非石墨型润滑剂的研究

针对目前广泛用在金属热模锻中的石墨型润滑剂存在的污染环境和难以清理等问题,以无机层状氮化物和硬脂酸盐为主要固体润滑材料,得到系列非石墨型润滑剂,并对其润滑性能和润滑机理进行了研究。结果表明,4种系列润滑剂中,以无机层状氮化物配以复合硬脂酸盐类为主要成分的热模锻润滑剂具备最优良的悬浮性、成膜性,并且润滑性能与石墨型润滑剂相当,清理容易。目前,该新型非石墨型润滑剂可以在一定范围内替代石墨型润滑剂,是一种环保型润滑剂。     

圆环零件液态模锻研究

通过圆环零件的液态模锻成形实验,对在不同比压和浇铸温度条件下,锻件的微观组织形貌和力学性能进行了分析研究.结果发现,在不同比压下,随着比压值的增加,α枝晶长度随之减小,枝晶被破碎,锻件力学性能也随之升高;在不同浇铸温度条件下,锻件微观组织也有着较大的差异,且随着浇铸温度的升高,粗大树枝晶被打断、破碎细化现象较为明显,锻件组织致密,力学性能逐渐上升.     

敷料设计对曲轴模锻金属充填的影响

以三缸曲轴的模锻工艺为例,研究敷料设计对曲轴模锻成形中的金属流动规律的影响。建立了不同的敷料和连皮设计方案,通过数值模拟获得了曲轴平衡块的成形效果,并分析了敷料处的金属流动速度、成形载荷和模具应力。研究结果表明,设置敷料可以有效改善曲轴平衡块的充填效果,同时不会引起成形载荷和模具应力的大幅上升;敷料位置应靠近连杆颈而远离飞边桥以减少金属外流,敷料体积应根据平衡块的充填效果而定。     

H11钢锻模液态模锻试验与模具结构改进

介绍了对H11钢锻模液态模锻试验的工艺流程,分析了原模具结构的不足,并进行了改进。模具设置了防飞溅装置、冷却系统及溢流装置。结果表明,得到的液态模锻制件的尺寸和性能都达到了设计要求。     

Microstructure and mechanical properties of AZ61 Mg alloy prepared by multi directional forging

AZ61Mg alloy was multi directionally forged(MDFed) during decreasing temperature condition from 643 K to 483 K at a true strain rate of 3×10-3 s-1 up to cumulative strain of∑△ε=4.0 at maximum.A pass strain of△ε=0.8 was employed.While average grain size decreased gradually with increasing cumulative strain,the evolution of fine-grained structure strongly depended on the MDF temperature.Under the condition where the temperature was higher than the most adequate one,grain coarsening partially took place during MDF.In contrast,at lower temperature,inhomogeneous microstructure composed of the initial coarse and newly appeared fine grains was evolved.After straining over∑△ε=3.2(i.e.,over 4 passes of MDF) ,equiaxed ultrafine grains(UFGs) having average size of about and lower than 1μm were uniformly evolved.While the MDFed alloy to∑△ε=4.0 possessed relatively high hardness of HV 99,and it accepted further about 20%cold rolling almost without cracking.Because of the superior formability of the UFGed AZ61Mg alloy,the hardness was further easily raised to HV 120 by following cold rolling.     

Grain size and texture changes of magnesium alloy AZ31 during multi-directional forging

Grain size and texture changes of magnesium alloy AZ31 were studied in multidirectional forging(MDF) under decreasing temperature conditions.MDF was carried out up to large cumulative strains of 4.8 with changing the loading direction during decrease in temperature from pass to pass.MDF can accelerate the uniform development of fine-grained structures and increase the plastic workability at low temperatures.As a result,the MDFed alloy shows excellent higher strength as well as moderate ductility at room ...     

影响搅拌摩擦焊金属塑性流动的因素

针对LF6/LD10、12／T2研究了搅拌摩擦焊(FSW)的金属塑性流动。通过工艺试验，分析了影响FSW金属塑性流动的因素。研究结果表明，被焊材料反复动态再结晶是其持续塑跬流动的前提条件。影响金属塑性流动的因素主要有两个——材料的变形温度和变形速率。搅拌工具使材料保持高应变速率，并对材料快速加热，致使层错能很高的铝发生动态再结晶，促使其稳定流动。保持一定的焊接温度有利于金属动态软化，促进塑性流动，实现焊接。     

等径三通多向模锻金属流动研究

通过对等径三通多向模锻过程的弹塑性有限元模拟和实验验证，揭示了等径三通成形过程中金属流动的一般规律，为此类锻件的工艺设计提供了有价值的参考依据。     

应用多点调形方法的柔性辗压技术研究

探讨了一种柔性辗压成形工艺,该工艺利用多点调形的思想,用多点支撑的柔性辊代替传统摆动辗压的上部锥形模,由柔性辊来实现坯料上部曲面的辗压加工.通过建立柔性辗压的有限元模型,分析了该工艺的可行性;利用点追踪技术分析了成形过程中的金属流动规律;探讨了加工过程中轴向总载荷及各单元的受力特点;研究了加工过程中出现的缺陷和问题,提出了改进方法.     

双金属层堆焊法制备铸钢基体大型锻模

采用在铸钢基体上堆焊双金属层（过渡层和强化层）的方法设计与制造大型或超大型模锻液压机锻模。用MDS金相显微镜、SEM电子扫描显微镜、显微硬度测和试落锤冲击实验技术对铸钢ZG310-570双层堆焊试样进行了分析。结果表明,过渡层中含有的大量细小针状铁素体能提高模具韧性并改善强度,防止裂纹产生,并且有效地将表面强化层与铸钢基体层结合在一起,使整个试样的力学性能、硬度等呈逐步提高趋势,使过渡层具有良好的塑韧性。将该方法运用到40 MN热模锻压机用锻模的实际生产中,成功生产合格锻件7166件,模具寿命提高50％,成本降低20％。