共查询到18条相似文献,搜索用时 859 毫秒
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采用有限元软件DEFORM-3D对楔横轧厚壁空心轴进行热力耦合数值模拟,得到了工艺参数对楔横轧厚壁空心轴不圆度的影响规律。结果表明,在成形角35°~45°、展宽角4°~7°、断面收缩率35%~65%、轧制温度900℃~1100℃时,轧件不圆度与成形角及断面收缩率的变化成反比,与展宽角及轧制温度变化成正比。采用H630楔横轧机进行轧制实验验证了有限元模型的正确性。模拟与实验结果证明,轧件横截面失圆是楔横轧成形厚壁空心轴类件常见的质量问题;变形区金属沿轴向的流动受到未变形金属的阻碍,是造成不圆度在轧件的对称面上最大并沿轴向逐渐减小的原因。研究结果为确定楔横轧厚壁空心轴的工艺参数提供了理论依据。 相似文献
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采用轧制工艺生产GH4169合金异型材,结合实验条件,基于有限元模拟软件建立了单轧槽少道次轧制过程的三维刚塑性有限元模型。采用异型坯作为坯料,分析了轧制过程中孔型充满度、变形温度、等效应变和等效应力的分布情况。模拟结果表明,采用Φ160 mm×200 mm轧机时,初轧温度为1070℃,断面收缩率为45%,单轧槽两道次轧制成形,孔型充满度良好,等效应变约为0.3~1.4。结合模拟结果,在轧机上进行了热轧实验,轧件厚度满足尺寸要求,宽度比成品小2 mm,没有发生晶粒细化。这主要是由于多火次、多次数轧制,使得加热引起的晶粒长大程度大于小变形量引起的晶粒细化程度,使得晶粒未细化,宽度不够。 相似文献
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楔横轧大断面收缩率一次楔成形轧件心部质量规律及原因 总被引:2,自引:0,他引:2
为确定楔横轧大断面收缩率一次楔成形工艺心部质量的加工界限,对大断面收缩率下轧件心部质量规律进行了深入探索。采用实轧实验方法得到轧件心部最大孔洞面积数据;对比常规断面收缩率下轧件心部最大缺陷尺寸数据,得到大断面收缩率一次楔成形轧件的心部质量规律;并利用有限元数值模拟方法对大断面收缩率与常规断面收缩率轧件心部应力、应变进行对比分析,找出规律的原因。所得规律为,大断面收缩率轧制轧件心部质量整体好于常规断面收缩率轧制,另揭示出其原因为,大断面收缩率轧制轧件金属瞬时轴向流动量大,杆部中心剩余金属少,可供缺陷发展的空间也较小;不利于轧件心部质量的应力应变作用的时间较短,与工艺时间相同时刻常规断面收缩率的应力应变最大值相差比例也较小,静水压力在整个轧制过程中有利于轧件心部质量。 相似文献
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利用DEFORM-3D有限元软件建立了其三维刚塑性有限元模型,通过仿真与实验相结合的方法,分析展宽角、成形角、断面收缩率对GH4169合金成形过程中力能参数的影响规律。结果表明在展宽段有:随着成形角的增大,径向力、横向力和轧制力矩均减小,轴向力略增大,但增大幅度不明显;随着展宽角的增大,径向力、横向力和轧制力矩均增大,轴向力减小;随着断面收缩率的增大,径向力、横向力和轧制力矩先增大后减小,轴向力增大。采用无量纲影响因子法,综合分析获得了工艺参数对力能参数影响的主次顺序。在此基础上,进行了1∶1楔横轧GH4169合金实验,得到轧制力矩与数值模拟结果相对误差在10%以内。研究结果为GH4169合金轴类件楔横轧成形合理选取工艺参数和轧机设计力能参数确定提供参考。 相似文献
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通过分析楔横轧内部空洞(疏松)缺陷的物理性质和形成特征,将内部空洞视为多孔材料,利用多孔材料的刚塑性有限元方法,建立7075铝合金坯料内部空洞缺陷的数值模型。采用相对密度研究成形角、展宽角、断面收缩率对内部空洞缺陷的影响规律。结果显示:内部空洞的扩展主要发生在展宽段,楔入段对它的影响很小。展宽角是影响内部空洞产生的主要因素,而断面收缩率的影响较小。成形角、展宽角、断面收缩率越大,越不易发生内部空洞缺陷。在模具设计时,为了防止铝合金坯料轧制后产生内部空洞缺陷,断面收缩率应选择在55%~65%之间,展宽角在8°~10°之间,成形角在29°~32°之间。 相似文献
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对Inconel 740H合金荒管进行了不同变形量的冷轧实验,分析了其冷变形特性。通过冷变形后不同制度的退火处理,对Inconel 740H合金组织演变规律进行研究,建立了退火过程中再结晶晶粒长大方程。同时引入不均匀因子Z对组织均匀性进行评定。研究表明,Inconel 740H合金中间退火处理中的静态再结晶过程主要受退火温度和保温时间影响,所构建的再结晶晶粒长大方程与实验值吻合度较好。冷轧变形量为20%,中间退火制度为1100℃/5 min时得到的组织最为均匀。 相似文献
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J. ChenK. Chandrashekhara C. MahimkarS.N. Lekakh V.L. Richards 《Journal of Materials Processing Technology》2011,211(2):245-255
Cold rolling is used to eliminate void defects in cast materials thus improving the material performance during service. A comprehensive procedure is developed using finite element analysis and neural network to predict the degree of void closure. A three-dimensional nonlinear dynamic finite element model was used to study the mechanism of void deformation. Experiments were conducted to investigate void closure during the cold flat rolling process. Experimental results are compared to the three-dimensional finite element predictions to validate the model. The void reduction predictions from finite element analysis are in good agreement with experimental findings. Plastic strain, principal stress distribution around the void and void reduction ratio are presented for various case studies. As finite element simulation is time-consuming, a back-propagation neural network model is also developed to predict void closure behavior. Based on the correlation analysis, the reduction in sheet thickness, the dimension of the void and the size of the rollers were selected as the inputs for the neural network. The neural network model was trained based on results obtained from finite element analysis for various simulation cases. The trained neural network model provides an accurate and efficient procedure to predict void closure behavior in cold rolling. 相似文献
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本文结合GCr15再结晶模型, 根据轧线实际孔型参数、轧线布置与轧制程序, 采用刚塑性有限元法, 利用模拟软件Deform对轴承钢线材GCr15粗轧进行了三维有限元模拟, 分析总结了粗轧过程中轧件温度场、等效应变和应变速率的变化规律, 得出粗轧过程动态、亚动态和静态再结晶的百分数和对应晶粒尺寸, 揭示了轧件在粗轧过程中再结晶规律及奥氏体晶粒细化规律, 并且证实了初始晶粒尺寸对粗轧过程奥氏体晶粒细化的影响规律。 相似文献
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Mohammad Reza Forouzan Iman Salehi Amir Hossein Adibi-sedeh 《Journal of Materials Processing Technology》2009,209(2):728-736
A detailed comparison between the quality of slabs formed by sizing press and vertical rolling mill is presented. ABAQUS/explicit commercial finite element software with elasto-viscoplastic constitutive model for material is used to study the geometric characteristics and deformation pattern during width reduction in these processes. Finite element models developed for both sizing press and vertical rolling processes are validated by comparing their results with experimental data available in literature. Parametric studies are performed using validated finite element models for sizing press mill to determine the effect of input process parameters such as initial slab width and thickness, width reduction and transfer pitch on the process outputs such as dogbone formation, head and end fishtail profiles, width necking at the leading end of the slab and slab edge quality. Similarly, developed finite element models for vertical rolling are used to investigate the effects of different input parameters on the slab deformation after passing through a vertical rolling stand with the aim of comparing the two width reduction processes. According to the results, benefits and drawbacks of each width reduction method are discussed. The enhancing effect of subsequent horizontal rolling after sizing press and vertical rolling processes on the final slab thickness is also presented. 相似文献
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为了提高W形金属密封环的成形质量,本文对W形金属密封环的超声振动滚压成形过程进行了研究。基于ABAQUS/Explicit有限元仿真软件,搭建了W形金属密封环超声振动辅助滚压成形三维有限元模型,研究了超声频率对环件不均匀变形的影响。结果表明:随着超声频率的增加,环件的应力不均匀度呈现先增后减的规律;环件的应变不均匀度呈现先略微减小,然后激增,再减小的规律;壁厚不均匀度呈现先减小,后增大,再减小的趋势。其中在超声频率为30kHz与40kHz时环件变形不均匀程度显著增大,这是由于环件产生了起皱现象造成的;通过对截面的应力、应变和壁厚不均匀分析,证明了波峰与波谷位置是成形过程中的关键部位。 相似文献
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