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平整过程中由于带钢下表面平整液滴落导致带钢出现上下表面摩擦因数不同的异步轧制现象,使用平整过程的轧制压力模型预报平整异步轧制过程中的轧制压力时精度不高。为此,针对普通工程适用的平整轧制压力模型计算平整异步轧制轧制压力误差较大的问题,提出适用于异步轧制的轧制压力计算方法。考虑到异步轧制的工艺特点与设备的实际工况,首先分析带钢上下表面润滑条件差异性和受力变形情况,建立变形区的平衡方程和单位轧制压力计算方程。其次研究了异步与同步轧制上下轧辊压扁的差异性,根据上下轧辊轧制过程中变形的几何关系和弹塑性力学理论,确定了变形区各参数的计算方法。在此基础上,采用迭代方法提升计算模型精度,建立了适用于平整机组异步轧制过程的轧制压力计算模型,同时给出了带钢上下表面摩擦因数返算方法。最后,为了验证模型的准确性,利用国内某平整机组的设备参数和实际生产过程中的典型规格带钢工艺参数,对比不同润滑条件下本轧制压力模型理论计算值与工程适用的平整轧制压力模型计算值和现场实测数据。结果表明,提出的平整过程中异步轧制轧制压力计算模型能适用于异步轧制情况下的轧制压力计算,与工程适用的平整轧制压力计算模型相比误差减小5%,具有... 相似文献
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研究了由平整工艺产生的平整轧制方向对半加工无取向电工钢板的磁性及方向性的影响。平整轧制方向大大地影响了电工钢的磁性得方向性。通过控制平整轧制方向 ,在需要的方向上 ,如 0°、90°及整个圆周方向上 ,可对B50 的大小进行调整 ,并且B50 值高于普通平整 0°轧制方向内B50 的大小。分批退火后 ,钢板的织构随着平整轧制方向的变化而发展 ,该结果表明 ,由平整工艺产生的剩余应变能随着平整轧制方向而变化 相似文献
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针对不锈钢/碳钢复合板在平整轧制过程中极易出现不均匀延伸并导致板形翘曲的行为,建立了不锈钢/碳钢复合板平整轧制过程的有限元数值模拟模型,对已实现工业化批量生产的不锈钢/碳钢复合板平整轧制过程的不均匀变形行为及其可能导致的板形翘曲缺陷进行数值模拟研究。在此基础上,对比分析了均质板、非对称不锈钢/碳钢复合板以及对称不锈钢/碳钢/不锈钢复合板平整轧制过程板形的遗传与演变规律,发现仅非对称不锈钢/碳钢复合板在平整轧制过程中极易产生板形翘曲缺陷,同时对比分析了平整和常规轧制对非对称不锈钢/碳钢复合板轧后翘曲缺陷的影响。揭示了不锈钢/碳钢复合板厚向分层特征以及复合板尺寸参数、平整工艺和平整机设备参数等对其板形翘曲缺陷的影响规律,研究表明,对复合板尺寸参数而言,平整过后翘曲高度与厚度比呈正比。对于平整工艺而言,当等张力平整轧制时,平整过后翘曲高度与张力呈正比;当不等张力平整轧制时,前张力的变化对平整过后翘曲缺陷的影响较大;同时平整过后翘曲高度与轧辊和碳钢层表面摩擦因数呈反比。对平整设备参数而言,平整过后翘曲高度与碳钢层表面接触的轧辊辊径、入口侧防皱辊抬起高度以及不锈钢层表面接触轧辊偏向入口侧的距离均呈正比关系。最后,采用轧制试验对数值模拟结果进行了验证,证明了复合板平整轧制模型的准确性。基于上述研究结果,提出了相应的工艺对策,为金属复合板平整轧制过程的板形翘曲控制提供了理论依据。 相似文献
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针对传统的以赫希柯克公式为基础的轧制压力模型不适合于平整轧制的问题,经过大量的现场数据回归与理论分析,充分考虑到不同平整机组的设备工艺特点与实际工况,综合轧制速度、变形抗力、张力、伸长率等平整轧制工艺参数的影响,根据平整轧制过程轧辊与带材交界面处接触弧更具平面性质而非圆柱表面性质的特点,在罗伯茨平整轧制压力模型的基础上,提出了一套工程上实用的平整轧制压力计算模型,同时给出了相应的模型自学习方案,并将其应用到宝钢冷轧薄板厂1220平整机机组的生产实践,95%以上的钢卷轧制压力预报值与实际值的相对误差在10%以内,达到了工程要求,取得了良好的使用效果,具有进一步推广应用的价值. 相似文献
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FEM Analysis of Physical Field in Level Rolling Process of Inversion Casting by ANSYS Program 总被引:4,自引:0,他引:4
Ininversioncastingprocessmothersheetisledthroughameltwhichthencrystallizesonthesurfaceofthestrip.Throughacoupleoflevelrollersabovethemeltthecastingstripisroughlyrolled,thefigureisshownintheReference[1].Levelrollingisveryimportantintheprocess. ThevaluesimulationtechnologyonthebasisofFEMhasbeenusedgraduallyinthefieldofmetalplasticforminginrecent20years.Thetheoriesareadoptedfromsmallelastic-plasticdeformationFEMtobigelastic-(viscidity)plasticdeformationFEM,andtheanalysistechnologyisbecomin… 相似文献
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The integrated casting and rolling of steel plates in processes such as Inline Strip Production or Arvedi Steel Technology is the latest and very efficient way of hot strip production. The numerical modelling is very helpful in developing a “know how” theory for the mentioned processes. One of the most important relationships having crucial influence on the metal flow path is the strain‐stress curve. The inverse method, which is usually the only method of calculating a real strain‐stress relationship, needs a good mathematical model describing the plastic behaviour of the material. The model presented in the current paper fills the gap in modelling of plastic deformation of semi‐solid materials. On the other hand, the mathematical modelling should be closely related to experiments. The well known machine allowing tests in the discussed temperature range is the GLEEBLE thermo‐mechanical simulator. However, carrying out experiments with steel deformation in the semi‐solid state using this machine is very expensive. Therefore, application of a dedicated computer simulation system is strictly required. Inverse analysis and appropriate modelling of the testing procedure makes tests possible, first of all, but it also results in lowering testing cost. The newest version of the Def_Semi_Solid is a unique FEM system supporting tests at extra high temperature. 相似文献
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An integrated mathematical model is proposed to predict the velocity field and strain distribution during multi-pass plate hot rolling. This model is a part of the mixed analytical-numerical method (ANM) aiming at prediction of deformation variables, temperature and microstructure evolution for plate hot rolling. First a velocity field with undetermined coefficients is developed according to the principle of volume constancy and characteristics of metal flow during rolling, and then it is solved by minimizing the total energy consumption rate. Meanwhile a thermal model coupling with the plastic deformation is exploited through series function solution to determine temperature distribution and calculate the flow stress. After that, strain rate field is calculated through geometric equations and strain field is derived by means of difference method. This model is employed in simulation of an industrial seven-pass plate hot rolling process. The velocity field result and strain field result are in good agreement with that from FEM simulation. Furthermore, the rolling force and temperature agree well with the measured ones. The comparisons verify the validity of the presented method. The calculation of temperature, strain and strain rate are helpful in predicting microstructure. Above all, the greatest advantage of the presented method is the high efficiency, it only takes 12 s to simulate a seven-pass schedule, so it is more efficient than other numerical methods such as FEM. 相似文献
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A thermal elastic-plastic finite-element analysis to roll-life prediction on the twin roll strip continuous casting process 总被引:12,自引:0,他引:12
The rolling force and roll deformation behavior in the twin-roll-type strip continuous casting process have been computed
to estimate the thermal characteristics of a caster roll. To calculate the rolling force, the relationship between the flow
stress and strain for a roll material and a casting alloy are assumed as a function of the strain rate and temperature, because
the mechanical properties of casting materials depend on temperature. The three-dimensional (3-D) thermal elastic-plastic
analysis of a cooling roll has also been carried out, to obtain roll stress and plastic strain distributions, with the commercial
finite-element analysis package of ANSYS. Temperature field data for a caster roll, provided by the authors, were used to
estimate the roll deformation. Therfore, numerical models considering the thermal and rolling forces have been developed to
estimate the roll life. Roll life considering the thermal cycle is calculated using thermal elastic-plastic analysis results.
The roll life is proposed in terms of roll revolution in the caster roll models with and without the fine crack failure on
the roll surface. To obtain plastic strain distributions of the caster roll, thermomechanical properties of a roll sleeve
with a copper alloy are obtained by a uniaxial tensile test for variation of temperature. The proposed analysis techniques
have improved in caster roll design. 相似文献
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超薄快速铸轧条件下轧制区内温度梯度很大,其轧制压力是温度的强耦合函数。本文在利用切块法推导出超薄快速铸轧过程轧制区的静力平衡微分方程的基础上,利用温度分布的线性假设建立了变形抗力关于位置坐标的简化模型,由此可根据铸轧条件下混合摩擦条件求出了各相应摩擦条件下的平衡微分方程的解析解,即获得轧制区轧制压力分布的解析计算模型,该模型同样适用于常规铸轧条件下的铸轧仿真研究。 相似文献
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The present investigation was undertaken in context with the development of the single‐belt strip casting process. In this new process the casting is directly connected to hot rolling which must be carried out at lower speed than in conventional hot rolling to match the casting rate. We have used an integrated thermal/mechanical finite element model to theoretically study the effect of rolling speed on rolling parameters. Since the model is general and the question of “slow hot rolling” is of general interest, the computations were carried out for a wide range of volumetric flow rate extending from that in thin slab casting to that in conventional finishing rolling. The results are given on the influence of rolling speed on roll force, torque, power, temperature change of stock and roll, and roll life. The most important effect of slow hot rolling seems to be the increased heat up of the rolls. This causes an increase of plastic strain in the near surface region of the rolls that will intensify the formation of fatigue cracks. 相似文献
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针对薄板坯连铸工艺中的关键技术液芯压下特点,选取沿柱状晶方向的铸态钢试样分别在不同温度和应变速率下进行热压缩模拟试验,为液芯压下结构提供材料高温流变应力模型。通过建立液芯压下过程数值模型,研究和分析液芯压下工艺中铸坯变形特征和凝固坯壳的应力应变分布规律,以及液芯形态变化情况。为了找到薄板坯连铸液芯压下工艺的最佳工艺参数组合,对坯壳厚度、压下量和辊间距三个参数进行优化设计。通过建立响应面来构造液芯压下近似模型,描述各工艺参数与液芯压下结果之间的关系。在近似的模型的基础上,利用遗传算法,通过全局最优优化算法寻找出构造近似模型的最优解,从而得到板坯液芯压下最佳工艺参数组合,并进行了压下试验。 相似文献
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在建立了铸造区,轧制区轧制压力模型的基础上,对常规铸轧条件进行了仿真计算,计算结果与实测数据相吻合,从而验证了模型的正确性,在此基础上,对超薄快速铸轧条件进行了虚拟仿真研究,研究结果表明:不增强铸轧辊内,外冷却能力的条件下,而仅仅减薄铸轧 板坯厚度即可提高铸轧速度,在其它工艺参数保持不变,且保持出口温度与常规铸轧时基本相近的出口温度时,铸轧 厚度 薄时轧制压力比常规铸轧高,随着铸轧速度与铸轧区增大,铸轧坯厚度减薄,铸轧 辊径增大,轧制压力峰值增大。 相似文献
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针对H型钢“V”形开裂问题,研究了连铸异形坯存在的质量缺陷,对同类连铸生产具有参考与借鉴意义。H型钢由异型坯轧制生产而成,其比表面积较大,通过连铸生产时铸坯表面冷却强度极不均匀,各面受力情况较为复杂,而对其整个生产工艺流程及质量控制方面均有较高要求。以新泰钢铁公司实际生产中发生轧制开裂的Y Q235B连铸坯为研究对象,通过对缺陷铸坯进行重熔检测,采用ANSYS软件与现场检测相结合的方法,分析了铸坯表面纵裂纹的形成原因及控制方法。结果表明,H型钢V形开裂的主要原因是由腹板和R角处的纵向裂纹造成的,而形成纵向裂纹的主要原因是冶炼过程中控制不合理,精炼脱不够;连铸过程中不能有效地控制和去除夹杂物;铸坯环向温度梯度过大,造成腹板和R角处冷却极不均匀,应力应变过大。通过采取优化改进工艺后,异型坯轧制出现V形开裂比例由原先的80%降低至5%以下,产品质量大幅提升。 相似文献