共查询到19条相似文献,搜索用时 454 毫秒
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提出了基于往复式喷射成形工艺制备大璧厚非规则管坯的近终形成形工艺及其工艺参数优化方法,以实现坯件从CAD设计到喷射成形的快速制备过程。该工艺方法包括三个阶段:非规则管坯的三维CAD设计、分层处理和单层沉积厚度计算;基于沉积厚度与往复速度和质量流率的对应关系,计算满足各层沉积厚度所对应的控制参数;利用控制系统和执行机构对控制参数进行实时控制和调节,采用往复式多层喷射成形工艺制备满足设计轮廓的管坯。通过试验进行了验证,喷射成形制备的管坯形状和轮廓与CAD设计模型较好地一致,表明了该工艺方法的可行和正确性。 相似文献
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喷射沉积过程是一个多参数共同影响的复杂过程。通过对雾化器往复扫描规律以及其它工艺参数的研究,可以对喷射沉积过程进行工艺优化。基于对沉积过程的分析,建立了雾化器往复扫描喷射沉积的数值模型。采用计算机数值模拟技术与实验结合的方法,着重研究了喷射成型过程中雾化器的扫描运动对成型的影响;实验证明,根据分析所得到的雾化器扫描曲线,可以准确预测这类成型产品的形状和尺寸。 相似文献
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Al10Zn2.9Mg1.7Cu超高强铝合金的喷射成形制备研究 总被引:12,自引:4,他引:8
采用喷射成形技术制备了Al10Zn2.9Mg1.7Cu高强高韧铝合金沉积坯件,研究了喷射成形制备过程中各工艺参数对沉积坯件的成形性、显微组织、致密度的影响,确定了适当的工艺参数,研究了沉积坯件的热挤压及热处理工艺,对材料的组织进行了分析并对不同状态的材料性能进行了比较。研究结果表明:当喷射成形工艺参数合理时,沉积坯件具有良好的成形性与致密度,在随后的热挤压过程中,通过较低的挤压比即可使材料达到全致密;通过对合金进行适当的热处理,材料的极限抗拉强度达到810MPa,同时延伸率保持在8%-11%,该材料是一种理想的轻质高强结构材料。 相似文献
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热挤压对喷射沉积7055铝合金显微组织和力学性能的影响 总被引:1,自引:0,他引:1
《粉末冶金材料科学与工程》2015,(5)
采用全自动控制往复喷射成形工艺制备工业规格7055铝合金锭坯,研究热挤压工艺对喷射成形7055铝合金的显微组织和力学性能的影响。采用电子背散射衍射技术对经不同热挤压后7055铝合金的织构进行研究。结果表明,喷射沉积锭坯组织为等轴状晶粒,均匀细小(30~50μm),基体中不存在枝晶型偏析。由于喷射沉积工艺本身的特点,在合金中存在大量的显微疏松缺陷。沉积锭坯经过热挤压致密化后,合金力学性能显著提高,抗拉强度σb为390 MPa,伸长率δ为13.3%,表明热挤压工艺可有效消除疏松缺陷,从而充分发挥出喷射沉积工艺的优越性。EBSD分析表明,挤压后沿着挤压轴方向形成丝织构,主要为?001?与?111?两种织构。 相似文献
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A transient simulation and dynamic spray cooling control model for continuous steel casting 总被引:6,自引:0,他引:6
Richard A. Hardin Kai Liu Christoph Beckermann Atul Kapoor 《Metallurgical and Materials Transactions B》2003,34(3):297-306
A two-dimensional heat-transfer model for transient simulation and control of a continuous steel slab caster is presented.
Slab temperature and solidification are computed by the model as a function of time-varying casting speed, secondary spray
cooling water flow rates and temperature, slab thickness, steel chemistry, and pouring and ambient temperatures. Typically,
the solidification path, temperature-solid fraction relationship, is prescribed. However, if these data are not available,
a microsegregation solidification model that approximates the effects of steel chemistry and cooling rate is incorporated
in the caster model. Measured slab surface temperatures recorded from an operating caster are compared with predictions from
the transient model. These demonstrate that the model typically can predict the temperature response at the slab surface within
30 °C. Results of several simulations are given to demonstrate the effects of changing casting conditions on the slab thermal
profile, end of liquid pool, and solidification end point. A control methodology and algorithm suitable for online control
of a continuous casting machine is described, and the ability to control the surface temperature profile by dynamically adjusting
secondary spray cooling flow rates is demonstrated by simulation. Results from a preliminary version of the model that is
capable of running in real time are presented and are compared with the slower, but more realistic, version of the model. 相似文献
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Hyun-Kwang Seok Jae-Chul Lee Ho-In Lee Hui Choon Lee Kyu Hwan Oh Hyung Yong Ra 《Metallurgical and Materials Transactions A》2000,31(5):1479-1488
In rod spray forming, the preform changes its shape continually from that of a disc to a rod (transient-state rod growth)
and then maintains its top surface profile once it has settled down (steady-state rod growth). The rod growth mechanism during
spray forming was analyzed using rod-forming models. At a sufficiently high substrate rotation velocity, the calculated results
based on the three-dimensional time-dependent model (3-D TDM) and the two-dimensional time-dependent model (2-D TDM) were
observed to be identical. The calculated results of the rod’s top shape, obtained by the TDMs, were almost identical to those
obtained by the two-dimensional time-independent model (2-D TIM), which means that there exists steady-state rod growth. The
effects of spray-forming parameters, such as initial eccentric distance, substrate withdrawal velocity, and spray angle, on
the shape-evolution behavior were analyzed in terms of the vertex growth velocity (
). The optimum spray-forming condition to minimize transient-state rod growth was also presented. Experimental verification
was made to confirm the proposed forming models. 相似文献
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In this paper, a compensation control model of secondary cooling process of billet continuous casting for quality steel has been presented. The effects on the spray control of the various parameters such as steel superheat, casting speed, cooling water temperature and chemical component of steel were considered. The parameters of control model were determined to associate with the two‐dimensional heat transfer equation and solved by finite‐difference method. Effects of steel superheat and cooling water temperature on surface temperature, solidification structure and solidifying end point were discussed. Results indicate that steel superheat significantly affects solidification structure and solidifying end point but has a little effect on slab surface temperature. Moreover, secondary cooling water temperature affects surface temperature and solidifying end point but has a little effect on solidification structure. The surface temperature and solidifying end point can be maintain stabilized through applying the compensation control model when steel superheat and cooling water temperature vary. The models have been validated by industrial measurements. The results show that the simulations are in very good agreement with the real casting situation. 相似文献
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Modeling and Simulation of Spray Forming of Clad Deposits with Graded Interface Using Two Scanning Gas Atomizers 总被引:1,自引:0,他引:1
A three-dimensional shape model based on a surface coordinate tracking method has been developed for clad deposits with graded interface which are spray formed using two scanning gas atomizers. The calculation of element distributions in the deposits has been incorporated into the shape model. On this basis, the deposit shape and the element distributions in the deposit have been simulated. It shows that the scanning mode of the atomizers and the degree of overlapping of the two sprays play important roles in the spray forming of clad deposits. A concentration gradient of chemical elements in the deposits can be achieved under proper processing conditions. Finally, the modeling and simulation of the spray forming of clad deposits have been validated by experimental investigations. 相似文献
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Analysis on the deposition behavior of spray on deposition surface was made and an optimization method for the movement parameters (u, ω) of substrate was obtained. Simultaneously, a mathematical model of growth of tubular preform, specifically aimed at the kind of atomizer that is fixed and with a tilt angle was established. By integrating the optimization method and the mathematical model, the growth process and shape of preform were simulated. The results show that the tilt angle of atomizer plays an important role on the dimensions and shapes of tubular preforms and it can provide a guidance for the development of spray forming equipment. 相似文献
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《钢铁冶炼》2013,40(6):497-502
AbstractAn analytical model has been developed to investigate the optimum pinch roll load and resulting slab thickness reduction during the continuous casting of a steel, constant thickness, thin slab in a vertical type machine. The pinch roll unit consists of two driven pinch roll sets, which support the solidified hot slab weight and take up the reaction forces owing to slab bending. Optimum conditions prevail when the pinch roll load required to support the slab weight is equally shared by the two pinch roll sets and has the minimum value allowing proper control of the slab speed. The model has been validated by being applied to an existing industrial case of thin slab continuous casting of plain low carbon steel. The effects of pinch roll radius, slab thickness, casting speed, slab temperature and the material carbon percentage on minimum pinch roll load and slab thickness reduction ratio have been investigated. Expressions have been obtained for the optimum pinch roll load and slab thickness reduction ratio related to the prevailing process parameters, which the plant operator can directly apply to determine the optimum pressure setting for the hydraulic cylinders fitted to the movable roll ends. The bending roll load is shown to be small compared with the pinch roll load. 相似文献