共查询到20条相似文献,搜索用时 46 毫秒
1.
钛合金扁形锭冷坩埚电磁约束成形工艺参数研究 总被引:2,自引:0,他引:2
在自行研制的多功能冷坩埚电磁约束定向凝固装置上进行了钛合金扁形锭的冷坩埚连续成形实验,考察了不同参数下的成形工艺过程,分析了工艺参数变化对所成形钛合金锭质量的影响程度。结果表明:增大感应线圈匝数和增加加热功率可提高铸锭表面质量,但是提高抽拉速度和降低底料与线圈之间的相对位置会降低表面质量。在所研究的参数中,对铸锭表面质量影响的上次因素为,感应线圈的匝数最大,加热功率次之,抽拉速度再次,最后为底料相对线圈位置。在讨论这些参数的作用原理基础上,提出了可获得良好表面质量的工艺参数,铸造出表面光滑、无裂纹缺陷的钛合金扁形锭。工艺参数对铸锭宏观组织的影响表现在随感应线圈匝数的增多和抽拉速度的减小,铸锭晶粒的数量减少,晶粒偏离轴向程度减小,后续实验表明在截面形状近似为矩形的冷坩埚下可以获得既有良好表面质量又具有定向组织的钛合金扁形铸锭。 相似文献
2.
3.
Titanium and TiAl-based alloys are promising structurematerials for aero/space-crafts of next generations due totheir excellent properties, such as high specific strength,high specific rigidity, high oxidization resistance and highcreep resistance at high temperature[1-3]. However, the Tialloys are highly active, especially in molten state they canreact with almost all other materials. This makes thespontaneous nucleation difficult during solidification andresults in coarse structures. These … 相似文献
4.
板坯热送热装或连铸连轧技术逐渐被越来越多的钢厂采用,然而其进一步发展受到连铸坯质量的制约。故针对连铸坯缺陷的有效判断可避免存在质量问题的铸坯进入轧制环节,从而降低额外的能耗。基于对铸坯质量的在线检测困难这一问题,从生产大数据的角度建立了板坯热轧卷的质量预测模型。首先根据正常与缺陷产品高度不平衡的数据特点,提出了相关性分析、不平衡数据随机分类与主成分数据降维三者相结合的数据预处理方法,随后选择GA-BP神经网络算法构建了针对低碳钢、包晶钢和中碳钢的热轧卷质量预测模型。预测模型具有较高的准确率,其中低碳钢模型总体预测准确率达到94.7%,缺陷预测准确率为82.8%;包晶钢模型总体预测准确率达到93.3%,缺陷预测准确率为87.5%;中碳钢模型总体预测准确率为85.4%,缺陷预测准确率为87.3%。最后,基于Python语言编写了热轧卷质量在线预测软件,可对热轧卷质量进行实时预测,方便快速地溯源缺陷发生原因。 相似文献
5.
采用直接测量固态导体内部磁场分布的方法,研究影响穿过式传感器实际渗透深度的各种因素。结果表明,实际渗透深度除与导体的电导率、磁导率及测试频率有关外,还与线圈的结构及激励磁场有关。最后利用遗传算法建立了涡流实际渗透深度的数学模型,为确定涡流在导体中的实际渗透深度提供了可靠依据。 相似文献
6.
This paper presents a combined analytical-numerical approach to solving the pulsed eddy current problem accurately and quickly. Considering the displacement current, the analytical solution to the voltage of a cylindrical coil above a laminated conductor in the complex-frequency domain is deduced by Laplace transform. The time-domain induction voltage values of a cylindrical coil with a pulsed current are calculated by the fourth-order integro-differential FFT-based numerical inversion of Laplace transform. At the same time, the time-domain analytical solution to the induced voltage of a cylindrical coil with a pulsed current above a half-infinite non-ferromagnetic conductor is derived, and has been verified by comparison with Finite Element Method (FEM) simulation results. The calculation results prove that the adopted numerical inversion method of applying Laplace transforms to the pulsed eddy current problem has a high accuracy and fast convergence. The transient voltages produced by a square-wave current excitation when considering the displacement current in the vacuum area are higher than those when ignoring the displacement current, by as much as 27.7% at certain times. The higher the lift-off is, the smaller the voltage peak is and the faster the voltage drops. As the application of this method, the induced voltages are computed in the measurements of metal's thickness and metal coating thickness. 相似文献
7.
8.
在自行研制的多功能冷坩埚电磁约束定向凝固装置上进行了钛合金扁形锭的冷坩埚连续成形试验,考察了工艺参数变化对所成形钛合金锭成形性的影响.结果表明增大感应线圈匝数和增加加热功率可提高铸锭表面质量,但是提高抽拉速度和降低底料与线圈之间的相对位置会降低表面质量.在所研究的参数中,对铸锭表面质量影响的主次因素依次为感应线圈的匝数、加热功率、抽拉速度、底料相对线圈位置.在讨论这些参数的作用原理基础上,提出了可获得良好表面质量的工艺参数,获得了截面为矩形、表面光滑、无裂纹缺陷的钛合金矩形锭. 相似文献
9.
Yen Fei Li Jing Zheng Shijun Jiang Donghui Liu Lu Liu Wei Ma Guangtong Wang Jiasu Wang Suyu Applied Superconductivity Laboratory Southwest Jiaotong University Chengdu China State Key Laboratory of Traction Power National Laboratory for Rail Transit 《稀有金属材料与工程》2011,(Z3)
The static thrust output on a superconducting coated conductor coil at different excitation and alternating current suspended above a three phase alternating current long-stator comprised of copper coils is presented. Excitation current up to 45 A was applied through the superconducting coil acting as the excitation system of the superconducting linear synchronous motor (SLSM), alternating current up to 9 A was applied to the armature and magnetic air gaps of 10 and 15 mm were investigated for four differen... 相似文献
10.
Novel solutions that correctly incorporate all electromagnetic interactions arising in inductively coupled circuits are presented for the case of a coaxial driver and pickup coil probe encircling a long ferromagnetic conducting rod. The differential circuit equations are formulated in terms of the rod׳s impulse response using convolution theory, and solved by Fourier transform. The solutions presented here are the first to account for feedback between a ferromagnetic conductor and the driver and pickup coils, providing correct voltage response of the coils. Experimental results, obtained for the case of square wave excitation, are in excellent agreement with the analytical equations. 相似文献
11.
研究了有限厚导电平板上方的倾斜圆形线圈在脉冲电流激励下产生的电磁场。推导了倾斜圆形通电线圈的电流密度表达式,解析求解了导体内部的涡流密度,并提出了一种计算时域响应的有效方法。结合算例,分析了瞬态涡流的时空特点,讨论了线圈倾角、板厚与响应的关系。计算结果显示,提出的方法可用于分析倾斜圆形线圈的线性瞬态涡流场问题。与软件仿真结果的对比验证了所提模型和方法。所得结果有助于了解在倾斜条件下所获得的脉冲涡流检测信号。 相似文献
12.
13.
14.
In the present work, the strength and distribution of electromagnetic field in the square cold crucible that designed for casting multicrystalline silicon were measured and analyzed by using a small coil method. The results show that in the perpendicular direction the maximum of magnetic flux density (B) appears at the position slightly above the middle of the coil, and then B attenuates toward both sides, and decreases more to the bottom of the crucible. In the horizontal direction, from the edge (corner) to the center, B firstly decreases gradually, and then slightly increases in the center. While along the inner sides of the crucible, the distribution is relatively uniform,especially in the effective acting range. B increases with the increasing of the input power. Moving the coil to the top of the crucible, B increases and the effective acting range of the electromagnetic field becomes bigger. For the coils with different tums, the five turns coil can induce the highest magnetic flux density. 相似文献
15.
开发了用于导电的1060铝合金挤压卷带材。为了保证电阻率稳定,对带材截面尺寸要求很高,并要求其外形整齐、无划沟,特别是在带材接头处不能有尺寸突变。通过多次试验研究制定了最佳的挤压工艺,生产出的卷带材表面质量、外形尺寸和性能稳定,均满足客户的要求。 相似文献
16.
本研究设计制作的高温超导直线同步电机样机中,次级使用由Y-Ba-Cu-O带材绕制成的4个跑道型硅钢芯超导线圈,以传统的铜线绕组作为初级,其中4个次级超导线圈串联并在其背部附加铁轭。通过改变初次级间的气隙,研究了不同气隙高度下该样机的推进力和法向力。结果表明,在气隙高度较低时,推进力随着气隙的增大迅速衰减,而气隙高度较高时,推进力的衰减减弱。并且本直线电机样机的推进力密度为117 N/m,而只用了不到16 m长的超导带材。可为今后大型直线同步电机的设计提供参考 相似文献
17.
针对钢管管端以交流线圈纵向磁化方式探伤时内壁周向缺陷难以检出,以及以交流电穿棒周向磁化方式探伤时内、外表面磁探灵敏度差异很大等现象,参照解释交流电磁场集肤效应的方法,建立了两个定性模型进行推导,得到结论:圆筒类工件采用交流线圈纵向磁化时,磁场主要集中在外表面,内壁磁场削弱甚至抵消;采用交流电中心导体法周向磁化时,磁场集中在内、外表面,但两处磁场的强度会有不遵循磁探经验公式的较大的差异。此结论能解释试验现象,有助于对圆筒类工件磁化方法的选择。 相似文献
18.
《International Journal of Cast Metals Research》2013,26(1-4):298-301
AbstractTo improve the surface quality of cast slabs in the steelmaking process, the pulsating electromagnetic casting (EMC) technique was developed and assessed using a slab casting bench scale test. Numerical simulation of the magnetohydrodynamic field and numerical simulation of the toughness of the mould were also conducted for the slab casting plant test. Consequently, the mould and coil for slab casting plant tests with pulsating EMC were manufactured and the basic functions were verified. Finally slab casting plant tests with the pulsating EMC technique were conducted. 相似文献
19.
20.
A study of pore closure and welding in hot rolling process 总被引:5,自引:0,他引:5
The design of processing conditions to eliminate porosity in steel during hot rolling has become more critical with the advent of continuously cast feed stock. To predict appropriate process parameters, experiments were performed in which holes were drilled in steel slabs, at different depth below the surface perpendicular to the rolling direction. After hot rolling, the state of the deformed holes was examined by optical microscopy. The fracture surfaces of tensile specimens notched in the plane of the closed holes were examined under a scanning electron microscope to investigate the bonding ( welding ) between the surfaces of the closed holes because this bonding is the most important factor indetermining the transverse mechanical properties of the rolled product. The deformation of such holes in the roll gap was modelled as an clastic / plastic plane strain problem using the FE software ABAQUS to investigate the strain and stress around holes and to analyze the conditions required to promote pore closure and welding between the closed surfaces.
Experiment results showed that the rate of pore closure was affected by the parameters of rolling process and the position of holes relative to the rolling contact surfaces. FE simulation of pore closure showed a good agreement with experimental results and showed that a certain level of hydrostatic pressure resulted in the closure of pore and that the holding period of the pressure in the compressive state determined the degree of welding of surface of pores; shear is favourable to this welding. 相似文献