用三辊行星轧机轧制钢管的新方法

<正> 三辊行星轧机(PSW)是第一种连续操作的、轧件断面压缩依赖于轧制的大压下轧机。在配置有三个轧辊、连续操作酌行星轧机上,轧制一道次就能得到15∶1的延伸率。到目前为止,三辊行星轧机都用于实心轧件的大压下变形。这种新型轧机的一台样机已经于1970—1974年在西德Wetzlar的Buderus特殊钢厂进行了成功的试验。在正常生产条件下操作的第一台三辊行星轧机,作为一台棒材轧机的粗轧机,从1975年就已在西德Schwerte的Hoesch公司投入使用。另外一台用作棒材轧机的粗轧机的三辊行星轧机已于1977     

三辊行星轧机(PSW)轧管研究

在理论分析三辊行星轧制的轧制力和轧制功率的基础上,进行了轧制试验,结果表明,采用三辊行星轧机轧管,无论是尺寸范围,还是表面质量、公差均能达到预期目的。     

三辊行星轧管机运动速度研究

通过对三辊行星轧管机(PSW)的结构和运动特点的分析,建立了轧制过程中轧辊的速度方程和轧件不旋转条件,通过在φ50mm三辊行星轧管机上进行的轧管试验,推算出了轴向和切向滑移系数。     

行星斜轧中轧辊与轧件的几何关系分析

利用行星斜轧轧件变形区微分几何模型和对行星斜轧中轧辊与轧件表面数值分析,结合轧制实际情况,研究了轧件的形状、轧辊与轧件的接触线、轧辊干涉及其检验,并给出了三辊行星轧机中的实例分析。     

采用三辊行星轧机的新型热轧管工艺

三辊行星轧机是大压下量轧机,目前这种轧机仅用于轧制捧材。西德施劳曼-西马克公司(SMS)制造的两台这种轧机至今仍在正常运转。三辊行星轧机的原理是三个锥形轧辊布置在轧件周围,相互成120°角,形成一个锥形变形区。由于轧辊倾斜布置,其旋转运动产生将轧件送入变形区的进给运动。1974年,西德布德鲁斯厂的三辊行星轧机曾试轧过空心管坯,其结果证实这种生产方法是有发展前途的。1977年6月至1979年12月,     

三辊行星轧机的应用

介绍了三辊行星轧机及轧制工艺特征和应用情况,并与其他几种轧制工艺进行了比较,结果表明,三辊行星轧管工艺具有优势,产品质量满足市场要求。     

500热连轧窄带钢粗轧工艺优化及有限元分析

针对某500热连轧窄带钢生产线Φ650三辊粗轧机组采用双根轧制代替单道次轧制的优化方案,利用ANSYS/LS-DYNA有限元软件对Q235B钢优化前、后的整个粗轧过程进行了数值模拟分析。分析结果表明:优化前后轧件断面温度、等效应力-应变分布规律基本一致;特征点温度与实测值吻合良好,前5道次轧件侧面出现了明显的双鼓形;由于采用共轭孔型轧制,上下轧槽直径不对称,轧件上表面应力、应变比下表面略大;对优化前后的轧制力及轧件尺寸进行了分析对比,校核了优化前后粗轧机的主设备能力。优化结果表明优化后的轧线生产能力提高28.47%。     

三辊行星斜轧机的辊形探讨

三辊行星斜轧机轧制时,三个轧辊在围绕轧件公转的同时进行自转,而轧件在变形过程中并不旋转,只有轴向运动。为此,必须保证轧辊公转转速与自转转速之比与变形区中轧辊直径与轧件直径之比相适应。采用差速传动系统可以无级调整轧辊公转转速与自转转速之比。此外,为了正常轧制,还必须采用合理的     

三辊行星轧机辊型的理论分析

本文通过对轧辊辊面上点的运动速度的分析,导出了三辊行星轧机的正常轧制条件及轧件不转条件,探讨了一种能保证轧件在变形区内不旋转的轧辊辊型的设计方法。     

三辊行星轧制中轧辊轧件接触区分布的计算改进

三辊行星轧制中,轧辊轧件接触区的分布是轧制力能参数的计算基础。在轧制过程中轧件的轴向延伸变形不可避免,这将直接影响到轧辊轧件接触区的分布。在已有的研究基础上,考虑到轧制过程中轧件轴向延伸变形的影响,运用理论分析得出了接触区的分布函数。给定轧制工艺参数,利用数值计算得到了轧辊轧件接触区分布的具体情况,结果显示,受到轧件轴向延伸的影响,轧辊轧件接触区变得更为狭窄。该结果不仅相比于已有的研究更加符合三辊行星轧制中的轧辊轧件实际的接触情况,还表明接触区的分布不仅只受到轧制常数、倾斜角、偏转角、轧辊转速和轧件进给速度的影响,同时还受到轧件的原始尺寸的影响。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.     

Structural Optimization of Electromagnetic Swirling Flow in Nozzle of Slab Continuous Casting

During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.