现代电弧炉炉型及其炉体结构设计

介绍了超高功率电弧炉炉体结构的变化， 对原有确定电弧炉炉型尺寸的方法进行了修正和补充； 其方法不但适合超高功率电弧炉， 也适合普通功率的小型电弧炉。     

意大利电弧炉技术的新发展

<正> 电炉是一个大的波动的负荷,会引起供电电网电压的波动(闪烁)。随着电弧炉安装容量的增大,对电网干扰的矛盾变得更加突出。为此,意大利的Danieli开发了新一代电弧炉,即高阻抗电弧炉、直流电弧炉和Danarc电弧炉。本文就各种电弧炉的特点及典型实例作一简单介绍。 1.特点 (1)低阻抗普通交流电弧炉低阻抗普通交流电弧炉通过断路器和隔离开关与供电线路相连。功率输入由调压变压器和电极调节系统中的电弧阻抗控制器来     

直流电弧炉操作效果

用交流电弧炉生产钢或铁合金,石墨电极的消耗在生产费用中仅次于电源的消耗。美国ASEA公司的新型单电极电弧炉可减少50％电极消耗。每吨钢可节约电极费用8.40美元。单电极直流电弧炉的投资大约高出普通三相交流电弧炉费用的25％。但所增加的投资通过每吨钢所减少的电极费,在不到一年的时间内收回。ASEA公司目前采用直流电弧炉用废钢生产了近10,000吨钢。这种电弧炉还可用铁矿粉直接还原铁,无需压块或球     

集成智能控制策略在高阻抗电弧炉炼钢过程中的应用

针对电弧炉炼钢过程的高度非线性、时变性、不确定性 ,采用了基于网络环境下的遗传神经控制、多级递阶控制和专家预估补偿控制等集成智能控制策略 ,实现了高阻抗电弧炉炼钢过程的最优化及实时监控。在石家庄钢铁厂的实际应用表明 ,该系统能较好地适应负荷变化与外部干扰 ,其控制性能优于普通电弧炉系统 ,降低了生产成本 ,提高了生产效率     

大吨位双炉室真空自耗电弧炉的研制

通过分析目前国内外大吨位真空自耗电弧炉普遍采用的结构型式，指出了这些型式的电弧炉存在的缺陷和不足，提出了一种双炉室真空自耗电弧炉结构。详细介绍了该SZHL8双炉室真空自耗电弧炉的主体设计方案、主要技术特点和性能指标，重点介绍了研制过程中主要解决的技术难点，包括双炉室共用整流电源技术、水冷炉室结构的优化、坩埚冷却系统、智能熔速控制系统、充氩熔炼实时控制系统等。     

电弧炉炼钢除尘系统

主要论述了电弧炉的烟尘产生以及除尘办法。提出利用侧吸罩、顶吸罩和活动罩相结合的方式对电弧炉冶炼进行除尘处理，不但能够收集电弧炉各个熔炼时期的烟气，而且还能够有效降低烟气温度，直接进入到布袋除尘器中进行处理，排放浓度远低于国家环保要求。     

交流电弧炉和直流电弧炉的变压器

在交流电弧炉和直流电弧炉技术获得长足发展的同时，变压器的设计原理也产生了巨大的变化。双臂电桥式六脉冲结构是直流电弧炉变压器的一种重要的设计型式（优点是可以节约电极，减少电弧噪声），对于高的额定功率，已采用许多专用部件，设计成12、18或更多脉冲的变压器。对于交流电弧炉，在熔化过程中，为了减少电流变化和电弧闪烁，首先采用带有加载调节装置的串联电抗器，后来应用饱和电抗器，最近又研制成功（并用于生产）带静态补偿装置的耦合变压器。这是提高交流电弧炉供电质量的最佳方法。Tamini是目前世界上第一家生产供电弧炉补…     

美国近年新投产电弧炉主要技术参数一览

美国是电弧炉炼钢发展最快的国家之一，电炉钢产量占粗钢总产量的比例已接近40％。尤其是近几年，每年都有新的电弧炉投入运行。这些新投产电弧炉的主要特点是：普遍采用现代电弧炉新工艺、新技术，如偏心炉底出钢、吹氧助熔、高功率冶炼、直流电弧炉等。冶炼时间大为缩短、劳动生产率成倍提高、钢水质量显著改善、生产成本不断下降。现将美国1988年以来新投产电弧炉的主要技术参数汇列如下：美国近年新投产电弧炉主要技术参数一览@徐树德     

Comelt电弧炉—未来的炼钢工艺

继节能型电弧炉一DC电弧炉诞生后，又一高效电弧炉一Comelt电弧炉异军突起。Comelt电弧炉在结构上的主耍特点是具有数支倾斜电极和在冶炼同时有另1个预热废钢的炉身。废钢用炼钢废气预热。C0melt电弧炉的投资回收期比一般的AC和DC电弧炉短。由于采用倾斜电极的熔化原理和特殊的废钢预热装置，Comelt电弧炉具有明显的经济效益和社会效益，它的主要优点是：1）高性能特征，特别适用炉容量大于150t的电炉。2）由于采用特殊的废钢预热方式，总能耗比传统的电弧炉降低约100kwb／t。3）高的生产率，出钢一出钢时间低于45mina4）电极消耗比常规…     

电弧炉烟尘回收技术创新

主要介绍冶金行业采用电弧炉进行烟尘回收装置的技术改进，改进后取得了明显的经济效益，彻底改善了电弧炉工作岗位的烟尘污染的工作环境．     

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.