用1.5 t·~(-h)冲天炉生产7.5t铸件

通过下冷铁等工艺措施,采用1.5t·h冲天炉成功地生产出7.5t铸件,并详细介绍了该铸件的造型及浇注工艺。     

发电设备用球墨铸铁缸体铸造工艺改进

针对缸体铸件生产中出现的缩松缺陷,分析了其产生的原因,增加了冷铁和工艺补贴,并对冒1：2和浇注系统进行了核算改进。生产实践表明,合理设置冷铁和冒1：2,使铸件中的缩松缺陷得以消除;采用开放式浇注系统,可降低铸件冲砂、夹渣缺陷产生的风险;大型球铁件合理使用过滤网,对于铁水的净化可以起到明显的作用。     

大型QT350-22AL轮毂铸件的铸造工艺

采用电炉熔炼、呋喃树脂砂造型、浇注温度为1 340～1 360℃的高温慢浇底注工艺生产单件质量超过12t的大型风电设备用QT350-22AL轮毂铸件.针对出现的缩松面积超标、铸件与冷铁接触表面气孔缺陷等问题,采取了提高铁液出炉温度、上调CE到4.55％、加强冷铁的使用管理等措施,结果使铸件的力学性能和探伤均符合要求.     

大型球铁件的铸造工艺设计

介绍大型球铁件铸造工艺设计的主要原则为:加工面向下;尽量采用一个分型面;采用底注;长度大的铸件采用两端同时浇注,重大件采用拔塞浇包浇注;铸件顶部设置明冒口;充分利用石墨化膨胀补缩.用具体实例说明适合于大型球铁铸件的各种铸造工艺原理和特点,以及浇注系统设计、冒口设计和冷铁使用的要点.     

用1.5 t·h-1冲天炉生产7.5 t铸件

通过下冷铁等工艺措施,采用15 t@h-1冲天炉成功地生产出7.5 t铸件,并详细介绍了该铸件的造型及浇注工艺.     

镦锻中心机身消失模铸造工艺

用消失模铸造生产牌号为HT300的Z46-18/4机身铸件。选择开放式浇注系统,适当设置内外冷铁,严格控制铁液的化学成分,并进行两次孕育;浇注后和开箱落砂前在型内保温适当时间。检测结果表明:整体铸件没有任何铸造缺陷;单铸试棒金相组织为:珠光体体积分数97%,碳化物3%;力学性能为抗拉强度325MPa,硬度229HB。     

内冷铁在厚大铸钢件生产中的应用

铸钢件生产中采用内冷铁是为了缩小铸件热节处的模数或缩小整个铸件的模数,减少冒口的体积或数量,消除缩孔、缩松缺陷. 1 内冷铁在54 t大板上应用的工艺设计 铸件尺寸为5 500 mm×2 860 mm×440 mm,模数Mc=22 cm,毛重54 t.冒口的个数为2,按放内冷铁和不放内冷铁工艺设计情况大不相同.     

激冷铸铁凸轮轴气孔缺陷原因及防止

神龙轿车用凸轮轴质量 3.5 kg,材质为无合金化灰铸铁 ,化学成分 (质量分数 ,% )为 :3.2～ 3.7C、1.7～ 2 .2 Si、0 .6～ 1.1Mn、≤ 0 .15 P、≤ 0 .18S。在 1t或5 0 0 kg中频炉内熔炼 ,包内硅铁孕育 ,铁水出炉温度(15 0 0± 10 )℃ ,浇注温度 136 0～ 14 0 0℃ ,采用壳型浇注 ,每型两件 ,浇注系统布置见图 1,铸件凸轮部位采用分块冷铁 36 0°激冷。批量生产中 ,常因在凸轮 (激冷面 )处出现气孔 ,造成铸件大量报废。图 1　凸轮轴浇注系统布置简图1　气孔缺陷特征气孔主要分布在中间两组凸轮的上表面。气孔的形状有规则的椭圆形、梨形、小圆…     

双包浇注冶金轧机牌坊的铸造工艺设计

针对冶金轧机牌坊毛坯截面厚、重量大,浇注钢液需33 t左右,一台25 t电弧炉无法实现浇注的问题,对冒口、冷铁、砂芯、浇注系统和熔炼浇注进行设计,并采用CAE进行工艺模拟验证,使用双包浇注工艺方案,能够生产出合格产品。结果表明,双包同时浇注是解决大型铸件超出熔炼设备能力而采用的一种可行工艺方案。     

转子支架铸造工艺设计与数值模拟

基于ProCAST软件模拟了转子低碳合金钢支架铸件的充型过程,分析了铸件可能出现夹渣原因,并提出浇注系统加过滤网、冒口与冷铁配合使用的工艺方案,并对改进方案进行了数值模拟分析。结果发现,浇注系统加过滤网可以吸附夹杂、平稳液流。冒口与冷铁配合使用可消除铸件缩孔、缩松缺陷。试生产表明,该工艺可获得品质良好,能满足使用要求的转子支架铸件。     

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.     

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.     

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。     

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.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).