拖拉机支架壳体的铸造工艺

通过设计合适的分型面和浇注位置、砂芯工艺和项冒口补缩,选取Cu-Sb合金化和低稀土球化剂,采用含Ba孕育剂包内孕育加75SiFe随流孕育的二次孕育等措施,支架壳体铸件中缩孔、缩松、冷隔、气孔和裂纹等缺陷得到有效控制,材质性能可稳定达到技术要求.     

中频感应电炉熔炼铁液特性研究及对策

中频电炉熔炼铁液的某些特性与冲天炉熔炼铁液相比存在许多差异,三角试片白口大,铸件中S含量低,石墨形态以E型或E D型为主,珠光体含量低,导致铸件“裂纹”缺陷的大量发生。生产中采取增硫和强化孕育工艺及“快熔快出”的操作工艺,以上缺陷可得到克服。     

大型HT300主轴箱的铸造工艺

鉴于大型HT300主轴箱技术要求不允许出现裂纹、缩孔、渣孔等铸造缺陷,精心设计了铸造工艺方案和浇注系统,合理布置了冒 口、冷铁和加强筋;在1台7t冲天炉和2台5t中频电炉同时熔炼的条件下,采用含Ba的75SiFe长效孕育剂进行孕育处理,浇注温度1 340～1 360℃,浇注时间183 s.经测试,单铸试棒抗拉强度为320 MPa,落砂、清理及粗加工后未发现任何缺陷.     

锻钢冷轧辊坯内裂缺陷控制研究

冷轧辊坯超声波探伤超标的主要原因是裂纹性缺陷,非金属夹杂物对裂纹性缺陷的产生起到了重要的作用。高温扩散可明显改善对冷轧辊坯超声波探伤超标缺陷,终锻工艺应充分利用夹杂性裂纹的变化特点控制裂纹性缺陷。     

汽车制动盘渣气孔缺陷成因及工艺改进

通过扫描电镜和能谱分析,对制动盘孔洞类铸造缺陷处进行分析,发现缺陷处存在Al、 Ca、 Si、 Mn、 Ba等元素,确认其为渣气孔缺陷。利用鱼骨分析法对渣气孔缺陷成因进行分析,对铸铁孕育工艺和型砂混砂工艺加以改进,采取使用Ca、 Al元素含量较低的孕育剂进行孕育处理,以及减少型砂含泥量来降低型砂水分的措施,有效减少了制动盘的渣气孔缺陷。     

陶瓷砂轮坯体缺陷及其产生裂纹的预防

裂纹是陶瓷砂轮的主要废品现象之一。本文分析了陶瓷砂轮成型后坯体的缺陷以及由缺陷产生裂纹的机理。对成型后砂轮坯体缺陷进行了分类,提出了减少成型后砂轮坯体缺陷及预防缺陷产生裂纹的工艺措施。     

ZL101配重球镶铸工艺设计

针对大型肥厚配重球铸铝件内腔产生的裂纹缺陷,分析了产生缺陷原因,改常规工艺为镶铸工艺,通过合理设计镶嵌件,正确选取固定、连接镶嵌件的方法,优化选取各种工艺参数等工艺措施,成功解决了铸件裂纹缺陷,生产出满足使用要求的铸件。     

铸钢大型履带板冒口设计及退火工艺的改进

分析大型履带板裂纹缺陷产生的原因.通过改进冒口设计,热割冒口工艺以及预备热处理工艺,消除大型履带板裂纹缺陷,合格率由60%提高到96%,使单件成本下降20%.     

离心复合铸造厚壁辊筒的裂纹缺陷

针对离心复合铸造厚壁辊筒裂纹缺陷,分析其产生的原因及影响因素,采取有效的工艺措施,克服了裂纹缺陷。     

高压闸阀的堆焊

在高压闸阀的闸板上堆焊钴基硬质合金,焊接裂纹是常见缺陷.而在基体材料为CA15铸钢件(马氏体不锈钢)的高压闸阀的闸板上堆焊钴基硬质合金CoCr-A而不出现裂纹缺陷则是更困难的工艺.基于焊接性分析、焊接工艺评定试验、试生产以及试生产后的工艺改进,焊接裂纹缺陷可以大幅度减少甚至消除.阀门制造商可根据阀门口径的大小选择合适的...     

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.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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.