锅炉喷嘴用耐热钢的高温抗氧化性研究

以25-20耐热钢为基准,与几种自配锅炉喷嘴用奥氏体耐热钢在900℃及1050℃做了高温氧化对比试验。结果表明:Cr25Ni12Mn1Si2钢的抗氧化性接近25-20钢。用它代替25-20钢,可因Ni的加入量减少而带来明显的经济效益。并用扫描电镜对氧化膜做了初步的研究。     

Al含量对Fe-22Cr-25Ni含铝奥氏体耐热钢高温抗氧化性能的影响

以HR3C合金成分为基础,通过调控Cr、Ni含量和添加1.5%,2.5%和3.5% (质量分数) 的Al制备了Fe-22Cr-25Ni型含铝奥氏体耐热钢,并研究了合金的高温抗氧化性能。利用SEM、EDS和XRD对含铝奥氏体钢700、800和900 ℃氧化后的氧化膜组成、结构进行了表征。结果表明：22Cr-25Ni-2.5Al和22Cr-25Ni-3.5Al含铝奥氏体耐热钢在700和800 ℃下具有优异的抗高温氧化性能。氧化后表层形成了连续致密的Al₂O₃保护膜,提高了其高温抗氧化性能。3种耐热钢经900 ℃氧化时形成外层为Cr₂O₃和MnCr₂O₄的复合氧化层,且氧化层下存在Al₂O₃内氧化物和AlN析出相,不能对基体起到有效保护作用。     

Al对ZG40Cr25Ni20抗磨耐热钢高温抗氧化性的影响

在ZG40Cr25Ni20抗磨耐热钢中加入不同含量的Al,在900℃和1100℃下分别进行循环高温抗氧化性试验。通过不同温度下氧化增重测量、氧化动力学分析,以及试验后试样形貌观察,得出了Al对ZG40Cr25Ni20高温抗氧化性能的影响规律,结果表明适量的Al能明显提高ZG40Cr25Ni20的高温抗氧化性。     

微合金化对40Cr25Ni20Si2耐热钢性能影响的研究

研究了Al、Ti、N、Nb等复合微合金化对ZG40Cr25Ni20Si2耐热钢组织和性能等的影响。结果表明,不同组合的复合微合金化ZG40Cr25Ni20Si2耐热钢均达到完全抗氧化级别;0.3%左右的Nb与Ti、Al等复合微合金化对耐热钢的抗高温氧化性能和高温变形抗力均有提升,继续增加Nb含量至0.7%以上,组织中出现大量Nb的碳氮化物析出,变形抗力继续增加,但抗高温氧化稳定性下降;Al、Ti复合微合金化抗高温氧化的稳定性最好,Cr₂O₃-Al₂O₃复合氧化层均匀、连续、致密且与钢基结合紧密,但高温变形抗力低于含Nb的试样。在N含量增加的情况下,适当降低Ni含量,结合微合金化,耐热钢总体性能保持稳定。     

Fe-Cr基耐热钢1250℃的抗氧化性能研究

采用X射线衍射(XRD)、扫描电镜(SEM)及能谱分析(EDS)等方法对三种Fe-Cr基耐热钢在1250℃的抗氧化性能进行了分析和研究.结果发现,1250℃下,ZG35Cr27Ni7Si耐热钢和ZG35Cr24Ni7SiN耐热钢具有较好的抗氧化性能,其原因是具有致密且连续的氧化膜,并且其氧化膜与基材结合得较为密实,不易剥落,保护了基材.ZG35Cr24Ni7SiN耐热钢的抗氧化性能最好,ZG35Cr24Ni7N耐热钢最差.     

稀土钇对FeCrNi耐热钢循环氧化行为的影响

采用增重法在1100℃、1150℃和1200℃条件下对Fe-21Cr-11Ni试验钢进行循环氧化试验,结合X射线衍射、扫描电镜及能谱等方法研究了钇元素在耐热钢抗高温氧化中的作用机理。结果显示,添加微量稀土钇元素能显著提高耐热钢的抗高温氧化性能。在氧化过程中,钇元素能促进铬元素向氧化层的扩散,在含钇耐热钢表面,形成了致密的粘附性好的Cr2O3层和FeCr2O4尖晶石外氧化物层,起到了很好的保护作用,在内氧化层中,钇元素不仅加强了SiO2钉扎,而且直接参与和强化了钉扎作用。     

Al对1Cr9Al(1-3)Ni(1-7)WVNbB合金相变与性能的影响规律

为了研究Al对铁素体耐热钢相变与性能的影响规律,通过在已有合金T92的成分基础上进行Al元素的添加及改性添加剂Ni的调整制备出了新型高铝铁素体耐热钢,研究了不同含量Al元素的加入及热处理工艺下铁素体耐热钢相变温度与淬火组织晶粒尺寸、硬度及抗氧化性的关系。结果表明,实验钢的平衡相变点随着Al元素含量的增加而升高,且实验钢的奥氏体晶粒尺寸越大,Ac1和Ac3温度越高;钢中添加的Al、Ni元素总量在2.4 wt %时,淬火后的奥氏体晶粒尺寸最小,且硬度最大;在650 ℃环境下,钢中添加3 wt %Al比添加1 wt %Al的抗高温氧化性能强;在750 ℃环境下,钢中所含改性添加剂Ni起到了一定的作用,Al-Ni比越大,钢便表现出了较强的抗氧化性。     

含铝奥氏体耐热钢的高温氧化性能

以Fe-18Cr-30Ni为基础,添加不同含量的Al设计了4组新型奥氏体耐热钢。利用氧化质量增加法研究了4组新型奥氏体耐热钢在700、800和900 ℃下空气中的氧化行为,绘制了氧化动力学质量增加曲线,并利用XRD、SEM和EDS对氧化膜的表面形貌及结构进行了表征。结果表明,1～3号钢在900 ℃时均形成了较为致密的Al2O3内层氧化膜,合金表面生成的复合氧化膜由内到外依次为 Al2O3、(Al0.9Cr0.1)2O3、尖晶石氧化物Fe(Cr, Al)2O4;1号钢氧化过程中还形成了富（Cr, Fe）的混合氧化物,降低了Al2O3氧化膜的连续性;4号钢900 ℃并没有形成致密的Al2O3内层氧化膜,生成的复合氧化膜由内到外依次为 (Al0.9Cr0.1)2O3、尖晶石氧化物Fe(Cr, Al)2O4。     

ZG35Cr24Ni7SiN耐热钢不同温度下的氧化膜特征分析

运用X射线衍射(XRD)和扫描电镜(SEM)等手段对900℃和1 250℃下的ZG35Cr24Ni7SiN耐热钢的氧化膜进行了分析和研究.结果发现,ZG35Cr24Ni7SiN耐热钢900℃下的氧化膜在氧化初期只有一层,为Cr2O3 膜,随着氧化时间的延长,其氧化膜分3层,外层为SiO2膜,中间层为Fe2O3膜,内层为Cr2O3 膜,并且在Cr2O3 膜与基材间存在着一个富镍层,由此具有非常好的抗氧化性.ZG35Cr24Ni7SiN 耐热钢1 250℃下的氧化膜在初期分两层,外层为Mn3 O4/NiFe2O4膜,内层为Mn3O4/Cr2O3/SiO2膜.随着氧化时间的延长变成一层,为Cr2O3/Mn3O4 膜,具有较好的抗氧化性.     

高铬白口铸铁高温氧化性能的研究

由于高铬白口铸铁中铬的碳化物（Fe,Cr）7C3呈孤立的花状、杆状和块状形态存在,从而使韧性、硬度提高,常用作耐磨铸铁.为拓宽应用范围、降低成本和节约贵重的金属镍,将20%Cr、25%Cr的高铬白口铸铁和Cr-Ni钢18-8钢分别在650℃、800℃、和950℃下保温20 h、60 h、100 h后,测定各个试样单位表面积氧化增重量、氧化膜的厚度、基体中铬含量、碳化物中铬含量、试样表面与内部铬含量变化,研究了3种材料的抗氧化性能.结果表明,20%Cr白口铸铁的抗氧化性能在任何温度下都是最差的.650℃、800℃时18-8钢的抗氧化性能与25%Cr白口铸铁相近;950℃时25%Cr白口铸铁的抗氧化性优于18-8钢.因此,25%Cr白口铸铁可以代替18-8钢用作高温耐热材料.     

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).