石油危机与自动轧管工艺的中兴~((A1))——《无缝钢管百年史话》(续释2-1)

以日本新日铁公司八幡厂的Φ406mm大型自动轧管机组为例,介绍了为满足20世纪70年代石油危机对石油管需求的增加,导致了对自动轧管机组特别是大型机组投资的热潮。详细介绍了Φ406mm自动轧管机组可生产的品种、采用方坯包括连铸坯的规格、热轧生产工艺流程、一般管的精整工艺、石油套管与石油油管的加工工艺以及热轧工艺设备的特点等。     

用水平连铸圆坯生产热轧无缝钢管

介绍了用水平连铸圆坯在φ１００ｍｍ自动轧管机组上生产热轧无缝钢管的工艺概况。     

浅谈三辊轧管机的发展(Ⅱ)

介绍了国外三辊轧管机发展简况、目前世界上三辊轧管机的基本情况和三辊轧管工艺的特点。同时较详细介绍了衡阳钢管厂φ108mm三辊轧管车间的主要工艺特点,并对我国φ76mm、φ100mm自动轧管机组改造及三辊轧管机发展提出了浅见。     

浅谈三辊轧管机的发展(Ⅰ)

介绍了国外三辊轧管机发展简况、目前世界上三辊轧管机的基本情况和三辊轧管工艺的特点。同时较详细介绍了衡阳钢管厂φ108mm三辊轧管车间的主要工艺特点,并对我国φ76mm、φ100mm自动轧管机组改造及三辊轧管机发展提出了浅见。     

φ50三辊轧管机组生产1Cr18Ni9Ti不锈钢管的试验

介绍了用φ50mm三辊轧管机组生产1Cr18Ni9Ti不锈钢管的试验及穿轧工艺参数。     

用三辊斜轧减径工艺生产厚壁管

分析了小型轧管机组生产热轧厚壁无缝钢管存在的问题,介绍了在φ108mm 三辊轧管机上采用斜轧空心减径生产小口径厚壁无缝钢管的工艺。该工艺可避免厚壁管出现内方并减少切头和降低金属损耗,适用于毛管或荒管的空心减径和定径。     

用Φ76mm自动轧管机组试产小直径冷拔管料的研究

介绍了在Φ７６ｍｍ自动轧管机组上试产小直径热轧荒管的有关工艺及参数，生产中需采取的技术措施。比较了用小直径热轧荒管生产小直径薄壁冷拔钢管的冷拔道次数、成材率、金属消耗等。实践表明，用Φ７６ｍｍ自动轧管机组为冷拔提供小直径热轧荒管，扩大了机组的产品规格范围，使冷拔小直径薄壁钢管的生产工艺趋于合理。     

周期轧管机组的改造与现代化

自上世纪末热轧周期轧管机组问世以来,至今已建有80套左右,年生产能力约800×10~4t。生产规格为Φ50～660mm、壁厚4～100mm的无缝钢管。50年代以前,热轧周期轧管机是生产无缝钢管的主要方式之一。但是随着对无缝钢管质量越来越高的要求及无缝钢管生产技术的发展,周期轧管机亦经历着新的技术改造及现代化的进程。     

小直径热轧荒管的生产工艺研究

介绍了用二辊或三辊轧机试轧φ57～76mm小直径热轧荒管的工艺参数、轧辊和芯棒的力能参数、荒管的表面质量及几何尺寸精度等。试验表明,在工业条件下,用二辊轧管机组可生产出符合要求的小直径热轧荒管。     

精密轧管技术现状

随着近20年精密轧管(Accu Roll)技术的飞速发展,精密轧管机组已经成为国内热轧无缝钢管生产的第二大主力机型。介绍了精密轧管技术的现状;指出了精密轧管技术存在的问题;探讨了精密轧管工艺改进的方向和可能性,如采用轧制荒管头尾削尖技术进一步提高芯棒限动速度的可能性,提高机组产能的途径及采用精密轧管机组生产大直径(Φ508mm以上)钢管等。分析认为,精密轧管机组投资少、技术先进,值得研究和选择。     

Molecular beam epitaxial growth of zinc-blende FeN(1 1 1) on wurtzite GaN(0 0 0 1)

We report a study of the growth of iron nitride on gallium nitride using molecular beam epitaxy with Fe e-beam evaporation and rf N-plasma growth. Thin iron nitride layers of thickness about 16 nm were grown and monitored in situ using reflection high energy electron diffraction. The samples following growth were analyzed ex situ using a variety of techniques including X-ray diffraction, Rutherford Backscattering, and atomic force microscopy. By monitoring the structure, morphology, and lattice constant evolution of the iron nitride film, the crystal phase and orientation with respect to the GaN substrate are deduced; and from RBS data, the stoichiometry is obtained. The growth is discussed in terms of a 2-D to 3-D growth mode transition, and a critical thickness is estimated.     

Early stage oxidation of Ni–Cr binary alloy (1 1 1), (1 1 0) and (1 0 0) surfaces: A combined density functional and quantum chemical molecular dynamics study

First-principles and tight-binding quantum chemical molecular dynamics were used in this study. The chemisorption energies of O and OH on the Ni–Cr (1 1 0) surface are lower than those of other surfaces. The oxygen 2p orbitals hybridise with Ni 3d, 4s and small amounts of p orbitals for the (1 0 0) surface while Ni p orbitals have no contribution for the (1 1 0) surface, which might reduce the adsorption energy. Additionally, oxygen acquires the maximum depth into the Ni–Cr (1 1 0) surface. Applied strain increases the oxygen diffusivity. This study reveals that the Ni–Cr (1 1 0) surface is easier for oxygen diffusion accordingly oxidation accelerates.     

Magneto-optical studies of 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61; PCBM

In the quest for better power conversion efficiency of organic photovoltaic cells (OPVC) various architectures have been considered. Bulk heterojunction type OPVC proved to be the most successful, where the polymer as electron donor is blended with fullerene molecule as electron acceptor. With the goal of improving power conversion efficiency of OPVC we studied 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM) as a film and dispersed in polystyrene matrix. We used a variety of continuous wave (cw) optical probes including photoinduced absorption (PA), photoluminescence (PL), and optically detected magnetic resonance (ODMR). The steady state photophysics of PCBM is dominated by triplet exciton. For both PCBM dispersed in polystyrene and PCBM film, the triplet exciton specie is characterized by a PA band at about 1.7 eV and spin 1 PA detected magnetic resonance (PADMR) powder pattern resonance around g ～ 2. However, in PCBM film the occurrence of a polaron PA band at 1.2 eV and spin 1/2 PADMR are also noticed.     

ANISOTROPY OF (1× 1)-SURFACE FREE ENERGIES OF CRYSTALS

The surface free energy (SFE) of (1× 1)-surfaces of crystals, without reconstructionand adsorption, is calculated using a bond-broken mode. In the mode, the potentialenergy of the crystals is treated as a sum of the energies of the bonds connectingpair-wise atoms (u-bonds). The SFE is calculated based on the bond energy and thearea density of dangling bonds which depends on the structure of the surface. Theresults provide a general expression for the SFE in terms of the bond energy (E)and the bond length (do) of the crystal and Miller indices hkl. The anisotropy ofthe SFE is therefore completely determined with the expression. As the examples,considering the nearest-neighboring bonding, the SFEs of sc, fcc, bcc and cth (cubictetrahedral) crystals are discussed, respectively. Wulff plots of bcc and fcc crystalsare then obtained. The equilibrium forms (EFs) of these crystals ave consequentlygot from their Wulff plots, respectively. It is found that the EFs of bcc and fcc arerespectively the rhombic dodecahedron and the truncated-octahedron that are their firstBrillouin zones, respectively.     

Temperature-dependent surface alloying in Au/Ni (1 1 0)

The kinetic Monte Carlo (KMC) simulations have been carried out to address the temperature dependence of the surface alloying in the Au/Ni (1 1 0) system. It was found that no surface alloying is observed when Au is grown on the Ni (1 1 0) surface at the low temperature (≤240 K). At the moderate temperature (255–300 K), the surface alloying forms with the dominated exchange mechanism of Au ad-dimmers. At the high temperature (350–400 K), the surface alloying with the dominated exchange mechanism of Au monomers is observed. The physical and chemical mechanisms of the unique surface alloying behaviors in the Au/Ni (1 1 0) were proposed on the basis of the atomic interactions.     

BiFeO3 thin films of (1 1 1)-orientation deposited on SrRuO3 buffered Pt/TiO2/SiO2/Si(1 0 0) substrates

BiFeO₃ (BFO) thin films of varying degrees of (1 1 1) orientation were successfully grown on SrRuO₃-buffered Pt/TiO₂/SiO₂/Si(1 0 0) substrates by off-axis radio-frequency magnetron sputtering. They demonstrate much enhanced ferroelectric behavior, including a much enhanced remnant polarization (2P_r ～ 197.1 μC cm^?2 at 1 kHz) measured by positive-up negative-down (PUND), at an optimized deposition temperature of 590 °C. The effects of film deposition temperature on the degree of (1 1 1) orientation, film texture, ferroelectric behavior, leakage current and fatigue endurance of the BFO thin films were systematically investigated. While the degree of (1 1 1) orientation is optimized at 590 °C, the defect concentration in the film increases steadily with increasing deposition temperature, as demonstrated by the dependence of leakage behavior on the deposition temperature. The polarization behavior is shown to strongly depend on the degree of (1 1 1) orientation for the BFO thin film. Oxygen vacancies are shown to involve in the conduction and dielectric relaxation of the BFO thin films deposited at different temperatures, as demonstrated by their dielectric and conduction behavior as a function of both temperature (in the range 294–514 K) and frequency (in the range 10^?1–10⁶ Hz).     

First-principles study of GaP(0 0 1) surfaces

First-principles total energy calculations have been performed on GaP(0 0 1) surfaces to determine the disordered structure during phase transitions. The Ga-rich and P-rich (2 × 1), (2 × 2) and (2 × 4) structures were discussed. The surface phase diagram showed that a disordered phase exist during phase transition between (2 × 1) and (2 × 4) structures, which was assigned to be the coexistence of three ordered structures: β₂(2 × 4), δ(2 × 4) and Ga(2 × 1)md. This result does not support the observations that the disordered structure is a mixture of (2 × 4) and β(2 × 4) [D.C. Law, Y. Sun, R.F. Hicks, J. Appl. Phys. 94 (2003) 6175]. Generally, good agreement in structural parameters was obtained with previous results. Total and partial density of states analysis for three stable phases was presented.     

In situ STM study of the duplex passive films formed on Cu(1 1 1) and Cu(0 0 1) in 0.1 M NaOH

In situ electrochemical scanning tunneling microscopy (ECSTM) investigations of the anodic Cu(I)/Cu(II) duplex passive layers grown on Cu(1 1 1) and Cu(0 0 1) in 0.1 M NaOH are reported. The outer Cu(II) part of the duplex film formed on both substrates is crystalline with a terrace and step topography. The observed lattices are consistent with a bulk-like terminated CuO(0 0 1) surface on both substrates. This common crystallographic orientation is explained by the hydroxylation of the otherwise polar and unstable oxide surface at the passive film/electrolyte interface. The epitaxy of the oxide layers is governed by the parallel alignment of the close packed directions of the CuO outer layers and Cu₂O inner layers on both substrates. A granular and amorphous layer covering the crystalline CuO(0 0 1) oxide has been observed on Cu(0 0 1) but not on Cu(1 1 1). It is assigned to a film of copper hydroxide corrosion products formed by a dissolution-precipitation mechanism. Its absence on the passivated Cu(1 1 1) surface is explained by the higher stability of the Cu₂O(1 1 1) precursor oxide formed on this substrate in the initial stages of growth of the duplex passive film, resulting in a lower amount of dissolved copper.     

Surface characteristics of micro-ultrasonically machined (1 0 0) silicon

Micro-ultrasonic machining of single crystal silicon was performed using 0.1 and diamond abrasives and a diameter cemented carbide cylindrical tool. The depth of cut was varied from 200 to 1400 nm and the average surface roughness was found to be 5–15 nm Sa. Confocal Raman microscopy of the cut surface indicated the presence of both diamond cubic and amorphous phases of silicon.