钢中含氮量对钢丝拉拔性能的影响

进行了钢包底吹氮，底吹氮－氩和底吹氩三种精炼工艺对比试验，结果显示，钢中含氮量对钢丝拉拔性能影响显著。钢丝拉拔性能随钢中含氮量下降而有所改善。     

焊丝镀铜色差分析及改进

ER70S-6X焊丝钢主要被用作制造CO2气体保护焊丝,主要用于机械制造、家电加工和压力容器加工等行业。为了提升产品市场竞争力,公司针对焊丝钢使用进行走访,对用户提出焊丝镀铜后出现的色差的问题,组织相关人进行了深入探讨,提出了相应的整改措施,解决了成品焊丝镀铜色差的问题。     

600MW超临界锅炉材料15NiCuMoNb5(WB36)钢的试验研究

我国石洞口二期工程600MW超临界锅炉首次选用了15NiCuMoNb5(WB36)钢作为锅炉侧水冷壁集箱、蒸发器、对流管等部件。这种Cu—Ni—Nb钢是西德30年代发展起来的钢种,使用温度400℃左右,也可用于管壁温度500℃的高应力管道。本文通过对该钢的机械性能、FATT50脆性转变温度、断裂力学性能、疲劳性能、持久强度及焊接工艺的试验研究为我国电站锅炉部件首次应用该钢提供了寿命预测和安全运行的可靠依据。同时为我国汽包用材国产化提供了必要的技术储备。     

电站锅炉新型18-8奥氏体热强钢的研制

日本火力发电站锅炉的过热器管,不但要求经济性好,而且还要求高温强度高的奥氏体钢材。为了满足这一要求,于是就开发了新钢种(0.1C—18Cr—9Ni—3Cu—Nb,N)。与ASME SA—213TP347H钢相比较,这种钢在600～700℃温度下100000小时的持久强度可高30％之多。此种钢的微观结构稳定性也是足够良好的。经过一年运行的考验证实了该钢种具有良好的机械性能和稳定的微观结构,而且这一钢种的耐蒸汽氧化性能几乎与细晶粒TP347H钢的相似。     

SA—335P91钢的焊接工艺试验研究

SA—335P91钢在大容量高参数锅炉机组中的应用日益广泛。本文介绍了该钢种的焊接性能、焊接工艺试验研究及结果；阐述了严格、详细的焊接工艺、焊后热处理工艺及操作技术要求。     

一种电炉钢液的高效脱氢方法

钢的纯洁度的不断提高 ,对钢液中氢含量提出了新的要求。影响电炉钢中氢含量的因素有 :大气水分 ,大气相对湿度、炉渣特性 ,电炉 ,钢包和中间包的耐火衬 ,合金添加剂 ,钢中硫含量和脱硫剂及脱氧剂 ,钢中氧含量 ,废钢和铁水。采用 10 0 t真空炉真空精炼电炉钢钢水 ,控制 6 7Pa高真空度、高真空时间、吹氩强度、真空温降、精炼渣量 ,能使真空脱氢率在 70 %以上 ,钢中氢含量最低为 0 .5× 10 - 6     

降低电炉管线钢氮含量生产工艺摸索

对绝大多数管线钢来说,氮是有害元素,钢水中氮含量偏高会使钢产生应力时效,降低管线钢的成型性及高温韧性、塑性和焊接性能。介绍了电炉冶炼高端管线钢钢水中氮元素来源,主要为废钢原料含氮不稳定以及电弧区钢液容易吸氮,并通过冶炼工艺的比对,对电炉不同钢渣性能、不同铁水比例、冶炼时熔池流场对N含量的影响进行了分析,找出控制电炉钢水氮含量的有效途径,主要有提高电炉钢渣性能、合理的铁水配比、电炉底吹CO2气体、精炼、连铸防二次增N工艺等,工艺改进后氮含量平均控制在8×10-5以下。     

E690海洋平台用钢第二相析出行为研究

研究了 E690海洋平台用钢中第二相析出过程,讨论了不同温度条件下该钢种第二相中的元素含量,在此基础上分析了钢中Cu含量对Cu析出量的影响,为实验钢成分设计提供理论指导.结果表明,该钢中15种析出物的生成顺序分别为:Ti4C2S2,FCC_A1#2,MnS,B2M,M3B2,BN_HP4,FCC_A1#3,AlN,HC...     

改善B12N—S钢转子冲击性能的研究

通过模拟试验及生产实践,对改善B12NS钢中压转子冲击性能的方法进行了分析研究,通过实际验证,找到了行之有效的热处理方法,可使该钢种的V型冲击功提高一倍左右     

WDL——80钢埋弧焊模拟HAZ冲击韧性的研究

对ＷＤＬ－８０钢进行了不同热输入埋弧烛ＨＡＺ模拟热循环试验，在此基础上开展地示波冲击和显微组织研究。结果表明，３５至４５ＫＪ／ｃｍ是该钢最佳热输入范围，此时示波冲击的裂纹扩展功Ｅｐ显著提高，贝氏体组织相对含量为１４．７％，１７．３％，且均呈长条交错分布，有效地分割马氏体板条，因而导致了优良的冲击韧性。     

输电线路导线及地线复用新型直流融冰装置技术研究综述

  [目的]  在雨雪冰冻气候环境下,为了避免输电线路冰雪灾害事故的发生,需对输电线路进行融冰以加强其抵御冰雪灾害的能力,直流融冰装置是一种近年来应用广泛且行之有效的融冰装置。  [方法]  通过建立一种可行且有意义的技术来解决采用完全独立的两套融冰设备直流融冰装置设备投资大,占地面积增大,运维等费用成倍增加,整体经济性差的问题。提出一种可行的方法,即介绍了一种导线及地线复用新型直流直流融冰装置的主电路拓扑结构,可以一套装置实现导线和地线复用直流融冰的功能。  [结果]  获得的结果证明了这种技术是可行的和有效的。  [结论]  这项技术为进一步研究解决输电线路导线和地线覆冰、降低直流融冰装置投资、提高输电系统抵御自然灾害的能力具有重要参考意义。     

Heat transfer improvement in a tube by inserting perforated conical ring and wire coil as turbulators

In the present study, two various passive methods for heat transfer enhancement, including conical ring and wire coil are placed in a tube as turbulators. Four conical rings with four side holes are utilized with the same distance. The wire coil is employed at the center of the tube. The considered Reynolds numbers are between 4000 and 10,000. The studied geometrical parameters contain the pitch and diameter of a wire coil. Four different pitches of wire coil, including 10, 12, 14, and 16 mm, are evaluated. Furthermore, four values of wire coil diameter such as 2, 4, 6, and 8 mm are certain. The obtained numerical results displayed that by declining the pitch of a wire coil (37.5%), the average Nusselt number increases by about 143%. Also, augmentation in wire coil diameter by 300% leads to a growth in average Nusselt number by about 131%. Moreover, owing to utilizing two various turbulators, the pressure drop is significantly high in comparison with the bare tube. At Re = 10,000, growth in the inner diameter of the wire coil by 300% leads to an increase in thermal performance by about 36.12%. Moreover, as the pitch of the wire coil rises by 60%, the thermal performance declines by about 35.71%.     

适应两种电压下的配电变压器的创新应用

对现用的6kV和10kV级电网的配电变压器制造和改造时,应能同时适应两种等级的电网电压(6kV、10kV)使用。提出利用Y、D联结的两用变压器,达到一台变压器适用两种电压的目的。     

The physics of heat transfer from hot wires in the proximity of walls of different materials

This paper concerns the physical process of heat transfer from hot wires located in the proximity of walls consisting of different thermal conductivities. It points out that it is common practice to calibrate hot wires in a free stream of constant and known velocity, but when utilized for near-wall measurements additional heat losses occur owing to the presence of the wall, resulting in erroneous velocity readings. Therefore, a combined experimental and numerical methodology for heat transfer from a heated wire in a flow field is proposed, taking the effects of wire diameter, overheat ratio, wall thermal conductivity, wall distance, wall thickness and shear rate on the measured velocity into account. The present investigations indicated that the flow under the plate, i.e., the corresponding shear rate at the wall opposite the location of the wire where velocity measurements were taken, changes the thermal boundary conditions around the hot wire. It was also observed that heat diffusivity is dominant in the wall region and plays the major role in heat transfer from the wire rather than convection, especially for highly heat-conducting materials. For highly heat-conducting walls, a universal correction law for the wall influence was given by Durst et al. [F. Durst, E.-S. Zanoun, M. Pashtrapanska, In situ calibration of hot wires close to highly heat-conducting walls, Exp. Fluids 31 (2001) 103–110]. However, for poorly heat-conducting walls, the correction law depends on the wall thickness and the heat transfer from the surface opposite the wall where the hot-wire measurements were performed.     

Large photocurrent generation of an ITO electrode modified with a red copper(II) complex

A film of copper complex [CuL](NO₃)₂ (L = 2,3,8,9-tetraphenyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene) formed on indium-tin oxide (ITO) coated glass by the solvent evaporation of the acetonitrile solution of the complex onto the ITO substrate, was characterized by ultraviolet-visible absorption spectroscopy, cyclic voltammetry, scanning electron microscopy, and photoelectrochemistry. The photoelectrochemical cell by using [CuL](NO₃)₂ modified ITO, a saturated calomel electrode, and platinum wire as working, reference and counter electrodes respectively in 1 M Na₂SO₄, was found to exhibit a large prompt and reproducible cathodic photocurrent density of 71 μA/cm² under white light irradiation of 70 mW/cm² at an applied potential of −0.4 V, and an incident photon to current efficiency (IPCE) of 1.1% at λ = 660 nm. This Cu(II) complex photosensitizer has advantages of simple synthesis, low-cost, environmentally benign and good photoelectrochemical performance.     

绞合型碳纤维复合芯软型铝绞线在线路增容工程中的应用

  [目的]  为解决某220 kV线路增容问题,在工程设计阶段,对常规导线和多种耐热导线进行综合比选。  [方法]  分析了要求输送容量下各型导线的最高运行温度;对比了机械荷载和导线弧垂变化对杆塔基础的影响;计算了不同导线的电能损耗;分析对比了施工运维和建设难度;从一次性投资和年费用上进行经济分析。  [结果]  结果显示:在满足输送容量和导线允许温度的情况下,常规导线方案需全线拆除并新建杆塔和基础;各型耐热导线弧垂和荷载均满足原线路设计条件;常规导线和绞合型碳纤维复合芯软型铝绞线的年费用较低,运维相对便利。  [结论]  绞合型碳纤维复合芯软型铝绞线综合性能较优,适用于利用已有线路杆塔实现线路增容的场合,尤其是在城区或近郊等新建杆塔较为困难的地方。     

Pool boiling on a titanium wire

This work conducted experiments of saturated methanol boiled on a titanium wire under atmospheric pressure, considering the construction of boiling curves based on voltage-ampere data. With a heating wire that exhibits phase transition in structure the construction of boiling curves faces difficulties. The reasons corresponding to these findings are discussed.© 1999 Scripta Technica, Heat Trans Asian Res, 28(6): 456–462, 1999     

中国输电线路规范的风荷载计算比较

  [目的]  在台风袭击下,一些20世纪80、90年代建设的110 kV和220 kV输电线路经常出现铁塔损坏的现象,为了加固和改造事故线路,需要分析铁塔损坏的原因。  [方法]  介绍了中国1979、1990、2002和2012四个版本规定的输电线路风荷载计算方法,比较了设计风速、风压高度变化系数、体型系数、风荷载调整系数和覆冰风荷载增大系数等主要计算参数的差异,计算了某铁塔节段和导线在四个版本规定中的风荷载。  [结果]  计算结果表明:12规定的设计风速相比79、90和02规定增大5%～10%;79规程中60 m以下铁塔不考虑风振系数的规定严重低估了塔身风荷载;四本规定中110 kV和220 kV输电线路不采用导地线风荷载调整系数的规定严重低估了导地线风荷载。  [结论]  各规定的铁塔和线条风荷载差异的主要影响因素是风速重现期、铁塔或导地线风荷载调整系数,这也是风灾倒塔的主要原因。     

High-rate deposition of polycrystalline silicon thin films by hot wire cell method using disilane

A new process, hot wire cell method, was developed and successfully used to grow polycrystalline silicon thin films at a low-temperature and high deposition rate. In the hot wire cell method, reactant gases are decomposed by a heated tungsten filament. Polycrystalline silicon films can be deposited at deposition rates of 1.2 nm/s for mono-silane (SiH₄) and 2.8 nm/s for disilane (Si₂H₆). By using disilane as a reactant gas, it is possible to achieve a high deposition rate without any change in the quality of the films.     

Measurements of thermal conductivity of 1‐butyl‐3‐methylimidazolium tetrafluoroborate at high pressure

Ionic liquids are salts that are liquid at room temperature. They have attracted considerable attention as new materials. In this study, a transient short‐hot‐wire apparatus was prepared, and the thermal conductivity of 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim] [BF₄]) was measured. The experimental temperatures were from 294 to 334 K, and the pressures were from 0.1 to 20 MPa. It was found that the thermal conductivity of an ionic liquid has a very small temperature and pressure dependence. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(6): 361–372, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20166