具有负偏差特性的快速圆弧插补算法

给出了一种圆弧插补递推算法,该算法简便,其执行速度接近于逐点比较法,其插补精度接近于最小偏差法,且具有负偏差特性。     

基于混合遗传算法的电弧炉终点目标温度预报模型

BP (Baek Propagation)算法和遗传算法相结合的混合训练方法步骤为:首先用遗传算法定位出一个较好的搜索空间,然后采用BP算法在这个小的解空间中搜索出最优解。分别用遗传算法和混合遗传算法训练100 t电弧炉终点温度神经网络预报模型。仿真结果表明:混合遗传算法有更快的收敛速度和更高的预报命中率。当目标温度的精度范围为±2℃、±4℃、±6℃和±8℃时,BP算法的温度命中率分别为75%、82%、86%和92%,混合遗传算法的温度命中率分别为80%、88%、90%和96%。     

40 t电弧炉高效化生产实践

兴澄特钢3座40 t电弧炉(变压器容量每座15MVA)经过氧枪等改造和添加铁水等工艺措施优化后,使每炉冶炼时间由3 h降至60～70 min,电耗降至160 kWh/t,氧耗为50 m³/t,电极消耗2.0 kg/t,3座电弧炉年产能力达85万t。操作实践表明,每炉20～25 t的铁水加入量可使40 t电弧炉得到最佳的经济指标。     

由二种烟煤制备碳纳米管的探索性研究

以一种中国烟煤和一种新西兰烟煤为原料,采用电孤等离子体法制备碳纳米管。碳纳米管及其副产物富勒烯烟灰的表征采用扫描电镜（SEM）和红外光谱（FT－IR）等技术。结果表明：电弧放电时的缓冲气体压力对碳纳米管的产率影响很大;在一定的缓冲气压下电极间电流和电极间距各存在一最佳值。在He气压力为0.0665MPa、工作电流为40A条件下进行电弧放电,阴极上棒状沉积物的内芯中碳纳米管含量高达75％以上。基于实验结果,讨论了以煤为原料用电弧等离子体法制备碳纳米管过程中的工艺参数对碳纳米管生长的影响。     

神经网络电弧炉—精炼炉的控制系统

用基于工业计算机网络的电弧炉控制系统,采用三层网络结构,可以实现炼钢过程的优化控制及数据监控,完成作业优化,提高作业效率,通过基于预估补偿的专家控制系统,使1台40t电弧炉的电耗由50kWh/t降至475kWh/t。     

70 t Consteel EAF-LF-CC生产耐热螺杆用钢 B7 的工艺实践

鄂钢股份有限公司采用70tConsteel超高功率电弧炉70t钢包精炼炉4流150mm×150mm方坯连铸连轧工艺生产耐热螺杆高强度标准件用钢B7(40CrMnMo)。电弧炉炉料为30%生铁+70%优质废钢,废钢预热温度≥600℃。生产结果表明,该钢成品化学成分可稳定控制(%):0.39～0.42C,0.86～0.91Mn,0.22～0.31Si,0.013～0.018P,0.005～0.013S,0.85～0.94Cr,0.16～0.18Mo,0.019～0.028Als,偏析与疏松级别为0.5～1.0,夹杂物0.5～2.0级,Φ18～Φ50mm钢材晶粒度8.5～9级,满足耐热螺杆标准件的使用要求。     

弧焊机器人摆动跟踪时摆幅与频率的模糊模式识别

针对10 mm厚钢板V形坡口接头的弧焊机器人摆动跟踪焊接,实时测量电弧电压和焊接电流的瞬时值,对其进行两次统计处理,构建不同摆幅和摆动频率时的焊接电参数特征矢量,采用模糊模式识别技术,建立了焊接电参数特征矢量与摆动焊接摆幅和频率的内在联系,为定量研究摆幅和频率对V形坡口焊缝成形的影响提供依据。     

Effects of incorporation of Si or Hf on the microstructure and mechanical properties of Ti-Al-N films prepared by arc ion plating (AIP)

Ti-Al-N, Ti-Al-Si-N and Ti-Al-Hf-N films were deposited on 1Cr11Ni2W2MoV stainless steel by arc ion plating (AIP) with a Ti₇₀Al₃₀, a Ti₆₀Al₃₀Si₁₀ and a Ti₆₈Al₃₀Hf₂ cathode, respectively. The effects of Si or Hf addition on the composition, microstructure and mechanical properties of the Ti-Al-N films were investigated by EPMA, TEM, SEM, XRD, micro-hardness and wear tests. The results show that all the deposited films possessed B1 structure. With the incorporation of Si or Hf, the texture of Ti-Al-N films remarkably changed from preferred orientation of (220) to mixture broadened orientations of (111), (200) and (220), the mean crystallite size of Ti-Al-N decreased from ~ 90 nm to ~ 30 and ~ 15 nm and no peaks of crystalline Si₃N₄ were detected from XRD analyses. Due to the addition of Si or Hf, the micro-hardness of Ti-Al-N films increased remarkably from 23.5 Gpa to 33.6 or 29.5 GPa, and the wear resistance was also enhanced. The effects of incorporation of Si or Hf on the microstructure and mechanical properties of Ti-Al-N films are discussed.     

Effect of deposition processes on residual stress profiles along the thickness in (Ti,Al)N films

The effect of deposition processes on the distribution of residual stresses in the thickness of the (Ti,Al)N films prepared by arc ion plating (AIP) was investigated in the present work, which indicates that the stress distribution exhibits a “bell” shape and the maximum compressive stress appears in the layer near the surface. The residual stress increases with the thickness of a film and the substrate bias voltage, respectively. The stress distribution can be altered, and the adhesion of the film/substrate can be improved by optimizing the deposition parameters. Finally, a film with a thickness of 7.57 μm was successfully directly deposited on the substrate through optimizing the bias voltage.     

Thermal behavior of curved roof buildings exposed to solar radiation and wind flow for various orientations

In this study air flow, solar radiation and heat transfer from a two dimensional curved roof with north-south and east-west faced are determined and results are compared with flat roof for the same size and orientation. Comparison are performed for their corresponding roof surface temperature, and heat flow for several roof rim angles and also for various wind flow velocities, as well as for different wind directions. Turbulence is modeled by RNG k–ε method and solar radiation distribution over the roof is determined based on an appropriate model applicable to hot arid regions of Iran. Solar radiation is calculated based on the summation of beam and diffuse radiation and ground reflected radiation. For certain inside roof temperature, over all heat transfer to the building is determined with day time for various wind flows and arc shapes and results are compared with flat roof. It was found that various wind flow condition over the vaulted roof makes substantial difference on the convection heat transfer coefficient and finally on the rate of heat transfer to the building with respect to flat roof. Based on heat transfer simulation, roof temperature, heat transfer convection coefficient and heat flow though the vault for different roof arrangement and flat roofs have been determined and advantages of specific vault orientation and wind direction are specified.