三种热喷涂工艺制备WC/Co涂层性能比较

分析比较了常规大气等离子喷涂、爆炸喷涂和超音速火焰喷涂的WC/Co涂层的形貌、显微组织、孔隙率、硬度、结合强度及其耐磨性。结果表明,超音速火焰喷涂和爆炸喷涂层性能相当,涂层具有与粉末相近的相结构,与大气等离子喷涂相比,涂层具有高的致密度、硬度和良好的耐磨性,涂层与基体的结合情况也得到很大的改善。     

Comparative Study of Fatigue Provisions for the AASHTO Fatigue Guide Specifications and LRFR Manual for Evaluation

The recently developed Manual for condition evaluation and load and resistance factor rating (LRFR) of highway bridges in 2003 provides an alternative procedure for practicing engineers to evaluate the fatigue life of steel bridge structures. Although the evaluation manual maintains several aspects used in the AASHTO fatigue guide specification in 1990, it also utilizes formulas and values specified in the AASHTO LRFD bridge design specifications in 1998. A comparative study of the fatigue lives provided by the procedures in the Evaluation manual and the Guide specifications was performed using a life prediction of 14 steel bridges with different structural configurations and various fatigue details. It has been shown that longer predicted fatigue lives are typically obtained when using the Evaluation manual. The ratio of the finite evaluation fatigue lives for the two procedures was found to be in a range of 0.99–2.14.     

网带式连续烧结炉炉温及网带速度微机控制系统

本文介绍一个基于ＳＴＤ总线的单片机网带式连续烧结炉炉温及网带速度控制系统，详细叙述了系统的硬件结构和控制算法。     

激光熔覆速率对熔覆层显微组织及耐磨性的影响研究

分别采用高速和常规的熔覆速率,进行了高硼不锈钢合金粉末的激光熔覆试验.试验结果表明,相同功率条件下,熔覆速率对组织的影响较大.熔覆速率越快,枝晶尺寸越细小.高速激光熔覆下,熔覆层晶粒尺寸可达1～2μm,且组织更均匀.高速激光熔覆制备的熔覆层中奥氏体含量偏高,从而熔覆层的耐磨性能有所下降.     

碱熔-电感耦合等离子体原子发射光谱法测定钒钛磁铁矿中钒和钛

钒钛磁铁矿是重要的炼钢原料,其中的钒、钛元素具有极高的综合利用价值.钒、钛元素的测定方法多样,其中化学湿法手段繁琐,而先采用微波消解法处理样品,再使用电感耦合等离子体原子发射光谱法(ICP-AES)测定需附加溶样设备,成本较高.样品采用硼酸-碳酸钠混合熔剂在1000℃熔融、盐酸浸出的方法溶解样品,选择V 309.311...     

有害微量元素对邯钢高炉炉料冶金性能的影响

为了降低有害微量元素对邯钢高炉冶炼的影响,研究了K,Na,Zn,Cl等有害微量元素对炉料冶金性能的影响,同时研究了抑制其危害的措施。研究结果表明:少量的有害微量元素即可对焦炭的冶金性能产生巨大的危害,而对于铁矿石的影响略轻,有害微量元素含量越高,炉料的冶金性能越差。在焦炭上喷洒质量浓度为0.04%的硼酸溶液,在铁矿石上喷洒质量浓度为0.04%的CaCl2溶液,可有效降低有害微量元素的危害。     

铈镧混合稀土对AZ91D压铸镁合金显微组织和蠕变性能的影响

研究了不同含量Ce/La(x=0,0.1,0.5,1.0)对AZ91D镁合金显微组织及蠕变性能的影响。通过X射线衍射(XRD)、金相显微镜(OM)、扫描电镜(SEM)及能谱分析(EDX)观察与分析表明,压铸AZ91D镁合金中添加Ce/La后,除了α-Mg,β-Mg17Al12相之外,还生成了新的稀土化合物Al11RE3(RE=Ce/La)化合物,并且细化了合金显微组织、提高了合金室温和高温力学性能。生成的Al11RE3(RE=Ce/La)高温热稳定相使AZ91D+xCe/La(x=0,0.1,0.5,1.0)合金在150℃,50MPa下的蠕变抗力优于AZ91D镁合金,1%Ce/La的合金与AZ91D相比,蠕变延伸率低了0.2%,最小蠕变速率从2.30×10-8s-1降低到2.02×10-8s-1。蠕变试样的微观组织结构分析表明:AZ91D合金的蠕变机制主要以晶界滑移方式为主,Al11RE3(RE=Ce/La)热稳定相在晶界处延缓和阻碍了晶界断裂的过程。     

太阳能汽车车身外形设计要素分析

太阳能汽车利用太阳能驱动且无有害排放物,被称为"未来汽车"。以太阳能汽车为主题,重点介绍了国内外具有代表性的各种太阳能汽车车身外形,分析了车身外形设计要素,认为降低空气阻力、减小滚动阻力,以及增加太阳能的采集,可以有效减少能耗、提高能效。着重从低风阻、车身轻量化,以及太阳能电池板放置来探讨太阳能汽车车身外形的设计。     

Composite with Recyclable Loads for the Manufacture of Blocks to Build Popular Houses

The science space in a state school in Natal city was built using a composite consisting of gypsum, EPS （expanded polystyrene）, shredded tire, cement and water. Mechanical and thermal resistances were evaluated. Inside the blocks, three types of fillings （EPS plates, aluminum cans and 500 mL bottles of mineral water） were placed in order to obtain a walls with higher thermal resistance, but also to give it an ecologically correct order, considering that both the tire and the EPS occupy a large space in landfills and require years to be degraded when released into the environment. Compression tests were conducted according to the rules. The experiments demonstrated that the temperature difference between the internal and external surfaces on the walls reached levels above 12.0 ℃. It was also demonstrated that the proposed composite has adequate mechanical strength to be used for sealing walls. The proposed use of the composite can contribute to reduce the significant housing deficit of Brazil, producing popular houses at low cost and with little time to work.     

矿热炉铁(渣)口用无水炮泥的技术探讨

为使矿热炉生产顺行,对出铁(渣)口使用的炮泥材质、配方进行了优化改进,采用了高纯原料通过添加不同的非氧化物和有机结合剂,使炮泥不仅具有良好的烧结性、耐侵蚀性、填充性,而且易打开铁(渣)口,同时新旧炮泥间结合强度高,从而提高了矿热炉炉口的整体稳定性,实现了矿热炉顺行、低耗、安全、延长使用寿命的目的。