钇基稀土对51CrV4弹簧钢冲击韧性的影响

运用扫描电镜观察了51CrV4弹簧钢显微组织、夹杂物及断口形貌,并结合能谱分析了钢中夹杂物成分组成,探究了钇基稀土对51CrV4弹簧钢冲击韧性的影响.结果表明,对于51CrV4弹簧钢,添加钇基稀土能明显提高其冲击韧性,纵向冲击功提升了68.8%,断口形貌由准解理断口转变为韧窝型断口,韧窝处存在大量细小球状的稀土复合夹杂.钇基稀土的添加促进了51CrV4弹簧钢回火组织中碳化物的球化,并使其分布更加弥散.钇基稀土对钢中夹杂物有很好的改性作用,夹杂物被球化且尺寸得到细化.      

Influence of gadolinium on microstructure and magnetic properties of sintered NdGdFeB magnets

The effect of Gd content on microstructure and magnetic properties of sintered Nd33.03-xGdxFe65.65B1.32 (x=0-2) was studied in this paper to improve the thermal stability of NdFeB and to reduce the raw material cost. The results showed that better magnet performance could be obtained by adding Gd (0-1.5 wt.%) with partial substitution of Nd in Nd33.03-xGdxFe65.65B1.32. It was also found that the Nd33.03-xGdxFe65.65B1.32 magnets showed the best performance when Gd addition increased to 1.0 wt.%. The temperature coefficient Br (α) could be improved from -0.15%/oC to -0.063%/oC (maximum work temperature 120 oC) and the Curie temperature could be improved from 315 oC to 323 oC because the Gd2Fe14B had positive temperature coefficient Br (α) and higher Curie temperature than that of Nd2Fe14B. The coercivity could be improved from 10.2 to 11.48 kOe and the microstructure was close to ideal microstructure. The magnetic performance decreased sharply by adding Gd (above 2 wt.%) with partial substitution of Nd in Nd33.03-xGdxFe65.65B1.32 because the Gd element concen-trated in the grain boundaries.     

基于B/S模式的校园网MIS系统

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电光天平翼支板对示值变动性的影响

<正>一、天平翼支板松动天平经过几年使用,尖端定位螺钉经过长时间的磨损或固紧螺帽松动,会使天平翼支板前后松动,因而产生跳针、带针、吊耳晃动等现象,致使天平示值变动。纠正天平翼支板松动,可把天平翼支板的固紧螺帽旋松,将尖端     

废杂铜再生铅黄铜HPb58-2A中Fe基相的特征分析

以废杂黄铜为原料,运用水平连铸工艺得到无裂纹的最小壁厚5 mm、外形十二边形的HPb58-2A异形管材,采用扫描电镜和能谱分析,分析管材显微组织中存在的黑色树枝晶。结果表明,树枝晶的主要成分是Fe,同时含有Si、Cu、Zn、Al等元素。一次枝晶的含Fe量比二次枝晶含量要高,同时发现大Pb粒为Fe基相的伴生相。黄铜中Fe基硬质相的形貌与相中Fe与Si的原子比值Fe/Si的大小有关:当Fe/Si比较小时(如1.4～1.64),形成金属间化合物,形状为菱形或细条状;当Fe/Si较大时(2.82～7.84),形成的Fe基相是Fe基固溶体,且当Fe/Si大于等于3.51时,Fe基固溶体的形貌为树枝晶。     

铜再生冶炼加工企业烟尘治理实践

本文介绍了金田铜业集团使用袋式除尘器处理再生冶炼烟气的技术,消除了烟尘污染而且回收了烟尘中的有用金属成分。通过进一步改造铜合金熔铸生产的转流方法、集尘装置和反射炉泄漏烟气的收集方法,净化了车间生产环境。同时加大了对噪声、酸雾、二氧化硫、有机废气的治理,初步实现了铜再生冶炼加工企业的清洁生产。     

应用目的规划法和广义距离法综合评价食品卫生工作质量的探讨

应用目的规划法和广义距离法综合评价食品卫生工作质量的探讨焦荣华王恩霖曹庆李建军李红卫河北省保定市卫生防疫站（０７１０００）１９９０年１０月，我们根据河北省卫生厅《关于对全省中小餐馆、肉食加工、肉食销售、饮食摊点四行业进行卫生整顿》的文件要求，组织人员...     

基于物联网的物流信息平台规划与设计

物流行业不仅是国家规划的振兴产业,也是物联网应用的重要领域,围绕物流发展战略规划,依据物联网理论,以物流信息化建设为研究对象,提出了物流信息平台建设的技术框架和功能框架,期望为物流信息化建设发挥积极作用,并对其他区域的物流信息化建设提供借鉴作用。     

Structure and permanent magnetic properties of SmFex （x=3-8） melt spun ribbons during heat treatment

Compounds with the composition SmFex（x=3–8） were prepared by melt spun method at a velocity of 40 m/s and subsequent annealing at temperature between 600–1000 ℃. The crystal structures of the as-quenched and as annealed powders were investigated by XRD methods with following Rietveld analysis. The glass forming ability could be enhanced by the increase of Sm content to x≤5.Metastable Sm5Fe17-type structure existed when 3≤x≤5 and temperature was lower than 800 ℃. SmFe2-type structure could be stable up to 1000 ℃ when x〉3 and temperature was under 800 ℃. The content of SmFe2-type decreased with the increase of x value and increased with temperature lower than 800 ℃, from which SmFe2-type started to bring the transition to SmFe3-type. As for Sm5Fe17-type compounds with x=3.4, the highest coercivity of 33.6 kOe could be obtained under a velocity of 30 m/s and heat treated under 700 ℃×1h.     

水工业中陶瓷阀开发应用及技术参数研究

对陶瓷热膨胀率、抗腐蚀抗磨损性良好等有关属性作了技术分析 ,论证了一些金属阀所无法比拟的优点 ,为工业陶瓷的重要应用与陶瓷阀的开发指出了前景和努力方向 .