阿根廷Φ139.7mm套管探伤缺陷的解剖分析

中原油田所用的阿根廷套管大量不合格，对其进行无损探伤和解剖分析后发现，主要缺陷是折叠和大型非金属夹杂物。     

陶瓷高速砂轮结合剂中不同成份对砂轮强度影响的探讨

针对我国陶瓷高速砂轮特别是粗粒度高速砂轮回转强度不稳定的问题，本文主要对粘土—钾长石—硼玻璃、粘土—钾／钠长石—硼玻璃、粘土—钾长石—钙玻璃、粘土—钾长石—锂辉石等系统的结合剂进行研究。在现行的同一工艺条件下，用白刚玉WA46#磨料90％、陶瓷结合剂10％制备成磨具进行陶瓷结合剂的性能比较，对结合剂中不同成份对砂轮强度的影响进行了探讨，以找到一种既能满足现行生产工艺，又能提高粗粒度陶瓷高速砂轮回转强度的陶瓷结合剂。研究结果表明：在常用的粘土一钾长石～硼玻璃系统中引入钠长石，当钠长石达到适当比例(2l％)，所制备的结合剂生产的陶瓷砂轮回转强度提高，且与现行生产工艺匹配，工艺性能稳定，有望成为改进陶瓷结合剂的一种新的途径。     

AGING BEHAVIOUR OF PARTICULATE REINFORCED ALUMINUM ALLOY MATRIX COMPOSITES

The process of aging precipitation in SiC_p/6061 and Al_2O_3/6061 composites were investigated. Hardness testing, differential scanning calorimetry(DSC) and transmission electron microscopy were employed. Results showed that the precipitation phase form directly along dislocation lines in the composites because the particles produce high densities of dislocations which makes vacancy densities in the composites decrease, and the main precipitation phase at peak hardness was β′ phase.     

水电站座环及导叶用钢SXQ500/550DZ35热力学计算及析出相分析

水电建设的发展，对水电站座环及导叶用SXQ500/550DZ35特厚板的性能提出了更高的要求，其成分中加入合金元素多，各种相的析出复杂，而析出相与钢的组织性能密切相关，因此利用Thermo Calc软件对SXQ500/550DZ35水电用钢进行了热力学计算及平衡相分析。结果表明，FCC_A1#2、FCC_A1#3及FCC_A1#4相析出温度区间集中于900~1 400 ℃之间，属于微合金元素V、Nb、Ti与C、N元素结合生成的碳化物以及碳氮化物，其能钉扎奥氏体晶界，细化奥氏体晶粒。通过钢板在970、1 020、1 070 ℃保温22 min后水淬至常温，并采用场发射电镜对其进行检测，析出相主要为NbC、TiC、Ti（C,N），与热力学软件计算相符合。     

室温固相反应法制备Ni0.66Mn2.34-xCoxO4(x=0.15,0.30,0.45,0.60)负温度系数热敏电阻

以Mn(CH3COO)2·4H2O,Ni(CH3COO)2·4H2O,Co(CH3COO)2·4H2O和H2C2O4·2H2O为原料,采用室温固相反应法制备出镍锰钴草酸盐前驱体,将该前驱体在850℃煅烧2 h得到尖晶石相Ni0 66Mn2.34xCoxO4(x=0.15,0.30,0.45,0.60)超细粉体.用XRD,TGA,SEM,沉降式粒度分析仪和热膨胀仪对镍锰钴草酸盐前驱体与Ni0.66Mn2.34-xCoxO4(x=0.15,0.30,0.45,0.60)超细粉体进行了表征.结果表明,由室温固相反应法得到的草酸盐前驱体是单相的镍锰钴复合草酸盐在850℃煅烧2 h得到镍锰钴氧化物为纯尖晶石相,粉体颗粒为球形,团聚较少,粒径均匀,平均粒径约为0.2μm,有较好的烧结活性,是制备热敏陶瓷材料的理想粉体.     

FeMoAl COATING AND ITS HIGHTEMPERATURE SULFIDATION PROPERTIES

ＦｅＭｏＡｌＣＯＡＴＩＮＧＡＮＤＩＴＳＨＩＧＨＴＥＭＰＥＲＡＴＵＲＥＳＵＬＦＩＤＡＴＩＯＮＰＲＯＰＥＲＴＩＥＳ①ＬｉＦａｎｇ，ＨｅＹｅｄｏｎｇ，ＱｉＨｕｉｂｉｎ，ＨｕａｎｇＺｈｅｎｚｈｏｎｇ，ＺｈｕＲｉｚｈａｎｇＢｅｉｊｉｎｇＣｏｒｏｓｉｏｎａｎｄ...     

大模数齿轮磨损后的堆焊修复工艺研究

通过试板的工艺试验，探索选用适当的焊条、采用适当的焊接工艺和焊后热处理工艺来修复ＺＧ４５钢大模数齿轮磨损齿面的可能性。试验结果表明，联合使用Ｄ１３２＋Ｄ１１２或Ｄ１３２＋Ｊ４２２进行堆焊，均可满足堆焊修复工艺的要求。     

Phase diagrams for lead-free solder alloys

The need for new, improved solder alloys and a better understanding of reactions during the soldering process grows steadily as the need for smaller and more reliable electronic products increases. Information obtained from phase equilibria data and thermodynamic calculations has proven to be an important tool in the design and understanding of new lead-free solder alloys. A wide range of candidate alloys can be rapidly evaluated for proper freezing ranges, susceptibility to contamination effects, and reactions with substrate materials before the expensive process of preparing and testing candidate alloys is initiated.     

The use of severe plastic deformation techniques in grain refinement

Severe plastic deformation (SPD) has emerged as a promising method to produce ultrafine-grained materials with attractive properties. Today, SPD techniques are rapidly developing and are on the verge of moving from lab-scale research into commercial production. This paper discusses new trends in the development of SPD techniques suchas high-pressure torsion and equal-channel angle pressing, as well as new alternative techniques for introducing SPD. The paper also contains a comparative analysis of SPD techniques in terms of their relative capabilities for grain refinement, enhancement of properties, and potential to economically produce ultrafine-grained metals and alloys. For more information, contact Terry C. Lowe, Science and Technology Base Programs, Los Alamos National Laboratory, Los Alamos, NM 87545; (505) 667-7824; fax (505) 665-3199; e-mail tlowe@lanl.gov.     

Effect of Powder Type and Compaction Pressure on the Density,Hardness and Oxidation Resistance of Sintered and Steam-treated Steels

Two types of Hoganas iron powders—sponge (NC), and highly compressible (SC) were investigated. These specimens were compacted with a pressure of 300, 400, 500, 600, and 700 MPa, before sintering in a production belt-type furnace. Steam treatment of the specimens was at 570 °C for 30 min. The sintered density and as-sintered hardness increase with increasing compaction pressure, and are significantly influenced by the powder structural characteristics. During steam treatment the type of powder and compaction pressure have an important influence on the extent of pore closure and weight gain. The maximum hardness was obtained for the components compacted at a pressure of 500 MPa for both groups of iron powders. Surface pore closure and oxidation resistance of the steam-treated components are improved with increasing compaction pressure.