大型迷宫压缩机气缸体的铸造

四列迷宫压缩机是中石化和科技部的攻关项目,气缸体是关键部件,其外形尺寸为2825 mm×1250 mm× 954 mm,壁厚30 mm,最厚处100 mm,铸件不得有缩孔、缩松、夹渣、裂纹等铸造缺陷,水道和内腔应分别进行水压试验,一级气缸试验压力为0.6 MPa,二级气缸试验压力为2.48 MPa,水道试验压力为0.6 MPa,历时30 min,不允许渗漏.     

缸体与排气缸铸件热处理工艺参数的选定

缸体与排气缸铸件热处理工艺参数的选定中国第二重型机械集团公司铸造分厂（四川德阳６１８０１３）方英照１前言燃气轮机缸体（以下简称缸体）与压缩机排气缸（以下简称排气缸）系我厂为美国某公司承制的火电设备用铸钢件。材料为美国“ＧＥ”公司工艺规程材料标准（Ｂ５...     

倒大双冲天炉熔炼铸锅铁水

我厂按实际情况设计制造了倒置风口两排大间距冲天炉用于铸铁锅熔炼铁水。一、主要结构参数 1.熔化带直径:φ600mm,风口区直径φ600mm; 2.风口参数:第一排为φ42×4×0°,第二排为φ35×4×10°,排距为600mm,风口比为3％,第二排:第一排=1.56:1; 3.炉缸高度:400mm,内径:φ600mm,下     

AV100轴流压缩机大型中分式机壳的铸造

AV100轴流压缩机是我公司为首都钢铁公司生产的大型机组,其机壳铸件是该机组的关键零件之一。AV100下机壳为水平中分式机壳,轮廓尺寸为7 860 mm×4 780 mm×2 445 mm,中分面两侧设计有4个猫爪,475 mm×420 mm,厚250 mm,进排气风口为天圆地方结构,铸件重53.3 t,材质为HT250,主要     

呋喃树脂砂生产后桥壳体类铸件的工艺设计

后桥壳体材质为HT250,重261 kg,轮廓尺寸为1 069 mm×4 200 mm×500 mm,壁厚10 mm～32mm,主要壁厚9～11 mm.铸件如图1所示.采用7 t/h双排大间距水冷冲天炉熔炼,铁液出炉温度1 420～1 450℃,炉后快速分析,用呋喃树脂砂生产工艺进行造型、制芯.     

轧辊铸造工艺的改进

轧辊是电厂锅炉碎渣机上的主要零件,材质为高锰钢.由于高锰钢加工困难,故在其加工较多部位放置易加工的铸钢材质预制件,铸造难度大. 1 轧辊零件和铸造工艺简介 轧辊的外形尺寸为φ470 mm×864 mm,主要壁厚为35 mm,在其外圆分布10排25 mm×60 mm×60 mm的轧齿120个,重400 kg.在其于轴装配处镶嵌φ200 mm×140 mm×50 mm预制件2个,预制件的材质为ZG1Cr19Ni9Ti,重约11 kg.     

铝合金气缸罩盖平面度影响因数及控制

轿车发动机铝合金气缸罩盖位于引擎的顶部,经常受热.对这种零件来说,无论是压铸毛坯、机械加工、物理性能,还是在外观方面,要求都十分严格.由于铝合金气缸罩盖平均壁厚仅为2mm,并且整体面积比较大(500mm×220mm),对产品的平面度控制比较难.     

扬子石化新建输水钢管采用水泥砂浆衬里

扬子石油化工公司自备水厂在2002年至2004年实施的改扩建工程中,新增的1根原水管道和1根排江管道均为大口径长距离输水钢管,材质Q235A低碳钢。原水管道管径DN1500(1520mm×12mm),长度3.31km;排江管道管径分别为DN1800(1820mm×12mm)、DN1500(1520mm×12mm),长度分别为0.43km、3.71km。输水钢管外壁防腐蚀层选用聚乙烯(PE)胶粘带,总厚度3.2mm;内壁选用水泥砂浆衬里,厚度10mm。由于输水水质的腐蚀性较小,而且输水钢管敷设沿线土壤的酸碱度呈中性,因此,本工程输水钢管不采用阴极保护技术。1输水钢管内壁防腐的必要性大口径长距离输水…     

基于焊接变形有限元分析的空调压缩机结构优化

建立了考虑相变的热弹塑性有限元法模型,针对敏感性参数如壳体高度、气缸材料性能、气缸与壳体接触状态以及气缸结构对压缩机焊接变形的影响进行了计算和讨论.气缸采用铸钢材料能有效降低压缩机滑片槽槽宽变形,压缩机壳体与气缸的接触状态对气缸变形有较大影响.为了提高计算效率,同时又能保证计算结果的准确性,进而采用了基于热弹塑性有限元法的固有应变法进行模拟.结果表明,固有应变法与热弹塑性有限元法及实测结果吻合较好,基于固有应变法的压缩机结构优化方法可以大大降低计算时间,这种方法可以应用于大型焊接结构的结构优化.     

道依茨-曼海姆TBD620V16柴油机气缸体铸造工艺

TBD620V16柴油机气缸体的轮廓尺寸为2 200×1 020×760 mm,重约2.2t,有两排共16个气缸,呈V型排列,材料牌号为QT500-7.铸造工艺要点如下：1）浇注位置为缸孔顶端向下,分型面选在气缸顶面外沿,双侧面底注;2）采用组芯造型;3）铸件尺寸收缩率取0.83%;4）浇注温度1 360～1 380 ℃;5）为防止缩松缺陷,在多处热节部位设置了冷铁.6件试制铸件检查结果表明,铸件全部达到技术要求.     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling those of biosystems. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product.     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described.     

试论洋务派教师聘任的思想

洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响.     

胫骨生物陶瓷复合材料的微结构增韧机理

扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性.     

Mechanism of Nucleation of Precipitates of Carbides of Refractory Metals Under Hot Rolling of Automotive Sheet Steel

Metal Science and Heat Treatment - The problem of formation of properties in microalloyed sheet steels is considered. The cause and the possible mechanism of precipitation of carbides of refractory...