共查询到20条相似文献,搜索用时 0 毫秒
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LIU Yongkun Southwestern Institute of Technology Engineering Chongqing ChinaYANG Shihao Shandong Polytechnical University Jinan China 《金属学报(英文版)》1992,5(10):263-267
Using liquid quenching technique,the change of growth mode of graphite in cast iron meltwas analysed.Based on the interface structure theory of crystal growth,the concept ofmultiplication of spiral growth steps was advanced and two basic multiplication modelswere given.It was proposed that multiplication of spiral steps is responsible for the changeof growth mode of graphite in cast iron melt.The modifying elements such as Ce promotemultiplication of spiral steps,which is regarded as the core of modification.Originationof screw dislocation and branch of the sector blocks in radius direction,both of whichare essential to spheroidization of graphite in the melt,are caused by multiplication ofspiral steps:and so is thickening of graphite plates. 相似文献
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ZHAI Qijie HU Hanqi University of Science Technology Beijing Beijing China Faculty of Foundry University of Science Technology Beijing Beijing China 《金属学报(英文版)》1993,6(8):151-155
The distribution of N and morphology of graphite in gray cast iron containing N werestudicd by adopting the man-made specimens of Fe-C-Si-Mn alloys with some N added.The N adsorbed along the interfaces between graphite and matrix together with solid-solutioned in graphite is believed to be the principal cause of morpholongical variationof graphite. 相似文献
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ZOU Zengda WANG Yong REN Dengyi Shandong Polytechnic University Jinan China 《金属学报(英文版)》1991,4(9):191-195
The structural change in heat affected zone(HAZ)and its influence on properties of welded white cast iron have been investigated by means of thermal cycle simulation technique.The structure of the white cast iron at peak temperature 800℃ was examined as cementite in pearlitic matrix,of which the hardness and impact toughness are the lowest,while the struc- ture after cyclic heating at high peak temperature is mainly cementite together with twin martensite,of which the hardness and impact toughness are rather higher.The phase bounda- ries in the structure of low hardness are smooth and regular as well as with fine precipitates. Both the cleavage and interphase fracture were revealed in the structure of low hardness,while the transgranular fracture was found in those areas of higher hardness. 相似文献
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氮对灰铸铁中石墨组织的作用 总被引:2,自引:0,他引:2
本文研究了氮在灰铸铁中的分布及含氮灰铸铁石墨组织结构,结果表明,氮在石墨与基体界面上的吸附和在石墨中的固溶是氮使石墨组织形态发生变化的主要原因。 相似文献
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WANG Yu SONG Weixi HAN Qiyong University of Science Technology Beijing Beijing China The Institute of Precise Special New Materials University of Science Technology Beijing Beijing China 《金属学报(英文版)》1993,6(8):92-97
Size distribution and precipitation of VC particles in ferritic nodular cast iron havebeen examined by techniques of ultrasonic screening,small angle X-ray scattering andchemical dissolution.The VC particles are sized over a wide range.The superfine ones,dispersed in the ferritic matrix,are the majority.A saturated dispersion with ultrafineVC particles may be approached as the V content increasing in the iron.Thi5 seems toplay an important role in the precipitation strengthening for ferritic nodular cast iron. 相似文献
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将铁水用75FeSi孕育后液淬,终止其溶解过程,在溶解区中出现已经生长石墨相的非金属夹杂物,它们随后又溶回铁水中去.但已经复盖有石墨相的晶核能存在较长的时间孕育剂的作用是提供一个碳的过冷溶液,使位于其中的非金属夹杂物活化成为晶核 相似文献
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ZHANG Anfeng Xinjiang Engineering College Urumqi ChinaXING Jiandong LU Wenhua Xi''''an Jiaotong University Xi''''an China associate professor Department of Mechanical Engineering Xi''''an Jiaotong University Xi''''an China 《金属学报(英文版)》1993,6(12):447-452
The oxidation behaviour of high Cr Cast iron was investigated at 950 and 800℃ in termsof Cr content in matrix and the amount of carbide.The morphology and types of oxidefilms and the microstructure of subsurface were also examined.The main conclusionsare:1)The original chromium content in the matrix determines the type of oxide filmand it is an important factor for the oxidation resistance of high chromium cast iron;2)The oxidation resistance improves with increasing carbide content at 950℃ because ofthe decomposition of the carbide,while the decompsition of the carbide do not take placeat 800℃ so the oxidation resisteance do not improve with increasing carbide volume. 相似文献
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WAMG Chunqi YANG Jiguang Tianjin University Tianjin China associate professor Faculty of Foundry Tianjin University.Tianjin China 《金属学报(英文版)》1993,6(12):411-415
Melted cast iron was inoculated by FeSi,then quenched to interrupt the dissolution,the non-metallic inclusions,in which the graphite phase was already occured,formed inthe dissolution region,They dissolved into the melt soon,but the inclusions coated bygraphite could exist for along time.The function of inoculant is to create an undercoolingsolution for carbon,thereby the non-metallic inclusions in the solution may be activatedas the nuclei for graphite. 相似文献
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石墨形态和基体组织对铸铁断裂过程的影响 总被引:4,自引:0,他引:4
研究了石墨片混乱度S=0的Fe-C合金和球墨铸铁在不同受力状态下的裂纹扩展现象,以及基体组织对断裂形貌的影响,试验发现:当裂纹遇到与其平行的片状石墨时,裂纹将在石墨内部以(0001)面之间的解理而扩展;当裂纹遇到与其垂直的片状石墨时,裂纹将沿石墨/基体界面处扩展,也即界面的脱粘;当裂纹遇到球状石墨时,裂纹主要的二次石墨中前进,裂纹在铁素体-下贝氏体中以在铁素体中的扩展为主。 相似文献
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GUO Chengbi ZHOU Weisheng Dalian Institute of Technology Dalian Liaoning China Professor Dept.of Shipbuilding Dalian Institute of Technology Dalian Liaoning China 《金属学报(英文版)》1989,2(3):194-200
The in-phase and out-of-phase thermal fatigue,the C-P type and P-C type isothermal fa-tigue of grey cast iron were experimentally studied.The fatigue life was evaluated analyticallyby using the elastic-plastic fracture mechanics method(mainly J integral).The results of ex-periments and calculations showed that the lifes of in-phase and C-P type fatigue are longerthan that of out-of-phase and P-C type fatigue respectively within the same strain range.This is in contrast to the results of other materials such as low carbon steel.On the other hand,the predicted lifes are consistent with experimental results.This suggests that J integral as amechanics parameter for characterizing the thermal fatigue strength of grey cast iron and themechanics model and the calculation method developed here are efficient.A parameterΔW_1 was proposed from energy aspect to characterize the capacity of crack propagation.The isothermal fatigue life is the same as the thermal fatigue life for identical ΔW_1 values. 相似文献
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FAN Zhikang WANG Yiqing Shanxi Institute of Mechanical Engineering Xi''''an ChinaHUANG Huisong Tsinghua University Beijing China 《金属学报(英文版)》1992,5(4):297-300
An optimal two-dimensional transverse section of eutectic cells or ellipsoid austenite dendritesin the grey cast iron specimen was prepared by polishing layer by layer together with etchingand coloring.The segregation of Mn and Si with relation to their contents in the grey cast ironwas examined by EMPA.The actual partition and segregation coefficients of Mn and Si inthe grey cast iron were found to be not varied with their contents,but their segregation gra-dient to be different to various contents of them. 相似文献
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本文通过试验分析了灰铸铁的同相和异相热疲劳及C-P型和P-C型高温低周疲劳特性,并应用弹塑性断裂力学方法对其寿命作了解析评价。试验和计算都表明,在相同应变范围下,同相和C-P型疲劳寿命分别高于异相和P-C型。这与低碳钢等材料结果相反。另外,计算值和试验吻合,说明J积分用作评价灰铸铁热疲劳强度的力学参量及本文所建立的力学模型和计算方法有效。文中从能量角度提出了一个用于描述裂纹扩展能力的参量ΔW_T,在相同ΔW_T值下,高温低周疲劳寿命和热疲劳相等。 相似文献
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氮对灰铸铁基体组织的作用 总被引:1,自引:0,他引:1
研究了氮对Fe—C-Si和Fe—C—Si-Mn灰铸铁基体组织的作用,实验结果表明,氮使灰铸铁共晶团组织细化,珠光体含量增多,并使珠光体和铁素体显微硬度提高氮对灰铸铁平衡及非平衡相变温度的影响和它溶入铁素体及渗碳体中是强化灰铸铁基体组织的重要原因. 相似文献