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石墨形态和基体组织对铸铁断裂过程的影响

蒋建清

金属学报

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,裂纹上要在二次石墨中前进。裂纹在铁素体-下贝氏体中时以在铁素体中的扩展为主。

关键词: Fe—C合金 , flake graphite , spheroidal graphite , crack propagation , cast iron

水平连铸铸铁棒材凝固过程数值模拟

朱宪华 , 董增章 , 苏俊义

金属学报

本文对直径为46mm的水平连铸灰铸铁棒材进行凝固数值模拟。通过实测石墨套内温度场及数值计算,用传热学反问题求解方法确定铸棒表面的热流边界条件。采用所求得的铸棒表面热流分布函数,进行了计及铸棒轴向传热的凝固数值模拟,所得凝固前沿形貌与实际情况大体接近。在此基础上,进一步用凝固模拟方法研究了水平连铸铸铁棒材生产中主要工艺参数对结晶器出口处棒材凝固层厚度的影响。

关键词: 连续铸造 , cast iron , solidification , numerical simulation

碱性溶液中阴极极化对模拟铸铁文物局部腐蚀闭塞区化学和电化学状态的影响

许淳淳 , 岳丽杰 , 欧阳维真

中国腐蚀与防护学报

采用模拟闭塞电池恒电流法研究在碱性溶液中阴极极化对模拟铸铁文物局部腐蚀闭塞区内溶液化学和电化学状态的影响.结果表明:对试样通入阴极电流后,闭塞区内溶液的pH值随着通电时间的延长及阴极电流密度的增大而升高;氯离子向闭塞区外迁移,迁移率和迁移速率随时间的延长和电流密度的增大而增高.由于Cl-的迁出及外部OH-的迁入 ,闭塞区内的腐蚀受到抑制.通阴极电流能加速闭塞区内Cl-的迁出,比铸铁文物通常采用的碱性溶液浸泡脱氯法更为有效,是一种快速的电化学脱氯方法.

关键词: 碱性溶液 , cast iron , occluded cell , cathodic polarization

铬铁矿液相氧化过程中材质腐蚀性能研究

郑诗礼 , 张懿

腐蚀学报(英文)

采用挂片失重法对比了6种不同材质在铬铁矿液相氧 化过程中的腐蚀性能,综合性能比较确定铸铁为首选可用材质,并研究了温度、氧气流量及 熔体介质对铸铁腐蚀性能的影响,其中以温度的影响最为显著.结果还表明铬化合物具有一 定的缓蚀作用.

关键词: 铬铁矿 , weight loss method , corrosion , cast iron

DISTRIBUTION OF SULFUR IN HIGH TEMPERATURE PHASES OF CAST IRON

HAN Qiyong YANG Ping SONG Weixi University of Science and Technolonology Beijing , Beijing , China Division of Metallography , Dept.of Materials , University of Science and Technology Beijing , Beijing , China

金属学报(英文版)

The distribution of subversive element sulfur in high temperature phases during solidification of cast iron was investigated by means of liquid quenching method and autoradiography.The results show that in grey cast iron,sulfur is concentrated in the liquid,flake graphite and in the peripherial area of D-type supercooled graphite eutectic cells,but less sulfur is in austenite. Besides,the content of sulfur in A-type graphite is higher than that in D-type graphite,and sulfur content in eutectic austenite is a little higher than that in primary austenite.While,in nodular graphite cast iron less sulfur is in liquid and austenite,but more in nodular graphite. The blackness of the spots on the emulsion film corresponds to the atomic percentage of radioactive substances located on the surface of the specimen.

关键词: cast iron , null , null , null

DYNAMIC SEGREGATION OF SULPHUR IN CAST IRON

QIN Ziqiang YU Zongsen University of Science and Technology Beijing , Beijing , China QIN Ziqiang Department of Metal Physics , University of Science and Technology Beijing , Beijing , China

金属学报(英文版)

The segregation of sulphur at iron/graphite interfaces in both grey and nodular iron was in- vestigated with AES.Sulphur was found to nonequilibratorily segregate at the interfaces in grey iron,but not in nodular iron.Such different behaviors of segregation,which will exagger- ate the difference of grey and nodular iron in sulphur content at iron/graphite interfaces, might be derived from the difference of solidification process between the two irons.

关键词: cast iron , null , null , null

SEGREGATION OF Mn AND Si IN GREY CAST IRON

FAN Zhikang WANG Yiqing Shanxi Institute of Mechanical Engineering , Xi'an , ChinaHUANG Huisong Tsinghua University , Beijing , China

金属学报(英文版)

An optimal two-dimensional transverse section of eutectic cells or ellipsoid austenite dendrites in the grey cast iron specimen was prepared by polishing layer by layer together with etching and coloring.The segregation of Mn and Si with relation to their contents in the grey cast iron was examined by EMPA.The actual partition and segregation coefficients of Mn and Si in the 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.

关键词: cast iron , null , null , null

ON THE M_7C_3 IN Cr27 CAST IRON

LI Yuqing WANG Cirong GU Zhaofeng Research Institute of Daye Steel Works , Huangshi , China Senior Engineer , Research Institute of Daye Steel Works , Huangshi 435001 , China

金属学报(英文版)

Determination of(Fe,Cr)_7C_3 in Cr27 cast iron results about 30 v.-%.Minor Si and Mn are present.Sectional area of the M_7C_3 grains is 1—50μm~2.Combining matrix analysis of elec- tron diffraction pattern with calculated angle between plane traces,{011}twins and also {013}twins producing local environment for Ru_7B_3 are observed in the orthorhombic M_7C_3. A crystallographic model for M_7C_3 is proposed.

关键词: cast iron , null , null , null , null

铸铁孕育处理时的石墨核心研究

王春祺 , 杨继光

金属学报

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

关键词: 铸铁孕育 , cast iron , activated nuclei

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