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Journal of Iron and Steel Research International 2019年第8期26卷 888-897页

作者： Hua Zhang yan-xin wu Qiu-ju Li xin Hong State Key Laboratory of Advanced Special Steel and Shanghai Key Laboratory of Advanced Ferrometallurgy and School of Materials Science and Engineering Shanghai University Shanghai 200072 China Jiangsu Yonggang Group Co. Ltd. Zhangjiagang 215628 Jiangsu China Institute of Engineering Technology University of Science and Technology Beijing Beijing 100083 China

The influence of matrix structure on mechanical properties and dry rolling-sliding wear performance of alloyed ductile iron was examined. Four kinds of alloyed ductile irons with different matrix structures were produced through an adequate balance of alloying elements. Tensile tests and dry rolling-sliding wear tests were carried out at room temperature. The results show that yield strength and ultimate tensile strength increase, while elongation decreases until the matrix fully becomes pearlite. The lower matrix hardness results in more graphite emerging on the contact surface, which yields the decrease in friction coefficient. Besides, the wear rate decreases with the increase in matrix hardness among alloyed ductile irons except that with full pearlite matrix, the wear performance of which seems to be deteriorated due to poor fracture toughness. The main wear mechanism is delamination under an air-cooling condition. Based on the results of mechanical and wear tests, ductile iron with about 80% pearlite exhibits better wear performance as well as relatively reasonable mechanical properties.

关键词： Ductile iron Microstructure Mechanical property Wear Delamination

Chiral iminophosphorane catalyzed asymmetric Henry reaction of α,β-alkynyl ketoesters

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Chinese Chemical Letters 2019年第8期30卷 1519-1522页

作者： yanxia Zhang xin-yan wu Jianwei Han Key Laboratory for Advanced Materials Institute of Fine ChemicalsSchool of Chemistry&Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis Shanghai Institute of Organic ChemistryThe Chinese Academy of SciencesShanghai 200032China

α,β-Alkynyl ketoesters were introduced to the enantioselective Henry reaction(nitroaldol condensation)with nitromethane catalyzed by tartaric acid derived chiral *** such,a variety of optically activeβ-nitro-substituted tertiary alcohols bearing alkyne moieties were obtained in good to excellent yields(42%–99%)and moderate to good level of enantiomeric excess(up to 87%ee).

关键词： Organocatalysis Iminophosphorane Nitroaldol Henry reaction Alkynyl ketoesters

Thermomechanical analysis of triangular zone cracks in vertical continuous casting slabs based on viscoelastic-plastic model

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Journal of Iron and Steel Research International 2018年第8期25卷 813-820页

作者： Juan Cheng yan-xin wu yang Wang Jian-xun Fu Materials Genome Institute and State Key Laboratory of Advanced Special Steel and School of Materials Science andEngineering Shanghai University Shanghai 200444 China

The triangular zone cracks in 2101 duplex stainless steel produced by the vertical continuous caster have troubled company A for a long time. To simulate the temperature and thermal stress distributions in the solidification process of 2101 duplex stainless steel produced by the vertical continuous caster, a two-dimensional viscoelastic-plastic thermomechanically coupled finite element model was established by the secondary development of the commercial nonlinear finite element analysis software MSC Marc. The results show that the thermal stress on the surface reaches a maximum at the exit of the mould, and the highest thermal stresses at the centre of the wide face and the narrow face are 75 and 115 MPa, respectively. Meanwhile, the internal temperature of slab is still higher than the solidus temperature, resulting in no thermal stress. The slab shows different high-temperature strengths and suffers from different stresses at different positions; thus, the risk of cracking also varies. At a location of 6-8 m from the meniscus, the temperature of the triangular zone is 1270-1360℃ and the corresponding permissible high-temperature strength is about 10-30 MPa, while the thermal stress at this time is 60 MPa, which is higher than the high-temperature strength. As a result, triangular zone cracks form easily.

关键词： Vertical continuous caster Triangular zone crack Thermomechanical coupling Viscoelastic-plastic model -Finite element analysis

Application of tellurium in free-cutting steels

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Journal of Iron and Steel Research International 2018年第8期25卷 787-795页

作者： Ping Shen Qian-kun yang Dong Zhang yan-xin wu Jian-xun Fu State Key Laboratory of Advanced Special Steel Shanghai Key Laboratory of Advanced Ferrous Metallurgy School of Materials Science and Engineering Shanghai UniversityShanghai 200444 China Institute of Material Science and Engineering National Taiwan University Taipei 10617 Taiwan China

Te is widely used in iron and steel industry. After adding a certain amount of Te in the steel, many physical and chemical properties can be improved. As a free-cutting element, a small amount of Te can significantly improve the machinability of steel. The existing form of Te in the steel, the modification law of MnS inclusion by Te and the influence rule and mechanism of Te on the machinability of steel are summarized and expounded in detail, providing a reference for further study and development of Te-containing free-cutting steels.

关键词： Tellurium - Inclusion Sulfide modification Free-cutting steel

Analysis on composition and inclusions of ballpoint pen tip steel

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International Journal of Minerals,Metallurgy and Materials 2018年第4期25卷 420-428页

作者： Qian-kun yang Ping Shen Dong Zhang yan-xin wu Jian-xun Fu State Key Laboratory of Advanced Special Steel Shanghai Key Laboratory of Advanced Ferrometallurgy School of Materials Science and Engineering Shanghai University

Ballpoint pen tip steel, a super free-cutting stainless steel, exhibits excellent corrosion resistance and good machining properties. In this study, inductively coupled plasma spectroscopy, metallographic microscopy, and scanning electron microscopy were used to determine the elemental contents in five ballpoint pen tips and their components, morphologies, and inclusion distributions. The results showed that the steels were all S–Pb–Te super free-cutting ferritic stainless steel. The free-cutting phases in the steels were mainly Mn S, Pb, and small amounts of Pb Te. Mn S inclusions were in the form of chain distributions, and the aspect ratio of each size inclusion in the chain was small. The stress concentration effect could substantially reduce the cutting force when the material was machined. Some of the Pb was distributed evenly in the steel matrix as fine particles（1–2 μm）, and the rest of the Pb was distributed at the middle or at both ends of the Mn S inclusions. The Pb plays a role in lubrication and melting embrittlement, which substantially increases the cutting performance. Pb Te was also usually distributed in the middle and at both ends of the Mn S inclusions, and Te could convert the sulfides into spindles, thereby improving the cutting performance of the steel.

关键词： ballpoint pen tip free-cutting stainless steel inclusions lead tellurium

Influence of on-line tempering parameters on microstructure of medium-carbon steel

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Journal of Iron and Steel Research International 2017年第1期24卷 59-66页

作者： Hua Zhang yan-xin wu Jian-xun Fu Jie Xu Qi-jie Zhai State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai 200072China

A new process involving ultra-fast cooling（UFC）and on-line tempering（OLT）was proposed to displace austempering process,which usually implements in a salt/lead bath and brings out serious pollution in the industrial *** optimization of the new process,involving the evolution of the microstructure of medium-carbon steel during various cooling paths,was *** results show that the cooling path affected the final microstructure in terms of the fraction of pearlite,grain size and distribution of cementite in *** the cooling rate or decreasing the OLT temperature contributes to restraining the transformation from austenite to ferrite,and simultaneously retains more austenite for the transformation of *** is also noted that bainite was observed in the microstructure at the cooling rate of 45℃/s and the OLT temperature of 500℃.Through either increasing the cooling rate or decreasing the OLT temperature,the distribution of cementite in pearlite is more dispersed and grain is *** the possibility of industrial applications into account,the optimal process of cooling at 45℃/s followed by OLT at 600℃ after hot rolling was determined,which achieves a microstructure containing nearly full pearlite with an average grain size of approximately 7μm and a homogeneously dispersed distribution of cementite in pearlite.

关键词： Medium-carbon steel Ultra-fast cooling On-line tempering Phase transformation kinetics

Enantioselective synthesis of 10-allylanthrones via iridium-catalyzed allylic substitution reaction

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Chinese Chemical Letters 2016年第5期27卷 619-622页

作者： Zheng-Le Zhao Qing Gu xin-yan wu Shu-Li You Key Laboratory for Advanced Materials and Institute of Fine Chemicals East China University of Science and Technology Shanghai 200237 China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

A highly enantioselective allylic substitution reaction of anthrones with aromatic or aliphatic allyl carbonates was realized by using iridium catalyst prepared from [Ir（COD）CI]2 and BHPphos. Substituted 10-allylanthrones were obtained in excellent yields and with excellent enantioselectivity and regioselectivity （up to 98% yield, 99700 ee） under mild conditions.

关键词： Allylic substitution Anthrone Asymmetric catalysis Enantioselectivity Iridium

Low Cycle Fatigue Behavior and Deformation Mechanism of TWIP Steel

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Journal of Iron and Steel Research International 2014年第3期21卷 352-358页

作者： yan-xin wu Di TANG Hai-tao JIANG Zhen-li MI Yao XUE Hai-peng wu Engineering Research Institute University of Science and Technology Beijing

Low cycle fatigue behavior of TWIP （twinning induced plasticity） steel was investigated in axial symmetric tension-compression cyclic loading pattern. Fracture surfaces and microstructures were examined by optical, scanning electron and transmission electron microscopes. It was found that the fatigue life at the strain amplitude of 0.4 % is up to 15 000 cycles, which is much longer than TRIP780 and HSLAS00 steels. The strain hardening and softening features are significant until the strain amplitude comes to 1.25 ~. Persistent slip bands and tiny mechanical twinning layers were observed after fatigue deformation. Deformation mechanism of TWIP steel at low cycle fatigue process is not only twinning, but a complex of both twinning and persistent slip bands.

关键词： TWIP steel low cycle fatigue fatigue property persistent slip band

Element distribution and difusion behavior in Q&P steel during partitioning

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International Journal of Minerals,Metallurgy and Materials 2013年第11期20卷 1050-1059页

作者： Hai-tao Jiang Bao-tong Zhuang Xiao-ge Duan yan-xin wu Zheng-xu Cai National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing

Carbon, manganese, and silicon distribution in quenching and partitioning （Q＆P） steel during partitioning process was investigated to reveal the diffusion behavior. The microstructure and chemical composition were analyzed by means of scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and three-dimensional atom probe. It is shown that the studied Q＆P steel consisted of martensite laths and thin, film-like retained austenite showing extraordinary phase transformation stability. Carbon atoms mostly diffused to the retained austenite from martensite at a higher partitioning temperature. In the experimental steel partitioned at 400℃ for 10-60 s, carbides or cementite formed through carbon segregation along martensite boundaries or within the martensite matrix. As a result of carbon atom diffusion from martensite to austenite, the carbon content in martensite could be ignored. When the partitioning process completed, the constrained carbon equilibrium （CCE） could be simplified. Results calculated by the simplified CCE model were similar to those of CCE, and the difference between the two optimum quenching temperatures, where the maximum volume fraction of the retained austenite can be obtained by the Q＆P process, was little.

关键词： steel heat treatment quenching partitioning element distribution diffusion microstructure

Dilatometric Analysis of Irreversible Volume Change during Phase Transformation in Pure Iron

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Journal of Iron and Steel Research International 2016年第8期23卷 828-833页

作者： Ren-jie ZHAO Jian-xun FU Yu-yuan ZHU Ye-jin yanG yan-xin wu State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory Advanced Ferrometallurgy &School of Materials Science and Engineering Shanghai University

One assumption underlying the conventional dilatometric analysis based on the lever rule is that the volume of the specimen changes isotropically during phase transformation,which conflicts with the irreversible length change shown in actual *** contribution of this irreversible effect to the dilation data of pure iron upon heating and cooling was respectively quantified via conversion equations based on lattice parameters.A model considering the elastic strain and creep deformation was established for both the interpretation of the irreversible volume change and the discrepancy between the results measured by a dilatometer and a micrometer.

关键词： irreversible Transformation micrometer interpretation specimen lever length creep ferrite shrinkage