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  • In-situ SEM observation on fracture behavior of austempered silicon alloyed steel
  • Crack initiation,propagation and microfracture processes of austempered high silicon cast steel have been investigated by using an in-situ tensile stage installed inside a scanning electron microscope chamber. It is revealed that micro cracks always nucleate at the yielding near imperfections and the boundary of matrix-inclusions due to the stress concentration. There are four types of crack propagations in the matrix:crack propagates along the boundary of two clusters of bainitic ferrite;crack propagates along the boundary of ferrite-austenite in bainitic ferrite laths;crack propagates into bainitic ferrite laths;crack nucleates and propagates in the high carbon brittle plate shape martensite which is transformed from some blocky retained austenite due to plastic deformation.Based on the observation and analysis of microfracture processes,a schematic diagram of the crack nucleation and propagation process of high silicon cast steel is proposed.
  • Properties of sodium silicate bonded sand hardened by microwave heating
  • The sodium silicate bonded sand hardened by microwave heating has many advantages,such as low sodium silicate adding quantity,fast hardening speed,high room temperature strength,good collapsibility and certain surface stability. However,it has big moisture absorbability in the air,which would lead to the compression strength and the surface stability of the sand molds being sharply reduced. In this study,the moisture absorbability of the sodium silicate bonded sand hardened by microwave heating in different humidity conditions and the effect factors were investigated. Meanwhile,the reasons for the big moisture absorbability of the sand were analyzed.Some measures to overcome the problems of high moisture absorbability,bad surface stability and sharply reducing strength in the air were discussed. The results of this study establish the foundation of green and clean foundry technology based on the microwave heating hardening sodium silicate sand process.
  • Effect of nitrogen addition on microstructure and erosion-corrosion behavior of stainless steel in acidic slurry
  • Effect of nitrogen content on the microstructure and erosion-corrosion (E-C) behavior of stainless steel (containing about 25%Cr,5%-6%Ni,and 1%-2%Mo)was investigated by using optical microscope(OM),potentiodynamic polarization curve and immersion method,a self-made rotating disk apparatus and scanning electron microscopy (SEM) and so on. The results show that with the increase of nitrogen content from 0 (no adding) to 0.485 wt.%,the Creq/Nieq ratio of the tested materials decreases from 4.14 to 1.23 and the ferrite volume percentage of the steel tested linearly decreases approximately from 90% to 10%. The effect of nitrogen content on polarization behavior of the studied steel was not significant. All the passive current densities (Ip)and pure corrosion rates (Vc) of the different N content specimens in the acidic solution (slurry containing 0.1 M H2SO4+0.06%CI-+0.4%F-,the simplified zinc hydrometallurgy slurry) are too low and nearly negligible. Whereas the pure erosion rates (Ve) of the four scenarios of the steels tested (N content,wt.%:N1,no adding;N2,0.143%;N3,0.289%;N4,0485%,respectively) are much higher than their Vc values. The Ve values of the tested steels are in the order of N4 > N1 > N3 > N2,at the same time,the total weight loss rates (Vt) follow the order of N4 > N1>N3 > N2,too. N2 steel consisting of approximately equal volume fractions of ferrite (α) and austenite (γ) exhibits the most excellent E-C resistance and erosion resistance,while the stainless steels possessing the big difference between a phase and γ phase,such as N1 steel nearly possessing single ferrite or N4 steel nearly possessing single austenite,show poorer E-C resistance and erosion resistance.
  • Simulation research on control algorithm of differential pressure casting process
  • To improve the precision of the filling pressure curve of differential pressure casting controlled with PID controller,the model of differential pressure casting process is established and two pressure-difference control systems using PID algorithm and Dahlin algorithm are separately designed in MATLAB. The scheduled pressure curves controlled with PID algorithm and Dahlin algorithm,respectively,are comparatively simulated in MATLAB.The simulated pressure curves obtained show that the control precision with Dahlin algorithm is higher than that with PID algorithm in the differential pressure casting process,and it was further verified by production practice.
  • Solute redistribution and Rayleigh number in the mushy zone during directional solidification of Inconel 718
  • The interdendritic segregation along the mushy zone of directionally solidified superalloy Inconel 718has been measured by scanning electron microscope (SEM) and energy dispersion analysis spectrometry (EDAX)techniques and the corresponding liquid composition profile was presented. The liquid density and Rayleigh number (Ra) profiles along the mushy zone were calculated as well. It was found that the liquid density difference increased from top to bottom in the mushy zone and there was no density inversion due to the segregation of Nb and Mo. However carbide formation in the freezing range and the preferred angle of the odentated dendrite array could prompt the fluid flow in the mushy zone although there was no liquid density inversion. The largest relative Rayleigh number appeared at 1,326℃ for Inconel 718 where the fluid flow most easily occurred.
  • Effect of minor Sc and Zr addition on grain refinement of as-cast AI-Zn-Mg-Cu alloys
  • The optical microscopy and scanning electron microscopy as well as energy dispersive spectroscopy were employed to investigate the influence of joint addition of Sc and Zr on grain refinement of AI-Zn-Mg-Cu alloys.Results show that the addition of 0.20% Sc has a little effect on grain refinement because Sc is mainly dissolved into the matrix and hardly any primary Al3Sc particles are precipitated. The alloy with addition of 0.30% Sc and 0.16%Zr has more equiaxed grains than that of others,giving cast grain sizes as fine as 13μm. This is because the Sc substitutes for AI atom in the AI-Zr crystal cell and forms AI-Sc-Zr unit cell,which grows and becomes AI3(Scx,Zr1.x)particle,acting as a nucleus for the formation of a-AI. The addition of 0.04% Ti and 0.008% B makes the grain size drop from 250 μm to 50 μm. Its refinement effect is less than the 13 μm achieved by the alloy including 0.30% Sc and 0.16% Zr.
  • Numerical simulation of stress field in inclusions of large rudder arm steel castings
  • The influence of non-metallic inclusions on quality and performance of steel depends on not only the quantity of inclusions,but also the type,shape,size,distribution,and deformation behavior. In this paper,ANSYS finite element analysis software is used to simulate the stress field of inclusions appearing in heavy rudder arm steel castings,the effects of inclusion type,shape,distribution,and various loading conditions were studied. The micromechanics of inclusions in such castings were also analyzed. Such research provides further cladficetion on reaction mechanism of inclusions under complex loading conditions.
  • Effect of strontium and solidification rate on eutectic grain structure in an AI-13 wt% Si alloy
  • The influence of strontium addition and solidification rate on eutectic grain structure in a near-eutectic AI-Si alloy was investigated. The characteristic temperature of eutectic nucleation (TN),minimum temperature prior to recalescence (TM),and the growth temperature (TG) during cooling were determined by quantitative thermal analysis. All characteristic temperatures were found to decrease continuously with increasing Sr content and solidification rate. Microstructural analysis also revealed that the eutectic grain size decreases with increasing Sr content and solidification rate. Such eutectic grain refinement is attributed to the increased actual under-cooling ahead of the liquid/solid interface during solidification.
  • Novel methodology for casting process optimization using Gaussian process regression and genetic algorithm
  • High pressure die casting (HPDC) is a versatile material processing method for mass-production of metal parts with complex geometries,and this method has been widely used in manufacturing various products of excellent dimensional accuracy and productivity. In order to ensure the quality of the components,a number of variables need to be properly set. A novel methodology for high pressure die casting process optimization was developed,validated and applied to selection of optimal parameters,which incorporate design of experiment (DOE),Gaussian process (GP) regression technique and genetic algorithms (GA). This new approach was applied to process optimization for cast magnesium alloy notebook shell. After being trained,using data generated by PROCAST (FEM-based simulation software),the GP model approximated well with the simulation by extracting useful information from the simulation results. With the help of MATLAB,the GP/GA based approach has achieved the optimum solution of die casting process condition settings.
  • Compacted graphite iron-A material solution for modern diesel engine cylinder blocks and heads
  • The demands for improved fuel economy,performance and emissions continue to pose challenges for engine designers and the materials they choose. This is particularly true for modern diesel engines,where the primary path to achieving improved engine performance and emissions is to increase the Peak Firing Pressure in the combustion chamber. The resulting increase in thermal and mechanical loading has required a change from conventional grey cast iron to Compacted Graphite Iron (CGI) in order to satisfy durability requirements without increasing the size or the weight of the engines. With at least 75% higher tensile strength,45% higher stiffness and approximately double the fatigue strength of conventional grey cast iron,CGI satisfies durability requirements and also provides the dimensional stability required to meet emissions legislation throughout the life of the engine.Currently,there are no CGI diesel engines running on the roads in North America. This is set to change considerably as new commercial vehicle and pick-up SUV diesel engines are launched with CGI cylinder blocks in 2008 and 2009. These initial programs will provide over 2 million CGI diesel engines when ramped to mature volume,potentially accounting for 10%-15% of the North American passenger vehicle fleet within the next four years.
  • The significance of total carbon in greensand systems
  • The need for control of raw materials is critical to the success of iron casting production from greensand systems. The base silica sand is often overlooked with the main focus on bentonite additions.Carbonaceous additives can be considered a “necessary evil“ to ensure a good surface finish and reduction in sand related surface defects. Other additives are used when systems get out of balance and these in turn add further to the complex nature of greensand systems.For castings requiring cores this becomes a bigger issue as many differing resin systems are employed for core production and these must be taken into consideration when controlling both the carbonaceous levels and the overall grading of the sand system. The twin effects on additional carbon and loss-on-ignition and overall sand grading need careful understanding and control.Various control methods are examined including traditional methods such as volatiles and loss-on-ignition along with bentonite determination methods and grading methods. Newer control methods such as total carbon are reviewed along with the overall package ot testing and control methods.Various predictive methods are looked at as a control feature as well.The quality of additives and their role and more importantly their interaction is highlighted,as this is an area often neglected as foundrymen battle for success in consistent quality castings. Suggested in-coming control tests are discussed allied to additions at the mixer.Also reviewed is the interpretation of results and the action required to ensure control and more importantly consistent quality castings from greensand systems with the emphasis on the understanding and control of carbonaceous additive on casting performance.
  • Colour Metallography of Cast Iron
  • This book consists of five sections:Chapter 1 Introduction,Chapter 2 Grey Iron,Chapter 3 Ductile Iron,Chapter 4Vermicular Cast Iron,and Chapter 5 White Cast Iron. CHINA FOUNDRY publishs this book in several parts serially,starting from the first issue of 2009.……
  • First Forum on China Casting Quality Standards & Overview of Revision History of China's National/Industrial Standards for Foundry Operations National Technical Committee 54 on Foundry of Standardization Administration of China (TC54)
  • Both national and local governments have been paying great attention to the work of industrial standardization with the enormous increase in international trade after China joined WTO. According to the standards revising plan of Standardization Administration Committee of China (SAC),TC54 has already revised a series of national standards and industrial standards for foundry operations,and proposed some new ones. As a result,some old fashioned standards containing low-level techniques have been gradually discontinued or replaced with new versions.……
  • Successful the 4th Global Foundry Sourcing Conference 2009
  • The 4th Global Foundry Sourcing Conference (FSC) 2009 was held at Rainbow Hotel Shanghai from April 16 to 17,2009. The FSC Conference was organized by China Foundry Suppliers Union and Suppliers China Information Consultation Co. Ltd. (SC),and co-sponsored by National Technical Committee 54 on Foundry of Standardization Administration of China.……
  • FICMES's Delegation Attended WTF 2009 and Visited Bǚhler AG Switzerland
  • The WFO Technical Forum 2009 (WTF),sponsored by World Foundrymen Organization,organized by Czech Foundrymens Society,was held on the 1st,2nd and 3rd June 2009,at the Hotel Voronez in Brno,Czech Republic. The 4 days included technical presentations,social events and the very important Ph.D conference. During the event there were the General Assembly bringing together the organizations members from around the world,and an exhibition,supported by 34 world‘s leading foundry based companies. In addition the event coincided with the Czech Foundrymens Society Foundry Days now in its 46th year.……
  • The 69th World Foundry Congress (WFC2010)
  • With the trust and support by WFO and its members,Foundry Institution of Chinese Mechanical Engineering Society (FICMES) will host the 69th World Foundry Congress (WFC2010). We cordially invite you to participate in the 69th WFC to be held on October 16-20,2010,in Hangzhou,China.……
  • In-situ SEM observation on fracture behavior of austempered silicon alloyed steel(Chen Xiang Vuorinen Esa Grahn Jonny)
    Properties of sodium silicate bonded sand hardened by microwave heating(Wang Jina Fan Zitian Zan Xiaolei Pan Di)
    Effect of nitrogen addition on microstructure and erosion-corrosion behavior of stainless steel in acidic slurry(Li Ping Cai Qi zhou Wei Bo kang Li Feng jun)
    Simulation research on control algorithm of differential pressure casting process(Chai Yan Jie Wanqi Yang Bo)
    Solute redistribution and Rayleigh number in the mushy zone during directional solidification of Inconel 718(Wang Ling Dong Jianxin Liu Lin Zhang Lei)
    Effect of minor Sc and Zr addition on grain refinement of as-cast AI-Zn-Mg-Cu alloys(He Yongdong Zhang Xinming Cao Zhiqiang)
    Numerical simulation of stress field in inclusions of large rudder arm steel castings(Yang Dixin Xie Jingpei Zhang Kefeng Liu Zongfa Wang Aiqin Wang Wenyan)
    Effect of strontium and solidification rate on eutectic grain structure in an AI-13 wt% Si alloy(Liao Hengcheng Bi Juanjuan Zhang Min Ding Ke Jiang Yunfeng Cai Mingdong)
    Novel methodology for casting process optimization using Gaussian process regression and genetic algorithm(Yao Weixiong Yang Yi Zeng Bin)
    Compacted graphite iron-A material solution for modern diesel engine cylinder blocks and heads(Steve Dawson SinterCast Sweden)
    The significance of total carbon in greensand systems(Alexander Brown)
    Colour Metallography of Cast Iron(Zhou Jiyang Liu Jincheng)
    First Forum on China Casting Quality Standards & Overview of Revision History of China's National/Industrial Standards for Foundry Operations National Technical Committee 54 on Foundry of Standardization Administration of China (TC54)
    Successful the 4th Global Foundry Sourcing Conference 2009
    FICMES's Delegation Attended WTF 2009 and Visited Bǚhler AG Switzerland
    The 69th World Foundry Congress (WFC2010)
    《中国铸造:英文版》封面

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