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Effect of gel time of 3D sand printing binder system on quality of sand mold/core

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China Foundry 2021年第6期18卷 581-586页

作者： yan Wang Rui-long Yu Shao-kui Yin Rui Tan yan-chun lou Shenyang Research Institute of Foundry Co. Ltd.Shenyang 110022China State Key Laboratory of Light Alloy Casting Technology for High-end Equipment Shenyang 110022China

Two important factors affecting the performance of sand mold/core generated by 3D printing(3DP)are strength and dimensional accuracy,which are not only closely related to the reactivity of furan resin and the phase transition of silica sand,but also the curing agent system of furan *** paper studies the influence of gel time on the strength and dimensional accuracy of a 3DP sand mold/core,taking the furan resin system as an example and using a sand specimen generated by a 3DP inkjet molding *** experiment demonstrates that the gel time of 3 to 6 min for the sand mixture suits 3DP core-making most under the experimental ***,it should be noted that under the same resin condition,the strength of a no-bake sand mold/core is higher than that of a 3DP sand mold/*** dimensional accuracy of the sand mold/core does not change significantly when the gel time is less than 15 *** the activity of binder and developing ultra-strong acid with low corrosion shall be an effective way to improve the quality of the mold/core by 3D printing.

关键词： 3D sand printing gel time sand strength dimensional accuracy

Factors influencing power consumption and power-saving measures in ESR process

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China Foundry 2019年第1期16卷 1-7页

作者： Yun-Long Xiong Zhao-Wei Song An-Guo Wang yan-chun lou Shenyang Research Institute of Foundry Co. Ltd.Shenyang 110022China

Since the USA patent of electroslag remelting(ESR) metallurgy was held by P. K. Hopkins in 1940, the ESR technology has now entered a relatively mature stage after a 70-year history of development. At present, the annual capacity of ESR steels around the world is approximately 2 million tonnes. ESR metallurgy emerged in China in 1958. Since then, electroslag furnaces were gradually installed in Chinese special steel plants. At present, there are more than 200 electroslag remelting furnaces in the metallurgical workshops of these steel plants with an annual production capacity of about 500,000 tonnes of ingots and components made of about 200 varieties of steels, including high quality steels and superalloys. This ESR technology is used as a special remelting and refining method for producing high quality steels and superalloys. However, traditional ESR technology has the disadvantages of environmental pollution and extremely high specific power consumption. High power consumption restricts, to a certain degree, the competitiveness of ESR steels in the marketplace. The measures of power saving in ESR have been researched in recent years. In this paper, some factors influencing power consumption, such as filling ratio, slag system, slag amount, melting rate and furnace structure are reviewed, and several new ESR technologies for power saving are proposed.

关键词： ESR power saving fill ratio slag system slag amount melting rate

Effect of vibrating electrode on temperature profiles,fluid flow,and pool shape in ESR system based on a comprehensive coupled model

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China Foundry 2015年第4期12卷 285-292页

作者： Fang Wang yan-chun lou Rui Chen Zhao-wei Song Bao-kuan Li School of Materials and Metallurgy Northeastern University Shenyang Research Institute of Foundry

The vibrating electrode method was proposed in the electro-slag remelting （ESR） process in this paper, and the effect of vibrating electrode on the solidification structure of ingot was studied. A transient three- dimensional （3D） coupled mathematical model was established to simulate the electromagnetic phenomenon, fluid flow as well as pool shape in the ESIR process with the vibrating electrode. The finite element volume method is developed to solve the electromagnetic field using ANSYS mechanical APDL software. Moreover, the electromagnetic force and Joule heating are interpolated as the source term of the momentum and energy equations. The multi-physical fields have been investigated and compared between the traditional electrode and the vibrating electrode in the ESR process. The results show that the drop process of metal droplets with the traditional electrode is scattered randomly. However, the drop process of metal droplets with the vibrating electrode is periodic. The highest temperature of slag layer with the vibrating electrode is higher than that with the traditional electrode, which can increase the melting rate due to the enhanced heat transfer in the vicinity of the electrode tip. The results also show that when the amplitude and frequency of the vibrating electrode increase, the cycle of drop process of metal droplets decreases significantly.

关键词： electro-slag remelting process vibrating electrode magneto-hydrodynamic numerical simulation

Elimination of misrun and gas hole defects of investment casting TiAl alloy turbocharger based on numerical simulation and experimental study

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China Foundry 2020年第1期17卷 29-34页

作者： Jun Zhao Zhi-yong Zhang Shi-bing Liu Kun Shi chun-ling Bao Zhao-sheng Ning Ping yan Lei Wang yan-chun lou State Key Laboratory of Light Alloy Casting Technology for High-end Equipment Shenyang 110022China Shenyang Research Institute of Foundry Co. Ltd.Shenyang 110022China Northeastern University Shenyang 110189China

Casting technology of thin-wall TiAl alloy turbochargers was studied by investment casting and numerical *** and gas holes were the main defects observed in preliminary work due to the poor fluidity of alloy,and to gas *** order to eliminate these defects,cast parameters,such as centrifugal rotation rate and mould preheating temperature,were optimized by numerical simulation,meanwhile,the structure of the shell mould was optimized to improve the filling capacity of TiAl *** experiments were carried out by vacuum induction melting furnace equipped with a water-cooled copper crucible based on the above *** quality of the TiAl alloy casting was analyzed by fluorescent penetrant inspection and X-ray *** results show that a centrifugal rotation rate of 200 rpm,mould preheating temperature of 600°C,shell preparation through organic fiber addition can dramatically improve the mould filling capacity,and integrated turbochargers were finally prepared.

关键词： titanium aluminide cast defects turbocharger investment casting

Directional solidification casting technology of heavy-duty gas turbine blade with liquid metal cooling(LMC) process

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China Foundry 2019年第1期16卷 23-30页

作者： Xiao-fu Liu yan-chun lou Bo Yu Gui-qiao Su Chang-chun Li Xin-li Guo Biao Li Guo-yan Shui State Key Laboratory of Light Alloy Casting Technology for High-end Equipment Shenyang Research Institute of Foundry Co.Ltd.Shenyang 110022China

In this work, some important factors such as ceramic shell strength, heat preservation temperature, standing time and withdrawal rate, which influence the formability of directionally solidified large-size blades of heavy-duty gas turbine with the liquid metal cooling(LMC) process, were studied through the method of microstructure analysis combining. The results show that the ceramic shell with medium strength(the high temperature flexural strength is 8 MPa, the flexural strength after thermal shock resistance is 12 MPa and the residual flexural strength is 20 MPa) can prevent the rupture and runout of the blade. The appropriate temperature(1,520 ℃ for upper region and 1,500 ℃ for lower region) of the heating furnace can eliminate the wide-angle grain boundary, the deviation of grain and the run-out caused by the shell crack. The holding time after pouring(3-5 min) can promote the growth of competitive grains and avoid a great deviation of columnar grains along the crystal orientation , resulting in a straight and uniform grain structure. In addition, to avoid the formation of wrinkles and to ensure a smooth blade surface, the withdrawal rate should be no greater than the growth rate of grain. It is also found that the dendritic space of the blade decreases with the rise of solidification rate, and increases with the enlarging distance between the solidification position and the chill plate.

关键词： liquid metal cooling (LMC) heavy-duty gas turbine large-size blade directional solidification microstructure

Influence of thermo hydrogen treatment on microstructure and mechanical properties of Ti-5Al-2.5Sn ELI alloy

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China Foundry 2017年第1期14卷 55-58页

作者： Ya-fei Ren Jun Zhao Hua-sheng Xie Shi-bing Liu yan-chun lou Ping yan Shenyang Research Institute of Foundry Shenyang 110022China State Key Laboratory of Light Alloy Casting Technology for High-end Equipment Shenyang 110022China Beijing Research Institute of Mechanical&Electrical Technology Beijing 100083China

Thermo hydrogen treatment （THT） of titanium is a process in which hydrogen is used as a temporary alloying element in titanium alloys. It is an attractive approach for controlling the microstructure and thereby improving the final mechanical properties. In the present study, the microstructure of the original （non-hydrogenated） sample has only a phase and the grains is coarse with an average size of - 650 pm. While the grain size of thermo hydrogen treated Ti-5Al-2.5Sn ELI alloy became finer and the mechanical properties were improved significantly. When the hydrogen content of the hydrogenated Ti-5Al-2.5Sn ELI alloy is 0.321wt.%, 13 phase and 6 titanium hydride appear. Also the average grain size decreases to 450 pm. When the hydrogen content is 0.515wt.%, the grain size decreases to 220μm. The mechanical properties were tested after dehydrogenation, and the mechanical properties improved significantly compared to the unhydrogenated specimens. The tensile strength of the Ti-5Al- 2.5Sn ELI alloy improved by 17.7% when the hydrogen content increased to 0.920wt.%, at the same time the percentage reduction of area （Z） increased by 33% and the impact toughness increased by 37%.

关键词： thermo hydrogen treatment microstructure mechanical properties

A novel Ti-5.55Al-6.70Zr-1.50V-0.70Mo-3.41Nb-0.21Si alloy designed using cluster-plus-glue-atom model for laser additive manufacturing

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China Foundry 2023年第5期20卷 414-422页

作者： Tian-yu Liu yan-chun lou Shuang Zhang Zhi-hao Zhu Jun Zhao Shi-bing Liu Kun Shi Ning Zhao National Key Laboratory of Advanced Casting Technologies Shenyang Research Institute of Foundry Co.Ltd.CAMShenyang 110022China School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028LiaoningChina School of Materials Science and Engineering Dalian University of TechnologyDalian 116024LiaoningChina

A novel Ti-5.55Al-6.70Zr-1.50V-0.70Mo-3.41Nb-0.21Si alloy was designed using the cluster formula approach(cluster-plus-glue-atom model)and prepared by laser melting deposition(LMD).Its composition formula 12[Al-Ti_(12)](AlTi_(2))+5[Al_(0.8)Si_(0.2)-Ti_(12)Zr_(2)](V_(0.8)Mo_(0.2)Nb_(1)Ti)features an enhancedβ-Ti via co-alloying of Zr,V,Mo,Nb and *** experimental results show that the cluster formula ofαandβphases in the novel alloy are respectivelyα-[Al-Ti_(11.5)Zr_(0.5)](Al_(1)Ti_(2))andβ-[Al_(0.8)Si_(0.2)-Ti_(13.2)Zr_(0.8)](V_(1)Mo_(0.4)Nb_(1.6)),both containing Zr *** fitted composition via the α andβphase cluster formulas has little difference with the actual alloy composition,suggesting that the validity of cluster-plus-glue-atom model in the alloy composition *** hot isostatic pressing(HIP),both the Ti-6Al-4V and the novel alloy by LMD are characterized by prior-βcolumnar grains,while the typicaltexture *** with Ti-6Al-4V,Ti-5.55Al-6.70Zr-1.50V-0.70Mo-3.41Nb-0.21Si alloy exhibits a combination of higher strength(1,056 MPa)and higher ductility(14%)at room temperature and higher strength(580 MPa)at 550℃ after HIP,and can potentially serves as LMD materials.

关键词： additive manufacturing laser melting deposition novel titanium alloy composition design cluster-plus-glue-atom model

Effect of Gd addition on mechanical and microstructural properties of Mg-xGd-2.6Nd-0.5Zn-0.5Zr cast alloys

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China Foundry 2020年第3期17卷 212-218页

作者： Liang Zhan Yi-zhi Le Zhi-jun Feng yan-chun lou Ming Ruan Hua-wen Li Key Lab of Electromagnetic Processing of Materials Northeastern UniversityShenyang 110819China State Key Laboratory of Light Alloy Casting Technology for High-end Equipment Shenyang Research Institute of Foundry Co.Ltd.Shenyang 110022China AECC Zhongchuan Transmission Machinery Co. Ltd.Changsha 410200China

The Mg-xGd-2.6Nd-0.5Zn-0.5Zr(x=0,3.0,4.5 and 6.0,wt.%)alloys were prepared by gravity casting and then T6 *** of the alloy were observed using optical microscopy and scanning electron *** show that the as-cast alloys contained network Mg3Gd phases,blocky and needle-like Mg12(Nd,Gd)*** a(Zr)particle inclusions in the a(Mg)matrix are also *** of the secondary phases decreases as Gd content *** test results show that the tensile and yield strengths of all the alloys increase as Gd content increases under the as-cast and T6 conditions,but the elongation exhibits the opposite *** blocky Mg12(Nd,Gd)phases appear and act as crack initiator and deteriorates the experimental alloys’ductility with the increase of Gd content,especially as Gd content increases to 6.0 wt.%,so the Mg-6.0Gd-2.6Nd-0.5Zn-0.5Zr alloy has the lowest elongation value compared to the other alloys *** T6 treatment,the Mg-4.5Gd-2.6Nd-0.5Zn-0.5Zr alloy exhibits the optimal mechanical properties both at room temperature and 250℃.

关键词： Mg-xGd-Nd-Zn-Zr alloys mechanical properties microstructure Gd addition

Influence of a low-frequency alternating magnetic field on hot tearing susceptibility of EV31 magnesium alloy

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China Foundry 2021年第3期18卷 229-238页

作者： Xin Su Zhi-jun Feng Jing-fu Huang Xu-dong Du Ru-shuang An Feng Wang yan-chun lou State Key Laboratory of Light Alloy Casting Technology for High-end Equipment Shenyang 110022China Shenyang Research Institute of Foundry Co. Ltd.Shenyang 110022China Shenyang Research Casting Technology Co. Ltd.Shenyang 110141China College of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

The effect of a low-frequency alternating magnetic field (AMF,0 A 0 Hz,5 A 10 Hz,10 A 10 Hz,15 A 10 Hz) on the hot tearing susceptibility (HTS) of a magnesium alloy (EV31) was systematically studied using a combination of experiment and numerical *** observing the macroscopic hot cracks in hot joints of the "T" samples,the hot tearing tendency of the samples was *** HTS of the alloy can be predicted via numerical simulation and the crack susceptibility coefficient (CSC).The microstructure and morphology of the hot tearing zone of EV31 were investigated using scanning electron microscopy (SEM).Results show that increasing the magnetic field strength reduces both the alloy solidification temperature range and the dendrite coherency temperature,which increases the feeding time during solidification and decreases the HTS of the *** the magnetic field parameters are 10 Hz 15 A,the EV31 alloy shows the lowest *** main component of the second phase in the microstructure is *** study also found that the electromagnetic field can effectively refine the grains,purify the melt,and reduce the oxide content in the *** obtained simulation results are consistent with the experimental results.

关键词： EV31 magnesium alloy electromagnetic field hot tearing susceptibility microstructure dendrite coherency temperature