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Chung Nguyen VAN; Hai TRAN THANH; Thuc Nhu NGUYEN; Jianchun LI
《结构与土木工程前沿(英文)》 2022年 第16卷 第11期 页码 1424-1435 doi: 10.1007/s11709-022-0870-9
关键词: ECC fiber orientation distribution casting direction casting position
Determining casting defects in near-net shape casting aluminum parts by computed tomography
Jiehua LI, Bernd OBERDORFER, Daniel HABE, Peter SCHUMACHER
《机械工程前沿(英文)》 2018年 第13卷 第1期 页码 48-52 doi: 10.1007/s11465-018-0493-y
Three types of near-net shape casting aluminum parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting (Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy), die casting (A356, Al-7Si-0.3Mg), and semi-solid casting (A356, Al-7Si-0.3Mg), respectively. Unlike die casting (second part), low-pressure die casting (first part) significantly reduced the formation of casting defects (i.e., porosity) due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi-solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.
关键词: near-net shape casting aluminum parts casting defects low pressure die casting die casting semi-solid casting computed tomography
王海舟,李美玲,庄景云
《中国工程科学》 2011年 第13卷 第10期 页码 19-27
采用原位统计分布分析表征技术系统研究了GH169高温合金压气机盘纵断面不同部位铌分布的规律。以所得到的与样品原位置相对应的数以万计原始信号系统解析为基础,进而获得压气机盘锻件的纵断面不同部位铌的定量统计分布信息以及加工工艺过程中铌的迁移规律。准确计算判定了盘纵断面不同部位铌的最大偏析度,提出了95 %置信度时中位值置信扩展率,即统计偏析度(S)新参数,用以表征铌在压气机盘中分布的均匀度;提出了所有数据在特定含量区间(C0±R)的频度(权重)比率,即统计符合度(F)新参数,用以表征预设质量控制区间铌含量的一致性的概率。采用原位统计分布分析的表征方法,准确定量地评定了高温合金压气机盘件纵断面不同部位铌的分布均匀度和符合度,为加工后盘件的质量控制评估提供了参考。
Novel casting processes for single-crystal turbine blades of superalloys
Dexin MA
《机械工程前沿(英文)》 2018年 第13卷 第1期 页码 3-16 doi: 10.1007/s11465-018-0475-0
This paper presents a brief review of the current casting techniques for single-crystal (SC) blades, as well as an analysis of the solidification process in complex turbine blades. A series of novel casting methods based on the Bridgman process were presented to illustrate the development in the production of SC blades from superalloys. The grain continuator and the heat conductor techniques were developed to remove geometry-related grain defects. In these techniques, the heat barrier that hinders lateral SC growth from the blade airfoil into the extremities of the platform is minimized. The parallel heating and cooling system was developed to achieve symmetric thermal conditions for SC solidification in blade clusters, thus considerably decreasing the negative shadow effect and its related defects in the current Bridgman process. The dipping and heaving technique, in which thin-shell molds are utilized, was developed to enable the establishment of a high temperature gradient for SC growth and the freckle-free solidification of superalloy castings. Moreover, by applying the targeted cooling and heating technique, a novel concept for the three-dimensional and precise control of SC growth, a proper thermal arrangement may be dynamically established for the microscopic control of SC growth in the critical areas of large industrial gas turbine blades.
关键词: superalloy investment casting Bridgman process directional solidification single crystal turbine blade
Novel technologies for the lost foam casting process
Wenming JIANG, Zitian FAN
《机械工程前沿(英文)》 2018年 第13卷 第1期 页码 37-47 doi: 10.1007/s11465-018-0473-2
Lost foam casting (LFC) is a green precision casting process categorized as a near net forming technology. Yet, despite its popularity, it still suffers from some technological problems, such as poor filling ability of the castings, coarse and non-dense microstructure, low mechanical properties for the Al and Mg LFC processes, and defective carburization for the low carbon steel LFC process. These drawbacks restrict the development and widespread application of the LFC process. To solve these problems, the present study developed several novel LFC technologies, namely, LFC technologies under vacuum and low pressure, vibration solidification, and pressure solidification conditions; expendable shell casting techno- logy; and preparation technology of bimetallic castings based on the LFC process. The results showed that the LFC under vacuum and low pressure evidently improved the filling ability and solved the oxidization problem of the alloys, which is suitable for producing complex and thin-wall castings. The vibration and pressure solidifications increased the compactness of the castings and refined the microstructure, significantly improving the mechanical properties of the castings. The expendable shell casting technology could solve the pore, carburization, and inclusion defects of the traditional LFC method, obtaining castings with acceptable surface quality. Moreover, the Al/Mg and Al/Al bimetallic castings with acceptable metallurgical bonding were successfully fabricated using the LFC process. These proposed novel LFC technologies can solve the current technological issues and promote the technological progress of the LFC process.
关键词: LFC under vacuum and low pressure vibration solidification pressure solidification expendable shell casting bimetallic castings
Hybrid forming mechanism of patternless casting and laser cladding
Zhongde SHAN, Fuzhen SUN, Yang LIU
《机械工程前沿(英文)》 2019年 第14卷 第4期 页码 393-401 doi: 10.1007/s11465-019-0550-1
关键词: patternless casting laser cladding hybrid forming rapid tooling
Experimental and CFD analysis of nozzle position of subsonic ejector
Xilai ZHANG, Shiping JIN, Suyi HUANG, Guoqing TIAN
《能源前沿(英文)》 2009年 第3卷 第2期 页码 167-174 doi: 10.1007/s11708-009-0001-5
An energy consumption prediction approach of die casting machines driven by product parameters
《机械工程前沿(英文)》 2021年 第16卷 第4期 页码 868-886 doi: 10.1007/s11465-021-0656-0
关键词: die casting machine energy consumption prediction product parameters
Thermal deflection analysis of the solidified shell in continuous casting of slab
LIU Hongzhao, WANG Zhongmin
《机械工程前沿(英文)》 2007年 第2卷 第2期 页码 175-179 doi: 10.1007/s11465-007-0029-3
关键词: s reciprocal loading deflection expression reciprocal opposite
Ultrasonic measurement of tie-bar stress for die-casting machine
《机械工程前沿(英文)》 doi: 10.1007/s11465-021-0663-1
柳百成
《中国工程科学》 2000年 第2卷 第9期 页码 29-37
面向市场经济,迎接全球化竞争的挑战,为国民经济的发展作贡献,就要十分重视制造业特别是铸造行业的发展。但是,我国铸造行业与国外相比有很大差距,它制约着国民经济的发展。世界各国在铸造成形加工技术的发展趋势方面,认识是一致的,即:一是大型工程中特大型铸件的关键铸造技术;二是向精确成形技术方向发展;三是用计算机模拟仿真逐步代替传统的经验性研究方法。铸造过程计算机模拟仿真是改造传统铸造产业的必由之路,是当今世界各国专家学者关注的热点。铸造充型凝固过程的数值模拟可以帮助工程技术.人员优化工艺设计,缩短试制周期、降低生产成本、确保铸件质量,已成为铸造领域最热门的研究课题之一。目前,凝固过程的流场、温度场数值模拟及缩孔缩松预测已应用于实际生产,应力分析、微观组织模拟等方面的基础研究及实用化进程都取得了很大进展。
《工程管理前沿(英文)》 2021年 第8卷 第4期 页码 595-614 doi: 10.1007/s42524-021-0173-1
关键词: robust train speed profile percentile reliability model scenario-based position–time–speed network mixed-integer programming
Strategic position and development prospects of nuclear energy in China
SHEN Wenquan
《能源前沿(英文)》 2007年 第1卷 第2期 页码 125-128 doi: 10.1007/s11708-007-0015-9
关键词: development excellent perspective long-term development comprehensive national
Digital high-efficiency print forming method and device for multi-material casting molds
Zhongde SHAN, Zhi GUO, Dong DU, Feng LIU, Wenjiang LI
《机械工程前沿(英文)》 2020年 第15卷 第2期 页码 328-337 doi: 10.1007/s11465-019-0574-6
关键词: multi-material casting mold 3D printing efficient print forming method
标题 作者 时间 类型 操作
Numerical investigation of the influence of casting techniques on fiber orientation distribution in ECC
Chung Nguyen VAN; Hai TRAN THANH; Thuc Nhu NGUYEN; Jianchun LI
期刊论文
Determining casting defects in near-net shape casting aluminum parts by computed tomography
Jiehua LI, Bernd OBERDORFER, Daniel HABE, Peter SCHUMACHER
期刊论文
Hybrid forming mechanism of patternless casting and laser cladding
Zhongde SHAN, Fuzhen SUN, Yang LIU
期刊论文
Experimental and CFD analysis of nozzle position of subsonic ejector
Xilai ZHANG, Shiping JIN, Suyi HUANG, Guoqing TIAN
期刊论文
Thermal deflection analysis of the solidified shell in continuous casting of slab
LIU Hongzhao, WANG Zhongmin
期刊论文
Robust energy-efficient train speed profile optimization in a scenario-based position–time–speed network
期刊论文