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Full-Text Articles in Engineering

Enhancing Impact Fracture Toughness And Tensile Properties Of A Microalloyed Cast Steel By Hot Forging And Post-Forging Heat Treatment Processes, Jingwei Zhao, Zhengyi Jiang, Chong Soo Lee Jan 2013

Enhancing Impact Fracture Toughness And Tensile Properties Of A Microalloyed Cast Steel By Hot Forging And Post-Forging Heat Treatment Processes, Jingwei Zhao, Zhengyi Jiang, Chong Soo Lee

Faculty of Engineering and Information Sciences - Papers: Part A

In the present work, the effects of hot forging and post-forging heat treatment on the impact fracture toughness and tensile properties of a microalloyed cast steel were investigated. Mechanical tests were used to evaluate the room temperature impact fracture toughness and tensile properties of the steel. The resulting microstructures were analysed by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The extraction replica technology was used to investigate the characterisation of complex precipitates formed during heat treatment. The obtained results showed that the coarse-grained microstructure of the forged specimen was significantly refined after post-forging heat treatment. …


Effects Of Tungsten Addition And Heat Treatment Conditions On Microstructure And Mechanical Properties Of Microalloyed Forging Steels, Jingwei Zhao, Zhengyi Jiang, Chong Soo Lee Jan 2013

Effects Of Tungsten Addition And Heat Treatment Conditions On Microstructure And Mechanical Properties Of Microalloyed Forging Steels, Jingwei Zhao, Zhengyi Jiang, Chong Soo Lee

Faculty of Engineering and Information Sciences - Papers: Part A

In the present work, the effects of tungsten (W) addition and heat treatment conditions on the microstructure, impact toughness and tensile properties of microalloyed forging steels were studied. Four kinds of microalloyed forging steels were produced by varying W additions (0, 0.5, 1 and 2 wt%). Heat treatment was carried out at temperatures ranging from 840 to 950 °C followed by air and furnace cooling. Mechanical tests were used to evaluate the room temperature Charpy impact and tensile properties. The resulting microstructures were analysed via optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show …


Effects Of Tungsten Addition On The Microstructure And Mechanical Properties Of Microalloyed Forging Steels, Jingwei Zhao, Taekyung Lee, Jeong Hun Lee, Zhengyi Jiang, Chong Soo Lee Jan 2013

Effects Of Tungsten Addition On The Microstructure And Mechanical Properties Of Microalloyed Forging Steels, Jingwei Zhao, Taekyung Lee, Jeong Hun Lee, Zhengyi Jiang, Chong Soo Lee

Faculty of Engineering and Information Sciences - Papers: Part A

In the current study, the effects of tungsten (W) addition on the microstructure, hardness, and room/low [223 K and 173 K (-50 C and -100 C)] temperature tensile properties of microalloyed forging steels were systematically investigated. Four kinds of steel specimens were produced by varying the W additions (0, 0.1, 0.5, and 1 wt pct). The microstructure showed that the addition of W does not have any noticeable effect on the amount of precipitates. The precipitates in W-containing steels were all rich in W, and the W concentration in the precipitates increased with the increasing W content. The mean sizes …


Effect Of The Sinter-Forging Deformation Rate On Properties Of Bi-2223 Current Leads, X. K. Fu, Y. C. Guo, W. M. Chen, Hua-Kun Liu, S. X. Dou Jan 2001

Effect Of The Sinter-Forging Deformation Rate On Properties Of Bi-2223 Current Leads, X. K. Fu, Y. C. Guo, W. M. Chen, Hua-Kun Liu, S. X. Dou

Faculty of Engineering - Papers (Archive)

The influence of the sinter-forging rate on the critical current density (Jc) behaviour in an external field and on the contact resistance Rc for Bi-2223 current leads has been investigated. The current leads were fabricated by a combination of cold isostatic pressing (CIP) and sinter-forging methods with the thickness reduction rate ranging from 0% to 90%. The two silver contact terminals of each sample were also prepared during the sinter-forging. The results revealed that Jc was strongly affected by the deformation rate of sinter-forging and reached a maximum of 725 A/cm2 at a deformation rate of 80%. From the measurements …