scholarly journals Research on the Micro-Extrusion Process of Copper T2 with Different Ultrasonic Vibration Modes

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1209
Author(s):  
Linhong Xu ◽  
Yulan Lei ◽  
Haiou Zhang ◽  
Zhaochen Zhang ◽  
Yuchu Sheng ◽  
...  
Keyword(s):  
Flow Stress ◽  
Ultrasonic Vibration ◽  
Extrusion Process ◽  
Transmission Efficiency ◽  
Vibration Modes ◽  
Micro Forming ◽  
Forming Process ◽  
Tool Vibration ◽  
Vibration Condition ◽  
Workpiece Vibration

As an effective method for the fabrication of miniature metallic parts, the development of micro-forming process (MFP) is still restricted by the existence of size effect. To improve the micro-forming performance of metal material, ultrasonic vibration assisted MFP had been studied extensively for its superiorities in improving materials flow stress and reducing interfacial friction. However, from the literature available, the high frequency vibration was usually found to be superimposed on the forming tool while seldom on the workpiece. Our group developed a special porous sonotrode platform which can realize tool vibration and workpiece ultrasonic vibration independently. In this work, ultrasonic micro-extrusion experiments for copper T2 material under tool vibration and the workpiece vibration condition, respectively, were conducted for comparing the micro-forming characteristic of different vibration modes. The micro-extrusion experiment results of copper T2 show that the lower extrusion flow stress, the higher micro-extrusion formability and surface micro-hardness, and more obvious grain refinement phenomenon can be obtained under the workpiece vibration condition compared with that of tool vibration. These findings may enhance our understanding on different ultrasonic forming mechanisms and energy transmission efficiency under two different vibration modes.

Experimental investigation into effects of different ultrasonic vibration modes in micro-extrusion process

2021 ◽  
Vol 67 ◽  
pp. 427-437
Author(s):  
Guangchao Han ◽  
Weiqiang Wan ◽  
Zhaochen Zhang ◽  
Linhong Xu ◽  
Fuchu Liu ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Ultrasonic Vibration ◽  
Extrusion Process ◽  
Vibration Modes

scholarly journals Process chain for the manufacture of hybrid bearing bushings

2021 ◽  
Vol 15 (2) ◽  
pp. 137-150
Author(s):  
Susanne Elisabeth Thürer ◽  
Anna Chugreeva ◽  
Norman Heimes ◽  
Johanna Uhe ◽  
Bernd-Arno Behrens ◽  
...  
Keyword(s):  
Extrusion Process ◽  
Steel Tube ◽  
Case Hardening ◽  
Process Chain ◽  
Forming Process ◽  
Die Forging ◽  
Material Contact ◽  
Hybrid Bearing ◽  
Case Hardening Steel ◽  
Tailored Forming

AbstractThe current study presents a novel Tailored Forming process chain developed for the production of hybrid bearing bushings. In a first step, semi-finished products in the form of locally reinforced hollow profiles were produced using a new co-extrusion process. For this purpose, a modular tool concept was developed in which a steel tube made of a case-hardening steel, either C15 (AISI 1015) or 20MnCr5 (AISI 5120), is fed laterally into the tool. Inside the welding chamber, the steel tube is joined with the extruded aluminum alloy EN AW-6082. In the second step, sections from the compound profiles were formed into hybrid bearing bushings by die forging. In order to set the required forming temperatures for each material—aluminum and steel—simultaneously, a tailored heating strategy was developed, which enabled successful die forging of the hybrid workpiece to the desired bearing bushing geometry. Using either of the case-hardening steels in combination with aluminum, this novel process chain made it possible to produce intact hybrid bearing bushings, which showed both macroscopically and microscopically intimate material contact inside the compound zone.

scholarly journals Ultrasound Effect on the Microstructure and Hardness of AlMg3 Alloy under Upsetting

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1010
Author(s):  
Przemysław Snopiński ◽  
Tibor Donič ◽  
Tomasz Tański ◽  
Krzysztof Matus ◽  
Branislav Hadzima ◽  
...  
Keyword(s):  
Flow Stress ◽  
Ultrasonic Vibration ◽  
Light And Electron Microscopy ◽  
Load Flow ◽  
Forming Limit ◽  
Ultrasonic Vibrations ◽  
Softening Effect ◽  
Simultaneous Application ◽  
Ultrasonic Assisted ◽  
Acoustic Softening

To date, numerous investigations have shown the beneficial effect of ultrasonic vibration-assisted forming technology due to its influence on the forming load, flow stress, friction condition reduction and the increase of the metal forming limit. Although the immediate occurring force and mean stress reduction are known phenomena, the underlying effects of ultrasonic-based material softening remain an object of current research. Therefore, in this article, we investigate the effect of upsetting with and without the ultrasonic vibrations (USV) on the evolution of the microstructure, stress relaxation and hardness of the AlMg3 aluminum alloy. To understand the process physics, after the UAC (ultrasonic assisted compression), the microstructures of the samples were analyzed by light and electron microscopy, including the orientation imaging via electron backscatter diffraction. According to the test result, it is found that ultrasonic vibration can reduce flow stress during the ultrasonic-assisted compression (UAC) process for the investigated aluminum–magnesium alloy due to the acoustic softening effect. By comparing the microstructures of samples compressed with and without simultaneous application of ultrasonic vibrations, the enhanced shear banding and grain rotation were found to be responsible for grain refinement enhancement. The coupled action of the ultrasonic vibrations and plastic deformation decreased the grains of AlMg3 alloy from ~270 μm to ~1.52 μm, which has resulted in a hardness enhancement of UAC processed sample to about 117 HV.

Microstructure Integrated Modeling of Multiscan Laser Forming

2002 ◽  
Vol 124 (2) ◽  
pp. 379-388 ◽  
Author(s):  
Jin Cheng ◽  
Y. Lawrence Yao
Keyword(s):  
Flow Stress ◽  
Numerical Models ◽  
Flow Behavior ◽  
Fem Simulation ◽  
Constitutive Models ◽  
Low Carbon Steel ◽  
Laser Forming ◽  
Low Carbon ◽  
Forming Process ◽  
Heating And Cooling

Laser forming of steel is a hot forming process with high heating and cooling rate, during which strain hardening, dynamic recrystallization, and phase transformation take place. Numerical models considering strain rate and temperature effects only usually give unsatisfactory results when applied to multiscan laser forming operations. This is mainly due to the inadequate constitutive models employed to describe the hot flow behavior. In this work, this limitation is overcome by considering the effects of microstructure change on the flow stress in laser forming processes of low carbon steel. The incorporation of such flow stress models with thermal mechanical FEM simulation increases numerical model accuracy in predicting geometry change and mechanical properties.

Deformation Behavior and Constitutive Equation of 42CrMo Steel at High Temperature

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1614
Author(s):  
Hongqiang Liu ◽  
Zhicheng Cheng ◽  
Wei Yu ◽  
Gaotian Wang ◽  
Jie Zhou ◽  
...  
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Thermal Processing ◽  
Deformation Behavior ◽  
Reduction Process ◽  
Ann Model ◽  
Forming Process ◽  
Temperature Reduction ◽  
42Crmo Steel

High-temperature reduction pretreatment (HTRP) is a process that can significantly improve the core quality of a billet. The existing flow stress data cannot meet the needs of simulation due to lack of high temperature data. To obtain the hot forming process parameters for the high-temperature reduction pretreatment process of 42CrMo steel, a hot compression experiment of 42CrMo steel was conducted on Gleeble-3500 thermal-mechanical at 1200–1350 °C with the rates of deformation 0.001–10 s−1 and the deformation of 60%, and its deformation behavior at elevated temperature was studied. In this study, the effects of flow stress temperature and strain rate on austenite grain were investigated. Moreover, two typical constitutive models were employed to describe the flow stress, namely the Arrhenius constitutive model of strain compensation and back propagation artificial neural network (BP ANN) model. The performance evaluation shows that BP ANN model has high accuracy and stability to predict the curve. The thermal processing maps under strains of 0.1, 0.2, 0.3, and 0.4 were established. Based on the analysis of the thermal processing map, the optimal high reduction process parameter range of 42CrMo is obtained: the temperature range is 1250–1350 °C, and the strain rate range is 0.01–1 s−1.

Dieless Water Jet Incremental Micro-Forming

2018 ◽  
Author(s):  
Yi Shi ◽  
Jian Cao ◽  
Kornel F. Ehmann
Keyword(s):  
Process Parameters ◽  
Thin Shell ◽  
High Speed ◽  
Single Point ◽  
Sheet Thickness ◽  
Water Jet ◽  
Micro Forming ◽  
Forming Process ◽  
Thin Foils ◽  
High Pressure Water Jet

Compared to the conventional single-point incremental forming (SPIF) processes, water jet incremental micro-forming (WJIMF) utilizes a high-speed and high-pressure water jet as a tool instead of a rigid round-tipped tool to fabricate thin shell micro objects. Thin foils were incrementally formed with micro-scale water jets on a specially designed testbed. In this paper, the effects on the water jet incremental micro-forming process with respect to several key process parameters, including water jet pressure, relative water jet diameter, sheet thickness, and feed rate, were experimentally studied using stainless steel foils. Experimental results indicate that feature geometry, especially depth, can be controlled by adjusting the processes parameters. The presented results and conclusions provide a foundation for future modeling work and the selection of process parameters to achieve high quality thin shell micro products.

scholarly journals Study on Generating Machining Performance of Two-Dimensional Ultrasonic Vibration-Composited Electrolysis/Electro-Discharge Technology for MMCs

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 617
Author(s):  
Jing Li ◽  
Wanwan Chen ◽  
Yongwei Zhu
Keyword(s):  
Ultrasonic Vibration ◽  
Orthogonal Experiment ◽  
Spindle Speed ◽  
Machining Efficiency ◽  
Matrix Composites ◽  
Two Dimensional ◽  
Machining Performance ◽  
Factors Affecting ◽  
Electro Discharge Machining ◽  
Workpiece Vibration

Ultrasonic vibration-composited electrolysis/electro-discharge machining technology (UE/DM) is effective for machining particulate-reinforced metal matrix composites (MMCs). However, the vibration of the tool or workpiece suitable for holes limits the application of UE/DM. To improve the generating machining efficiency and quality of flat and curved surfaces, in this study, we implemented two-dimensional ultrasonic vibration into UE/DM and constructed a novel method named two-dimensional ultrasonic vibration-composited electrolysis/electro-discharge machining (2UE/DM). The influence of vibration on the performance of 2UE/DM compared to other process technologies was studied, and an orthogonal experiment was designed to optimize the parameters. The results indicated that the materiel remove rate (MRR) mainly increased via voltage and tool vibration. The change current was responsible for the MRR in the process. Spindle speed and workpiece vibration were not dominant factors affecting the MRR; the spindle speed and tool and workpiece vibration, which reduced the height difference between a ridge and crater caused by abrasive grinding, were responsible for surface roughness (Ra) and form precision (δ). Additionally, the optimized parameters of 1000 rpm, 3 V, and 5 um were conducted on MMCs of 40 SiCp/Al and achieved the maximum MRR and minimum Ra and δ of 0.76 mm3/min, 3.35 um, and 5.84%, respectively. This study’s findings provide valuable process parameters for improving machining efficiency and quality for MMCs of 2UE/DM.

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