Warm-Forming of Light-Weight Alloys under Multi-Stage Forming Process

2009 ◽  
Vol 83-86 ◽  
pp. 88-93 ◽  
Author(s):  
Chi Ping Lai ◽  
Luen Chow Chan ◽  
Chi Loong Chow ◽  
Kai Ming Yu
Keyword(s):  
Experimental Investigation ◽  
Titanium Alloy ◽  
Aluminium Alloy ◽  
Warm Forming ◽  
Light Weight ◽  
Forming Process ◽  
High Quality ◽  
Heating Device ◽  
Multi Stage ◽  
Forming Condition

This paper aims at presenting an experimental investigation to obtain the optimum formability of light-weight alloys under the multi-stage forming process. Titanium alloy sheets (Ti-6Al-4V) and aluminium alloy sheets (AA5052) are selected as forming specimens. The special fixture with heating device is applied in order to carry out the prestraining process. The swift forming test at warm-forming condition is performed for measuring the limit dome heights after the multi-stage formign process. The outcomes of this investigation are valuable for engineers to design and fabricate high-quality light-weight components efficiently.

Thermal forming of light-weight alloys under a multi-stage forming process

2010 ◽  
Vol 224 (4) ◽  
pp. 797-803 ◽  
Author(s):  
C P Lai ◽  
L C Chan ◽  
C L Chow ◽  
K M Yu
Keyword(s):  
Experimental Investigation ◽  
Titanium Alloy ◽  
Yield Strength ◽  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Heating System ◽  
Light Weight ◽  
Forming Process ◽  
Thermal Forming ◽  
Multi Stage

This article presents an experimental investigation aimed to obtain the optimum formability of light-weight alloys under the multi-stage forming process. Titanium alloy sheets (Ti-6Al-4V) and aluminium alloy sheets (AA5052) of thickness 1 mm with different widths (i.e. 20, 90, and 110 mm) are selected as forming specimens. In order to carry out the multi-stage forming process, a special fixture with a heating system for the pre-straining process is designed and manufactured. The limit dome heights of both titanium alloys and aluminium alloys are measured and recorded. The experimental results reveal that both of the light-weight alloys yielded enhanced ductility at higher working temperatures, because of a decrease in the yield strength. The formability of selected materials is found to be sensitive to the forming temperatures and multi-stage forming processes.

Evaluation of Uniaxial Tensile Behavior under Pulsed Current for Electrically Assisted Warm Forming of Light Weight Alloys

2017 ◽  
Vol 744 ◽  
pp. 254-258
Author(s):  
Jung Han Song ◽  
Injea Jang ◽  
Suh Yun Gwak ◽  
Jun Ho Bang ◽  
Yong Bae Kim ◽  
...  
Keyword(s):  
Electric Current ◽  
Test System ◽  
Warm Forming ◽  
Uniaxial Tensile ◽  
Light Weight ◽  
Test Results ◽  
Forming Process ◽  
Uniaxial Test ◽  
Electrically Assisted ◽  
Deep Drawing Test

In this study, the electric current effects in the deformation of light weight alloys are investigated to improve the formability. To begin with, a test system is built up to carry out the tensile test with heavy electric current flowing through the specimen. The evolutions of the flow stresses and failure elongations were obtained using this test system. The thermal and athermal effect such as electro-plastic effect of metallic materials induced by high density current make significant reduction of the flow stress, which is beneficial to the forming process of less formable metal. From the uniaxial test results, pulse current-assisted deep drawing test were conducted. The experimental results demonstrate that electrically assisted warm forming provides lower energy consumption and higher efficiency.

An Analytical and Numerical Investigation on Flange Wrinkling Behavior in Warm Forming Process of AA5754 Using Macro-Textured Tool Design

2016 ◽  
Vol 716 ◽  
pp. 586-594 ◽  
Author(s):  
Kai Lun Zheng ◽  
Lei Zhu ◽  
Denis J. Politis ◽  
Jian Guo Lin ◽  
Trevor A. Dean
Keyword(s):  
Aluminium Alloy ◽  
Draw Ratio ◽  
Elevated Temperatures ◽  
Material Model ◽  
Damage Mechanism ◽  
Alloy Sheet ◽  
Warm Forming ◽  
Forming Process ◽  
Flange Wrinkling ◽  
Forming Temperature

In this paper, an analytical buckling model is established to predict the flange wrinkling behavior of deep drawn cylindrical cups of aluminium alloy sheet in warm forming conditions using macro-textured blankholders for the first time. A continuum damage mechanism (CDM) based material model was utilized to reflect the visco-plastic feature of material at elevated temperatures. Forming speed and temperature effects were investigated, and texture ratio and draw ratio effects were also discussed. The developed analytical buckling model was validated by finite element simulations. The increase of forming temperature and forming speed is prone to cause wrinkling for AA5754, but the effects are not as significant as the texture geometry and draw ratio. The analytical model presented in this paper can be used as a design guide to determine tool texture geometry necessary to avoid wrinkling defects in the warm forming processes of aluminium alloy.

scholarly journals Experimental investigation of forming limit curves and deformation features in warm forming of an aluminium alloy

2016 ◽  
Vol 232 (3) ◽  
pp. 465-474 ◽  
Author(s):  
Zhutao Shao ◽  
Qian Bai ◽  
Nan Li ◽  
Jianguo Lin ◽  
Zhusheng Shi ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
Elevated Temperatures ◽  
Warm Forming ◽  
Dome Height ◽  
Forming Limit ◽  
Thickness Variation ◽  
Forming Process ◽  
Deformation Features ◽  
Forming Temperature ◽  
Forming Limit Curves

The determination of forming limit curves and deformation features of AA5754 aluminium alloy are studied in this article. The robust and repeatable experiments were conducted at a warm forming temperature range of 200 °C–300 °C and at a forming speed range of 20–300 mm/s. The forming limit curves of AA5754 at elevated temperatures with different high forming speeds have been obtained. The effects of forming speed and temperature on limiting dome height, thickness variation and fracture location are discussed. The results show that higher temperatures and lower forming speeds are beneficial to increasing forming limits of AA5754; however, lower temperatures and higher forming speeds contribute to enhancing the thickness uniformity of formed specimens. The decreasing forming speed and increasing temperature result in the locations of fracture to move away from the apexes of formed specimens. It is found that the analysis of deformation features can provide a guidance to understand warm forming process of aluminium alloys.

scholarly journals A dataset on affiliation of venture capitalists in China between 2000 and 2016

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jin Chen ◽  
Tianyuan Chen ◽  
Yifei Song ◽  
Bin Hao ◽  
Ling Ma
Keyword(s):  
Data Sources ◽  
Venture Capitalists ◽  
High Quality ◽  
Public Agency ◽  
Multiple Data Sources ◽  
Multiple Data ◽  
Multi Stage ◽  
The World ◽  
Prior Literature ◽  
Innovation And Entrepreneurship

AbstractPrior literature emphasizes the distinct roles of differently affiliated venture capitalists (VCs) in nurturing innovation and entrepreneurship. Although China has become the second largest VC market in the world, the unavailability of high-quality datasets on VC affiliation in China’s market hinders such research efforts. To fill up this important gap, we compiled a new panel dataset of VC affiliation in China’s market from multiple data sources. Specifically, we drew on a list of 6,553 VCs that have invested in China between 2000 and 2016 from CVSource database, collected VC’s shareholder information from public sources, and developed a multi-stage procedure to label each VC as the following types: GVC (public agency-affiliated, state-owned enterprise-affiliated), CVC (corporate VC), IVC (independent VC), BVC (bank-affiliated VC), FVC (financial/non-bank-affiliated VC), UVC (university endowment/spin-out unit), and PenVC (pension-affiliated VC). We also denoted whether a VC has foreign background. This dataset helps researchers conduct more nuanced investigations into the investment behaviors of different VCs and their distinct impacts on innovation and entrepreneurship in China’s context.

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